Fydp II Group 17 Final Report_24th August 2011_1

CAB 4023

PLANT DESIGN PROJECT II

MAY SEMESTER 2011

PRODUCTION OF AMMONIA

671,200 METRIC TONNES PER YEAR AMMONIA

GROUP 17

MUHAMMAD MUSTAQIM BIN RAZAK 10847

MUHD IRSYADUDDIN ZAKWAN BIN NOR SAERAN 10875

MUZAKKIR BIN AZIZ 10877

NOR ALWANI BINTI ABD GHANI @ YAACOB 10909

CHEMICAL ENGINEERING PROGRAMME

UNIVERSITI TEKNOLOGI PETRONAS

BANDAR SRI ISKANDAR, 31750 TRONOH, PERAK DARUL RIDZUAN

a

PRODUCTION OF 671,200 TONNES OF AMMONIA ANNUALLY FYDP GROUP 17

CERTIFICATION OF APPROVAL

CAB 4023

PLANT DESIGN PROJECT II

MAY SEMESTER 2011

PRODUCTION OF AMMONIA

671,200 METRIC TONNES PER YEAR AMMONIA

GROUP 17

MUHAMMAD MUSTAQIM BIN RAZAK 10847

MUHD IRSYADUDDIN ZAKWAN BIN NOR SAERAN 10875

MUZAKKIR BIN AZIZ 10877

NOR ALWANI BINTI ABD GHANI @ YAACOB 10909

APPROVED BY,

___________________________________(DR KHALIK MOHAMAD SABIL)

CHEMICAL ENGINEERING PROGRAMME

UNIVERSITI TEKNOLOGI PETRONAS

b


c


ACKNOWLEDGEMENT

It is a pleasure to thank those who made Final Year Design Project II (FYDP 2) possible,

Our group – FYDP group 17 would like to take this opportunity to thank and

acknowledge all parties who played role in making the project’s successful.

First of all, we would like to thank Dr. Khalik Mohamad Sabil from Chemical

Engineering Department for his endless and priceless guidance and support throughout

of the project period. Special thanks go to Dr. Risza Rusli and Dr. Rajashekhar Pendyala

who have supportively helping the group during the project as the project coordinators.

Our group also would like to convey our gratitude to our family members and friends for

their moral support throughout of the project period. Thank you.


TABLE OF CONTENTS

ACKNOWLEDGEMENT...........................................................................................................................II

TABLE OF CONTENTS...........................................................................................................................III

EXECUTIVE SUMMARY.......................................................................................................................VII

LIST OF FIGURES.................................................................................................................................VIII

LIST OF TABLES........................................................................................................................................X

1 CHAPTER 1 INTRODUCTION.........................................................................................................1

1.1 PROJECT BACKGROUND.........................................................................................................................1

1.2 OBJECTIVES...........................................................................................................................................1

1.3 SCOPE OF PROJECT................................................................................................................................1

2 CHAPTER 2 LITERATURE REVIEW.............................................................................................5

2.1 HISTORY OF AMMONIA..........................................................................................................................5

2.2 AMMONIA USAGE AND PROCESSABILITY...............................................................................................6

2.3 AVAILABLE TECHNOLOGY.....................................................................................................................7

2.4 PRODUCT MARKET SURVEY................................................................................................................10

2.4.1 Demand........................................................................................................................................10

2.4.2 Climax..........................................................................................................................................12

2.4.3 Ammonia Market Lengthen..........................................................................................................12

2.4.4 Import and Export........................................................................................................................13

2.4.5 European Market review.............................................................................................................15

2.4.6 Asia Market Review.....................................................................................................................16

2.4.7 Malaysia Market Review.............................................................................................................16

2.5 SITE STUDY..........................................................................................................................................18

2.5.1 Introduction.................................................................................................................................18

2.5.2 Criteria in Selection of Plant Site................................................................................................18

2.5.3 Proposed location........................................................................................................................20

2.5.4 Conclusion Remark......................................................................................................................25

2.1 PREVIOUS PLANT ACCIDENT................................................................................................................26

2.1.1 Accident 1....................................................................................................................................26

2.1.2 Accident 2....................................................................................................................................26

3 CHAPTER 3 CONCEPTUAL PROCESS DESIGN AND SYNTHESIS......................................28

3.1 GENERAL PROCESS DESCRIPTION........................................................................................................28

3.1.1 The reactions and reactions conditions.......................................................................................28

3.2 PRELIMINARY REACTOR OPTIMIZATION USING - HIERARCHICAL DECOMPOSITION METHOD


(DOUGLAS METHOD).................................................................................................................................34

3.3 BATCH VERSUS CONTINUOUS..............................................................................................................34

3.4 INPUT-OUTPUT STRUCTURE OF THE FLOWSHEET................................................................................36

3.4.1 Number of product streams..........................................................................................................37

3.5 REACTOR DESIGNED AND RECYCLE STRUCTURE OF THE FLOWSHEET.................................................38

3.5.1 Reactor design.............................................................................................................................38

3.5.2 Reaction Conditions.....................................................................................................................43

3.5.3 Catalysts.......................................................................................................................................47

3.5.4 Recycle structure..........................................................................................................................48

3.6 PROCESS SCREENING OR SEPARATION SYSTEM SYNTHESIS................................................................49

3.6.1 General structure of the separation system.................................................................................49

3.6.2 Vapour recovery system...............................................................................................................49

3.6.3 Liquid separation system.............................................................................................................51

3.6.4 Carbon Dioxide removal.............................................................................................................51

3.6.5 Ammonia absorption unit.............................................................................................................53

3.6.6 Knock out drum............................................................................................................................54

3.7 : HEAT INTEGRATION....................................................................................................................56

3.7.1 Introduction.................................................................................................................................56

3.7.2 Stream Identification....................................................................................................................56

3.7.3 Minimum Temperature Difference ΔTmin.....................................................................................56

3.7.4 Pinch Technology Method...........................................................................................................57

3.7.5 Stream Identification for pinch....................................................................................................58

3.7.6 Corrected Temperature................................................................................................................59

3.7.7 Problem Table Algorithm............................................................................................................59

3.7.8 Heat Cascade...............................................................................................................................59

3.7.9 Grand composite curve................................................................................................................61

3.7.10 Heat Exchanger Network...........................................................................................................62

3.7.11 Energy saving evaluation...........................................................................................................63

4 CHAPTER 4 INSTRUMENTATION AND CONTROL................................................................65

4.1 INTRODUCTION....................................................................................................................................65

4.1.1 Safety............................................................................................................................................65

4.1.2 Production specifications............................................................................................................66

4.1.3 Environmental Regulations..........................................................................................................66

4.1.4 Operational constraints...............................................................................................................66

4.1.5 Economics....................................................................................................................................66

4.2 BASIC CONCEPT OF ADVANCED PROCESS CONTROL..........................................................................68

4.2.1 Feedback Control........................................................................................................................68

4.2.2 Feedforward Control...................................................................................................................68


4.2.3 Cascade Controller......................................................................................................................69

4.2.4 Ratio Control...............................................................................................................................70

4.3 AMMONIA PLANT CONTROL SYSTEM..................................................................................................71

4.3.1 Introduction.................................................................................................................................71

4.3.2 Feed Control System....................................................................................................................72

4.3.3 Air and reactant mixture..............................................................................................................73

4.3.4 Primary Reformer Reactor..........................................................................................................74

4.3.5 Secondary Reformer Reactor.......................................................................................................75

4.3.6 High Temperature Shift Reactor..................................................................................................77

4.3.7 Low Temperature Shift Reactor...................................................................................................79

4.3.8 Methanation Reactor...................................................................................................................80

4.3.9 Ammonia Synthesis Reactor.........................................................................................................81

4.3.10 Carbon Dioxide Removal...........................................................................................................83

4.3.11 Water Removal...........................................................................................................................84

4.3.12 Ammonia Separation..................................................................................................................85

5 CHAPTER 5 SAFETY AND LOSS PREVENTION.......................................................................87

5.1 INTRODUCTION....................................................................................................................................87

5.2 SAFETY ISSUES IN CHEMICAL PLANTS................................................................................................87

5.2.1 Hazard awareness reducing accident risk...................................................................................88

5.2.2 Precautions against toxic risk......................................................................................................88

5.2.3 Organization for meeting up an emergency................................................................................89

5.3 HAZARD AND OPERABILITY STUDIES (HAZOP).....................................................................91

5.3.1 Introduction.................................................................................................................................91

5.3.2 Basic Principle of HAZOP...........................................................................................................91

5.3.3 Process HAZOP...........................................................................................................................92

5.3.4 HAZOP procedure.......................................................................................................................92

5.3.5 Worksheet entries.........................................................................................................................93

5.3.6 Process parameters......................................................................................................................95

5.3.7 Selected node...............................................................................................................................96

5.3.8 HAZOP Analysis: Node 1............................................................................................................98

5.3.9 HAZOP Analysis: Node 2..........................................................................................................103

5.3.10 HAZOP Analysis: Node 3........................................................................................................107

5.4 PLANT LAYOUT.................................................................................................................................111

5.4.1 Introduction...............................................................................................................................111

5.4.2 Plant Arrangement Description.................................................................................................114

5.4.3 Process Area..............................................................................................................................115

6 CHAPTER 6 WASTE TREATMENT............................................................................................121

6.1 INTRODUCTION..................................................................................................................................121


6.2 WASTE IDENTIFICATION....................................................................................................................121

6.2.1 Solid Waste................................................................................................................................121

6.2.2 Liquid Waste..............................................................................................................................122

6.2.3 Gaseous Waste...........................................................................................................................122

6.2.4 Others Waste..............................................................................................................................123

6.3 LAWS AND REGULATIONS.................................................................................................................123

6.3.1 Liquid Wastes.............................................................................................................................123

6.3.2 Solid Wastes...............................................................................................................................124

6.3.3 Gaseous Wastes.........................................................................................................................125

6.4 WASTEWATER TREATMENT STRATEGY.............................................................................................126

6.5 WASTE WATER (EFFLUENT) TREATMENT PROCESS FLOW DIAGRAM..............................................126

6.5.1 Waste Water Treatment Process................................................................................................127

6.5.2 Solid Wastes Handling...............................................................................................................128

6.5.3 Labeling of packaging:..............................................................................................................131

7 CHAPTER 7 PROCESS ECONOMICS AND COST ESTIMATION........................................133

7.1 INTRODUCTION..................................................................................................................................133

7.2 CAPITAL COST/ CAPITAL EXPENDITURE (CAPEX)...........................................................................133

7.2.1 Working Capital.........................................................................................................................136

7.3 ANNUAL OPERATING COST...............................................................................................................136

7.3.1 Manufacturing Cost...................................................................................................................136

7.1 PROCESS ECONOMIC ANALYSIS.........................................................................................................139

7.2 NET PRESENT VALUE (NPV).............................................................................................................140

7.3 PAYBACK PERIOD..............................................................................................................................146

7.4 INTERNAL RATE OF RETURN (IRR)...................................................................................................146

8 CHAPTER 8 CONCLUSION & RECOMMENDATION............................................................148

REFERENCES..........................................................................................................................................150

APPENDIX 1: PFD DIAGRAM..............................................................................................................153

APPENDIX 2: PLANT LAYOUT............................................................................................................154

APPENDIX I: SITE LOCATION............................................................................................................155


EXECUTIVE SUMMARY

The purpose of writing this report is to present the tasks, projects and work completed by

our group – group 17 throughout of Final Year Design Project II (FYDP 2). The title

given for the project is the production of Ammonia. There are seven chapters in the

report; starting with the introduction which consists of the project background, the

objectives of the project, the scope of the project, the history of ammonia, ammonia

usage and processability and available technology, followed by chapter 2 which is the

literature review focusing on ammonia synthesis process, product market survey and site

study. Chapter 3 highlights the conceptual process design, there are 5 levels in

conceptual process design using Douglas hierarchical approach. Continues with chapter

4, which discussed the instrumentation and control, in this particular chapter, the control

strategy is performed at each of the process stage. The discussion is then followed by

chapter 5 which is regarding safety and loss prevention. This chapter will zoom on

hazard and operability studies (HAZOP) and the plant layout. Moving to the next

chapter, chapter 6 will elaborate more on waste treatment where the ethical and statutory

requirement must be fulfilled concerning on waste disposal and treatment. Chapter 7 will

stress on process economics and cost estimation. Finally, the project will be concluded

by conclusion and recommendation.


LIST OF FIGURES

FIGURE 1-1: TYPICAL AMMONIA PLANT CONSISTING OF EIGHT CATALYTIC STAGES.......................3

FIGURE 2-1: AMMONIA USAGE......................................................................................................11

FIGURE 2-2: WORLD AMMONIA DEMAND.....................................................................................12

FIGURE 2-3: AMMONIA WORLD IMPORT........................................................................................14

FIGURE 2-4: AMMONIA WORLD EXPORT.......................................................................................14

FIGURE 2-5: AMMONIA NET PRICE PER QUARTER.........................................................................15

FIGURE 2-6: MALAYSIA AMMONIA PRODUCTION BY YEAR..........................................................17

FIGURE 3-1: COMPARISON BETWEEN NATURAL GAS REFORMING, HEAVY OIL AND COAL

GASIFICATION IN EUROPE.............................................................................................29

FIGURE 3-2: BLOCK DIAGRAM OF THE STEAM/ AIR REFORMING PROCESS [1].................................30

FIGURE 3-3: GENERAL INPUT-OUTPUT STRUCTURE OF AMMONIA PLANT EXCLUDING THE INNER

LOOP.............................................................................................................................36

FIGURE 3-4: COMPLETE INPUT-OUTPUT STRUCTURE OF AMMONIA PLANT....................................36

FIGURE 3-5: REACTION RATE FOR AMMONIA SYNTHESIS DEPENDENCE ON THE AMMONIA

CONCENTRATION AT VARIOUS PRESSURES...................................................................43

FIGURE 3-6: REACTION RATE FOR AMMONIA SYNTHESIS DEPENDENCE ON THE AMMONIA

CONCENTRATION AT VARIOUS TEMPERATURES...........................................................44

FIGURE 3-7: AMMONIA SYNTHESIS RATE CONSTANT DEPENDENCE ON HYDROGEN: NITROGEN

RATIO...........................................................................................................................45

FIGURE 3-8: RECYCLE STRUCTURE OF THE FLOWSHEET................................................................48

FIGURE 3-9: SEPARATION SYSTEM RECYCLE LOOP AFTER AMMONIA SYNTHESIS..........................50

FIGURE 3-10: CARBON DIOXIDE ABSORBER UNIT..........................................................................51

FIGURE 3-11: CARBON DIOXIDE REMOVAL PROCESS.....................................................................52

FIGURE 3-12: AMMONIA ABSORPTION UNIT...................................................................................53

FIGURE 3-13: AMMONIA PURIFICATION PROCESS..........................................................................54

FIGURE 3-14: BASIC VAPOUR-LIQUID SEPARATOR.........................................................................55

FIGURE 3-15: WATER REMOVAL SYSTEM.......................................................................................55

FIGURE 3-16: PROBLEM TABLE ALGORITHM.................................................................................59

FIGURE 3-17: HEAT CASCADE USING MANUAL CALCULATION......................................................60

FIGURE 3-18: HEAT CASCADE USING SPRINT CALCULATION......................................................60

FIGURE 3-19: COMBINED GRAND COMPOSITE CURVES..................................................................61

FIGURE 3-20: GRAND COMPOSITE CURVE.....................................................................................62

FIGURE 3-21: HEAT EXCHANGER NETWORK FOR AMMONIA PRODUCTION PLANT.........................63


FIGURE 3-22: HEAT EXCHANGER AFTER THE SECONDARY REFORMER TO GENERATE STEAM AS

UTILITIES......................................................................................................................63

FIGURE 4-1: EXAMPLE OF FEEDBACK CONTROL SYSTEM...............................................................68

FIGURE 4-2: EXAMPLE OF FEEDFORWARD CONTROL SYSTEM........................................................69

FIGURE 4-3: EXAMPLE OF CASCADE CONTROL SYSTEM.................................................................70

FIGURE 4-4: EXAMPLE OF RATIO CONTROL SYSTEM......................................................................70

FIGURE 4-5: AMMONIA PRODUCTION PROCESS DIAGRAM..............................................................71

FIGURE 4-6: STEAM AND NATURAL GAS MIXTURE CONTROL SYSTEM...........................................72

FIGURE 4-7: AIR AND REACTANT MIXTURE CONTROL SYSTEM......................................................73

FIGURE 4-8: PRIMARY REFORMER REACTOR CONTROL SYSTEM....................................................74

FIGURE 4-9: SECONDARY REFORMER REACTOR CONTROL SYSTEM...............................................75

FIGURE 4-10: HIGH TEMPERATURE SHIFT CONVERTER CONTROL SYSTEM....................................77

FIGURE 4-11: LOW TEMPERATURE SHIFT REACTOR CONTROL SYSTEM..........................................79

FIGURE 4-12: METHANATION REACTOR CONTROL SYSTEM...........................................................80

FIGURE 4-13: AMMONIA SYNTHESIS REACTOR CONTROL SYSTEM.................................................81

FIGURE 4-14: CARBON DIOXIDE REMOVAL CONTROL SYSTEM......................................................83

FIGURE 4-15: WATER REMOVAL CONTROL SYSTEM......................................................................84

FIGURE 4-16: AMMONIA SEPARATION CONTROL SYSTEM..............................................................85

FIGURE 5-1: ILLUSTRATION OF HAZOP PROCEDURE (M. RAUSAND, 2005).................................93

FIGURE 5-2: STUDY NODE 1- SYNGAS COMPRESSOR......................................................................97

FIGURE 5-3: STUDY NODE 2 – AMMONIA CONVERTER.................................................................102

FIGURE 5-4: STUDY NODE 3 – AMMONIA ABSORPTION TOWER...................................................106

FIGURE 6-1: WASTE WATER TREATMENT FLOW DIAGRAM.........................................................126

FIGURE 7-1: ESTIMATED COST FOR EQUIPMENT...........................................................................133

FIGURE 7-2: CASH FLOW DIAGRAM FOR NON-DISCOUNTED RATE, I=0%.....................................143

FIGURE 7-3: CUMULATIVE CASH FLOW RATE FOR I=10%, I=20% AND I=30%...........................145


LIST OF TABLES

TABLE 1-1: AMMONIA PROPERTIES..................................................................................................4

TABLE 2-1: DESCRIPTION OF AMMONIA USAGE AND PROCESSABILITY............................................6

TABLE 2-2: COMPARISON BETWEEN STEAM METHANE REFORMING (SMR), THERMAL PARTIAL

OXIDATION (POX) AND AUTO THERMAL REFORMING (ATR)......................................9

TABLE 2-3: SUMMARY OF SITE CHARACTERISTICS.......................................................................22

TABLE 2-4: WEIGHT MARKS AND EXPLANATION ON THE PLANT SITE LOCATION FACTORS..........24

TABLE 2-5: WEIGHTED EVALUATION ON POTENTIAL SITES..........................................................25

TABLE 3-1: CRITERIA OF SELECTING THE PROCESS TYPE..............................................................35

TABLE 3-2: COMPONENTS EXPECTED TO LEAVE THE REACTOR.....................................................37

TABLE 3-3: NATURAL GAS COMPOSITION......................................................................................37

TABLE 3-4: SUMMARY OF DECISION IN LEVEL 2-INPUT-OUTPUT STRUCTURE OF FLOWSHEET......38

TABLE 3-5: COMPARISONS BETWEEN CSTR AND PFR..................................................................39

TABLE 3-6: PRACTICAL REACTOR TO BE USED FOR AMMONIA PLANT...........................................41

TABLE 3-7: CATALYSTS USED IN THE CATALYTIC STAGES IN AMMONIA PRODUCTION PROCESS. .47

TABLE 3-8 OPTIMUM ΔTMIN IN DIFFERENT INDUSTRIES..................................................................57

TABLE 3-9: THE OVERALL NUMBER OF STREAMS..........................................................................58

TABLE 3-10: STREAM USED FOR PINCH ANALYSIS.........................................................................58

TABLE 3-11: ENERGY SAVING EVALUATION..................................................................................64

TABLE 4-1: STEAM AND NATURAL GAS MIXTURE CONTROL STRATEGY........................................72

TABLE 4-2: AIR AND REACTANT MIXTURE CONTROL STRATEGY...................................................73

TABLE 4-3: PRIMARY REFORMER REACTOR CONTROL STRATEGY.................................................75

TABLE 4-4: SECONDARY REFORMER REACTOR CONTROL STRATEGY............................................76

TABLE 4-5: HIGH TEMPERATURE SHIFT CONVERTER CONTROL STRATEGY....................................78

TABLE 4-6: LOW TEMPERATURE SHIFT REACTOR CONTROL STRATEGY.........................................80

TABLE 4-7: METHANATION REACTOR CONTROL STRATEGY..........................................................81

TABLE 4-8: AMMONIA SYNTHESIS REACTOR CONTROL STRATEGY................................................82

TABLE 4-9: CARBON DIOXIDE REMOVAL CONTROL STRATEGY......................................................84

TABLE 4-10: WATER REMOVAL CONTROL STRATEGY....................................................................85

TABLE 4-11: AMMONIA SEPARATION CONTROL STRATEGY...........................................................86

TABLE 5-1: THE BASIC HAZOP GUIDE-WORDS (M. RAUSAND, 2005)..........................................95

TABLE 6-1: IDENTIFICATION OF WASTE BY OPERATION.............................................................122

TABLE 6-2: MISCELLANEOUS WASTE..........................................................................................123

TABLE 6-3 STANDARD A AND B VALUES OF ENVIRONMENTAL QUALITY ACT 1974.................124

TABLE 6-4: STANDARDS OF DARK SMOKE PERMISSIBLE IN PLANTS...........................................125


TABLE 6-5: WASTE CLASSIFICATION LINED BY KUALITI ALAM.................................................128

TABLE 6-7: ORGANIC WASTES FOR INCINERATION.....................................................................129

TABLE 7-1: TYPICAL FACTORS (JAMES M. DOUGHLAS, 1988)....................................................135

TABLE 7-2: TYPICAL FACTORS FOR PLANT (DOUGLAS, 1988)....................................................135

TABLE 7-3:NON-DISCOUNTED CASH FLOW (I=0%)......................................................................142

TABLE 7-4: DISCOUNTED CASH FLOW FOR I=10%, I=20% AND I=30%.......................................144

TABLE 7-5: NET CASH AT EOY OF 20 YEARS FOR I=20% AND I=30%.......................................147


1

CHAPTER 1

INTRODUCTION

1.1 Project Background

The final year design project is divided into two phase which are Plant Design

Project I and Project Plant Design II. The designed team has been assigned to propose a

plant that produces 671,200 ton per year (pre determined based on market demand) of

Ammonia, using Purified Hydrogen and Nitrogen as the feedstocks. The reaction takes

place in a gas phase with supported iron oxide catalyst.

The core design is to include facilities that are located within the battery limits of

ammonia production. The designs for offsites, utility plant or waste water treatment are

not required. However, the design must include the offsites, utility plants and waste

water treatment in the economic evaluation.

1.2 Objectives

The aims of the Plant Design Project II are:

To perform instrumentation and control studies

The perform process design and mechanical design of the major process units

(individual project)

To perform safety and loss prevention studies including plant layout

To deal with the waste from the plant to flow the rules and regulation

To perform the economic evaluation

1.3 Scope of Project

This project is primarily to design an Ammonia process plant. All researches and

literatures used for this project include the scope of the chemical compositions, usage

and cost, alternative process route for Ammonia manufacture, current productions of

Ammonia, preliminary hazards and safety analysis, process design configurations and

selections, and configuration of plant equipment (i.e. reactor, compressor, separation

system, heat integration). The designing phase of the best process route is then executed


using a complete material and energy balance of manual engineering calculation and

PETRONAS iCON software. The design is aided with heat integration study in

economical decision. The uprising design problems are resolved by making the

necessary decisions, judgements and assumptions. The scope of the project is solely

aimed for achieving the objectives of the plant design process.

Anhydrous ammonia is produced in about 80 countries worldwide (in 2001). About 86%

was used for nitrogen fertilizer production which including about 4% that was directly

applied to the field. In United States however, the distribution of ammonia use slightly

different from the worldwide uses. Only 80% of the ammonia is used to make fertilizers

and out of it, 20% is used as a direct application fertilizer (Ammonia properties –

encyclopedia airliquide.com).

Generally, there are eight catalytic stages in a typical continuous ammonia plant, which

are:

1. Purification

2. Pre-reforming

3. Primary reforming

4. Secondary reforming

5. High temperature shift

6. Low temperature shift

7. Methanation

8. Ammonia synthesis


Figure 1-1: Typical ammonia plant consisting of eight catalytic stages

Figure 1-1 shows typical ammonia plant which is consisting of eight catalytic stages.

Considering this, it is know that the input output structure of the flowsheet and the

recycle structure of the flowsheet must consider the other stages of the plant and not only

focussing on the ammonia synthesis. Therefore, for the input output structure, two

different ways of doing it will be represented.


Table 1-1: Ammonia properties

PROPERTIES

Molecular

Structure

Other names Hydrogen nitride, Trihydrogen nitride, Nitro-Sil

Molecular Formula NH3

Molar mass 17.031 g/mol

Appearance Colourless gas with strong pungent odour

Density 0.86 kg/m³ (1.013 bar at boiling point)

Melting Point -77.73 °C

Boiling Point -33.34 °C

Solubility in Water 700.0 g/1000 mL at 10°C

Specific Gravity 0.597 at 1.013 bar and 21°C

Hazards

PHYSICAL DANGERS:

Explosive if mixed with halogens, silver mercury or iodide salt.

CHEMICAL DANGERS:

Toxic and explosive if mixed with halogens.

INHALATION RISK:

Exposure to high concentration of gaseous ammonia results in

lung damage and death.

EFFECTS OF SHORT-TERM EXPOSURE:

The substance is irritating and burning to the eyes and the skin.

Sources: Ammonia properties , retrieved from the website, 15th April 2011, at http://encyclopedia.airliquide.com/Encyclopedia.asp?GasID=2

http://encyclopedia.airliquide.com/Encyclopedia.asp?GasID=2


2

CHAPTER 2

LITERATURE REVIEW

2.1 History of Ammonia

Shortage of naturally occurring and nitrogen-rich fertilizers at the beginning of the 20th

century had prompted the German Chemist Fritz Haber, and others, to look for ways of

combining the nitrogen in the air with hydrogen to form ammonia, which is a convenient

starting point in the manufacture of fertilizers. This process is apart of interest to the

German chemical industry as Germany was preparing for World War I and nitrogen

compounds were needed for explosives.

The hydrogen for the ammonia synthesis was made by the water-gas process (a Carl

Bosch invention) which involves blowing steam through a bed of red hot coke resulting

in the separation of hydrogen from oxygen. The nitrogen was obtained by distillation of

liquid air, then by cooling and compressing air.

These days, the hydrogen is produced by reforming light petroleum fractions or natural

gas (methane, CH4) by adding steam:

CH4(g) + H2O(g)

Ni catalyst

---------->

700oC

CO(g) + 3H2(g)

Enough steam is used to react with about 45% of the methane (CH4), the rest of the

methane is reacted with air:

2CH4(g) +O2(g) + 4N2(g)

(air)

Ni catalyst

--------->2CO(g) + 4H2(g) + 4N2(g)

All the carbon monoxide (CO) in the mixture is oxidised to CO2 using steam and an iron

oxide catalyst:


CO(g) + H2O(g)iron oxide catalyst

------------------>H2(g) + CO2(g)

The carbon dioxide (CO2) is removed using a suitable base so that only the nitrogen gas

(N2) and hydrogen gas (H2) remain and are used in the production of ammonia (NH3).

In ammonia production the hydrogen and nitrogen are mixed together in a ratio of 3:1 by

volume and compressed in high pressure system supported with catalytic system.

2.2 Ammonia usage and processability

Table 2-2: Description of ammonia usage and processability

Industry Use

Fertilizer For production of:

Ammonium sulfate, (NH4)2SO4

ammonium phosphate, (NH4)3PO4

ammonium nitrate, NH4NO3

urea, (NH2)2CO,also used in the production of

barbiturates (sedatives), is made by the reaction of

ammonia with carbon dioxide

CO2

carbon dioxide+

2NH3

ammonia

H2NCOONH4

ammonium carbonate

heat, pressure (NH2)2CO

urea

Chemicals synthesis of:

Nitric acid, HNO3, which is used in making explosives

such as TNT (2, 4, 6-trinitrotoluene), nitroglycerine

which is also used as a vasodilator (a substance that

dilates blood vessels) and PETN (pentaerythritol

nitrate).

sodium hydrogen carbonate (sodium bicarbonate),

NaHCO3

sodium carbonate, Na2CO3


hydrogen cyanide (hydrocyanic acid), HCN

hydrazine, N2H4 (used in rocket propulsion systems)

Explosives ammonium nitrate, NH4NO3

Fibres and plastics nylon, -[(CH2)4-CO-NH-(CH2)6-NH-CO]-,and other

polyamides

Refrigeration used for making ice, large scale refrigeration plants, air-

conditioning units in buildings and plants

Pharmaceuticals used in the manufacture of drugs such as sulfonamide which

inhibit the growth and multiplication of bacteria that require p-

aminobenzoic acid (PABA) for the biosynthesis of folic acids,

anti-malarials and vitamins such as the B vitamins

nicotinamide (niacinamide) and thiamine.

Pulp and paper ammonium hydrogen sulfite, NH4HSO3, enables some

hardwoods to be used

Mining and metallurgy used in nitriding (bright annealing) steel.

used in zinc and nickel extraction.

Cleaning ammonia in solution is used as a cleaning agent such as in

'cloudy ammonia'

2.3 Available technology

The major hydrogen production technologies for ammonia manufacture used in

refineries are Steam Methane Reforming (SMR) and Thermal Partial Oxidation (POX).

The other new develop technology is Auto Thermal Reforming (ATR). In Steam

Methane Reforming (SMR), the hydrogen production for ammonia synthesis supply is

accomplished via several steps: steam reforming, water gas shift, carbon dioxide removal

and methanation. SMR plant use steam to react with methane in producing hydrogen. For

Thermal Partial Oxidation (POX), methane or other hydrocarbon feedstock such oil is

oxidized to produce hydrogen. The technology includes a partial oxidation reactor, water

gas shift reactor and hydrogen purification equipments. Auto Thermal Reforming (ATR)


combine best features of SMR and POX. In Auto Thermal Reforming (ATR), methane or

liquid fuel feed is reacted with both steam and air to produce hydrogen rich gas. All of

the technology reviewed are different in the initial stages of the primary feedstock

commonly methane reaction to produce hydrogen. The technologies still incur the water

gas shift reactors and hydrogen purification stages before the ammonia synthesis

reaction. The main different is the capability of hydrogen production efficiency and the

capital cost of initial stage of feedstock reaction. Below is the summarized comparison

between the three (3) technologies:


Table 2-3: Comparison between Steam Methane Reforming (SMR), Thermal Partial Oxidation

(POX) and Auto Thermal Reforming (ATR).

Comparison Steam methane reforming Partial oxidation Auto thermal

reaction

Feedstock Natural gas, light

hydrocarbon, coal and

steam.

Natural gas, liquid fuel,

heavy oil and oxygen.

Natural gas,

liquid fuel and

steam.

External heat

needed[3]

Yes Yes No

Indirect heat

exchanger[3]

Yes Yes No

Active catalyst Yes No (hydrogen yield

enhanced if use catalyst)

Yes

Hydrogen

production

efficiency

Up to 85% 70-80% More than 85%

Estimated plant

capital cost

Moderate Highest Lowest

Advantages[3] Heat can be recovered;

flue gas to raise steam for

reaction, purge gas as

reformer burner for

endothermic reforming

reaction.

Partial oxidation reactor

less expensive than

steam reformer vessel.

Feedstock cheap; heavy

oil available at low cost.

Not sensitive to

poisoning.

All heat

generated by

POX is fully

utilized to drive

SMR reaction.

Higher yield.


Disadvantages Twice CO2 emission than

hydrogen product.

Less energy efficient

than SMR because

higher temperature

involved (excess heat

loss, heat recovery

problem), purge gas

cannot fully recovered

Downstream and

purification stages more

expensive than SMR.

Lower thermal

efficiency than

SMR.

Poisoning of

catalyst

Catalyst sensitive

to mixing of

oxygen.

Solution for

low cost

technology

Low cost of natural gas

prices. Capital cost lower

with PSA design

Low cost technology at

purification stages

Pure hydrogen feed

Low cost of

feedstock

Other Incorporate with oxygen

plant rather using air

Reduce size and reactor

cost

Higher operating

temperature.

Sources:1. Review of small stationary reformers for hydrogen production by Dr. Joan M. Ogden Research scientist, Center for Energy and Environmental Studies,Princeton University, Princeton, NJ 08544. 2.Reforming and auto thermal reforming available at www.chrisgas.com and http://www.ics.trieste.it/media/139818/df6497.pdf 3. Mr. Ali Al-Sanadi Ammonia Sales Manager-QAFCO, Ammonia Outlook Supply/Deman & Trade of Suez and Oceania, 2008

2.4 Product Market Survey

2.4.1 Demand

Ammonia, an essential feedstock for a wide range of downstream nitrogen based

products, is one of the most common and voluminously produced in organic chemical

worldwide. The largest share of ammonia is primarily used in the production and

consumption of fertilizer, while industrial applications and others account for the

remainder. Ammonia production increases at an annual growth rate of 2-3% with China

leading global production and capacity surplus. Growth in ammonia production is

directly related to the demand for phosphate and nitrogen fertilizers, as nearly 90% of

http://www.ics.trieste.it/media/139818/df6497.pdf

http://www.chrisgas.com/


ammonia and ammonium derivatives are applied in mineral fertilizer production

worldwide IFA annual conference, (2011). The trio of China, United States and Morocco

are considered as market leaders in the production of ammonium phosphate worldwide.

International ammonia prices are highly dependent on natural gas prices, and move in

tandem with the United States market, more precisely with natural gas prices in the

United States.

Figure 2-2: Ammonia Usage

The end-use market of ammonia, particularly fertilizers is undergoing significant

changes with the emergence of new market such as biofuels and AdBlue abatement of

NOx emission. There has been stupendous growth in biofuels production particularly

bioethanol and biodiesel in recent years. AdBlue (Aqueous Urea Solution) is the other

niche end-use market gaining prominence due to its capability in reduction of

diesel/NOx emissions, a prime concern in the automobile industry. The need for

complying with stringent environmental regulations drives demand for this urea solution.

The market share of urea in ammonia-based fertilizer consumption was pegged at more

than 50% in 2008, the largest in comparison to other nitrogen-based fertilizer.

In term of end-use segments, fertilizers dominate the ammonia market demand,

accounting for a major share. Carbamide or urea and Ammonium Phosphate are two

significant fertilizer types holding sway over market.


2.4.2 Climax

R. Clarke (2011) the onset of worldwide financial crisis in 2008 and 2009

adversely affected the overall consumer purchasing power resulting in substantial

decrease of fertilizer prices. The most noticeable price declines were for the MAP/DAP

varieties, which fell by a huge 75% in 2009 as compared to 2008. Other fertilizers such

as urea witnessed similar drop in prices. As a consequence of high inventory levels

during the end of 2008, nitrogen and phosphate fertilizers declined, both in terms of

volume and prices in 2009. Surplus supply of ammonia in market of North America and

Europe also contributed to low prices during the year. Production in developed markets,

such as United States and Europe, has been relatively flat over the past few years with

rising natural gas prices leading to numerous plant closures. The market demand and

prices for ammonia however entered a revival phase in the year 2010. Future growth in

terms of expansion of production capacity will be powered mainly from developing

markets.

2.4.3 Ammonia Market Lengthen

According to the International Fertilizer Industry Association (IFA), the world

nitrogen market in 2009 recovered from a depressed demand conditions seen in 2008 in

both the fertiliser and industrial sectors. World ammonia production in 2009 remained

stable at 153m tonnes ammonia. Global ammonia trade fell 7.4% to an estimated 17.4m

tonnes.

Figure 2-3: World Ammonia Demand


Global ammonia capacity was 152m tonne/year in 2009, with the main addition

occurring in Chine, Trinidad, Indonesia, Oman, India and Egypt. The IFA noted that

many projects that were slated for commissioning in 2009 have been delayed by six

months or more. According to IFA 2010 world capacity survey, global ammonia

capacity will increase by 20% to 224m tonne/year by 2014. The bulk of the growth will

be in China, Middle East, Latin America and Africa. IFA estimated global seaborne

ammonia availability will be close to 19m tonnes in 2014, a net increase of 17.4m tonnes

over 2009.

In terms of nitrogen supply, world capacity will reach 184m tonnes in 2014. IFA

estimated global nitrogen supply from G.Wheeler, (2011), capability to grow from

134.8m tonnes in 2010 to 158.5m tonnes in 2014. For the period 2009 to 2014,

consumption of nitrogen nutrient fertilizer is projected by the IFA to grow at 2.0% per

year to 111.7m tonnes in 2014, compared to 103.9m tonnes in 2010. Nitrogen demand in

the non-fertilizer sector is forecast to grow at 4.6% per year from 21.6mtonnes in 2009 to

26.6m tonnes in 2014. Taking into account distribution losses, IFA estimated global

nitrogen demand will reach 142m tonnes in 2014.

Demand for nitrogen fertilizers in China was soft in 2009 with ammonia

production increasing at a moderate rate 3.8% compared to 2008 to 50.8m tonnes of

ammonia. Much of the increase was related to higher urea and DAP output. In medium

term, China’s ammonia capacity is projected by the IFA to increase from 62m tonne per

year in 2014.

2.4.4 Import and Export


Figure 2-4: Ammonia World Import

Figure 2-5: Ammonia World Export

The import and export of ammonia have fluctuated slightly over the last few

years. In 2005, the amount of ammonia imported around the world was slightly around

18 million tonnes. In both 2006 and 2007, the amount of ammonia imported was slightly

less than 20 million tonnes. These years reflect a 11% increase in the amount of

ammonia imported compare to 2006. World exports of ammonia flat during the years

following the change in domestic production and import from the abroad. Export in 2001

was approximately 15478 million tonnes, and in 2002, 16093 million tonnes were

exported. Exports then increased to 2/3 of those reported in the previous years. In 2004,

when domestic production dropped and imports increased, only 17325 million tonnes of

ammonia were expected.


2.4.5 European Market review

Figure 2-6: Ammonia Net Price per Quarter

From the global strategic business report on market research, (2011), Ammonia

prices in Europe were firm in the $390 per tonne in mid-November. Expectations of a

normal seasonal decline were diminishing amid production problems at a Gorlovka in

Ukraine which were impacting yuzhny availability and continued strong demand from

United States, as some suppliers looked to keep systems from running empty. Despite

bids from traders at lower levels there was little pressure for lower prices.

Through December prices remained in the $390-$400 per tonne range as

sentiment was still firm. Although production at Gorlovka restarted, demand, particularly

from the United States, was sufficient to absorb the extra available. At the same time,

production curtailments in Trinidad took any slack out of the market and supported

prices.

At the end of the year, the ammonia market was in a bullish mood. January

business was reported at $400 per tonne and offers moved higher. Early in the New year,

business was reported at $430 per tonne as limited supply and strong demand combined

to push prices up. Deals quickly followed at a $450 per tonne and $460 per tonne as

production problems in Trinidad and Algeria persisted, while in United States, European

and North African demand remained strong.

At mid-February, the short term prospects for ammonia prices remain strong.

Demand from the United States and Europe is still strong and supply limited. Yuzhny

prices have risen to $470 per tonne and could move higher with suppliers reporting bids

from the traders at $480 per tonne.


2.4.6 Asia Market Review

The Asia-Pacific region reigns over the world market as the single largest and

fastest growing Ammonia market, as stated by the new market research report. Growth

and demand of Ammonia largely stems from China, where ammonia is finding increased

application in NPK/NP production. Europe, driven by regions such as Russia, Ukraine,

Croatia, Germany and other Eastern Europe countries is the second largest and fastest

market for ammonia worldwide.

India is ranked as the world’s third largest producer and importers of ammonia.

Imports which are estimated at 1.9m tonnes in 2009 are used for phosphate fertilizers

since domestic ammonia production is mostly integrated with urea production. Excluding

any plant restarts, IFA expected India’s ammonia capacity to reach 20m tonne per year in

2014.

Prices in the Asian as interpreted by G.Wheeler, (2011), ammonia market picked

up momentum in the last couple of months of 2010, driven by the tight supply and

healthy demand in the region. Robust conditions in the United States and Europe offered

additional support to Asia pricing, and high numbers for other nitrogen products also

helped buoy ammonia levels. Prices rose from $445-$475 per tonne in mid-November

2010 to $465-$500 per tonne in early February 2011.

Ammonia values were anticipated to remain high throughout the first quarter of

the year. A scheduled turnaround at an ammonia facility in Indonesia in December and a

turnaround in Malaysia plant in February contract price in Tampa, together with

climbing indications in Yuzhny and Middle East, offered additional support to ammonia

values in Asia.

2.4.7 Malaysia Market Review

The petroleum and petrochemical industry covers natural gas, petroleum products

and petrochemical. The industry is an important sector in Malaysia with investment

totalling RM57.2 billion as at 2008.

According to J.C Wu (U.S Geological Survey Minerals Yearbook), Malaysia has

the world’s 14th largest natural gas reserves and 23rd largest crude oil reserves. In 2008,

Malaysia produced 5,891 million standard cubic feet per day of natural gas. Malaysia


also has the world’s largest production facility at a single location of liquefied natural

gas with production capacity of 23 million metric tonne per year. The long term

reliability and security of gas supply ensures the sustainable development of the

country’s petrochemical industry. The existence of a trans-peninsular gas transmission

pipeline system and six gas processing plants, has resulted in a ready supply of gas to the

industry.

Three major petrochemical zones have been established in Kerteh, Terengganu;

Gebeng, Pahang; and Pasir Gudang/Tanjung Langsat, Johor. Each zone is an integrated

complex with crackers, syngas and aromatics facilities to produce feedstocks for

downstream products. Ammonia plant had built in Bintulu, Sarawak; Kerteh,

Terengganu; and Gurun, Kedah. The production of ammonia in Malaysia keeps

increasing from 2004 onwards.

Figure 2-7: Malaysia Ammonia Production by Year

Malaysia produced ammonia and urea using natural gas as feedstock. ASEAN

Bintulu Fertilizer Sdn. Bhd. (ABF) and PETRONAS Fertilizer (Kedah) Sdn. Bhd. (PFK)

produced ammonia and granular urea, and PETRONAS Ammonia Sd. Bhd.(PA)

produced only ammonia. Ammonia production capacity (in nitrogen content) of ABF in

Bintulu was 395,000 tonnes per year while PFK in Gurun, 378,000 tonnes per year and

PA in Kerteh, produced 378,000 tonne per year.

In 2003, Malaysia produced 909,500 tonnes of ammonia (in nitrogen content), of

which 578,800 tonnes was delivered to the home market and 340,900 tonnes was

exported to overseas market. The usage of ammonia in Malaysia mostly contributes to


agriculture sector. Ammonia is used as fertilizer in agriculture sector mainly, such

developed states currently focused on agriculture sectors including Pahang, Kedah,

Perlis, Perak, Sabah and Sarawak. For example, the agriculture focus on Pahang is to

develop and promote pineapple growing and integration into oil palm plantations in

Rompin, fruit agriculture park in Lanchang, vegetables growing as well as Neclues

Cattle Breeding & Research Centre in Muadzam Shah. Besides, northern states also rich

with paddies, vegetables as well as grapes ville.

2.5 Site Study

2.5.1 Introduction

To build a plant, we need to review all the current available and proposed the

most suitable site. Many theories describing plant location have been proposed by the

economics. The location of the plant can have a crucial effect on the profitability of the

project and the scope for future expansion and also is crucial to ensure availability of the

raw materials and the interconnection of the feedstock provider. Therefore, a suitable site

must be chosen as well as environment analysis need to be performed to ascertain the

expected effect of the plant and the chemicals on the surrounding area. A proper

screening process of all the sites based on our criteria of selection need to be done

systematically.

2.5.2 Criteria in Selection of Plant Site

In selecting the most suitable site for manufacturing which is ammonia, we have

taken into consideration a number of criteria that is vital in ensuring the success of the

plant. These are:

1. Raw material supplierTo minimize the transportation cost of the raw material, a closer source of the

raw material to the operating plant is needed. If the needed raw material is to be

imported, it would be important to consider a location to a seaport with excellent

infrastructure.

2. Transportation facilitiesThe plant should be located near to an at least three forms of major transportation


facilities, which are road network, seaport and airport. These will help facilities

ant import and export activities. Seaport facilities will help in the exportation and

importation of the product and raw materials via tankers while the availability of

airport is convenient for the movement of personnel and essential equipment

suppliers.

3. Land pricesMost of the industrial land price depends on the location. It is very important to

choose an economical land price which can reduce the total investment cost.

Besides that, it is important to choose the lowest land price when starting a new

plant to gain the highest economic value.

4. Availability of utilities, water, fuel and powerIn petrochemical industries, large quantities of water supply are usually needed

for cooling and general use in a chemical plant. Besides that, petrochemical

plants need power in the form of electricity to run machines and equipments.

Thus it is important to have sufficient power and local supply in order to ensure

the plant running smoothly.

5. Regulatory laws and waste disposalSite selected should have efficient and satisfactory disposal system for factory

waste and industrial effluent if it is decided that the waste should be treated off-

site.

6. Taxes and government incentiveMost state governments offer attractive incentives to investors. Some incentives

grant partial or total relief from income tax payment for a specified period, while

indirect tax incentives come in the form of exemptions from import duty, sales

tax and excise duty. This can help reducing initial operating cost.

7. Availability of low cost labour and servicesPlant should be located where sufficient labour supply is available. Skilled

construction worker will usually be brought in from outside local area but there

should be an adequate pool unskilled workers available locally and workers


suitable for training to operate the plant. Available, inexpensive manpower from

the surrounding area will contribute in reducing the cost of operations.

2.5.3 Proposed location

The proposed plant had to be reconsidered all the criteria as stated. Several locations

have been identified, which are:

1. Gebeng (Phase IV) Industrial Estates, Kuantan, PahangGebeng Industrial Estates is promoted by the Pahang State Development

Corporation (PSDC) as an industrial predecessor in the East Asian region for

petrochemical and chemical based plants. The federal government’s move to

develop the eastern industrial corridor ensures beneficial and rapid progression for

the industrial growth of Gebeng estate. According to Kuantan Port Consortium

(2007), the first and second phase category, comprises about 900 hectares. A third

phase, spanning some 1600 hectares, has attracted mega industrial from

multinational companies, namely from US, Japan, Germany and Belgium.

Kuantan proximity to Malaysia’s oil and gas fields make it logical choice for

petrochemical industry growth.

2. Pasir Gudang, Industrial Estate, JohorPasir Gudang, Industrial Estate is located 36 km from Johor Bharu. The type of

industry develop in Pasir Gudang is light, medium and heavy industry. Johor Port

is about 5 km from Pasir Gudang, and this will enable easier import and export

processes. Good infrastructure facilities are also available here, such as North-

South highway to Kuala Lumpur and the main road to Singapore. Railroads are

also available here. The line ruins from northern terminal in Butterworth to

Singapore and Pasir Gudang in the south.

3. Kerteh Industrial Estate, TerengganuKerteh Integrated Petrochemical Complex, Terengganu located at the south of

Terengganu, is developed by PETRONAS. Plants can be sited within the vicinity

of raw materials thus saving in production cost. Availability of cheap industrial

land and supply of relatively productive and adaptable labour from a young and

literate population give merit to the location. Special incentives are offered such


as cheaper land and lower quit rent and assessment rates. Terengganu is also

home of the Malaysia deepest port versioned to be new gateway to the Asia

Pacific.


Table 2-4: Summary of Site Characteristics

Selection Criteria Kerteh Industrial Estate Gebeng Industrial Estate Pasir Gudang Industrial Estate

Location 5 km from Paka 30 km from Kuantan City 36 km from Johor Bharu

Type of Industry Chemical, petrochemical, other Chemical, petrochemical, other Light, Medium and Heavy

Area available 500 hectares 1557.2 hectares 430 hectares

Land price (per feet2) RM 15-20 RM 7-14 RM 17-25

Raw Material Supplier PETRONAS Gas Berhad PETRONAS Gas Berhad PETRONAS Gas Berhad

Power Supply Tasik Kenyir Hydroelectric Dum Tanjung Gelang TNB Sultan Iskandar Power Station (644MW)

Paka Power Plant (900 MW) CUF Gebeng IPP YTL Power Generation Sdn. Bhd.

CUF Kerteh

Water Supply Bukit Sah Loji Air Semambu Loji Air Sungai Layang

Sungai Cherol CUF Gebeng Syarikat Air Johor

CUF Gebeng Loji Air Sungai Buluh

Port Facilities Kerteh Port Kuantan Port Pasir Gudang Port

Kuala Terengganu Port Kemaman Port

Airport Kerteh Airport Sultan Mahmud Airport Senai International Airport, Johor

Sultan Mahmud Airport Changi International Airport, Singapore


Roadways Kuala Terengganu -Kuantan Kuala Terengganu – Kuantan Main road to Singapore

Karak Highway Karak Highway North – South Highway

Railway Facilities Kuantan – Kerteh Railway Kuantan – Kerteh Railway Singapore and North Peninsular Malaysia Railway

Incentive Infrastructure allowance Infrastructure allowance Incentive for exports

Five years exemption on import duty

Five years exemption on import duty

Incentive for research development

5% discount on monthly electrical bills for first 2 years

5% discount on monthly electrical bills

Incentives for training tariff protection

25-38% exemption on daily water cost for 4545 m3 of water

85% tax exemption on gross profit Exemption from import duty on direct raw materials/components

Pioneer Status and Investment Tax Allowance and Reinvestment Allowance



Incentive for high tech industries Incentive for high tech industries Incentive for high tech industries

Waste water management Kualiti Alam Sdn. Bhd. Kualiti Alam Sdn. Bhd. Kualiti Alam Sdn. Bhd.

Indah Water Konsortium Indah Water Konsortium

Sources: 1. Invest in Pahang, (2010). Retrieved March 2011, at “http://www.investinpahang.gov.my/index.php?ch=en_investinpahang&pg=en_industrialareas&ac=9”. 2. Lembaga Pelabuhan Johor, (2011). Retrieved March 2011, at “http://www.lpj.gov.my/”.3. Land for sale Pahang, (2011). Retrieved March 2011, at “http://www.mudah.my/Gebeng+Sg+Karang-6145773.htm”. 4. Property Listing, iProperty, (2011). Retrieved March 2011, at “http://www.iproperty.com.my/propertylisting/486107/Kerteh_Industrial_Land_ForSale”. 5. Property Listing, iProperty, (2011). Retrieved March 2011, at“http://www.iproperty.com.my/propertylisting/506304/Pasir_Gudang_Industrial_Land_ForSale”.

http://www.iproperty.com.my/propertylisting/506304/Pasir_Gudang_Industrial_Land_ForSale

http://www.iproperty.com.my/propertylisting/486107/Kerteh_Industrial_Land_ForSale

http://www.mudah.my/Gebeng+Sg+Karang-6145773.htm

http://www.lpj.gov.my/

http://www.investinpahang.gov.my/index.php?ch=en_investinpahang&pg=en_industrialareas&ac=9



Table 2-5: Weight marks and explanation on the plant site location factors

Factors 5-4 Marks 3-2 Marks 1-0 Marks

Supply of raw material Able to obtain large supply locally thus saving on import cost

Having long pipeline networks for the transportation of raw materials.

Source of raw materials from neighbouring states or countries with the distance not exceeding 80km

Uses pipeline system as well.

Unable to obtain raw material from close sources with the distance exceeding 80km

Forced to import from foreign countries

Uses pipeline as wellPrice and area of land Land area exceeding 60

hectares Price of land is considerable

Land area below 60 hectares Price of land is moderate

Land area below 40 hectares Price is expensive

Government Incentives Incentives from the Local Organization of Country Development

Incentive from special companies

Incentives from the Local Organization of Country Development

No incentives from the Local Organization of Country Development

Transportation Complete network and well maintained highway, expressways and roads.

International airport facilities access to the main location around the world

Good federal road and highway system

Limited railway system access More distant from port Airport only provides

domestic flight.

Average road system No highway or expressway

system in close proximity No railway system Very distance from port or

harbours Distance from nearest airport

more than 100km awayUtilities Well provided utilities supply

Efficient waste management Moderate provided utilities. Moderate waste management

Least provided utilities Satisfactory waste

management


Table 2-6: Weighted Evaluation on Potential Sites

Site ConsiderationWeight Kerteh Gebeng

Pasir

Gudang

Availability of land 20 4 4 3

Price of land 30 3 4 2

Close proximity to port 15 4 4 4

Supply of raw material 25 4 4 2

Utilities provider 20 4 4 3

Transportation 20 4 4 5

Waste water disposable 15 4 4 4

Workers supply 20 4 4 4

Numerous telecommunication

system network10 4 4 5

Conductive living conditions 15 3 3 4

Weather 10 4 4 4

TOTAL 200 755 785 680

3.775 3.925 3.4

2.5.4 Conclusion Remark

Based on matrix comparison made, Gebeng Industrial Estate, Pahang has been

chosen as the site for ammonia plant. The location of Gebeng Industrial Estate is

highly strategic compared to others where the reason is focused on the cheap land

price, close to port as well as has good and complete network and well maintained

highway, expressway and roads. Also near the raw material supplier, PETRONAS

Gas Berhad contributes to low cost of operating system. With good pipeline

connection between Gebeng Kuantan and Kerteh, the transportation of raw material


had been eased. In addition, a centralized Utility Facilities (CUF) is also offering its

services to plant owner in Gebeng to provide the supply of electricity, industrial

gases and utilities such as steam and pre-treated water.

2.1 Previous Plant accident

2.1.1 Accident 1

One person died and nearly a dozen were injured in a freak accident at an ammonia

manufacturing plant at Vatva GIDC on Sunday. The mishap occurred when a vessel

emitting ammonia gas burst, damaging the factory premises. R K Industries produces

petro-nitroaniline, a by-product of ammonia. The factory is based in Phase IV of

Vatva GIDC and is run by Karshan Patel, an Ahmedabad based chemical trader.

Nearly 25 to 30 workers were present in the factory at the time of the accident. Two

workers, Ramesh Zala and Kishan Bhandari, were buried in the debris. The injured

were later shifted to LG Hospital where their condition is reported to be critical.

Investigating Officer Inspector G R Gadhvi said it was a major blast and fragments

of the vessel were found even half a kilometre away. “The blast took place in a 15-

foot high vessel emitting ammonia gas. A rise in temperature led to pressure build-up

inside the vessel. The explosion also damaged the cement shades and walls of the

factory,” he said.

(Resource: Indian Express.com, Monday, April 12, 2010)

Link: http://www.indianexpress.com/news/blast-at-vatva-ammonia-plant-kills-one/604942/

2.1.2 Accident 2

Nangal, March 20, three persons were killed and one sustained serious burns in a

blast at the ammonia plant of National Fertilisers Limited here today. The Ropar

Deputy Commissioner has ordered a magisterial inquiry into the accident.

The incidence took place at around 11:40 am, when an explosion reverberated in the

factory premises due to bursting of a boiler. Three people, including two engineers

and a labour, died on the spot.

http://www.indianexpress.com/news/blast-at-vatva-ammonia-plant-kills-one/604942/


Eyewitnesses said the impact of explosion and pressure of the gas was so great that

the victims were thrown high in the air. Glass of the control room was shattered into

pieces.The NFL authorities have banned the entry of outsiders, including the cops,

and declared emergency in the plant.

A spokesperson for the company said the explosion occurred in the shift conversion

section of the plant. “The saturator tower fell and some pipelines were found

detached,” he stated.

The ammonia plant and other allied plants on the factory premises were immediately

shut down. Total system was isolated and depressurised. The authorities have refused

to divulge details of the damage.

The deceased have been identified as mechanical manager Deepak Chhabra (47),

shift engineer (production) Mahinder Anand (52) and Jarnail Singh (49).

Deepak is survived by wife Neeru Chhabra and two children while Mahinder is

survived by wife Saroj Anand, two daughters and a son.

Engineer Umesh Kumar suffered 50 per cent burns while trying to help in rescue

operations. He has been referred to Dayanand Medical College and Hospital,

Ludhiana.

Deputy Commissioner Priyank Bharti reached spot after 1 pm and ordered Nangal

SDM Lakhmir Singh to conduct an inquiry. Lakhmir Singh said preliminary inquiry

would be submitted by tomorrow after taking the statements. Detailed technical

inquiry would take some time.

(Resource: The Tribune Online Edition, Sunday March 21, 2010)

Link: http://www.tribuneindia.com/2010/20100321/main3.htm

http://www.tribuneindia.com/2010/20100321/main3.htm


3

CHAPTER 3

CONCEPTUAL PROCESS DESIGN AND SYNTHESIS

3.1 General Process Description

3.1.1 The reactions and reactions conditions

The reaction above shows the heart of the reaction of producing ammonia

(NH3). The reaction is reversible, telling us that only part of the hydrogen and

nitrogen is converted into ammonia. The reaction is exothermic (ΔH= - 46kJmol -1) at

298K and it is favoured by high pressure and low temperature.

From production of ammonia, EFMA, (2000), the ammonia synthesis

pressure is usually in the range of 100-250 bars. The temperature for the synthesis is

from 350-550° (high temperature), but considering the reaction rate as lower

temperature would contribute to slower reaction and high yield is important for the

industry. Iron catalyst was used in the processed.

Again, the reaction above is referred. The synthesis of ammonia needs two main

raw materials which are the nitrogen (g) and hydrogen (g). The nitrogen can be easily

got from the processed air; hydrogen however, is very expensive. After doing some

literature research on the topic on how to produce hydrogen, 6 possible ways of

producing hydrogen managed to be found. They are:

1. Steam methane reforming

2. Partial oxidation of heavy oil or vacuum residue

3. Coke gasification of coal

4. Electrolysis of water

5. Biomass

6. Autothermal reformer


The methods found were analysed and the best and the most economical and

practical method was chosen.

Figure 3-8: Comparison between natural gas reforming, heavy oil and coal gasification in

Europe

Although the comparison was made in Europe, the figure used which is in

term of ratio is a help to rationalize everything. From Figure 3-8, it can be seen that

natural gas reforming is the simplest and the most effective way of producing

hydrogen for ammonia synthesis.

Electrolysis, it is undeniable fact that electrolysis of water has a very huge

potential in producing hydrogen, however, this process is very expensive and the

effectiveness is dependent on cell’s total reversible reduction potential. Thus, this

method is not really effective and economical.

Biomass however, is not suitable due to the problem with the raw material.

Since a lot of raw materials will be needed for the process. Autothermal reformer

(ATR) is the latest technology nowadays which is elegant for its energy saving and,

for a very high ammonia plant capacity, ATR can be the best answer.


Steam methane reforming in Ammonia production

Figure 3-9: Block diagram of the steam/ air reforming process [1]

Feedstock desulphurization

Sulphur compound is poisonous to most of the catalyst used in the process.

The feed gas is preheated to 350-400°C, usually in the primary reformer convection

sector, and then treated in a desulphurization vessel, where the sulphur compounds


are hydrogenated to H2S, typically using a cobalt molybdenum catalyst, and then

adsorbed on pelletized zinc oxide. Zinc sulphide remains in the adsorption bed. The

hydrogen is usually recycled from the synthesis section (production of ammonia,

EFMA,(2000)).

Primary reforming

The gas from the desulphurizer is mixed with process steam, usually coming

from an extraction turbine, and the steam/gas mixture is then heated further to 500-

600°C in the convention section before entering the primary reformer. In some new

revamped plants the preheated steam/gas mixture is passed through an adiabatic pre-

reformer and reheated in the convection section, before entering the primary

reformer. (Special pre-reformer catalysts are offered by several suppliers). Also, in

some plants, part of the process steam is supplied by feed-gas saturation.

The amount of process steam is given by the process steam to carbon molar

ratio (S/C ratio), which should be around 3.0 for the best reforming processes. The

optimum ratio depends on several factors, such as feedstock quality, purge gas

recovery, primary reformer capacity, shift operation, and the plant steam balance. In

new plants the optimum S/C-ratio may be lower than 3.0.

The primary reformer consists of a large number of high–nickel chromium

alloy tubes filled with nickel-containing reforming catalyst. The overall reaction is

highly endothermic and additional heat is required to raise the temperature to 780-

830°C at the reformer outlet section (production of ammonia, EFMA,(2000))

The heat for the primary reforming process is supplied by burning natural gas

or other gaseous fuel, in the burners of a radiant box containing the tubes. The flue-

gas leaving the radiant box has temperatures in excess of 900°C, after supplying the

necessary high level heat to the reforming process. Thus only about 50-60% of the

fuel’s heat value is directly used in the process itself. The heat content (waste heat)

of the flue-gas is used in the reformer convection section, for various process and


steam system duties. The fuel energy requirement in the conventional reforming

process is 40-50% of the process feed gas energy section (production of ammonia,

EFMA,(2000)).

The flue-gas leaving the convection section at 100-200°C is one of the main

sources of emissions from the plant. These emissions are mainly CO2, NOx, with

small amounts of SO2and CO section (production of ammonia, EFMA,(2000)).

Secondary reforming

Only 30-50% of the hydrocarbon feed is reformed in the primary reformer

because of the chemical equilibria at the actual operating conditions. The

temperature must be raised to increase the conversion. This is done in the secondary

reformer by internal combustion of part of the gas with the process air, which also

provides the nitrogen for the final synthesis gas. In the conventional reforming

process the degree of primary reforming is adjusted so that the air supplied to the

secondary reformer meets both the heat balance and the stoichiometric synthesis gas

requirement. The process air is compressed to the reforming pressure and heated

further in the primary reformer convection section to around 600°C. The process gas

is mixed with the air in a burner and then passed over a nickel-containing secondary

reformer catalyst. The reformer outlet temperature is around 1,000°C, and up to 99%

of the hydrocarbon feed (to the primary reformer) is converted, giving a residual

methane content of 0.2-0.3% (dry gas base) in the process gas leaving the secondary

reformer. The process gas is cooled to 350-400°C in a waste heat steam boiler or

boiler/superheated downstream from the secondary reformer section (production of

ammonia, EFMA,(2000)).

Shift conversion

In the High Temperature Shift (HTS) conversion, the gas is passed through a

bed of iron oxide/chromium oxide catalyst at around 400°C, where the CO content is

reduced to about 3% (dry gas base), limited by the shift equilibrium at the actual

operating temperature. There is a tendency to use copper containing catalyst for


increased conversion. The gas from the HTS is cooled and passed through the Low

Temperature Shift (LTS) converter. This LTS converter is filled with a copper

oxide/zinc oxide-based catalyst and operates at about 200-220°C. The residual CO

content in the converted gas is about 0.2-0.4% (dry gas base). A low residual CO

content is important for the efficiency of the process section (production of ammonia,

EFMA,(2000)).

CO2 removal

The CO2 is removed in a chemical or a physical absorption process. The

solvents used in chemical absorption processes are mainly aqueous amine solutions

(Mono Ethanolamine (MEA), Activated Methyl Diethanolamine (aMDEA) or hot

potassium carbonate solutions. Physical solvents are glycol dimethylethers (Selexol),

propylene carbonate and others. The MEA process has high regeneration energy

consumption and is not regarded as the best process.

For new ammonia plants the following CO2 removal processes are currently regarded

as best technique:-

1. aMDEA standard 2-stage process, or similar

2. Benfield process (HiPure, LoHeat), or similar

3. Selexol or similar physical absorption processes

After making literature research regarding the topic, it is observed that aMDEA for

CO2 removal is the best.

The benefits of the usage of a-MDEA are:

1 high CO2 purity

2 minimum H2 loss

3 no corrosion

4 low energy requirement

5 low capital investment


Methanation

The small amounts of CO and CO2, remaining in the synthesis gas, are

poisonous for the ammonia synthesis catalyst and must be removed by conversion to

CH4 in the methanator section (production of ammonia, EFMA,(2000)).

The reactions take place at around 300°C in a reactor filled with a nickel

containing catalyst. Methane is an inert gas in the synthesis reaction, but the water

must be removed before entering the converter. This is done firstly by cooling and

condensation downstream of the methanator and finally by condensation/absorption

in the product ammonia in the loop or in a make-up gas drying unit section

(production of ammonia, EFMA,(2000)). The next step will be the ammonia

synthesis which is already been discussed in the beginning.

3.2 Preliminary Reactor Optimization using - Hierarchical Decomposition Method (Douglas Method)

In performing the design process, Douglas method is chosen to be used. Douglas

method can be further divided into some hierarchical decisions which are:

1. Level 1: Batch or continuous

2. Level 2: Input-output structure of the flowsheet

3. Level 3: Recycle structure of the flowsheet

Decision 1: Reactor performance

Decision 2: Operating conditions of the reactor, (1)

concentration, (2) temperature, (3) pressure, (4) phase, (5)

catalyst

Decision 3: configuration of the reactor, reactor volume

(capacity of reactor in terms of input and output flow rates,

orientation, and configuration)

4. Level 4: General structure of the separation system

5. Level 5: Heat Exchanger Network


3.3 Batch versus Continuous

Continuous processes are designed so that every unit will operate 24 hr/day, 7

days/week for close to a year at almost constant conditions before the plant is shut

down for maintenance. While, batch processes normally contain several unit (in

some cases the entire unit) that are designed to be started and stopped frequently.

During a normal batch operating cycle, the various units are filled with material,

perform their desired function for a specified period, are shut down and drained

before the cycle is repeated. (Douglas, 1988)

Table 3-7: Criteria of selecting the process type

Criteria Batch process Continuous process

Decision

Production rates

For plant having a capacity of less than 453.5924 tonnes/yr or 1x106 lb/yr

For plants having a capacity of greater than 4535.924 tonnes/yr or 10x106

lb/yr

Continuous process is chosen because the ammonia plant designed to be built is 678, 810 tonnes/yr.

Market forces

For products with a seasonal demand.

For yearly, continuous production.

Continuous process is decided because the production of is throughout the year based on 7920 operating hours per year or 330 days per year

Operational problems / Scale up problems

For slow reaction.Good when dealing with slurry

For fast reaction. Continuous process because no slurry materials are involved in ammonia production.

Therefore, based on the analysis which is simplified in the table above, continuous

process was selected for the ammonia plant that is going to be built with a capacity

of 671,200 tonnes per year or 2034 tonnes per day.


3.4 Input-Output Structure of the Flowsheet

Figure 3-10: General input-output structure of ammonia plant excluding the inner loop

Figure 3-11: Complete input-output structure of ammonia plant

Figure 3-10 and Figure 3-11 shows the input output structure of the ammonia

plant. Figure 3-10 described the process as a whole where there only the ultimate

inputs and output are shown while Figure 3-11 shows the complete input output

structure showing eight stages in the process.


3.4.1 Number of product streams

In order to determine the number of product streams that will leave the process,

we need to list all the components that are expected to leave the plant. The

components which are expected to leave the reactor are listed in Table 3-8

Table 3-8: Components expected to leave the reactor

Component Boiling point Destination code

NH3/Ammonia -77.8°C Primary product

CO2 -56.6°C Valuable by product

Water 100°C Waste water treatment

N2 30°C Recycle and purge

H2 -253°C Recycle and purge

CH4 -182.5°C Recycle and purge

With reference to the supplier, the natural gas composition which will use as the raw

material is below:

Table 3-9: Natural gas composition

Source: PETRONAS Gas Sdn. Bhd. Kerteh Terengganu.vWith reference to Zulkifli

Abdul Majid, Zulkefli Yaacob, Yasmin binti Ahmad Khan, The Use of Natural Gas as

a Fuel. Available at: http://eprints.utm.my/4056/1/4ASTC2002_Kertas_Kerja.pdf

http://eprints.utm.my/4056/1/4ASTC2002_Kertas_Kerja.pdf


Table 3-10: Summary of decision in level 2-Input-output structure of flowsheet

Criteria Decision Justification

Is it necessary to purify

the feed stream?

No The natural gas contains

NO sulphur and mercury

Do we need to

remove/recycle reversible

by product?

No There is NO by-products

formed during ammonia

synthesis

Do we need a purge

stream?

Yes Purging is very important

in order to avoid build-up

in the reactor

Should we recover and

recycle some material?

Yes Recycling the reactants,

especially hydrogen will

be very economical

What are the design

variables?

Reactor conversion, optimized nitrogen: hydrogen ratio,

operating pressure, operating temperature, type of

catalyst used.

3.5 Reactor designed and recycle structure of the flowsheet

3.5.1 Reactor design

From section Batch versus Continuous, it is known that continuous system will be

used in the process. Table 3-11 shows the comparisons between CSTR and PFR.

Looking into this matter considering that the ammonia production process contains

catalytic stages, a plug flow reactor packed with catalyst will be chosen for the

process. It is known as packed bed reactor (PBR). Therefore, it can be said that

CSTR is unsuitable for this process.


Table 3-11: Comparisons between CSTR and PFR

CSTR PFR

Run at steady state with continuous flow of reactants and products; the feed assumes a uniform composition throughout the reactor, exit stream has the same composition as in the tank

Primarily used for:

Liquid phase reaction Steady state operation

Arranged as one long reactor or many short reactors in a tube bank ; no radial variation in reaction rate (concentration); concentration changes with length down the reactor

Primarily used for:

Liquid Gas Slurry

A typical plug flow reactor could be a tube packed with some solid material (frequently a catalyst). Typically these types of reactors are called packed bed reactors or PBR's

When agitation is required Series configurations for

different concentration streams Continuous production

Large Scale Fast Reactions Homogeneous and

heterogeneous reactions Continuous Production High Temperature

Continuous operation: feed and product run takeoff are both continuous

Uniform temperature throughout the reactor because of perfect mixing

High volumetric unit conversion

Run for a long period of time without maintenance

Continuous Operation Heat transfer can be optimized


Easily adapts to two phase runs Simplicity of construction Low operating (labour) cost Easy to clean

by using more thinner tubes Residence time is the same for

all the reactants

Perfectly mixed in the radial

direction

Lowest conversion per unit volume because the feed is diluted by the product when the it reach the tank

By-passing and channelling possible with poor agitation

The residence time cannot be controlled because the reactant can come and leave instantly.

Undesired thermal gradients may exist

High temperature are hard to control

Shutdown and cleaning may be expensive.


Table 3-12: Practical reactor to be used for ammonia plant

TYPE OF REACTOR

CHARACTERISTICS USES ADVANTAGES DISADVANTAGES

FIXED-BED CATALYTIC REACTOR

The solid catalyst pellets are held in place and do not move with respect to a fixed reference frame

Most frequently used as continuous tubular reactors

Kinds of Phases Present Gas phase/ solid catalyzed Gas-solid reactions

Used primarily in heterogeneous gas phase reactions with a catalyst

High conversion per unit mass of catalyst

Low operating cost Continuous operation Efficient contacting of the

reactants and catalyst because the tube in the fixed bed is packed with solid catalyst

Temperature control is difficult due to variation of heat load through the bed

In exothermic reaction, ‘hot spots’ can cause onset of undesired reactions or catalyst degradation

Channelling may occur Extremely short-circuiting

and bypass Not good for small particle of

catalyst because of high pressure drop and plugging

FLUIDIZED-BED

CATALYTIC REACTOR

Solid material in the form of fine particles is held in suspension by the upward flow of the reacting fluid

A fluid is passed through a granular solid material (catalyst) at high enough velocity to suspend the solid and cause it to behave as though as it was a fluid

Multiphase chemical reactions

Gas-solid phase reaction that requires large interfacial surface to react

Catalytic cracking of petroleum naphtha to form gasoline

Prevents the formation of ‘hot spots’ due to uniform temperature gradient

High heat transfer rate Catalysts can be removed,

regenerated, and recycled back to the bed

Good for fast reactions in which pore and diffusion may influence the rate.

Can handle large amounts of feed and solid

Uniform particle mixing Ability to operate reactor in

continuous state

Attrition of the catalyst can cause the generation of catalyst fines

Increased reactor vessel size High cost of the reactor Erosion of internal components,

thus required expensive maintenance and upkeep for reactor vessel and pipes


MOVING-BED CATALYTIC REACTOR

Catalyst is kept in motion by the feed to the reactor and the product

The force of gravity is used to shift the catalyst from top to bottom

Operate adiabatically especially when endothermic reactions are involved

Fluid (gas) phase Single-phase flow

Possible to remove the catalyst continuously for regeneration

Possible to use for cases with rapid deactivation of catalyst is encounter

Suitable for short-active life catalyst

Can avoid stagnant zones in the bed

Can obtain high conversion rates under good conditions of selectivity

Temperature control is poor Attrition of the catalyst can

cause the generation of catalyst fines


3.5.2 Reaction Conditions

For ammonia production, there more than one reaction occurs in the process.

However, ammonia synthesis is the most critical part in ammonia plant where the

process is a reversible process with a conventional conversion of 20-30%.

Knowing that knowledge of the macrokinetics is important for solving the industrial

problem of designing ammonia synthesis reactors, the optimal operating conditions

for computer control of ammonia plant must be determined.. Some of the

considerations are:

Effect of pressure on the reaction rate

Figure 3-12: Reaction rate for ammonia synthesis dependence on the ammonia concentration at

various pressures

According to G. R Maxwell (2004), high pressure promotes a high rate of

56


ammonia formation. This is based on Le Chatelier’s principle that says a reaction

that reduces the number of moles of gas (in this case from four moles of reactants to

two moles of ammonia) will be favoured by an increase in pressure. From the figure,

it can be seen at ratio of 3:1 of hydrogen to nitrogen, higher pressure will give higher

reaction rate. Thus, sufficiently high pressure would give better reaction rate.

However, higher pressure would result to higher operating cost due to the duty of the

compressor. Thus, an optimum pressure must be chosen.

Effect of Temperature to Reaction Rate

Figure 3-13: Reaction rate for ammonia synthesis dependence on the ammonia concentration at

various temperatures

Referring to G. R Maxwell (2004) the rate of formation initially increases

57


with rising temperature but then goes through a maximum as the system approaches

thermodynamic equilibrium (see Figure 3-13). From here, it can be seen there is a

limit to increase the temperature so that the reaction rate will be sufficiently high for

the process. Thus, here, it can be said that there is a limit for the temperature to be

increased. However, too low temperature will lower the rate of reaction. Hence, the

temperature must be optimized in order to get better rate of reaction.

Figure 3-14: Ammonia synthesis rate constant dependence on hydrogen: nitrogen ratio

The figure above shows that ammonia synthesis rate constant is dependent on

hydrogen: nitrogen ratio. It can be seen that for 1:1 ratio, at lower temperature the

rate constant is much higher however at higher temperature the rate constant

decreases. It is known that, for the ammonia production process, the temperature

must be sufficiently high so that the rate of reaction will be higher. For 3:1 ratio, it 58


can be seen that the rate of reaction increases as the temperature increases. Hence, it

can be concluded that 3:1 hydrogen nitrogen ratio better for ammonia production

process.

All the data above is from a commercial iron catalyst Haldor Topsøe KMIR. The

data shows a sharp drop in reaction rate with declining temperature at a 3:1 ratio in

contrast to a 1:1 ratio. This may be attributed to a hindering effect by absorbed

hydrogen at low temperature

59


3.5.3 Catalysts

Table 3-13: Catalysts used in the catalytic stages in ammonia production process

Process stage Optimum

condition

Catalyst Efficiency

Purification 350°C-400°C Cobalt

molybdenum

(CoMo)

99%

Pre-reforming 750°C-950°C Alumina supported

high Ni

99%

Primary reforming 700°C-800°C Nickel oxide;

Nickel 25%

40-80%

Secondary reforming >750°C Nickel oxide;

Nickel 15%

99

High temperature shift 330°C -360°C Iron-chromium

(90-95% magnetite

iron oxide, 5-10%

chromia, Cr2O3)

Combination of

HTS and LTS

allow conversion

of CO at 92%

based on LTS

reactor outletLow temperature shift 200°C -300°C CuO (15-30%),

ZnO (30-60%) and

the balance is

Al2O3.

Methanation 320°C Nickel oxide 99%

Ammonia synthesis 300°C Iron oxide 20.7

Sources: 1.G R. Maxwell (2004). Synthetic Nitrogen Products, A Practical Guide to the

Products and Process. DuPont Chemical Solutions Enterprise, Memphis, Tennessee 2. Mr.

Kenneth Windridge (1998), Mineral Fertilizer Production and the Environment part 1,

International Fertilizer Industry Association. 3. Ram B. Gupta (2009), Hydrogen Fuel

60


Production, Transport and Storage, CRC Press

The pre reforming stage is basically for the conversion of higher hydrocarbon

into methane. This stage is really preferable if the feedstock contain higher

hydrocarbon. The conversion is expected to be higher since the feedstock contains

less than 7% percentage of higher hydrocarbon.

The reforming consists of 2 stages which are primary and secondary. The

primary reforming efficiency is contains of higher percentage of nickel component as

the catalyst compared to the second stage. The second stage is basically to increase

the conversion of methane up to 99%. The Water Gas Shift (WGS) is commonly

consists of 2 stage of high temperature and low temperature. The combination of

high temperature and low temperature of WGS reactor allow converting 92% of the

CO in the reformate gas into H2 and lowering the CO2 content to about 0.1 vol%.

Before entering the methanation stage, the CO and CO2 is reduced to below 100ppm

in the CO2 removal stage. This small value can be assumed total conversion to

methane in the methanation stage.

Thus, in this level, it is decided that fixed bed catalytic reactor will be used as the

reactor for ammonia synthesis

61


3.5.4 Recycle structure

Figure 3-15: Recycle structure of the flowsheet

The unreacted reactants will be recycled back to the reactor via syngas

compressor. The recycle structure can be seen in the figure above. Some of the

unreacted gases will be purged in order to avoid build up in the reactor.

3.6 Process Screening or Separation system synthesis

3.6.1 General structure of the separation system

In order to determine the general structure of the separation system, the phase of the

reactor effluent streams must be considered. In the ammonia production plant, there

are two possibilities:

1. Reactor effluent is liquid. In order to recover ammonia, the ammonia, the

unreacted hydrogen and nitrogen and methane need to be separated. At first,

ammonia will be removed from the gaseous mixture by having a counter

current absorption column using water, producing ammonia aqueous as the

bottom product. Later on, the ammonia will be separated from water using

distillation column.

2. Reactor effluent is all vapour. There are three cases where the reactor effluent

62


is all vapour. The first case is during carbon dioxide removal, the second one

is the water removal and the last one is during ammonia removal which is

already been discussed above.

3.6.2 Vapour recovery system

With an aim to attempt synthesizing a vapour recovery system, two decisions must

be made

What is the best location?

What type of vapour system is cheapest?

Location of vapour recovery system

According to Douglas , there are for the location of the vapour recovery system:

1. The purge stream

2. The gas-recycle stream

3. The flash vapour stream

4. None

Vapour recovery system on the purge, will be installed to recover hydrogen to avoid

significant loss of it in the purge.

Type of vapour recovery system

In accordance to Douglas, the most common choices of vapour recovery system

(with current technology) are:

1. Condensation – high pressure or low temperature, or both

2. Absorption

3. Adsorption

4. Membrane separation process

5. Reaction systems

Strategy

Vapour recovery system need to be designed before considering liquid

separation system because each of the vapour recovery processes usually generates a

63


liquid stream that must be further purified. In the project, ammonia separation is

done by absorption of ammonia using water producing ammonia aqueous and then

separation of ammonia from ammonia aqueous using distillation process.

Figure 3-16: Separation system recycle loop after ammonia synthesis

Figure 3-16 shows the separation system for ammonia recovery unit and

hydrogen recovery unit. For hydrogen recovery unit, it is very crucial to set up it in

order to maintain 3:1 hydrogen, nitrogen ratio in the ammonia converter.

3.6.3 Liquid separation system

In our case, the liquid separation unit is only exists for ammonia separation

whereas the ammonia aqueous needs to be separated to produce ammonia.

In the process, distillation column was used to separate ammonia from ammonia

aqueous. Separation structure of ammonia aqueous to produce ammonia can be seen

in Figure 3-16.

64


3.6.4 Carbon Dioxide removal

Figure 3-17: Carbon dioxide absorber unit

The method used for separating carbon dioxide from the stream gas is

absorption by using aMDEA (activated methyldiethylamine) solution. In the carbon

dioxide removal, the feed contain of hydrogen, nitrogen, carbon dioxide, carbon

monoxide and argon. The feed gas then entering absorber which already load with

lean solution of aMDEA. The aMDEA solutions will absorb carbon dioxide

components and leaving at the bottom of the absorber as a rich solution of carbon

dioxide. The product gas leaving contains a very small percentage of carbon dioxide

(around 100ppm). The aMDEA solution is then entering the stripping column to

regenerate the rich solution of aMDEA into lean solution by removing the carbon

dioxide. The lean solution then entering the absorber again as the process is

continuous.

65


Figure 3-18: Carbon dioxide removal process

3.6.5 Ammonia absorption unit

Figure 3-19: Ammonia absorption unit

66


In the gas absorber, the solvent use; water will react with ammonia from the

feed gas to form ammonium ion, NH4+ and hydroxide ion, OH- . The product leaving

at the bottom of the stream as liquid and enter a distillation unit to purification of

ammonia. The solvent is continuously supply at the inlet of ammonia absorber unit.

The solvent which is water is not being regenerated since the solvent is cheap plus

the regeneration unit cost is high. Reaction in the ammonia absorber:

NH3(aq) + H2O(l) NH4+(aq) + OH-(aq)

The product gas leaving the ammonia absorber unit contains small percentage of

ammonia roughly 2%.

Figure 3-20: Ammonia purification process

3.6.6 Knock out drum

Since the ammonia synthesis uses Iron oxide as the catalyst, removing water

before the process is very essential. Therefore, in order to remove water, knock out

drum will be used. Since the reactants are in the gaseous phase, thus the gas needs to

be compressed and cooled so that water will condense and exist in the liquid form.

The knock out is selected because the mixture the mixture is heterogeneous and after

compressing and cooling it contains mostly vapour and little liquid.

67


Figure 3-21: Basic vapour-liquid separator

A knock-out drum is a vertical vessel into which a liquid and vapour mixture

(or a flashing liquid) is fed wherein the liquid is separated by gravity, falls to the

bottom of the vessel and then being withdrawn. The vapour travels upward at a

design velocity which minimizes the entrainment of any liquid droplets in the vapour

as it exits the top of the vessel. It is an undeniable fact that the usage of simple

knock-out drum with gravity forces will be very effective and cost saving.

Figure 3-22: Water removal system

68


3.7 : HEAT INTEGRATION

3.7.1 Introduction

Heat integration is undoubtedly important in energy conservation in production

plant. By doing heat integration, heat heating and cooling duties can be optimized,

reducing the operating cost. In industrial application, there are many types of heat

exchanger used. In this case, the shell and tube heat exchanger will be used. Utilities

consumption, whether hot or cold utility requirement in order to obtain the targeted

temperature of a stream is one of the main contributions to operating cost and capital

cost. Thus, in this heat integration section, maximum energy recovery method is used

to optimize the usage of heating and cooling utilities.

3.7.2 Stream Identification

In order to do heat integration, firstly, the hot stream (source of heat) and cold

stream (source of sink) need to be identified. While doing the heat integration, the

heat exchange streams for absorption and stripping section and condenser and

reboiler of distillation columns are not included in the in heat integration. This is

because these operation units are very sensitive towards temperature change and thus

affecting the product purity.

3.7.3 Minimum Temperature Difference ΔTmin

The driving force for heat transfer, ΔTmin is very important in heat integration as

it sets the relative location of the hot and cold streams and thus determining the

amount of recoverable heat. As .the energy is increases, capital cost decreases. The

optimum ΔTmin varies for different industries. Table 3-14 shows the suggested

optimum ΔTmin in different industries

Table 3-14 Optimum ΔTmin in different industries

Industrial sector Optimum ΔTmin Remarks

69


values (oC)

Oil refining 20 – 40Relatively low heat transfer coefficients, parallel composite curves in many applications, fouling of heat exchangers

Petrochemical 10 – 20Reboiling and condensing duties provide better heat transfer coefficients, low fouling

Chemical 10 – 20 As for petrochemicals

Low temperature

Processes3 – 5

Power requirement for refrigeration system is very expensive. ΔTmin decreases with low refrigeration temperatures

Source: Pinch Analysis Foundation Training Course (1997)

Production of ammonia is in petrochemical industries, thus, ΔTmin of 10oC is chosen

3.7.4 Pinch Technology Method

Introduction

Pinch technology can be described as a systematic method for energy saving.

The methodology is based on thermodynamic principle. A Pinch Analysis starts with

material and heat balances for the process [1]. Using Pinch Technology, it is possible

to identify appropriate changes in the core process conditions that can have an impact

on energy saving. After establishing the heat and material balance, targets for energy

saving can be set prior to the design of the heat exchanger network [1].

In this section, the method to calculate the amount for the ammonia

production process by constructing composite curves to set an energy target,

developing the problem table algorithm and doing the heat cascade diagram.

In doing the Pinch Analysis, it is a mandatory to follow two principles of

thermodynamics namely as the First and Second Law of Thermodynamics in

determining the direction of Pinch Analysis application.

1. The First Law of Thermodynamics – known as the conservation of energy

principles which provide a sound basis for studying the relationship among

the various forms of energy and energy interactions. Based on experimental

70


observations, the first law of thermodynamics states that energy can be

neither created nor destroyed during a process but change from one form to

another.

2. The Second law of Thermodynamics – stated that energy cannot be

transferred from a cold stream to a hot stream.

3.7.5 Stream Identification for pinch

Streams number

Table 3-15: The overall number of streams

Stream Type Supply Temperature(°C) Target temperature(°C) ΔT (° C ) CP (kW/K) Enthalphy (kW)S3/S4 Cold 355.4 750 394.6 145.4674254 57401.44607

S10/S11 Hot 1056 350 -706 197.7804676 -139633.0101S12/S13 Hot 452 200 -252 187.680276 -47295.42956S16/S17 Hot 220 110 -110 536.6576154 -59032.3377S19/S20 Cold 110 320 210 108.3218207 22747.58234S21/S22 Hot 327 110 -217 108.9785386 -23648.34288S25/S26 Hot 206 110 -96 148.1324729 -14220.71739S29/S30 Hot 207.69 110 -97.69 118.0656055 -11533.829S33/S34 Cold 179.88 360 180.12 105.7033083 19039.27989

For pinch analysis process, 6 streams are selected, the stream listed are as follow

Table 3-16: Stream used for pinch analysis

Stream TypeSupply

Temperature(°C)Target

temperature(°C) ΔT (° C ) CP (kW/K) Enthalphy (kW)

S12/S13 Hot 452 200 -252 187.680276 -47295.42956

S25/S26 Hot 206 110 -96 148.1324729 -14220.71739

S29/S30 Hot 207.69 110 -97.69 118.0656055 -11533.829

S3/S4 Cold 355.4 750 394.6 145.4674254 57401.44607

S19/S20 Cold 110 320 210 108.3218207 22747.58234

S33/S34 Cold 179.88 360 180.12 105.7033083 19039.27989

Stream S10/S11 which is the stream from secondary reformer to high temperature

shift converter is excluded because it is decided that the heat will be used to generate

71


steam as utilities as it will give better profit.

3.7.6 Corrected Temperature

The corrected temperature for hot streams and cold streams need to be

determined first before calculating the minimum utility requirement.

For hot stream, Corrected temperature = T – (ΔTmin)/2

For cold stream, Corrected temperature = T + (ΔTmin)/2

3.7.7 Problem Table Algorithm

Figure 3-23 shows the problem table algorithm, process the figure the surplus –

source of heat and deficit – heat sink (heat deficiency can be determined).

Interval temp(°C) Streams Delta T Cp(kW/K) Enthalpy(kW) surplus/deficit755

308 145.4674 44803.9592 Deficit447

86.6 -42.2129 -3655.632862 Deficit360.4

-4.6 -187.68 863.3292696 Deficit365

40 -81.977 -3279.078708 Surplus325

122.31 26.34485 3222.23897 Deficit202.69

1.69 -91.7208 -155.0081102 Surplus201

6 -239.853 -1439.119352 Surplus195

10.12 -52.1729 -527.9902449 Surplus184.88

69.88 -157.876 -11032.39289 Surplus115

10 -266.189 -2661.890784 Surplus105

S1/S2

S12/S13

S29/S30

S25/S26

S33/S34

S19/S20

Figure 3-23: Problem Table Algorithm

3.7.8 Heat Cascade

Figure 3-24 shows the heat cascade using manual calculation while Figure 3-25

shows the heat cascade using SPRINT calculation. From the figures, it can be seen

that the pinch temperature is 452°C, the minimum heating requirement is 44804 kW

and the minimum cooling requirement is 20806 kW.

72


745

447

355

115

105

184.88

360.4

195

202.69

201

44803.9592

0

2792.30359

16003.653

18664.5447

4971.26104

3655.63286

4443.27079

6071.3823

3004.15144

PINCH T=452°C

QH min = 44803.9592 kW

QC min= 20805.796kW

0

-44803.9592

-42011.6556

-39832.6982

-28800.3052

-40360.6884

-41118.3263

-41799.8078

-38732.5679

-41954.8159

184.88

447

355

115

105

184.88

360.4

195

202.69

201

184.88

745

20805.796

T (°C) T (°C)

Figure 3-24: Heat Cascade using manual calculation

*Dt min = 10°CMinimum hot utility: 44803.967052 kWMinimum cold utility: 18665.634762 kW

Grand Composite Curve

Temperature Enthalpy---------------------------------------110.000000 18665.634762120.000000 16003.653978189.880000 4971.261074200.000000 4443.270824206.000000 3004.151469207.690000 2849.143397330.000000 6071.382316365.400000 3169.397652370.000000 3461.453757452.000000 0.000000

760.000000 44803.967052

Figure 3-25: Heat Cascade using SPRINT calculation

3.7.9 Grand composite curve

Figure 3-26 and Figure 3-27 shows the combined grand composite curve and

73


grand composite curve. From the grand composite curve, the possible energy saving

can be determined which is the overlapped of the curve.

Figure 3-26: Combined grand composite curves

74


Figure 3-27: Grand Composite Curve

3.7.10 Heat Exchanger Network

In order to build heat exchanger network, Maximum Energy Recovery (MER)

method must be taken into consideration.

For streams above the pinch, CpC > CpH, while

For streams below the pinch CpH > CpC

Furthermore, as a rule of thumb, heat cannot be transferred across the pinch.

Figure 3-28 shows the heat exchanger network for the ammonia production plant.

The red line shows the hot streams those need to be cooled while the blue lines

indicate the cold streams that need to be heated. From the figure, it can be seen that 2

heat exchanger will be used. Besides, another heat exchanger is installed in stream

S10/S11, stream after secondary reformer in order to generate steam as utilities.

75


Figure 3-28: Heat exchanger network for ammonia production plant

Figure 3-29: Heat exchanger after the secondary reformer to generate steam as utilities

3.7.11 Energy saving evaluation

After installing the heat exchangers, the energy saving can be evaluated. Table 3-

17 shows the evaluation of the energy saving.

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Table 3-17: Energy saving evaluation

It is true that hot utilities saving after heat exchanger network is not as

significant as cold utilities saving. However, considering steam is produced as

valuable and important utilities in the plant, thus, the decision is produced steam as

utilities instead of using it in heat exchanger network is justified.

If streams S10/S11 are taken into consideration in heat integration without

considering into generating steam as utilities, a threshold problem will be faced

where there is no heating needed since the hot streams S10/S11 after the secondary

reformer is sufficient to heat most of the streams. However, generating steam using

the abundant heat after the secondary reformer is a common practice in industry and

it is considered as more beneficial than using it in heat exchanger network.

Therefore, the decision of using it for steam generation is justified.

77


4

CHAPTER 4

INSTRUMENTATION AND CONTROL

4.1 Introduction

The plant wide control strategy is designated to maximize the specified

throughput of the plant with the highest purity value that can be achieved. The plant

control strategy is divided into different sections that involve control of different unit

of operations. The control of a process is often accomplished by measuring the

variables (controlled variables), comparing this measurement with the value at which

it is desired to maintain the controlled variables (set point), and adjusting some

further variables (manipulated variables) which has a direct or indirect effect on the

controlled variables.

For the proposed Ammonia production plant, the vital objectives of designing

control system are:

1. To have a safe plant operation and to avoid abnormal operation accident.2. To control the production rate at 678,810 tonnes of ammonia per year.3. To maintain the ammonia product purity above 99 wt%.4. To avoid excess usage of cooling and heating utility.

During operation, the ammonia plant needs to satisfy requirements to guarantee

the satisfaction of the operational objectives above. According to Stephanopoulos

(1984), among such requirements are:

4.1.1 Safety

The safe operation of the ammonia plant is a primary requirement for the

well-being of the people in the plant and for its continued contribution to the

economic development. Thus it is important:

a. To keep the process variables within known safe operation limits.b. To make sure the temperature and pressure at the desired level for

reactor and columns

78


c. To detect danger as they develop and to provide alarms and automatic shutdown systems.

d. To provide interlocks and alarms to prevent dangerous operating conditions.

4.1.2 Production specifications

Continuous control of the process will give the desired amounts and quality

of the final ammonia and carbon dioxide product with the purity specified.

The desired ammonia product purity is 99%.

4.1.3 Environmental Regulations

The federal and state laws have specified that the temperatures,

concentrations and flow rates of the effluents from the plant be within certain

limits. Therefore, for example, control on the quality of the water returned to

a river from the plant is important.

4.1.4 Operational constraints

The various types of equipment used in the plant have constraints inherent to

their operation. Such constraints should be satisfied throughout the operation.

For example the pumps must maintain a certain net positive suction head,

tanks should not overflow or go dry and also the distillation columns should

not be flooded.

4.1.5 Economics

The operation of the ammonia plant should confirm to the market conditions

that are availability of the raw materials and the demand of the final product.

It should be as economical as possible in its utilization of raw material,

energy, capital and human labour. Thus, control strategies are required to

operate at optimum level:

e. To operate at the lowest production cost, corresponding with the other objectives

79


f. To minimize the usage of heating and cooling utility, and thus reducing the utility cost.

All the requirements listed can be accomplished through a rational arrangement of

the equipment (measuring devices, valves, controllers, and computer) and human

intervention including plant engineers and operators which together constitute the

control system.

These are the important terms used in process control:

1. Controlled variables: This variable must be maintained or controlled at desired value also known as set point.

2. Set point: Desired value to be achieved and set earlier.3. Manipulated variable: Variable used to maintain the controlled variable at its

set point.4. Disturbance variable: Any variable that can cause the controlled variable to

deviate from the range of set point.

Seborg (2004) classified the process variables to be either input or output

variables. For section of the controlled variables, the guidelines are:

1. Guideline 1: All variables that are not self-regulating must be controlled.2. Guideline 2: The output variables must be kept within equipment and

operating constraints.3. Guideline 3: The output variables represent a direct measure of product

quality.4. Guideline 4: The output variables interact with other controlled variables.5. Guideline 5: The output variable has favourable dynamic and static

characteristics.

For selection of the manipulated variable from input variables, the guidelines are:

6. Guideline 6: Inputs that have large effect on controlled variable.7. Guideline 7: Inputs that have rapidly effect on controlled variable.8. Guideline 8: The manipulated variable should affect the controlled variable

directly rather than indirectly.9. Guideline 9: Avoid recycling disturbance.

80


4.2 Basic Concept of Advanced Process Control

4.2.1 Feedback Control

Feedback control needs to control one variable and compare with set point.

Correction action occurs regardless of the source and type of disturbance. Due to

figure below, feedback controller measures the controlled variable. In order to

maintain controlled variable at its set point value, feedback controller adjusts

manipulated variable which is the input value. Thus, feedback control takes no

corrective action until a deviation in a controlled variables occurred.

Figure 4-30: Example of feedback control system

4.2.2 Feedforward Control

Feedforward control measure important disturbance variables and take corrective

action before they upset the process. Due to figure below, feedfoward control

measure the disturbance despite the controlled value. It measure disturbance, adjust

input value in order to maintain control variable at its set point value. Feedfoward

control takes corrective action before the process is upset where theoretically capable

of “perfect controller”.

81


Figure 4-31: Example of feedforward control system

4.2.3 Cascade Controller

The disadvantage of conventional feedback control is that the corrective action

does not begin until after the controlled variable deviates from the set point.

Feedforward control offers large improvement over feedback control for process that

has large time constant or delay. However, feedforward control requires that the

disturbance be measured explicitly and a model be available to calculate the

controller output.

And alternative approach employs a secondary measurement point and a

secondary feedback controller. The secondary measurement point is located so that it

recognizes the upset condition sooner than the controlled variables, but the

disturbance is not measured. Particularly useful when disturbances are associated

with manipulated variable or when the final control element exhibits nonlinear

behaviour.

82


Figure 4-32: Example of cascade control system

4.2.4 Ratio Control

Ratio control system is special type of feedforward control system. The main

objective is to maintain the ratio of two process variables at a specified value. The

two variables are usually flow rates, a manipulated variable, U and a disturbance

variable, d.

Figure 4-33: Example of ratio control system

The flow rate of the disturbance stream is measured and transmitted to the ratio

station (RS). RS multiplies this signal by an adjustable gain, K whose value is the

83


desired ratio. The output from RS is used as the set point for the flow controller. The

controller will adjust the input signal to its desired value.

4.3 Ammonia Plant Control System

4.3.1 Introduction

Ammonia plant consists of various kind equipments including vessel, knock

drum, distillation column, reactor, heat exchanger and heater. These equipments are

controlled using several types of controllers which are:

1. Temperature indicator controller (TIC)2. Pressure indicator controller (PIC)3. Flow indicator controller (FIC)4. Level indicator controller (LIC)

Control system for each of equipment is analyzed and the respective P&ID

diagram is attached. The control system includes:

1. Feed control system2. Reactor control system3. Separation system4. Heat exchanger control system5. Recycle stream control system

Figure 4-34 show the overall diagram regarding ammonia production.

84


Figure 4-34: Ammonia production process diagram

4.3.2 Feed Control System

1. Steam and natural gas mixture

Figure 4-35: Steam and natural gas mixture control system

The purpose of the feed control system is to maintain the desired stream flow

rate of steam and natural gas. The flow rates of the streams need to be controlled

before mix up in order to avoid pipe leakage due to over pressure or flood accidents.

Both flow rate of steam and natural gas stream are maintained at a specified value

using ratio control system. As flow rate of the steam is despite from desired value,

valve v-1 will be adjusted in order to maintain the flow ratio between both flow rate

85


before combine.

Table 4-18: Steam and natural gas mixture control strategy

Control Variable

Measured Variable

Manipulated Variable

DisturbanceType of

ControllerFlow rate of natural gas stream

Flow rate of steam and natural gas stream

Flow rate of natural gas stream

Flow rate of steam stream

Ratio controller

4.3.3 Air and reactant mixture

Figure 4-36: Air and reactant mixture control system

After through primary reformer, the mixture needs to be mixed with air in

order to collect Nitrogen compound into the stream for further reaction. The flow

rate of the mixture and the air stream need to be adjusted in order prevent the

runaway reactor condition. Ratio control system is employed here. The flow rate of

mixture stream is controlled since it has higher stochiometric ratio to ensure the

production rate of ammonia.

Table 4-19: Air and reactant mixture control strategy

Control Variable

Measured Variable


DisturbanceType of

ControllerFlow rate of mixture stream

Flow rate of air and mixture stream

Flow rate of mixture stream

Flow rate of air stream

Ratio controller

86


Throughout ammonia production flow, there are several reactors used including:

4.3.4 Primary Reformer Reactor

Figure 4-37: Primary reformer reactor control system

Primary reformer reactor in ammonia plant is endothermic. Therefore, in

order to maintain the temperature to its set point, a furnace system is needed. The

important parameters that are crucial to be controlled in a reactor are temperature and

pressure.

The reactor temperature is affected by changes in disturbance variables such

as reactant feed temperature or feed composition. However, an increase in the inlet

steam water temperature, an unmeasured disturbance, may cause unsatisfactory

performance. So, to improve it, a feedback controller for fuel gas, whose set point is

determined by the reactor temperature controller, will be used. The control system

measures the pressure of fuel gas stream, compares it to the set point value and uses

the resulting error signal as the input to a controller for the fuel gas makeup. The

temperature set points and both measurement are used to adjust a single manipulated

variables which is the fuel gas makeup rate. The process system called Cascade

control system.

The fuel gas flow system is flow out where the used fuel will be transferred to

the tank for storage. The volume of the water inside the tank is controlled by level

87


control system. The fuel will be flowed out to the waste stream as the fuel inside the

tank reaches maximum level.

Table 4-20: Primary reformer reactor control strategy

Control Variable

Measured Variable


DisturbanceType of

ControllerTemperature of R-101

Temperature of R-101 and pressure of fuel stream

Flow rate of fuel gas into reactor

Temperature of the reactant

Cascade controller

4.3.5 Secondary Reformer Reactor

Figure 4-38: Secondary reformer reactor control system

Secondary reformer in the ammonia plant is exothermic. Therefore, in order

to maintain the temperature to its set point, a cooling jacket is needed. The important

parameters that are crucial to be controlled in a reactor are temperature and pressure.


as reactant feed temperature or feed composition. However, an increase in the inlet

reactant stream temperature, an unmeasured disturbance, may cause unsatisfactory

performance. So, to improve it, a feedback controller for jacket temperature, whose

set point is determined by the reactor temperature controller. The control system 88


measures the jacket temperature, compares it to the set point value and uses the

resulting error signal as the input to a controller for the cooling water makeup. The

temperature set points and both measurement are used to adjust a single manipulated

variables which is the water makeup rate. The process system called Cascade control

system.

The cooling water flow system is recyclable where the used water will be

transferred to the tank for storage. The volume of the water inside the tank is

controlled by level control system. The water will be flowed out to the waste stream

as the water inside the tank reaches maximum level. Some of it will be recycled for

cooling system.

The reactor pressure is affected by changes in disturbance variable which is

reactant flow rate and temperature of reactor. The pressure inside the reactor is

measured in order to provide set point value to final control element which is valve.

The valve will be coordinated due to desired value. Feedback control system is

applied. Backup valve is installed as due to failure valve in future.

Table 4-21: Secondary reformer reactor control strategy

Control Variable

Measured Variable


DisturbanceType of


Temperature of R-101 and temperature of cooling jacket

Flow rate of cooling water into jacket


Cascade controller

Liquid level in water surge tank


Flow rate of water out

- Feedback controller

Pressure of R-102

Pressure of R-102 and flow rate of reactant

Flow rate of the reactant

Volume of reactant enter the reactor

Feedback controller

89


4.3.6 High Temperature Shift Reactor

Figure 4-39: High temperature shift converter control system

Heat temperature shift reactor operates at high temperature which is 350C.

After through secondary reformer, the reactant is cooled down through heat

exchanger using water from 1056C to 350C. The important parameter that is crucial

to be controlled in high temperature shift is temperature.


as reactant feed temperature or feed composition. Thus, the water flow into the heat

exchanger needs to be controlled in order to get satisfied value of feed stream

temperature. The temperature inside the reactor is identified and provides the set

point value to the flow meter system in order to control the valve opening. The

control system measure the water flow rate and compares to its set point and uses the

resulting error signal as the input to the valve for valve opening makeup.

90


The pressure inside the reactor is controlled by installing release valve. The

corrective action will be taken as the pressure inside reactor is overpressure by

controlling the opening of release valve. The control system applied is feedback

control system.

Table 4-22: High temperature shift converter control strategy

Control Variable

Measured Variable


Disturbance Type of Controller

Temperature of R-103

Flow rate of water and R-103 temperature.

Flow rate of water into heat exchanger


Cascade Controller




- Feedback Controller

Pressure inside reactor R-103

Pressure inside reactor

Pressure released via release valve

Volume of reactant inside reactorTemperature of reactor

Feedback Controller

91


4.3.7 Low Temperature Shift Reactor

Figure 4-40: Low temperature shift reactor control system

Low temperature shift in the ammonia plant is exothermic. Therefore, in

order to maintain the temperature to its set point, a cooling jacket is needed. The


pressure.

Using the same concept applied in secondary reformer, cascade controller is

implemented in order to control the temperature of low temperature shift reactor.

The pressure inside the reactor is controlled by installing release valve. The

corrective action will be taken as the pressure inside reactor is overpressure by

controlling the opening of release valve. The control system applied is feedback

control system.

92


Table 4-23: Low temperature shift reactor control strategy

Control Variable

Measured Variable


DisturbanceType of





Cascade controller





Pressure of R-104

Pressure inside reactor


Volume of reactant inside the reactorTemperature of reactor

Feedback controller

4.3.8 Methanation Reactor

Figure 4-41: Methanation reactor control system

Methanation reactor in the ammonia plant is exothermic. Therefore, in order

to maintain the temperature to its set point, a cooling jacket is needed. The important

93


parameters that are crucial to be controlled in a reactor are temperature and pressure.


implemented in order to control the temperature of methanation reactor. The pressure

inside the reactor is controlled by controlling the opening release valve for

decreasing pressure level inside the reactor. The control system applies is feedback

control system.

Table 4-24: Methanation reactor control strategy

Control Variable

Measured Variable


DisturbanceType of





Cascade controller





Pressure of R-105


Pressure released via release valve.

Volume of reactant inside the reactor.Temperature of reactor

Feedback controller

4.3.9 Ammonia Synthesis Reactor

94


Figure 4-42: Ammonia synthesis reactor control system

Ammonia synthesis reactor in the ammonia plant is exothermic. Therefore, in

order to maintain the temperature to its set point, a cooling jacket is needed. The


pressure.


implemented in order to control the temperature of ammonia synthesis reactor.

Ammonia synthesis part is including recycle stream system. The flow rates of

the streams need to be controlled before mix up in order to avoid runaway reactor

condition and leakage. Both flow rate of reactant and recycle stream are maintained

at a specified value using ratio control system. The flow rate of reactant stream is

controlled since it has higher stochiometric ratio to ensure the production rate of

ammonia. As flow rate of the steam is despite from desired value, valve will be

adjusted in order to maintain the flow ratio between both flow rates before combine.

The reactor pressure is affected by changes in disturbance variable which is

reactant flow rate and temperature of reactor. The pressure inside the reactor is

measured in order to provide set point value to final control element which is valve.

The valve will be coordinated due to desired value. Feedback control system is

applied. Backup valve is installed as due to failure valve in future.

Table 4-25: Ammonia synthesis reactor control strategy

Control Variable

Measured Variable



Temperature of R-106




Cascade controller





Pressure of R-106



Volume of reactant inside the reactor.Temperature of reactor

Feedback controller

95


Flow rate of reactant stream

Flow rate of reactant and recycle streams

Flow rate of reactant stream

Flow rate of recycle stream

Ratio controller

Besides, throughout ammonia production flow system, there are several separation

process involved including:

4.3.10 Carbon Dioxide Removal

Figure 4-43: Carbon dioxide removal control system

Control strategy for adsorption tower is subjected to flooding and condenser

limit. In separation process, overloading and flooding will cause poor separation.

Therefore, there are two area need to be controlled in adsorption tower.

After the reactant through absorption tower, carbon dioxide inside the stream

is removed and sends to regeneration column for purification. Level control is

installed inside absorption tower in order to prevent flooding accident. Control

system applied is feedback controller.

The flow rates of the streams need to be controlled before going through

regeneration column as to avoid runaway reactor condition. Both flow rate of top

feed and bottom feed stream are maintained at a specified value using ratio control

system. As flow rate of the top feed is despite from desired value, valve at bottom

96


feed will be adjusted in order to maintain the flow ratio between both flow rates

before go through regeneration process.

The carbon dioxide is then collected at the top stream where it will be flow

into a column for temperature and pressure configuration. The temperature of

regeneration column is controlled by manipulating flow out of carbon dioxide at the

top stream. The strategy used is feedback control system.

Table 4-26: Carbon dioxide removal control strategy

Control Variable

Measured Variable



Flow rate of top feed stream (C-102)

Flow rate of top and bottom feed stream (C-102)

Flow rate of steam

Flow rate of top feed stream (C-102)

Ratio controller

Liquid level in absorption tower (C-101)

Liquid level in column

Flow rate of bottom product


Temperature of regeneration column

Temperature of regeneration column

Flow out of carbon dioxide


4.3.11 Water Removal

Figure 4-44: Water removal control system

Many knock up drums are used in ammonia production in order to remove

certain percentage of water from the stream. Knock up drum is then attached to

97


compressor or pump in order to increase the pressure of the reactant. Figure above

shows the water removal system where it consist of 3 main components including

compressor, heater and knock up drum.

In order to remove the water, the pressure and temperature must be reduced.

Feedback control system is applied for both components. The parameters of

temperature and pressure are identified before taking further corrective action.

Control strategy for knock up drum is feedback controller for all the control

system needed. Reactant volume inside the vessel is identified and as it reaches

specified level, the valve will be rearrange at bottom stream so that there is no

flooding inside knock up drum.

Table 4-27: Water removal control strategy

Control Variable

Measured Variable


DisturbanceType of

ControllerLiquid level in knock up drum

Liquid level in knock up drum


- Feedback Controller

Temperature of the stream

Temperature of the stream

Flow rate of the reactant passing through.


Feedback Controller

Pressure of the stream

Pressure of the stream

Flow rate of the reactant passing through


Feedback Controller

98


4.3.12 Ammonia Separation

Figure 4-45: Ammonia separation control system

Control strategy for ammonia separation is feedback controller. Reactant

volume inside the tower is identified and as it reaches specified level, the valve will

be rearrange at bottom stream so that there is no flooding inside absorption tower.

Bottom stream of ammonia separation absorption tower consist mixture of

ammonia and water. Thus knock up drum is used along the flow until storage in

order to remove 100% water and reduce temperature and pressure at storage

conditions. Feedback control system is applied in order to avoid flooding or overload

inside knock-out drum.

Pressure inside absorption tower, V-105 is controlled by manipulating flow

out of the reactant at top product. Control system applied is feedback control system.

Table 4-28: Ammonia separation control strategy

Control Variable

Measured Variable


DisturbanceType of

ControllerLiquid level in absorption tower

Liquid level in absorption tower

Flow rate of bottom product




Flow rate of water flow out


99


Pressure inside tower, V-105

Pressure of absorption tower

Flow rate of top product

Temperature of reactant feed

Feedback Controller

100


5

CHAPTER 5

SAFETY AND LOSS PREVENTION

5.1 Introduction

Ensuring safety in chemical plant is a must. This concern is related to the industry

potential to cause accidents and deaths. For an example, the Bhopal, India tragedy

causes more than 2000 civilian casualties due to the released of methyl isocyanate

(MIC) to atmosphere. MIC is considered as an extremely dangerous compound

which is reactive, toxic, volatile and flammable. 25 tons of toxic MIC vapor

estimated was released, the toxic cloud spread to the adjacent town, killing more than

2000 civilians and injuring an estimated 20,000. (D.A Crowl, 2002) From this

incident, it can be seen that guaranteeing safety is not only important for the

company but also for the civilians. Knowing how an incident can lead to deaths of

people, safety at the workplace should not be taken lightly.

5.2 Safety Issues in Chemical Plants

Considered as one of the most critical issues in chemical plants – safety must be

practiced in line with the safety regulations in order to eliminate accidents and

probability of accidents. Safety starts with people, safety awareness among the

workers and civilians would result in better understanding of the importance of

safety. Safety is an undeniably a very crucial element in a chemical plant. It protects

workers from illness, injuries and deaths while ensuring the survival of company

business.

Therefore, it is a necessity to establish safe working environment in a chemical

plant. Thus, a management team to cater health safety and environment (HSE) must

be developed. The aim of establishing this team is to reduce and eliminate any

undesired accident in the plant.

101


5.2.1 Hazard awareness reducing accident risk

Awareness of the hazards that could happen in a chemical plant can increase the

awareness of the importance of working in a safe environment. For an example,

knowledge about ammonia would lead to better processes handling. Ammonia is

liquefied under pressure in refrigeration systems and liquid ammonia released by

accident may be in the form of an aerosol i.e., small liquid droplets along with

ammonia gas. Behaves as a dense gas even though it is lighter than air, it may travel

along the ground instead of immediately rising into air. Hence, this behaviour may

increase the potential of risk for the exposure of workers and the public. Ammonia

vapours are not flammable at concentration of less than 16%, however, there may be

fire and explosion hazard at concentrations between 16% and 25%). Mixtures of

ammonia vapours contaminated with lubricating oil from the system may have a

much broader explosive range (R.K Gangopadhyay and S.K Das, 2007)

Thus, a training program should be done to ensure the ammonia plant is operated and

maintained by knowledgeable personnel.

5.2.2 Precautions against toxic risk

The precaution against toxic risk can be done in a few ways:

1. Personal Protective Equipment

2. Evacuation and Emergency Procedures

3. Ventilation

4. Training in Plant Operation and Maintenance

These precautions can be taken to avoid undesired accident in an ammonia plant.

Workers should wear personal protective equipment at the designated workplace

without any exception. Besides, an evacuation and emergency procedures should be

prepared which details the precise duties of all staff and the arrangements for

evacuation, rescue, first aid, plant isolation and etc. (R.K Gangopadhyay and S.K

Das, 2007)

For ventilation, normal ventilation should be provided to prevent build-up of

toxic concentration of hazardous gaseous, i.e., ammonia from leakage. Other than

102


that, emergency ventilation provisions should be made for adequate mechanical

ventilation to prevent flammable air mixtures accumulating in the event of

reasonably foreseeable plant or operational failure (e.g., valve failure) (R.K

Gangopadhyay and S.K Das, 2007).

Besides, all personnel involved in the operation and maintenance of the plant

must be sufficiently trained. The training done should cover both general principle of

the plant and specific points related to the particular plant which applies as much to

maintenance contractors as to an employer’s own staff. (R.K Gangopadhyay and S.K

Das, 2007)

5.2.3 Organization for meeting up an emergency

In handling of a plant emergency situation, in house planning, proper education

for the local authority and communication with the surrounding neighbours is must.

An emergency situation cannot possibly be tackle by a group of personnel, thus, the

emergency team should be a collaboration of maintenance, fire, safety and

environment, personnel, security and medical. (R.K Gangopadhyay and S.K Das,

2007) The steps below can be taken for organization to tackle emergency situation:

1. Communication

2. Emergency Control Centre

3. Testing of the Plan by Rehearsing

Communication – in communicating, the terminal manager or manager of the

plant will act as the on-site works main controller (WMC). While, the shift

manager/engineer in charge of the plant will act as the on-site work incident

controller (WIC), the WIC should be familiar with the plant and be readily

recognizable at the scene of the incident. After being alerted by the WIC, WMC

should take charge of the charge of the situation, opening an emergency control room

and the controlling the situation from there. The WMC should be familiar with the

plant and should have the necessary authority to make decisions regarding the

affecting part of the plant and the neighbourhood. After the incidence, the first

person who activated the emergency alarm shall report to the WIC on the location of

the incident. (R.K Gangopadhyay and S.K Das, 2007)103


Emergency Control Centre – Theoretically, the emergency control center (ECC)

should be positioned in a location of minimum risk and with good access both to the

affected side and the outside road system so that the controllers could be reaching

with mluch difficulty. (R.K Gangopadhyay and S.K Das, 2007) The ECC should

comprise of:

Sufficient chairs, tables and stationeries

Several telephones for internal and external communication

The Material Safety Data Sheets (MSDS) of all chemicals used on site

A computer with internet facility for communication and data entry purposes

Radio contact with all sections of the plant

Log book

Important telephone number on display board

Data pertaining to the decision making

Emergency lights

Canned food materials and beverages

Charts for communication network inside the plant and outside localities

Charts for dispersion distances

Diagram to assess weather category, and

Layout map for escape routes, assembly points, location for personnel

protective equipment, site entrance and road systems, medical centre location,

location of fire extinguisher and etc. (R.K Gangopadhyay and S.K Das, 2007)

Testing of the Plan by Rehearsing – The emergency plan must be developed and

distributed to WMC, WIC, fire, safety and environmental, security, medical and

personnel departments, and on-site emergency control room. The plan must be

tested using models and necessary modifications incorporated. An actual mock drill

should follow this exercise. The shortcomings and inadequacies in the plant must be

identified and rectified accordingly. The mock drill done should adequately address

the on-site emergency plant, communication network and procedures, and

coordination between various departments and their roles. On the basis of the mock

drill, all suggestions from various departments/observers/government agencies

should be incorporated to prepare an updated version of the on-site emergency plant

104


for both on-site and off-site. (R.K Gangopadhyay and S.K Das, 2007)

5.3 HAZARD AND OPERABILITY STUDIES (HAZOP)

5.3.1 Introduction

Hazard and operability (HAZOP) analysis was established in the late 1960s at

ICI in UK based on the basic principle of that hazards arise in a plant due to

deviations from normal behaviour. Thus, a group of experts thoroughly identify

every possible deviations from design intent in a plant, find all the possible abnormal

causes and adverse hazardous effects of the deviations (V. Subramaniam et al, 2000)

In HAZOP analysis, hazards assume to arise in a process plant due to deviations

from ‘designers intent’ or from acceptable normal behaviour. It is performed by

systematically examining the process P&IDs in order to determine abnormal causes

and adverse consequences for every conceivable abnormal behaviour of the process

plant. To cover all possible malfunctions in the plant, the process deviations for

HAZOP analysis are generated by systematically applying a set of ‘guide words’ for

examples MORE OF, LESS OF, NONE, REVERSE, PART OF, AS WELL and

OTHER THAN. (R. Vaidhyanatham et al, 1995)

5.3.2 Basic Principle of HAZOP

Initially, the development of the HAZOP techniques was to analyse chemical

process systems, but later been extended to other types of systems also to complex

operations and to software systems (M. Rausand, 2005)

In order to give a significant influence on the design, the HAZOP study should be

carried out in the early stage of the design phase. However, in order to perform a

HAZOP analysis, a rather complete design is needed. Hence, the HAZOP is usually

carried out as a final check when the detailed design has been completed. A HAZOP

study may also be conducted on an existing facility to identify modifications that

should be implemented to reduce risk and operability problems (M. Rausand, 2005)

The HAZOP studies may be used during these stages (M. Rausand, 2005):

105


1. At the initial concept stage when design drawings are available

2. When the final piping and instrumentation diagrams (P&ID) are available

3. During construction and installation to ensure that recommendations are

implemented

4. During commissioning

5. During operation to ensure that plant emergency and operating procedures are

regularly reviewed and updates as required

5.3.3 Process HAZOP

In order to conduct a HAZOP study, the following information should be available

(M. Rausand, 2005)

1. Process flow diagrams

2. Piping and instrumentation diagrams (P&IDs)

3. Layout diagrams

4. Material safety and data sheets

5. Provisional operating instructions

6. Heat and material balances

7. Equipment data sheets start-up and emergency shut-down procedures

5.3.4 HAZOP procedure

The procedure of HAZOP can be broken into these steps (M. Rausand, 2005):

1. Dividing the system into sections (i.e., reactor, storage)

2. Choosing a study node (i.e., line, vessel, pump, operating instruction)ent

3. Describing the design intent

4. Selecting a process parameter

5. Applying a guide-word

6. Determining cause(s)

7. Evaluating the consequences or problems

8. Recommending actions

9. Recording the information

106

NOT SURE

Divide system into study nodes

Select a study node

Apply relevant combinations of guide words

Need more information

Record the consequences and causes and suggest remedies

YES

NO


10. Repeating the procedure (from step 2)

Figure 5-46: Illustration of HAZOP procedure (M. Rausand, 2005)

Figure 5-46 shows the illustration of HAZOP procedure. It starts according to the

numbering in the previous section.

Modes of operation

In HAZOP, the following modes of plant operation should be considered for each

node:

1. Normal operation

2. Reduced throughput operation

3. Routine start-up

4. Routine shutdown

5. Emergency shutdown

6. Commissioning

7. Special operating modes

107


5.3.5 Worksheet entries

Node – A node is a specific location in the process in which (the deviations of) the

design/process intent are evaluated. (For examples, separators heat exchangers,

scrubbers, pumps, compressors, and interconnecting pipes with equipment) (M.

Rausand, 2005)

Design Intent – The design intent is a description of how the process is expected to

behave at the node; this is qualitatively described as an activity (e.g., feed, reaction,

sedimentation) and/or quantitatively in the process parameters, like temperature, flow

rate, pressure, composition, etc. (M. Rausand, 2005)

Deviation – A deviation is a way in which the process conditions may depart from

their design/process intent. (M. Rausand, 2005)

Parameter – the relevant parameter for the condition(s) of the process (e.g. pressure,

temperature, composition)

Guideword – a short word to create the imagination of a deviation of the

design/process intent. (M. Rausand, 2005)

Safeguard – facilities that help to reduce the occurrence frequency of the deviation or

to mitigate its consequences. There are 5 types of safeguards in principle (M.

Rausand, 2005):

1. Identifying the deviation (e.g., detectors and alarms, and human operator

detection)

2. Compensating for the deviation (e.g., an automatic control system that

reduces the feed to a vessel in case of overfilling it which is usually an

integrated part of the process control)

3. Preventing the deviation from occurring (e.g., an inert gas blanket in storages

of flammable substances)

4. Preventing further escalation of the deviation (e.g., by (total) trip of the

activity. The facilities are often interlocked with several units in the process,

often controlled by computers)

5. Relieving the process from the hazardous deviation (e.g., pressure safety

108


valves (PSV) and vent systems)

5.3.6 Process parameters

Process parameters can be classified into the following:

Physical parameters related to input medium properties

Physical parameters related to input medium conditions

Physical parameters related to system dynamics

Non-physical tangible parameters related to batch type processes

Examples of process parameters are flow, pressure, temperature, mixing, stirring,

transfer, level, viscosity, reaction, composition, addition, separation, time, phase,

speed, particle size, measure, control, pH, sequence, signal, start/stop, operate,

maintain, services and communication. (M. Rausand, 2005)

The basic HAZOP guide-words are:

Table 5-29: The basic HAZOP guide-words (M. Rausand, 2005)

Guide-word Meaning Example

No (not,

none)

None of the design intent is

achived

No flow when production is

expected

More (more

of, higher)

Quantitative increase in a

parameter

High temperature than designed

Less (less of,

lower)

Quantitative decrease in a

parameter

Lower pressure than normal

As well as

(more than)

An additional activity occurs Other valves closed at the same

time (logic fault of human error)

Part of Only some of the design

intention is achieved

Only part of the system is shut

down

Reserve Logical opposite of the design

intention occurs

Back-flow when the system shuts

down

Other than Complete substitution – another Liquids in the gas piping

109


(other) activity takes place

5.3.7 Selected node

In our case, three HAZOP nodes selected, which are the syngas compressor before

entering the ammonia converter, the ammonia converter itself and the ammonia

absorption tower in order to separate ammonia from the unreacted syngas.

These nodes are selected due to the fact that they are very essential to the process in

the production of ammonia. If the pressure cannot be increased, the desired process

cannot be achieved and therefore the conversion of syngas in the ammonia converter

fails. Besides, after the process, ammonia separation from the other unreacted

syngas. Due to these fact, those node are selected.

110


Figure 5-47: Study node 1- syngas compressor

5.3.8 HAZOP Analysis: Node 1

HAZOP study HAZOP analysis on node 1

111


Node 1 – compressor

Intention Suppy 11501.22 kPa of syngas to the compressor at the desired temperature to increase the pressure

ParametersGuide

WordsDeviation Possible causes Consequences Recommendation Safeguards Action required

Action

assigned to

FLOW

NO No Flow

1.Valve opening failure of stream 34 (S34) before entering CP104

2.Line blockage of S34

3.Pipe fracture and large leakage of S34

1.Decrease pressure-pressure increment not accomplished

2.Decrease temperature – desired pressure not accomplished.

1.Install flow indicator at S34

2.Install low flow alarm at S34

If manually

handle

condition,

PPE must be

worn

Bypass S34 pipe

into the

compressor

Engineer/

Technician

LESS Less Flow 1.Control valve Oof S34 failed in partially open position

2.Leakage in pipeline at S34

3.Pressure control system

1.Decrease pressure – desired pressure increment not accomplished

As “No Flow” As “No

Flow”

As “No Flow” Engineer/

Technician

112


failure at S34 2.Increase temperature- possible compressor overheated

MORE More flow

1.Valve closing of partially open valve of S34 failed

2.Check valve of S34 defect

3.Pressure controller system failure of S34

1.Compressor overload –possible compressor overheated

2.Vibration in compressor – possible reactor rupture

3.Increase pressure- possible compressor overpressure

4.Increase temperature-possible compressor overheated

1.Install flow indicator

2.Install high flow alarm

As “No

Flow”

Manually control

the opening of

S34 valve

Technician

REVERSE Reverse

Flow

1.Backflow due to back pressure from downstream S35

2.Check valve

1.Breakdown or leakage in compressor


As “No

Flow”

Manually control

the opening of

S35 valve

Engineer/

Technician

113


defect of S353.Pressure

control system failure of S35

TEMPERATURE

LESSLess

Temperature

1.Failure of previous cooler E-110 (more cooling water flow)

1.Decrease pressure in compressor- desired increment in pressure is not accomplished

1.Install temperature controller

2.Install pressure controller

3.Install low pressure alarm

4.Install low temperature alarm

Wear appropriate PPE if manually dealing with the equipment

Manipulate the

flow to stabilize

the temperature

Technician

MORE

More

Temperature

1.Failure of E110 (less cooling water flow)

1.Increase pressure – possibly compressor overpressure, may lead to rupture

As “ Less

Temperature”

Monitor

HIPS as to

determine

either

process

intervention

or total

shutdown is

needed

As “Less

Temperature”

Technician

PRESSURE LESS Less

Pressure

2.Undetectable leakage in pipeline (low

1.Decrease temperature- desired

As “Less

Temperature”

As “Less

Temperature

Bypass the S34

pipeline

Engineer/

114


flow) in S343.Valve opening

failure of S34

increment is not accomplished

2.Reverse flow- possibly compressor vibrating

” Manually control

valve opening of

S34

Technician

MORE

More

pressure

1.Control valve opening failure of S34 (fail-to-close)

2.High feed S34 temperature entering the compressor

1.High temperature- compressor oveheated

2.Compressor ruptured

1.Install temperature controller

2.Install pressure controller

3.Install high pressure alarm

4.Install low temperature alarm

As “Less

Temperature

”

Manually control

S34 valve

opening

Technician

115


Figure 5-48: Study node 2 – ammonia converter

116




Node 2 -ammonia converter

Intention Supply 25000kPa syngas into the reactor at desired temperature and flow

ParametersGuide

WordsDeviation

Possible

causesConsequences Recommendation Safeguards Action

Action

assigned to

FLOW

NO No Flow

1.Valve opening failure of stream 37 (S37)


3.Pipe fracture and large leakage of S37

1.No significant effect – Desired process is not accomplished


2.Install low flow alarm

If manually

control the

valve

opening,

proper PPE

must be

worn

Manually control the

valve opening of S37

if control system

failure

Bypass the S37 if

line blockage/

fracture/leakage

Engineer/

Technician

LESS Less Flow 1.Control valve failed in partially open of S37 position

2.Line leakage of S37

1.Less pressure inside converter – Desired process is not accomplished.

1.Install pressure control system


As “No

Flow”

Control the valve

opening of S37

Bypass the S37 line

if line blockage/

Engineer/

Technician

117


fracture/leakage

MORE More Flow

1.Valve closing of partially closed of S37 failure

1.Overpressure – possibly reactor runaway

2.Increase temperature – possibly reactor runaway

3.Converter ruptured

4.Converter breakdown


2.Install temperature control system

3.Install high pressure alarm

4.Install high temperature alarm

Monitor

HIPS as to

determine

either

process

intervention

or total

shutdown is

needed

Control the S37

valve opening

Technician

REVER

SE

Reverse

flow

1.Backflow due to high pressure at R106 downstream

1.Feed accumulated before entering due to high pressure inside reactor

1.Install syngas pressure control system

As “No

Flow”

Control the syngas

pressure output

Technician

TEMPERATURE LESS Less

Temperatu

re

1.Failure of cooling system of R106 (fail-to-close)

2.Pressure control system

1.Less pressure inside convertor- desired process is not accomplished

1.Install temperature control system at cooling system

2.Install alarm indicator for low

As “No

Flow”

Decreease volume of

cold water into

cooling jacket

Control feed S37

valve opening

Technician

118


failure of R106 (fail-to-open)

temperature

MORE

More

Tempreatu

re

1.Cooling system failure of R106 (fail-to open)

2.Pressure control system failure of R106 (fail-to-close)

1.High pressure inside converter- possibly reactor runaway

2.Overheated –possibly runaway

1.Install temperature control system

2.Install alarm indicator for high temperature

Monitor

HIPS as to

determine

either

process

intervention

or total

shutdown is

needed

Increase volume of

cold water entering

cooling jacket of

R106

Control feed S37

valve opening

Technician

PRESSURE

LESSLess

pressire

1.Valve opening failure of S37

1.Low temperature inside converter


2.Install alarm indicator for low pressure

As “No

Flow”

Increase S37 valve

opening

Technician

MOREMore

pressure

1.Valve closing failure of S37

1.High temperature inside reactor

2.Reverse flow


2.Install alaram indicator for low pressure

As “No

Flow”

Decrease S37 valve

opening

Technician

119


Figure 5-49: Study node 3 – Ammonia absorption tower

120




Node 3 Absorption tower

Intention Supply ammonia gas with unreacted syngas to the separator at desired temperature, pressure and flow

ParametersGuide

WordsDeviation

Possible

causesConsequences Recommendation Safeguards Action required

Action

assigned

to

FLOW

NO

No Flow 1.Valve opening failure of stream 38(S38)



1.No significant effect – the desired process not accomplished

1.Install flow control system


If

manually

control the

conditions,

proper PPE

must be

worn

Increase feed valve

opening of S38

Bypass the S38 line

if

blockage/leakage/ru

ptured

Engineer/

Technician

LESS Less Flow 1.Valve opening failure of S38


1.No significant effect- the desired process not accomplished

As “ No Flow” As “No

Flow”

As “No Flow” Engineer/

Technician

121



MORE

More Flow 1.Valve closing of partially closed failure of S38

1.Increase pressure- possibly absorber overpressure

2.Increase temperature- possible overheated

3.Increase level of ammonia aqueous inside the absorber- possible causing flooding

4.Reverse flow containing liquid aqueous ammonia back to converter causing reactor runaway

1.Install flow control system at ammonia aqueous outlet

2.Install high flow alarm

Monitor

HIPS as to

determine

either

process

interventio

n or total

shutdown is

needed

Increase ammonia

aqueous outlet

valve opening of

S38

Technician

REVERS

E

Reverse

flow

1.Valve opening

1.Reverse flow containing

1.Install flow control system at ammonia

As “No

Flow”

As “More Flow” Technician

122


failure of S38

aqueous ammonia into feed gas pipe – possibly flow to converter causing runaway

aqueous outlet2.Install high level

alarm

TEMPERATURE

LESS

Less

Temperatur

e

1.Cooler failure before entering the V105

1.Low pressure in absorber – desired process not accomplished

1.Install pressure control system ( to control temperature)

2.Install alarm for low temperature

As”No

Flow”

Decrease the flow

of the cooling into

the cooler

Technician

MORE

More

Temperatur

e

1.Cooler failure before entering the V105

1.High pressure in the absorber- overpressure – possibly absorber ruptured

1.Install pressure control system (to control temperature)

2.Install alarm for high temperature

Monitor

HIPS as to

determine

either

process

interventio

n or total

shutdown is

needed”

Increase the flow of

the cooling water

into the cooler

Technician

PRESSURE LESS Less

Pressure

1.Valve opening failure at Stream 39

1.Low temperature in the absorber-


2.Install alarm for low pressure

As “ No

Flow”

Decrease the

opening of the

valve at the top

Technician

123


(S39)2.Cooler

failure before entering the V105

Desired process is not accomplished

product of the

absorber

Decrease the flow

of the cooling water

into the cooler

MORE

More

Pressure

1.Valve opening failure at the S39

2.Cooler failure before entering V105

1.High pressure in the absorber – overpressure- possibly causing absorber ruptured.


2.Install alarm for high pressure

As “No

Flow”

Increase the

opening of the

valve at the top

product of the

absorber

Decrease the flow

of the cooling water

into the cooler

Technician

124


5.4 Plant Layout

5.4.1 Introduction

The location of the plant is the key in order to achieve and maintain the overall

profitability of the future constructed plant. The designated plant layout must

consider on the expansion slot to make up with the future demands. There are plenty

of factors need to be consider before choosing the location of the plant. Below is the

factor considered:

1. Location, with respect to the marketing area

2. Raw material supply

3. Transport facilities

4. Availability of labor

5. Availability of suitable land

6. Environmental impact and effluent disposal

7. Local community consideration

8. Climate

9. Political and strategic consideration

The Ammonia plant is to be located at Gebeng, Kuantan, Malaysia which occupies

about 104000 m2 (400 m x 260 m). Generally, the site layout can be divide into two

parts:

1. Process Area

2. Non-Process Area

The plant layout is designed referring to PETRONAS Technical Standard (PTS) as

the main guideline. PETRONAS Technical Standard (PTS) is a complete guideline

for technical issues and several section have been used appropriately for constructing

the plant layout xxxxx. The main factors of plant layout design can be summarize as

follow:

To maximize safety in plant

125


To facilitate feasible plant operation and management

To minimize construction cost

To consider future expansion.

From PTS, such as all processing units, reactor, cooling tower and utilities plant are

spaced at least at minimum distance. In example the storage area that contains

hazardous materials such as ammonia should be sited at least 70m from the site

boundary. It is important to comply to these as the minimum clearance suggested put

safety consideration first. For instance, 100ft around the flare is required as flare is

an area where combustion occurs; ignition of flammable gas and effective heat

transfer via radiation at the high temperature making fire hazards more likely to

occur. In addition, it is also specified that the dike capacity must be 10% more than

the largest tank in the tank farm. Knowing that dike is actually a drain used to

capture the liquid chemical, a 10% safety factor is needed so that leaked liquid are

contained as much as possible.

Besides the location of the plant, the effective layout design of the plant ensure the

viability of the plant to run in a long term period.The economic construction and

operation of a process unit will depend on how well the plant equipment specified on

the process flow sheet and laid out. From the general factor stated earlier, below are

the details need to be consider in designing the plant layout:

No. Factor Description

1 Costs The cost of construction can be minimized by adopting a layout that

gives shortest run of connecting pipes between equipment, and

adopting the least amount of structural steel work. However, the

distance between the reactor or vessel must not be less than a

minimum requirement for safety measures.

126


2 Process

requirement

All the required equipments have to be placed properly within

process. Even the installation of the auxiliaries should be done in

such a way that it will occupy the least space.

3 Operation Equipment that needs to undergo frequent monitoring should be

located closed to the control room. Manual valves and sample

points should be located at convenient position and height.

Sufficient working space and headroom must be provided to allow

easy access to the specific access space.

4 Maintenance Heat exchangers need to be sited so that the tube bundles can be

easily withdrawn for cleaning and tube replacement. Equipment

that requires dismantling for maintenance, such as compressors and

large pumps, should be placed under cover. Vessels that require

frequent replacement of catalyst or packing should be located on

the outer of the plant area

5 Safety Blast walls may be needed to isolate potentially hazardous

equipment, and confine the effects of an explosion. At least two

escape routes for operator must be provided from each level in the

process building.

6 Modular

construction

In recent years, there has been a move to assemble sections of the

plant at the manufacturer site. These modules will include the

equipment, structural steel, piping and instrumentation. The

modules then transported to the plant site, by road or sea.

7 Plant Equipment should be located so that it can be conveniently tied in

127


expansion with any future expansion of the process. Space should be left on

pipe alleys for future needs, service pipes oversized

to allow for future requirements.

.

5.4.2 Plant Arrangement Description

Non-Process Area

Revolving Gate

There are 2 revolving gates in the plant and the only access to the process

area. The purpose is to control and monitor all the personnel in and out of the

process area. It is electronically controlled for record and security reason. The

gates only allow the authorized employees to access via their personal card

issued by human resource department. For the visitors, they only can access

the gates by requesting “visitor card” from security department. Any

personnel can be listed and tracked especially in emergency situation.

Guard post

Guard posts are located at the entrance of the site. Indeed, the security

checkpoints are important to ensure no unauthorized access whether into

administration building or the process area. There are 2 guard posts in this

site:

1. Main entrance guard post – to control the flow in and out of personnel or cars

between the site and public area. Besides, it is the mere access to the

administration building.

2. Process area/Contractor guard post – security check to ensure that there is

no hazardous or undesired materials being brought into the process area.

Besides, contractors who possess permits will be allowed to enter the process

area at different entrance with their heavy transport such as crane and lorry. It

128


is a common practice in some places where personnel should have a ‘safety-

briefing’ card or permit to be allowed to enter the process site.

Administration Building

Administration office building is located quite distance away from the

process area. This is to minimize to any occurrence of explosion and fire

hazard since this is the place where a lot of personnel. This building is

intended to locate all employees which are non-technical such as plant

managers, human resource and Information technology personnel.

Cafeteria

Located in the non process area and can be accessed by all employees in both

process and non-process area.

Clinic

The location of clinic has been chosen in convenient place and can be reached

easily either from the process area or non-process area. It offers emergency

and fast treatment to the injured employees before being sent to the nearest

hospital for further treatment.

5.4.3 Process Area

Process area is the area where ammonia will be produced. Thus, this is a

hazardous area since it deals with a lot of chemicals as well as heavy

machines. Besides, arrangement and location of main process site as well as

other ancillary buildings are done carefully. Process area is divided into 2

main areas which are Inside Battery Limit (IBL) as well as Outside Battery

Limit (OBL). Below are the units and buildings in the Process Area:

129


1) Inside Battery Limit (IBL)

IBL is the area where the main process of ammonia production takes place. In

addition, there are 9 areas locating all major equipments and units which are divided

into Area1, Area 2, Area 3, Area 4, Area 5, Area 6, Area 6, Area 7, Area 8, and Area

9.

Area 1 – Primary Reformer/ Furnace

Area 1 is the major processing unit where the synthesizing of natural gas into

methane gas takes place. The main equipment in this area is a side-burner furnace to

maintain high feed temperature in the reactor for desired methane conversion. The

outlet of the furnace will be sent to the secondary reformer.

Area 2 – Secondary Reformer

Area 2 consists of compressor, secondary reformer and heat exchanger for generating

steam. Here, the NG will be compressed and be further goes methane-formation

process in secondary reformer. Then, the syn gas will passes through heat exchanger

for generating steam for the usage as feed stream of the primary reformer.

Area 3- HTS and LTS/ Carbon monoxide conversion

Area 3 consists of two reactors for further conversion of generated carbon monoxide

to hydrogen. In the area, from the secondary reformer, the carbon monoxide undergo

water gas shift conversion through the two reactor for optimum conversion under

two different condition. The syngas from HTS passes through two heat exchanger

which is located in Area 5. The syngas the entering LTS and leaves for acid gas

removal stages.

Area 4- Carbon Dioxide/Acid gas Removal

Carbon dioxide removal consists of 2 main column which are absorber column and

stripper column for regeneration of amine. In the stage, the carbon dioxide is

130


absorbed by amine reactive solvent. The rich solvent then floe through the bottom of

the absorber column and being regenerated in the stripper column before flow back

into as lean solvent. The treated gas is then flow to the pressure knockout drum.

Area 5- Pressure Knockout Drum, Heat exchanger and Methanator

Methanator is used to convert the left carbon monoxide to methane. Pressure

knockout drum is used to drain out water content in the flow composition. It is

mainly to increase the purity of the hydrogen nitrogen before the ammonia synthesis

takes place. The heat exchanger is place in the middle of the processing plant area for

the close flow transport to connect between two area or equipment. In the area also

consist compressor for increase the flow pressure stage by stage before entering the

ammonia converter.

Area 6 – Ammonia Converter and Separation Unit

Area 6 consists of 4 major equipments which is compressor, ammonia converter,

absorber column and distillation column. The compressor set the pressure to ideal

condition of 250 bar for ammonia synthesis in the converter. The synthesis ammonia

then absorb by flash with water in the absorber column. Then flow through

distillation column for separation of ammonia. Then flow through the pressure

knockout drum for purification of ammonia by water drainage. The ammonia then

flow through stages of cooler and valve to decrease temperature and pressure for the

storage purpose. Then, the pure ammonia liquid will be sent to the ammonia tank

which located in tank farm.

2) Outside Battery Limit (OBL)

This area locates all the supplementary and supportive process systems such as

utilities and wastewater treatment unit.

131


No Area Description

1Utilities

This unit will supply cooling water as well as high

pressure steam to the main process unit. Thus, it

contains several equipments such as cooling towers and

burners.

2

Water

Treatment Unit

This unit will process the raw water from supplier in

order to produce different specification of water quality

for different uses such as demineralized water etc.

3

Wastewater

Treatment Unit

The wastewater effluent from the process unit will be

sent to Wastewater Treatment Unit to be treated before

being released to the environment.

4 Laboratory

Quality of feed and product should be taken into

considerations. Laboratory is the place where the

sample for both feed and product is tested and analyzed

to determine its specifications. All the result will be

sent to the control room and some adjustments in

controlling will be made, if needed. Thus, the distance

between laboratory and control room is close.

Laboratory workers will also perform an analysis

regarding waste of the process before being released to

nearby environment.

5Chemical

storage

These vessels store chemical substances, lubricants, and

catalyst pellet used for the process. Thus, it is located

closed to the process unit.

6Storage farm

Storage farm or Tank Farm consists of some big tanks.

These tanks store the product before being exported.

Storage farm is located away from the major processing

unit to avoid explosion hazard.

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7Pump house

The pump house contains pumps used to control the

material stream flow between the process units with the

storage farm.

8Control room

All the control valves for the whole process area will be

controlled and monitored from this central control

building. Even it is near to the main process area, it still

can be considered as a safe place since it is provided

with explosion proof doors and very thick concrete

walls.

9Emergency

control room

In case of emergency occurs in the plant, control room

will be the assembly point in the process area.

9Fire water tank

There is a fire water pond inside the process area

nearby the utilities area. It will be used for emergency

cases such as fire, explosion etc.

10Flares Area

Flares or venting area is used to vent all excess gases

that are emitted from the process units and burnt before

being released to environment. In our plant, the flares

area is located at back of the area to avoid effect of

wind blowing into non-process area.

11Warehouse

Warehouse stores all the equipment’s spare parts. It is

placed near to the workshop to ease the maintenance

job.

12Expansion Site

There are some free areas allocated for the future plant

expansion. They occupy enough space for further

expansion, whether for process reaction or producing

the plant’s own utility such as steam production.

13 Assembly point There are a few zones that have been identified to be as

assembly area. Assembly points are located for every

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personnel to gather in case of emergency occur, and the

assembly areas are located in both process area and

non-process area. For the non process area, the

assembly points are determined to be in front of the car

park and administration building compound.

14

Emergency

Exit

It is a common practice to have some alternatives way

to exit from the chemical plant. In this site, there are

three emergency exits available, two of them are

provided in the process area while the other one is near

to the workshop building.

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6

CHAPTER 6

WASTE TREATMENT

6.1 Introduction

Waste generated in a plant are divided into three type, solid, effluent and gaseous

waste. In order to obey the regulation, we need to make sure that the waste is handled

according to the rules set by Department of Environment (DoE). In ammonia plant,

we won’t be producing much solid waste and gaseous waste since we are dealing

with mixture and liquid form.

6.2 Waste Identification

There are usually three types of wastes produced by chemical plant. The three wastes

are Solid Waste, Liquid Waste (effluent) and Gas Waste.

1. Solid Waste: Any of a variety of solid materials as well as some liquid in

containers, which are discarded or rejected as being spent, useless, worthless

or being excess

2. Liquid Waste: Waste in the form of liquid and usually is not needed

anymore in a process plant.

3. Gaseous waste: Waste in form of gas and usually is not needed anymore in a

process plant

After doing a study of ammonia plant, we manage to identify a few o components

that can be classified as waste. Below are the materials that we detected as potential

waste:

6.2.1 Solid Waste

For our plant, there’s not much solid waste produce since we are always handle

the material in liquid and mixed form. However, in our plant we use some catalyst.

This catalyst will need to be change after they’ve reached at the end of their lifespan.

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However, this is not considered as mere solid waste since the catalyst is hazardous

material. We need to handle the catalyst as hazardous solid waste and not mixed it

with another solid waste so that the solid waste will not become another Hazardous

Waste. Disposing hazardous wastes are expensive compared to Solid Waste.

6.2.2 Liquid Waste

In our Ammonia plant, liquid wastes are more likely since most of our materials

are in liquid form. For example, the water that is disposed from the condenser is not

100% water. It usually has some other composition such as dissolved Ammonia,

dissolved Carbon Dioxide and others. So this water cannot be disposed directly and

needs to be treated first to reduce the amount of other component before being

discharged to the ground.

6.2.3 Gaseous Waste

The main source of gaseous ammonia emission is from the inert gas purge and

from the ammonia storage section of the ammonia plant. In the case of non-

functioning or breakdown of the equipment, large quantity of ammonia emission

increases ammonia concentration in the atmosphere.

Table 6-30: Identification of Waste by Operation

Source/Operation Pollutants Potential HazardCondenser Dissolved

AmmoniaMay cause suffocation to aquatic life form

CO2 Removal Carbon Dioxide May cause suffocation to aquatic life formAmmonia Storage Ammonia Gas Ammonia that comes into contact with

human skin will react to form Ammonium Hydroxide and can cause corrosion. Can cause death if inhale at a long time.

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6.2.4 Others Waste

There is also another waste that needs to be taken into account such as:

Table 6-31: Miscellaneous Waste

Waste Types

Sources Contaminant

Solid Non-process area Municipal solid waste (garbage)Liquid Cooling Wastewater Water with High Temperature

Non-process area Domestic wastewaterBackwash Contaminated waterOil from mechanical parts

Oil from mechanical parts may mix with water thus contaminated the water

Gas Steam Reboiler Vent gas, usually water vapor

6.3 Laws and Regulations

Generally, the statutory requirement that needs to be complied is the

Environmental Quality Act 1974 (EQA 1974). Under this act, all industries in

Malaysia have to comply with the regulations stated under this act and the failure to

do so will cause them penalty. There are 3 main subsidiary regulations that need

attention, namely

1. Environmental Quality (Clean Air) Regulation 1978

2. Environmental Quality (Sewage and Industrial Effluent) Regulation 1979

3. Environmental Quality (Scheduled Waste) Regulation 1989.

Following the enactment of the act, the Department of Environment (DOE) is

established to administer and enforce the act. Hence, any consultation regarding

environmental issues and regulations should be made to them.

6.3.1 Liquid Wastes

The effluent that to be released to Malaysian water needs to comply with

Environmental Quality (Sewage and Industrial Effluents) Regulations, (Regulation

8(1) Third Schedule, Standard A, EQ 1979). Since we decided to discharge the waste 137


to the drain, we need to make sure that the wastes complied with the regulation as

stated in the law. This is also to make sure that no bad effect will be caused to the

surrounding area. The main consideration of wastewater treatment system is the

COD and BOD value. Below are the Standard sets in Environmental Quality

(Sewage and Industrial Effluents) Regulations. Be informed that the list present

below are the list of the parameter needed to be taken note in Ammonia Plant and not

representing all the compound mention in the law book.

Table 6-32 Standard A and B Values of Environmental Quality Act 1974

Parameter Unit Standard A Standard B

Temperature ˚C 40 40

pH value - 6.0 - 9.0 5.5 – 9.0

BOD5 at 20˚C mg/L 20 50

COD mg/L 50 100

Suspended solids mg/L 50 100

Oil and Grease mg/L Not Detectable 10

Since the waste water are going to be discharged in a drain in Baluk area which are

near to Sungai Baluk, according to regulation, the Standard A will applied to the

effluent from Ammonia Plant

6.3.2 Solid Wastes

Environmental Quality (Scheduled Wastes) Regulations 1989 requires that scheduled

wastes be treated and disposed of at facilities approved by Department of

Environment (DOE). Presently most local authorities in Malaysia dispose solid

wastes in landfills. For industry, waste is normally sent to Kualiti Alam Sdn Bhd

which responsible in handling scheduled waste and waste disposal. The off-site

treatment and disposal of scheduled wastes is operated by the Integrated Scheduled

138


Waste Management Centre (WMC) at Bukit Nanas, Negeri Sembilan. There are

many ways for handling the solid wastes. For non-hazardous solid wastes, we can

send the waste for incineration, solidification or send to a landfill. For Hazardous

Solid Wastes, it is necessary to send it for a physical or chemical treatment first to be

transformed into solid waste or other form that won’t affect people’s life negatively.

In Malaysia, Kualiti Alam Sdn. Bhd are responsible in handling industry’s related

wastes. As a matter of fact, the facility has been awarded 10 years consensus until

2010 to treat all scheduled wastes generated in the country.

6.3.3 Gaseous Wastes

Environmental Quality (Clean Air) Regulation 1978 has lined out rule about the limit

of certain component that needed to be aware of its emission to environment.

However, none of the component listed are present in our Ammonia plant. However,

we cannot be sure if the dark smoke will be produced in the plant. If the dark smoke

does produced, then the limits shall follow the standards. Table below is the

standards for dark smoke permissible in plants.

Table 6-33: Standards of Dark Smoke permissible in plants

Substance Emitted Source of Emission Standards

Dark Smoke Equipment using non-solid fuel

Ringelmann

Chart No. 1 for

new facilities

Ringlelman Chart No. 2 for existing facilities

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6.4 Wastewater Treatment Strategy

In handling the wastes, we have divided the section into three parts. First are the

Effluent treatment, Solid Waste Handling and Gaseous waste treatment.

6.5 Waste Water (Effluent) Treatment Process Flow Diagram

Figure 6-50: Waste water Treatment Flow Diagram

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6.5.1 Waste Water Treatment Process

Waste water for an Ammonia plant is usually storm water, cooling water and

wastewater in manufacturing process. Generally, the effluents produced by Ammonia

plant are not very hazardous to the environment. In treating the effluent, we have

several steps that need to be done before the effluent can be discharged to the drain.

First, the contaminated water will go through oil separator to remove the oil that is

mixed with the effluent. The oil may come from mechanical part in the plant. The oil

that has been separated from waste water may be disposed accordingly or being reuse

for another purpose.

After oil removal, the waste water will be sent to the equalization basin. Here, the

waste water will be mixed with sewer water. The purpose of this basin is to reduce

the variation in the flow and the composition of the waste water before sending it to

the next stage of treatment. It can also act as stabilizer of the flow as well as create

uniformity of the inlet in term of quality of water such as BOD. Next, the wastewater

will be sent to the neutralization basin. The pH of the waste water will be reduced or

will be increase accordingly until the waste water become neutral using Caustic Soda

(NaOH) and Sulfuric Acid (H2SO4). Other than that, we also add Alum to act as

flocculants to bring together many suspended solid to form a larger suspended solid

The wastewater will then send into coagulant basin. The waste water will be

mixed with polymer to bring together the large suspended solid from the flocculation

process to larger suspended solid. The wastewater will be separated between the

waste water and sludge in the thickener. The sludge will be sent to the sludge basin

while the effluents are sent to final pH adjustment basin. The sludges in the sludge

basin are then sent to dehydrator to further remove the effluent leaving only the

sludge cake. The remaining effluent will be sent to equalization basin along with the

sewer water. The sludge cake will be sent out to Kualiti Alam Sdn Bhd as solid

waste.

In Final pH Adjustment Basin, the pH of the waste water are measured to make

sure that the waste water are safe to be discharged to environment. If the pH are

measured to be more or less than the standard, Caustic Soda (NaOH) and Sulfuric

141


Acid (H2SO4) will be added to make sure that the pH of the waste water are safe to be

released to the drain. Waste water is then sent to Treated Waste Water Effluent Basin

before being discharged to the drain.

6.5.2 Solid Wastes Handling

Dewatered sludge from waste water treatment and catalyst is classified as

scheduled wastes from specific source under Environmental Quality (Scheduled

Wastes) Regulations, 1989. Other scheduled wastes are spent chemicals, lab

chemicals and batteries containing materials that are hazardous to the environment.

Kualiti Alam Sdn. Bhd. is the designated company providing off-site scheduled

waste treatment disposal services in Peninsular Malaysia. Its waste management

centre is located at Bukit Nanas in Negeri Sembilan. Table 9.5 below shows the

waste classification lined by Kualiti Alam.

Table 6-34: Waste Classification Lined by Kualiti Alam

Waste Group

Waste Type

AMineral Oil WastesWastes containing lubricating oil, hydraulic oil, etc.

BOrganic Chemical Wastes Containing Halogens and/or Sulphur > 1%Freon, PVC wastes, chloroform, solvents, capacitors and transformers containing PCB, etc.

C

Waste Solvents Containing Halogens and/or Sulphur < 1%Acetone, alcohols (eg. ethanol, methanol), benzene, turpentine, xylene, etc. Waste should be pumpable, containing < 50% water and 18MJ/kg calorofic value

HOrganic Chemical Wastes Containing Halogens and/or Sulphur < 1%Glue, latex, paint, phenol, printing ink, synthetic oils, soap, epoxy, etc.

KWastes Containing MercuryMercury, vapour lamps, COD-fluids, mercury batteries, etc.

TPesticide WastesInsecticides, fungus and weed killers, rat poison, etc

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XInorganic WastesAcids, alkaline, sodium hypochlorite, inorganic salts, metal hydroxide sludge, chromate and cyanide waste, etc.

ZMiscellaneousMedicine wastes, lab-packs, asbestos wastes, mineral sludges, isocyanates (MDI,TDI), batteries, etc.

Based on the constituents in the waste generated in our plant, it falls under Group Z.

Table 6-35 below is the price set by Kualiti Alam for incinerating the solid waste

Table 6-35: Organic Wastes for Incineration

Waste Group

Packaged Wastes* Bulk Wastes

Pumpable liquid Solid Pumpable liquid Solid

per tonne per tonne

RM US$ RM US$ RM US$ RM US$

A 810 213 - - 630 166 - -

B 3,150 829 3,600 947 - --

-

C 1,350 355 - - - - - -

H/Z 1,890 497 2,790 734 1,800 474 2,700 711

T 1,890 497 2,790 734 - - -

Note: Packaged waste refers to wastes packed in standard 200-litre drums or 1m3 PP Bag

143


Aside from sending for incineration, we can also send the waste for landfill.

Table below show the table for the price of landfill

Waste Group

Packaged Wastes* Bulk Wastes

per tonne per tonne

RM US$ RM US$

X/Z 495 130 450 118

We also have to consider the transportation cost of the wastes. Currently, the

price set by Kualiti Alam is RM 77/tonne for Gebeng area. Sludge is usually being

turned to a suitable sludge cake for ease of loading into plastic lined drums before

being transported to the Solid Waste Storage Building. They will then being

transported to Kualiti Alam Sdn. Bhd. (KA), Bukit Nenas, Negeri Sembilan Darul

Khusus for further treatment or disposal to landfill.

Proper packaging is vital for the safe transportation and handling of

hazardous waste. The waste producer shall be responsible for the correct packaging,

labeling, transportation and specification of the waste as stated in the Environmental

Quality (Scheduled Wastes) Regulations 1989 and is also in line with Kualiti Alam's

effort to obtain the ISO 9002 and ISO 14001.

The following rules of thumb apply when selecting the appropriate packing:

i. Solid waste and empty contaminated container: Open top drums

(steel/plastic) with covers and clamp.

ii. Dry solid waste and contaminated rags: One ton PP bags.

Standard packaging is:

i. Open top drums with clamp for solid waste:

a. Maximum dimensions: Height - 90 cm, Diameter - 60 cm

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b. Drums should not to be filled more than 10 cm from the top

c. Drums must not be used for free fluids.

ii. One ton PP bags:

a. Must be double liner

b. Bags not to be filled more than 10 cm from the top.

c. Bags must not be used for free fluids.

Choice of appropriate packaging:

i. The packaging must be robust and capable of withstanding

transportation by lorry.

ii. In order to qualify as robust, the packaging must be capable of

withstanding normal chemical reaction.

iii. Packaging should be leak-proof.

iv. The packing is not weakened by bulging, corrosion or tear.

6.5.3 Labeling of packaging:

A few simple rules apply to the labeling of waste containers. There must be no

room for doubt as to the waste category in any given packaging. The labeling must

adhere to the Third Schedule (Regulation 8) of the Environmental Quality

(Scheduled Wastes) Regulations 1989.

i. All obsolete marks, hazard label, etc must be removed, erased.

ii. The packaging to be marked on the side with the following information:

a. Consignment number (e.g. 123456 - 001)

b. DOE Code (e.g. N 151)

c. Warning label corresponding to the type of waste

iii. The label must be square in shape and set at an angle of 45 degrees. The

dimension of the label shall not be less than 10cm by 10cm except where the

size of the container or package warrants a label of a smaller size.

iv. The label may be of the following types:-

a. Stick on

b. Metal Plate

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c. Stenciled or printed on the container or package

v. All labels shall be able to withstand open weather exposure without a

substantial reduction

vi. In case of waste capable of presenting two or more hazards, all the hazards

must be clearly identified and the waste labeled accordingly.

vii. All marking on the packaging must be clear and easy to identify.

9.5.2 Domestic Waste

Domestic or municipal waste usually does not contain hazardous materials.

However, certain wastes from process operation may contain soil- polluting

compounds such as rags and gaskets. The waste categorized under domestic waste

are; office waste, canteen waste, maintenance waste, production waste and landscape

waste. The waste is disposed via contractors assigned by local authorities.

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7

CHAPTER 7

PROCESS ECONOMICS AND COST ESTIMATION

7.1 Introduction

Process economics and cost estimation is carried out with a purpose to decide

whether it is economically justified to invest in this ammonia production plant. In

this particular chapter, the economics of carrying out of the plant will be discussed;

the capital costs, operating costs and economic potential will be estimate. The plant

lifetime are fixed at 20 years. According to Malaysian Industrial Development

Authority (MIDA):

“A person carrying on petroleum upstream operations is subject to a Petroleum

Income Tax of 38%. With effect from the year of assessment 2010, the assessment

system on income derived from upstream petroleum and self assessment system.

Income tax for the year of assessment 2010 based on income received in 2009 shall

be allowed to be paid by instalment for 5 years”

(Source: http://www.mida.gov.my/en_v2/index.php?page=company-tax, retrieved on

14th July 2011)

147

http://www.mida.gov.my/en_v2/index.php?page=company-tax


7.2 Capital cost/ Capital Expenditure (CAPEX)

The total purchase cost of the major and minor equipment are summarized in Table 1

Figure 7-51: Estimated cost for equipment

Equipment Cost,$ (USD) RM

Reactor 1, R-101 1,528,602.21 4,616,378.66

Reactor 2, R-102 2,124,890.10 6,417,168.10

Reactor 3, R-103 1,561,745.08 4,716,470.13

Reactor 4, R-104 1,134,215.52 3,425,330.86

Reactor 5, R-105 1,134,806.93 3,427,116.92

Reactor 6, R-106 2,919,495.45 8,816,876.26

Heater, E-101 5,262,457.13 15,892,620.53

Heater, E-102 13,736,204.73 41,483,338.27

Heater, E-103 931,693.31 2,813,713.79

Heat Exchanger, E-103 1,214,704.04 3,668,406.19

Heat Exchanger, E-104 982,789.59 2,968,024.57

Heat Exchanger, E-105 922,883.69 2,787,108.75

Cooler, E-201 2,016,000.00 6,088,320.00

Cooler, E-202 2,016,000.00 6,088,320.00

Cooler, E-203 2,016,000.00 6,088,320.00

Cooler, E-204 2,016,000.00 6,088,320.00

Cooler, E-205 2,016,000.00 6,088,320.00

Cooler, E-206 2,016,000.00 6,088,320.00

Cooler, E-207 2,016,000.00 6,088,320.00

148


Cooler, E-208 2,016,000.00 6,088,320.00

Cooler, E-209 2,016,000.00 6,088,320.00

Cooler, E-210 2,016,000.00 6,088,320.00

Cooler, E-211 2,016,000.00 6,088,320.00

Carbon dioxide Remover, C-101 235,459.65 711,088.13

Regeneration Column. C-102 235,459.65 711,088.13

Pressure Knockout Drum, V-102 679,782.87 2,052,944.28







Compressor, K-101 20,241,836.16 61,130,345.21

Compressor, K-102 28,225,701.08 85,241,617.25

Compressor, K-103 28,026,675.30 84,640,559.39

Compressor, K-104 21,401,165.00 64,631,518.31

Compressor, K-105 91,994,147.33 277,822,324.93

Expander, K-106 8,640,000.00 26,092,800.00

Expander, K-107 8,640,000.00 26,092,800.00

Valve 2,808,000.00 8,480,160.00

Product Separation 5,164,992.00 15,598,275.84

Delivery Cost 3,031,824.50 9,156,110.00

Total(PCE) 279,034,228.51 842,683,370.19

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In addition to the total equipment cost, the fixed capital for the project also includes

design and engineering fees, contractors’ fees and contingency. It is once only cost

that is not recovered at the end of the project life other than scrap value. The detailed

factorial method gives the estimation of fixed capital cost based on the factors given

in Table 7-36.

Table 7-36: Typical Factors (James M. Doughlas, 1988)

Items Factor

f1 Equipment erection 0.40

f2 Piping 0.70

f3 Instrumentation 0.20

f4 Electrical 0.10

f5 Buildings 0.15

f6 Utilities 0.50

f7 Storages 0.15

f8 Site development 0.05

f9 Ancillary building 0.15

Total factor +1 3.00

Physical plant cost (PPC) 359,302,500

The indirect costs for the proposed plant consists of design and engineering costs, 150


which covers purchasing, procurement and construction supervision fee, contractor’s

fees and contingency allowances. The factors are shown in Table 7-37

Table 7-37: Typical Factors for Plant (Douglas, 1988)

Items Factor

f10 Design and Engineering 0.08

f11 Contractor fee 0.03

f12 Contingencies 0.05

Total Factor + 1 1.18

Fixed capital cost, FCI 416,790,900.00

Fixed capital = PCE(1 + f10 + f11 + f12) = USD$ 416,790,900.00

7.2.1 Working Capital

Working capital is the additional investment needed, over and above the fixed

capital, to start the plant up and operate it to the point when income is earned. It

includes the cost of start –up, initial catalyst charges, raw material and intermediate

in process, and others. To determine the working capital for Ammonia plant, 5% of

fixed capital to cover cost of initial raw material charge is allowed (Coulson and

Richardson, 1996).

Working capital, WC = USD$ 416,790,900.00 x 0.05 = USD$ 20,839,545.00

Startup cost, SC = USD$ 416,790,900.00 x 0.08 = USD$ 33,343,272.00

Total investment required for the project

= fixed capital + working capital +startup cost

=USD$416,790,900.00 + USD$20,839,545.00 + USD$33,343,272.00

= USD$ 470,973,717.00

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7.3 Annual Operating Cost

7.3.1 Manufacturing Cost

Cover of variable operating costs including raw materials, miscellaneous operating

materials, utilities, shipping and packaging cost.

1. Raw materials

The raw material used in ammonia production including of natural gas, air

and steam. The cost of raw material is estimated from the flow rate of natural

gas needed to produce 678,810 tonnes of ammonia annually. (the current

price is based on ICIS website)

a. Natural gas price = 0.0031USD$/kg

Natural gas used for production = 405,060,480.0 kg/year

Cost of natural gas used annually =1,259,738.093

USD$/year

b. Catalyst

As there is no price available, we assume 25% of total price of natural

gas used. Thus,

Cost of catalyst used/3year = 0.25 X 1,259,738.093 USD$/

= 314,934.52 USD$/year

2. Utilities

a. Steam water

As for hot utilities and cold utilities, the value of these utilities got

from heat energy section where

Total cold utilities = 45,972.25 kW

Total hot utilities = 57,401.45 kW

The cost for steam used in plant is due to Centralised Utility Facility

(CUF), Gebeng reference where the cost is RM63/kg

Total cold utilities = RM 823,534.74

Total hot utilities = RM 1,028,274.85

Total = RM 1,851,809.59

= 616,242.79 USD$/year

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b. Electricity

The electricity cost is estimated

Typical Factor = 0.10

Estimated electricity cost = 35,027,215 USD$/year

Table below shows the variable operating cost of the plant

Table 7-38: Summary of Manufacturing Cost

Manufacturing expenses USD/year

Raw material (natural gas) 1,259,738.093

Catalyst and solvent 314,934.52

Steam 27,202,242.00

Cooling Water 900,000

Electricity 2,083,954.50

Miscellaneous 2,500,745.40

Total variable cost 33,946,679.99

Table 7-39: Direct production cost

Direct production cost USD/year

Maintenance, take as 2% of fixed capital 8,335,818.00

Operating labour 480,000.00

Plant overheads, 50% of operating

labor+supervision+maintainance

4,431,909.00

Laboratory, take as 5% of operating

labor

24,000.00

Insurance, 0.4% of fixed capital 16,671,636.00

153


Local taxes, 1% of fixed capital 4,167,909.00

Operating Suppliers, 10% maintenance

& repair

833,581.80

Direct Supervision & clerical labour ,

10% operating labor

48,000.00

Royalties, 1% of fixed capital 390,833.80

Total Fixed cost 35,383,687.60

Total Expenses, raw material + utilities +

maintenance + supply + labor+

supervision + lab charge

39,083,379.89

Table 7-40: General expenses of ammonia plant

General expenses USD/year

Administration cost, 10% of operating

labor, supervision and maintenance

886,381.80

Distribution and selling expenses,

5% of total fixed cost

1,769,184.38

Research and development, 3% of fixed

cost

1,061,510.63

Total general expenses 3,717,076.81

Table 7-41: Total manufacturing expenses

Total manufacturing expenses USD/year

Total variable cost + Total fixed cost 69,330,367.59

Total production cost, TPC 73,047,444.40

Table 7-42: Revenue generated

Revenue generated, product USD/year

154


Ammonia 241,633,497.00

Carbon dioxide 50,729,580.00

Total 292,363,077.6

7.1 Process Economic Analysis

The feasibility of the ammonia plant will be evaluated in economics point of view.

Some of the basic investment rules that will be used are:

1. Net Present Value (NPV)

2. Payback period

3. IRR

From the previous section, these values are estimated:

Plant cost (total investment) : USD$ 241,567,000.00

Annual operating cost : USD$332, 444,323.10

The forecast income from the sales of ammonia will be as below

Income : production rate x ammonia price

: 671200tonnesx360USD$/tonne

: USD$241,632,000

In doing the analysis, some assumptions were made:

1. All the ammonia produced are sold by the end of each year

2. The selling price of ammonia is USD$360/tonne and is going to remain

constant throughout the lifetime of the project

3. The annual production cost (COM) is assumed to remain constant throughout

of the project

4. The tax rate is linear throughout the lifetime of the project – 38%

5. Depreciation rate is assumed to be linear throughout the life time of the

155


project.

6. Annual depreciation = equipment cost/plant lifetime

= USD$241,567,000/20years

= USD$12,078,350 annually

7. The discount rate is 10

7.2 Net Present Value (NPV)

The idea of time value of money is grounded due to the fact that the value of

money can increase or decrease over time. The changes that happen to the value of

money can be explained by the interest rate, expressed as an annual percentage.

Thus, in order to determine the cash flow for the plant, all the costs are firstly

converted to a common time. The future project cash flow will be discounted to an

equivalent present value using the formula:

NPV ∑i=0

n C t

(1+i)i=¿

Where,

Ct : Cash flow occurring at that time

NPV : Net present value

T : Number of years in the future

I : Discount rate

In our case, the desired minimum attractive rate of return, (MARR) is 10%. In order

to evaluate the economics of the ammonia plant, the cumulative discounted cash flow

is proposed to be used. The project will be considered as profitable when the

calculated NPV is larger than zero which shows that the return of the project is larger

than the expected rate

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Table 7-43:Non-discounted cash flow (i=0%)

YearCapital cost

($USD)Sales Income

A(SI)

Operating Cost

A(OI)

DepreciationA(BD)

Income before tax, A(IBT)

IncomeTax (38%)

Income after tax, A(IAT)

Cash Income, A(CI) $USD

Net Cash Flow, A(NCF)

$USD

Cumulative cash flow, $USD

0 01 470973717.00 -470973717 -470,973,7172 20,839,545 -20839545 -491,813,2623 41,679,090 -41679090 -533,492,352

4 292,363,077.60 73,047,444 41,679,090 219,315,633 83,339,941 135,975,693 177,654,783 177654783 -355,837,569

5 292,363,077.60 73,047,444 41,679,090 219,315,633 83,339,941 135,975,693 177,654,783 177654783 -178,182,787

6 292,363,077.60 73,362,378 41,679,090 219,000,699 83,220,266 135,780,434 177,459,524 177459524 -723,263

7 292,363,077.60 73,047,444 41,679,090 219,315,633 83,339,941 135,975,693 177,654,783 177654783 176,931,519

8 292,363,077.60 73,047,444 41,679,090 219,315,633 83,339,941 135,975,693 177,654,783 177654783 354,586,302

9 292,363,077.60 73,362,378 41,679,090 219,000,699 83,220,266 135,780,434 177,459,524 177459524 532,045,825

10 292,363,077.60 73,047,444 41,679,090 219,315,633 83,339,941 135,975,693 177,654,783 177654783 709,700,608

11 292,363,077.60 73,047,444 41,679,090 219,315,633 83,339,941 135,975,693 177,654,783 177654783 887,355,391

12 292,363,077.60 73,362,378 41,679,090 219,000,699 83,220,266 135,780,434 177,459,524 177459524 1,064,814,914

13 292,363,077.60 73,047,444 41,679,090 219,315,633 83,339,941 135,975,693 177,654,783 177654783 1,242,469,697

14 292,363,077.60 73,047,444 41,679,090 219,315,633 83,339,941 135,975,693 177,654,783 177654783 1,420,124,479

15 292,363,077.60 73,362,378 41,679,090 219,000,699 83,220,266 135,780,434 177,459,524 177459524 1,597,584,003

16 292,363,077.60 73,047,444 41,679,090 219,315,633 83,339,941 135,975,693 177,654,783 177654783 1,775,238,785

17 292,363,077.60 73,047,444 41,679,090 219,315,633 83,339,941 135,975,693 177,654,783 177654783 1,952,893,568

18 292,363,077.60 73,362,378 41,679,090 219,000,699 83,220,266 135,780,434 177,459,524 177459524 2,130,353,091

19 292,363,077.60 73,047,444 41,679,090 219,315,633 83,339,941 135,975,693 177,654,783 177654783 2,308,007,874

20 292,363,077.60 73,047,444 41,679,090 219,315,633 83,339,941 135,975,693 177,654,783 177654783 2,485,662,657

157


0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 200

2

4

6

8

10

12

Cash Flow Diagram for Non-Discounted Rate

Year

Cum

ulati

ve C

ash

Flow

(,00

0) R

M

Figure 7-52: Cash flow diagram for non-discounted rate, i=0%

Table 7-44: Discounted cash flow for i=10%, i=20% and i=30%

158


year of completio

n

Net Cash FlowA(NCF)

Discounted cash flow

for 0% cumulative

Discount factor, fdi= 10%

discounted cash flow for 10% (A(NCF)*fd)

Discounted cash flow

for 10% cumulative



Discounted cash flow for 30%

cumulative



Discounted cash flow for 20%

cumulative

0 0.00 0.00 0.00 0.00 0.00

1-

470,973,717.00-470,973,717.00 0.9091

-428,162,206.12

-428,162,206.12 0.7692-

362,272,983.12-

362,272,983.120.8333

-392,462,398.38

-392,462,398.38

2 -20,839,545.00 -491,813,262.00 0.8264 -17,221,799.99 -445,384,006.11 0.5917 -12,330,758.78-

374,603,741.890.6944 -14,470,980.05

-406,933,378.42

3 -41,679,090.00 -533,492,352.00 0.7513 -31,313,500.32 -476,697,506.43 0.4552 -18,972,321.77-

393,576,063.660.5787 -24,119,689.38

-431,053,067.81

4 177,654,782.58 -355,837,569.42 0.6830 121,338,216.51 -355,359,289.92 0.3501 62,196,939.38-

331,379,124.280.4823 85,682,901.64

-345,370,166.17

5 177,654,782.58 -178,182,786.83 0.6209 110,305,854.51 -245,053,435.42 0.2693 47,842,432.95-

283,536,691.330.4019 71,399,457.12

-273,970,709.05

6 177,459,523.50 -723,263.33 0.5645 100,175,901.02 -144,877,534.40 0.2072 36,769,613.27-

246,767,078.060.3349 59,431,194.42

-214,539,514.62

7 177,654,782.58 176,931,519.26 0.5132 91,172,434.42 -53,705,099.98 0.1594 28,318,172.34-

218,448,905.710.2791 49,583,449.82

-164,956,064.81

8 177,654,782.58 354,586,301.84 0.4665 82,875,956.08 29,170,856.10 0.1226 21,780,476.34-

196,668,429.370.2326 41,322,502.43

-123,633,562.38

9 177,459,523.50 532,045,825.35 0.4241 75,260,583.92 104,431,440.02 0.0943 16,734,433.07-

179,933,996.300.1938 34,391,655.66 -89,241,906.72

10 177,654,782.58 709,700,607.93 0.3855 68,485,918.69 172,917,358.70 0.0725 12,879,971.74-

167,054,024.570.1615 28,691,247.39 -60,550,659.33

11 177,654,782.58 887,355,390.51 0.3505 62,268,001.30 235,185,360.00 0.0558 9,913,136.87-

157,140,887.700.1346 23,912,333.74 -36,638,325.60

12 177,459,523.501,064,814,914.0

20.3186 56,538,604.19 291,723,964.19 0.0429 7,613,013.56

-149,527,874.14

0.1122 19,910,958.54 -16,727,367.06

13 177,654,782.581,242,469,696.6

00.2897 51,466,590.51 343,190,554.70 0.0330 5,862,607.83

-143,665,266.31

0.0935 16,610,722.17 -116,644.89

14 177,654,782.581,420,124,479.1

90.2633 46,776,504.25 389,967,058.96 0.0254 4,512,431.48

-139,152,834.84

0.0779 13,839,307.56 13,722,662.67

15 177,459,523.501,597,584,002.6

90.2394 42,483,809.93 432,450,868.88 0.0195 3,460,460.71

-135,692,374.13

0.0649 11,517,123.08 25,239,785.75

16 177,654,782.581,775,238,785.2

70.2176 38,657,680.69 471,108,549.57 0.0150 2,664,821.74

-133,027,552.39

0.0541 9,611,123.74 34,850,909.49

17 177,654,782.581,952,893,567.8

60.1978 35,140,116.00 506,248,665.57 0.0116 2,060,795.48

-130,966,756.91

0.0451 8,012,230.69 42,863,140.18

18 177,459,523.50 2,130,353,091.3 0.1799 31,924,968.28 538,173,633.85 0.0089 1,579,389.76 - 0.0376 6,672,478.08 49,535,618.27

159


6 129,387,367.15

19 177,654,782.582,308,007,873.9

50.1635 29,046,556.95 567,220,190.80 0.0068 1,208,052.52

-128,179,314.63

0.0313 5,560,594.69 55,096,212.96

20 177,654,782.582,485,662,656.5

30.1486 26,399,500.69 593,619,691.49 0.0053 941,570.35

-127,237,744.28

0.0261 4,636,789.83 59,733,002.79

160


0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

-600,000,000.00

-400,000,000.00

-200,000,000.00

0.00

200,000,000.00

400,000,000.00

600,000,000.00

Cumulative Cash Flow Diagram for Discounted Rate

i=10%i=20%i=30%

Year

Cum

ulati

ve C

ash

Flow

(,00

0) R

M

Figure 7-53: Cumulative cash flow rate for i=10%, i=20% and i=30%

161


7.3 Payback Period

Payback period can be interpreted as the time required for the cumulative cash flow

to cover the capital cost. Short payback period project is a good project. It shows that

the project does not need much time to recover the capital cost.

Figure 7-52 shows the non-discounted cash flow. From the figure, the simple

payback period can be determined. The simple payback period (i=0%) is at the

seventh (7th) year where positive cumulative cash flow is generated.

While Figure 7-53 shows the cumulative discounted cash flow at i=10%, i=20% and

i=30%. If i=10%, the payback period is at the sixth (6th) year. If =20%, the payback

period is at the thirteenth (13th) year, while if i=30%, the payback period is never pay

back.

From this, it can be concluded, the project reasonable to be done as it gives fast

payback period to recover the capital cost. The payback period of MARR=10% is at

the sixth year.

7.4 Internal Rate of Return (IRR)

According to Sullivan et al (2009), the IRR method is the most widely used rate-

of return method for performing engineering economics analyses. It is also known by

several names such as investor method, the discounted cash flow method, and the

profitability index. This is used to solve the interest rate that equates the equivalent

worth of an alternative’s cash inflows (receipt or savings) to the equivalent worth of

cash outflows (expenditures, including investment cost).

IRR is the value of the discount which corresponds to zero cumulative cash flow at

the end of the studies period, here is 20 years.

From Figure 7-53 , it can be seen that the cumulative cash flow will be zero at

20%<i<30%. In order to effectively estimating the value, interpolation must be

made.

162


Table 7-45: Net cash at EOY of 20 years for i=20% and i=30%

i(%) Net cash flow at EOY of 20 year (RM)20 59,733,002.7930 -127,237,744.28

IRR=(0−59733002.79)

(−127237744.79−59733002.79)× (20−30 )+30=26.8 %

Thus, the value of IRR is 26.8% which is bigger than MARR (10%). Therefore, the

investment decision is justified. The ammonia production plant is profitable to be

done.

7.5 Sensitivity analysis

According to Sullivan, sensitivity analysis is used to explore what will happens to a

project ‘s profitability when the estimated value of study factors are changed. Figure

7-54 shows the sensitivity graph where the capital investment, annual revenue,

annual operating cost and the useful life of the plant are tested. From the graph, it can

be seen that the annual revenue is the most sensitive element. Decrement of 30% of

annual revenue will give no profit to the project.

Figure 7-54: Sensitivity graph

163


8

CHAPTER 8

CONCLUSION & RECOMMENDATION

After finishing the Final Year Design Project II (FYDP 2), it has been proven

conceptually that the establishment of an ammonia production plant in Malaysia is

feasible. Based on matrix comparison made, Gebeng Industrial Estate, Pahang is

identified to be the best location for an ammonia production plant. This is due to the

fact that the location is highly strategic compared to others, much cheaper, close to

port as well as having good and complete network such as well-maintained highway,

expressway and road embedded with other advantages as discussed before.

The planned built plant will be operated in continuous mode, where nitrogen will

react with hydrogen to produce ammonia. The reactor selected for ammonia

synthesis will be catalytic fixed-bed reactor where iron oxide will be used as the

catalyst. The process requires 3 types of separation process which are water removal,

carbon dioxide removal and ammonia purification.

The purity of ammonia is 99.4% with a 671, 200 metric tonnes production rate

annually. The plant that has been proposed is economically justified and therefore it

is viable for investment based on economic potential done. The calculate IRR is

26.8% which is bigger than the MARR (10%), thus justify the profitability of the

plant. The plant will take about six years to recover the investment. Besides, while

designing the plant, the safety and environmental rules aspects are taken into

consideration. Thus, the production of ammonia project is proven to be technically

possible to be done and economically profitable.

It is suggested that further heat integration to be done so that the utilities cost can be

reduced. Well integrated plant will minimize the purchase of utilities and raw

materials and thus minimizing the operating cost. Besides, human resources

department must hire workers accordingly; the usage of auto-controlled machine

would further reduce the cost of workers. Other than that, maintenance must be done

according to schedule to prevent unwanted incident. Practicing safe and effective

164


work environment will further enhance the workers’ motivation thus improving the

work quality as to mention, it is human who the most unpredictable variable in the

production plant is.

Ending the FYDP 2, it can be seen that the team managed to meet all the objectives

of the project. The project is very important as it helps in improving and enhancing

the knowledge of the team and experiencing the process of designing plant. It is an

undeniable fact too that this project has improved the team presentation and

communication skills via interaction between the group members and presentation

done. Thus, via this project, the team managed to improve the teamwork.

165


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APPENDIX 1: PFD DIAGRAM

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170


APPENDIX 2: PLANT LAYOUT

171


APPENDIX I: SITE LOCATION

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Fydp II Group 17 Final Report_24th August 2011_1

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