A Design on Natural Gas Processing Plant: Production of Liquefied Processed Gas (LPG)

Presented byNilima Sarwar (1002022)

Sk Aysha Rashid (1002049)Razia Hasan (1002055)

Asma-Ul-Husna (1002059)SupervisorDr. Md. Tanvir SowgathAssistant ProfessorDepartment of Chemical Engineering, BUET

Overview Project definition Design basis Selection of process Process description Process block diagram Process flow diagram List of auxiliaries and package units List of process licensors List of major equipments List of vendors Codes and standards Engineering specification of one major equipment

1. Definition of the project The aim of the project is to design a natural gas processing plant located at Ashuganj, Brahmanbaria in Bangladesh, with a production capacity of 8000 metric tons per year, corresponding to a daily production of 24.24 metric tons from 44.89 metric tons of NGLs and 2.18 metric tons of condensate with sales gas, as by-product, including all offsite auxiliaries, utilities and support facilities using natural gas as feedstock an fuel.

2. Design Basiso Geographical information – Ashuganj, Brahmanbaria; 44 mile north-east of Dhaka.o Climate condition

Ambient temperature: Max. = 38C, Min. = 15 C Average relative humidity: 85% Annual maximum rainfall : 2800 mm Average annual rainfall: 1550 mm Barometric pressure (at sea level): 99.967 kPa Wind direction: In Summer, from south-east In Winter, from north-east

oUtility conditions Electric power: Power generation - 40 KV, 3 phase, 50 Hz Motor and pumps – 440 volts, 3 phase, 50 Hz Fuel: Raw natural gas or pipeline gas, Ethane

2. Design Basis (Cont’d)o Raw material: Feed gas inlet at 104F and 2620 psia

Components Mole fraction Components Mole fractionMethane 0.9535 n-Nonane 0.0001

Ethane 0.0272 n-Decane 0.0001

Propane 0.0077 C-11 0.0001

i-Butane 0.0018 C-12 0.0001

n-Butane 0.0018 C-13 0.0001

i-Pentane 0.0009 C-14 0.0001

n-Pentane 0.0007 Water 0.0005

n-Hexane 0.0011 Carbon di oxide 0.0016

n-Heptane 0.0005 Nitrogen 0.002

n-Octane 0.0002

3. Selection of process

• Centrifugal separation• Gravity settling

• Multistage separation• Liquid-gas coalescers

Phase Separation

• Flash vaporization• Fractionation

Condensate Stabilization

• Refrigeration• Adsorption by solid

desiccant • Absorption by liquid

desiccant

Gas dehydration

• Refrigeration • Lean oil absorption• Solid bed adsorption• Membrane separation

NGL recovery

NGL Fractionation yields LPG Economical Higher recovery of condensate Higher recovery levels of NGL

4. Process descriptionI. Phase separation: Three phase separator

WATER OUT

GAS OUT

HYDROCARBON CONDENSATE

THREE PHASESEPARATOR

Raw gas HYDROCARBON CONDENSATE

FLARE

CONDENSATE

CONDENSATESTABILIZER

II. Condensate stabilization: Fractionation

4. Process description (Cont’d)III. Gas dehydration: Absorption by Tri Ethylene Glycol

GAS OUT

GLYCOL CONTACTOR

RICH SOLVENT

LEAN SOLVENT

DRY GAS

GAS-GLYCOLHEAT

EXCHANGER

GLYCOL-GLYCOL

HEAT EXCHANGER

STRIPPING COLUMN

WATER

4. Process description (Cont’d)IV. NGL recovery: Cryogenic refrigeration V. LPG production: Fractionation

GAS-GASHEAT

EXCHANGER-1

SEPARATOR

GAS-GASHEAT

EXCHANGER-2

COLDSEPARATOR EXPANDER

DEMETHANIZER

NGLs

COMPRESSOR

RECOMPRESOR

DEETHANIZER LPG TO

STORAGE TANK

ETHANE

CONDENSATE

NGLs

5. Process block diagram

6. Process flow diagram

1 2

V-111

EH-112

3

FA-110

4

5

6 V-311

V-211

7

EH-312

EH-212

4140

DA-210

42

43

8

DA-310

10V-331

11

13

12 12a

G-333FA-332 EA-330

17

14

DA-340

16

15

18

EA-320

9

20

21

EA-43022

36

EA-420

FA-410

24

23

25

FA-460

32

26

27 29

2830

31

DA-470 33FA-511

34

35

35a44

DA-510

45

46

GB-440

38

GB-450

39

22a

EC-411

G-321G-512

Raw gas

19Make-up glycol

Drain

Flare

Flare

Water

Sales gas

Ethane

LPG

Flare

37

7. List of Auxiliaries & Package Units• Tank firm • Water Treatment plant • Cooling Tower • Steam generator or boiler • Power generator • Instrument Air • Fire pump• Safety & Fire protection unit • Waste Water Treatment unit • Loading/unloading unit • Flare

8. List of major equipments

Equipment Identification No. Number of equipment used

Three phase separator FA-110 1Separator FA-410, FA -460 2Absorber DA-310 1

Stripping column DA-340 1Distillation column DA-210, DA-470, DA-510 3

Heat exchanger EA-320, EA-330, EA-420, EA-430 4Compressor GB-440, GB-450 2

9. List of process licensorsNatural gas processing- LurgiNGL extraction process- Ortloff Engineers Ltd.

10. List of vendorsEquipments Vendors

Distillation column J.D. Cousins Inc.

Shell and tube heat exchanger J.F.D. Tube and Coil Products Inc.

Separators Q.B. Johnson Manufacturing Inc.

11. Codes and StandardsASME Boiler and pressure vessel code section VIII, Division 1 and 2

12. Engineering specification for one major unit (EA-320)Heat Exchanger Specification Sheet

Company: X Job No. 23450Address: Location: Y Reference No.Plant location: Z Proposal No:Service of Unit: Glycol cooler Rev No.:Date: 7.11.15 Item No.: EA-320 Size: Type Horizontal  Connected in Series ParallelSurf/unit(eff.) ft2 Shells/unit Surf/shell (eff.) ft2

PERFORMANCE OF ONE UNITFluid allocation Shell Side Tube SideFluid name  Glycol Dry gasFluid quantity, Total lb/h 8188   43810Vapor (In/Out lb/h     43810 43810Liquid lb/h 8188 8188Noncondensable kg/s    Temperature (In/Out) F 384 320 170 184 Dew / Bubble point FDensity lb/ft3 60.87 1.88Viscosity cp 0.634 0.0014Molecular wt, Vap  150   17.1Specific heat BTU/(lb*F) 107.2   10.42Thermal conductivity BTU/(ft*h*F) 0.0079   0.0026Pressure psi 600   70Velocity ft/s    Pressure drop, allow./calc. psi 10   2Fouling resist. (min) ft2*h*F/BTU    Heat exchanged 353400 BTU/h MTD corrected F

12. Engineering specification for one major unit -EA-320 (Cont’d)CONSTRUCTION OF ONE SHELL Sketch

  Shell Side Tube Side        

Design/Test pressure psi 400 / 800 100/130Design temperature F 250-400   Number passes per shell 1  2 Corrosion allowance in  0.12 0.12ConnectionsSize/rating 

In  OutIntermediate  

Tube No. 160 OD 0.787 In, Thk (Min/Avg) 0.079 In; Length 19.685 Ft; Pitch 1.969 In Triangular 30Tube type Material Shell ID OD 29.1 In Shell coverChannel or bonnet Channel coverTube sheet-stationary Tube sheet-floatingFloating head cover Impingement protectionBaffle-crossing Type Single Cut(%d) 20 horizontal Spacing: c/c 31.5 inBaffle-longSupports-tube U Bend Type Bypass seal Tube-tubesheet jointExpansion joint  TypeRhoV2-Inlet nozzle Bundle entrance Bundle exitGaskets - Shell side Tube SideFloating headCode requirements TEMA class A E L Weight/Shell Filled with water Bundle

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