Hoang Th Aches A

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Hoang Thach Cement - Energy Audit Report September 2009 INTERNATIONAL INSTITUTE FOR ENERGY CONSERVATION (flEC> TANo:7 2~ IE SUPPORrlNG IMPLEMENTATION OF THE NATIONAL ENERGY EFFICIENCY PROGRAM PROJECT - VIET NAM NE GY SYS EM ASSES AT HAG THACH CEME LAT Prepared for VIETNAM CEMENT INDUSTRY CORPORATION (VICEM) 228 Le Duan, Ha Noi, Viet Nam and As:tAN DEVELOPMENT BANK 6 ADB Avenue, Mandaluyong City, 040] Metro Manila, Philippines by International Institute for Energy Conservation - Asia 12th Floor, United Business Center II Building, 59], Sukhumvit Road U'aftana, Bangkok 101]0, TlfAILAND September 2009

Transcript of Hoang Th Aches A

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Hoang Thach Cement - Energy Audit Report September 2009

INTERNATIONAL INSTITUTE FORENERGY CONSERVATION (flEC>

TANo:7 2~ IESUPPORrlNG IMPLEMENTATION OF THE NATIONAL ENERGY

EFFICIENCY PROGRAM PROJECT - VIET NAM

NE GY SYS EM ASSESAT

HAG THACH CEME LATPrepared for

VIETNAM CEMENT INDUSTRY CORPORATION (VICEM)228 Le Duan, Ha Noi, Viet Nam

and

As:tAN DEVELOPMENT BANK

6 ADB Avenue, Mandaluyong City, 040] Metro Manila, Philippines

by

International Institute for Energy Conservation - Asia12th Floor, United Business Center II Building, 59], Sukhumvit Road

U'aftana, Bangkok 101]0, TlfAILAND

September 2009

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Hoang Thach Cement - Energy Audit Report September 2009

The Energy Assessment was conducted by U V Krishna Mohan Rao Associatesunder contract to the International Institute for Energy Conservation (IIEC).

Report No: UVKAR 900-4-0909

U V Krishna Mohan Rao Associates6, Rajaji Nagar Main Road, Madipakkam, Chennai 600091, India

Phones: + 91 93823 82859, +91 94440 72262, Fax: +91 44 2483 2859Email:[email protected]

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Hoang Thach Cement - Energy Audit Report September 2009

EXECUTIVESUMMARY

The objective of this Energy Audit is to identify energy efficiency improvement andenergy cost savings opportunities existing at the Hoang Thach Cement plant (Client)in Vietnam. Two international energy consultants from U V Krishna Mohan RaoAssociates, India and three national consultants from Vietnam (Consultants)conducted this Energy Audit during July 27-29,2009.

The site data indicates that the plant spent about US $ 15.2 million (279 million kWh,equivalent to VND 273,600 million) during a 1-year period for purchased electricityand about US $ 14.9 million (286,916 tons equivalent to VND 268,200 million) forcoal during the same period. In March 2009, the electricity tariff was revised and theelectrical energy savings calculations here are based accordingly.

Based on the site visit, observations on the plant operations and discussions with theoperating personnel and the technical information collected, the Consultants haveidentified the following list of energy conservation measures (ECM) for further actionand development consideration:

s.Energy Conservation Measure Title

Annual energyAnnualInvestmentNo savingssavings

GWh/GCal/ yr

VNDVND millionyr

million

Improve kiln combustion efficiency by reducing false air 3.1ingress at the preheater section and reducing marginally the 1804424203890

sintering level of clinker3.2

Improve cooler performance by uniform clinker distribution22906

30702380over the grate plates

3.3

Install a new preheater cyclone at stage-1 and recover78123

1048027000additional waste heat from kiln exhaust gases

3.4

Utilize cooler vent air as primary air to the kiln burner 5106685740

3.5

Generate electricity from the waste heat of PH exhaust and29.49

32180187200cooler vent streams

3.6

Install variable frequency drive for raw mill fan (R2S20)- line 22.0820407200

3.7

Replace existing inefficient equipment - preheater fans in1.92

18853000Line 1

3.8Replace existing inefficient equipment - raw mill fan in Line 11.4914603000

3.9

Install mechanical conveying system for kiln feed in line 1 to2.29

22506000eliminate energy-intensive present pneumatic conveying

3.10

Install variable frequency drive for coal mill fan (P22)- line 20.49480600

Total

37.7612417956,950241,010

While savings estimates have better accuracy (unless the plant data and assumptions'change) the investment estimates are only preliminary. All the above preliminary investmentis based on the Consultants' experience in similar projects elsewhere. Necessary detailedengineering has to be done to evaluate more accurate investment grade estimates.

More details for all the ECMs are provided in Section 3.0 of this Report.

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1.01.1

2.0

2.12.22.32.42.52.6

3.0

3.1

3.2

3.3

3.43.5

3.63.73.83.9

3.10

4.0

5.0

Hoang Thach Cemcnt Encrgy Audit Rcport: Scptcmbcr 2009

ENERGY SYSTEM ASSESSMENT AT HOANG THACH CEMENT PLANT

CONTENTS

INTRODUCTION AND BACKGROUND

Brief highlights about the plant

ENERGY SYSTEMS AND CONSUMPTION DATA

Energy systems at the cement plantEnergy consumption data at the plant and specific energy consumptionEnergy cost dataHeat balance and energy consumption analysisMetering, measurement and savings verificationManagement aspects of energy conservation

ENERGY COST SAVING MEASURES

Improve kiln combustion efficiency by reducing false air ingress at thepreheater section and reducing marginally the sintering level of clinkerImprove cooler performance by uniform clinker distribution over the grate. platesInstall a new preheater cyclone at stage-1 and recover additional wasteheat from kiln exhaust gasesUtilize cooler vent as primary air to kilnGenerate electricity from the waste heat of preheater exhaust and coolervent streamsInstall variable frequency drive for raw mill fan (R2S20)-line 2Replace existing inefficient equipment-preheater fans in line 1Replace existing inefficient equipment-raw mill fan in line 1Install mechanical conveying system for kiln feed in line 1 to eliminateenergy-intensive pneumatic conveyingInstall variable frequency drive for coal mill fan (P22)-line 2

ATTACHMENTS, BASIS DATA AND CALCULATIONS

PATH FORWARD

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ENERGY SYSTEM ASSESSMENT AT HOANG THACH CEMENT PLANT

1.0 INTRODUCTION AND BACKGROUND

1.1 Brief highlights about the Hoang Thach Cement Plant

This plant, with two production lines, is one of the largest and most technologicallyadvanced cement companies in Vietnam. The plant has a total installed capacity of2.3 million tonnes per annum (tpa). The first line, with a rated production of 3,100 tpdwas commissioned in 1983. The second production line, with rated production of3,500 tpd was commissioned in 1996 and has a single stream, 5-stage preheaterwith a precalciner. A third line is under construction and is expected to be on streamin year 2010.

The individual sections are briefly described here:

1.1.1 Raw material for clinker production

The main raw material for the cement manufacturing is lime stone. Clay is a minoradditive to the main raw material, which needs to be supplied as a fine powder forcement manufacturing. While clay is an easily grindable material, lime stone is ahard rocky material. A 300 tph vertical roller mill (VRM) of FLS-make, grinds thelimestone and other additives including clay. The fine powdered raw materialmixture from VRM, also known as raw meal is fed to the kiln system forc1inkerization.

1.1.2 Clinkerization of raw meal

Clinkerization is the sintering or fusing of the calcined-raw meal at high temperaturesaround 1450°C. Calcination of raw meal is the removal of CO2 from lime stone andconverting it into free lime. Calcination of limestone occurs at temperatures above850°C. At the kiln system, the raw meal is calcined, then fused into clinker and thenquickly cooled to about 100°C, before sending to clinker storage.

The line 2 is predominantly in operation on a continuous basis. The system is of dryprocess design, with a single stream of 5-stage preheater cyclones, feeding to therotary kiln. A grate cooler, Coolax, supplied by FLS, cools the clinker from -1350°Cto about 100°C and is provided with 14 fans to supply the cooling air. The coal millthat supplies pulverized coal to the system is a vertical roller mill. The kiln and theprecalciner are the most critical components of a cement plant and it is called thepyro-processing section.

The line 1 is a rotary kiln equipped with planetary cooler and is producing about 3100tpd. The preheater is a four-stage, twin-stream arrangement, and the kiln feed is byway of pneumatic conveying system.

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1.1.3 Cement production from clinker

Clinker with minor additives is ground into very fine particles to yield cement. Thefineness of the cement particles is critical for its quality and usually measured by thetotal surface of the particles per gram of material, also called the Blaines. Thecement milling consists of two conventional ball mills, one of capacity 200 tph, forline 2 and the other of capacity 176 tph, for line 1. The ball mills have 2compartments each, provided with a high efficiency separator and operate in closedloop (line 2).

1.1.4 Dust cleaning systems for better environment

Since cement manufacturing involves large quantities of dusty material, the exhaustgas streams from a cement plant are provided with dust collection and filteringsystems. Electro static precipitators (ESP) are in service for removing theparticulates from the exhaust-gas and vent-air streams. The main ESP takes care ofthe kiln, preheater and raw mill exhaust gases. The coal mill, cooler vent and cementmill are also provided with their dedicated ESPs. The exhaust filter fan and theexhaust fan of cement mill are equipped with variable frequency drives.

1.1.5 Coal milling

Coal for firing in the line 2 is pulverized in a vertical roller mill, Atox, supplied by FLS.This is the only site of the five plants where there is a vertical roller mill (VRM) forcoal grinding.

Typical operating parameters of all the above, as seen in the control room, are givenas Attachment 1.1

2.0 ENERGY SYSTEMS AND CONSUMPTION DATA

2.1. Energy systems at the plant

Cement making is an energy intensive process and has both thermal and electricalenergy systems in service. Both coal and fuel oil are consumed in the thermalprocesses and electricity is consumed in every step of the cement making process atthe plant. All the thermal and electrical energy needs of the plant is purchased fromnational grid. At present there is no internal energy generation at the site.

The kiln and precalciner burners are designed with indirect firing system andprovided with weigh-scales. About 60% of the process heating load is applied at the·precalciner burners and the rest 40% heat load is applied at the kiln burner. The coalfiring at the kiln and precalciner is of indirect system (Coal mill feeds the coal silosand silos feed the burners at the required quantities). The burner of kiln 2 is of multi­channel type, and is equipped with separate primary air fan that is estimated to besupplying about 15% of the combustion air.

Most of the fine material conveying in line 2 uses mechanical systems like bucketelevators and belt conveyors. However in line 1, the raw meal feeding to thepreheaters of kiln is by pneumatic conveying. The pulverized coal from coal mill silo

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to burners is pneumatically conveyed. Compressed air and water are the utilitiessystem in service at the plant. Compressed air is used for the instruments and fordust cleaning services.

2.2 Energy Consumption data at the Hoang Thach cement plant

Coal and electricity are the major energy sources. Fine coal is consumed by the kilnand precalciner burners. Unlike the thermal energy (coal and to some extent, fueloil) that is consumed only at the pyro-processing section (kiln and precalciner),electricity is consumed all around the plant by the drives and lighting.

Total purchased electricity consumption for a one-year period was 279 million kWh,as shown in the following table:

5. No. MonthValuemillion kWh1

July 2008 24.872

August 22.783

September 24.814

October 26.975

November 24.316

December 27.307

January 2009 15.018

February 17.86

9March 21.67

10April 21.78

11May 27.32

12June 23.95

Total279

Consumption pattern of coal and fuel oil are as below:

FuelUnit

200620072008

HT1HT2HT1HT2HT1HT2

Production

clinkermillion

1.0061.0611.0271.0921.0131.124

tonsHeat loss

Kcal/kg980960962955956953Total coal consumptionCoal3B

tons129,74476,92477,48174,67484,27584,271Coal3C

tons917067,91162,40072,69952,55065,820Total oil

tons96516801505185614972716

consumption

2.2.1 Specific energy consumption

The values of section-wise consumption could not be obtained till the audit period.

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Hoang Thach Cement Energy Audit Repol1: September 200lJ

2.3 Energy cost data

Detailed break up of coal and fuel oil purchase / consumption data, from the plantwas not available. Hence the following unit energy cost data is computed based onthe coal and oil prices prevailed at a cement plant located in a neighboringprovince and used in the Report.

The average cost comes to VND 982/kWh, after taking into account the 10 % VAT,(there was an increase in tariff since March 2009)

For all the savings calculations in this Report, the average cost (including VAT)based on 12-months' figures is considered, since this is the actual cost incurred bythe client.

Electricity Tariff Structure for 110kV consumers in Vietnam

WeekdaysCostSundaysCost

Hours!

No. ofHours

AmountNo. of

day

days!Sub total! day

VNDdays!Sub totalyear

year

b

d=bf= d X e

h=gxij=h xia ce 9bXC

Peak169058450313264485000520

Normal

835131085

3133397615181503052781560

5Off

455627303138544906273052141960

peak Total6,896,955923,520

Overall total costs VND7,820,475

No. of daysdays/year365

WeightedVND/kWh893

average tariffVAT

%10

Weighted average tariff

VND/kWh982(incl VAT)

2.4 Heat balance and energy consumption analysis for Hoang Thach

The specific thermal energy consumption for the plant as evaluated by the heatbalance is 870 kcals/kg of clinker.

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Iloang Thach CClllent Energy Audit Rep0l1: September 2009

HeatcontentOf RaW Meal

H~dtll"l.ltby furl

Specific Heat Consumption 870,6kl~lc;/kO of Clinkw

HealCClflCent

ufOln"~

This is about 11 % higher than a modern dry process plant of similar designelsewhere. Comparative performance parameters for some energy-efficient plantsoperating in India are given below:

Cement plantCement plantCement plantCement plantsupplied by

supplied bysupplied bysupplied byFuller

FLSFullerPolysiusCapacity

3000650020006000

Sp. electricity consumption,59.9**

83.676.782.8kWh/ton cement

Sp. thermal energy consumption,729

732786741Kcallkg clinker

**The lowest electrical energy consumption is in a plant supplied by Fuller and is oneof the most energy-efficient plants in the world.

2.5 Metering, measurement and savings verification

Line 2 has DCS control system with good graphics for operation and monitoring.Section-wise metering is not available at present and if made available, will provideenough insights into the energy consumption pattern and hence will facilitate findingout specific energy consumption. This in turn will help the management take actionwherever it is appropriate.

2.6 Managementaspects of energy conservation

Cost of energy has a significant share in the total cost of production in a cementplant. Hence energy management is a critical need in all cement plants and this.plant is no exception to it. The Chiefs of Maintenance and Operation groupsshowed great enthusiasm in providing information during the site study.

Kiln 1 is still in operation with a planetary cooler (an outdated design) and this line isexpected to be taken up for up-gradation, once the third line is commissioned.

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Hoang Thach Ccmcnt Encrgy AudIt Rcpol1: Scptcmbcr 2()()l)

The following aspects need immediate attention:

Requirement of a dedicated person for energy management

Assigning an experienced manager to monitor the thermal and electrical energyconsumption could bring positive results. The full time Energy Manager can focus onimplementing energy savings recommendations and monitor results.

Section-wise energy consumption monitoring for major process sections

Each of the major sections like raw mill, coal mill, pyro-processing, and cement millmust have dedicated energy measuring and monitoring infrastructure. This will helpcontinuous monitoring of energy consumption and can take actions wheneverdeviations are found and also for fixing targets for energy consumption.

Energy conservation fund

Every year, 1-2 % of the previous year's energy bill must be allotted for projects forenergy conservation. Yearly targets must be set, in such a way that the target mustbe at least 10 % better than the previous year or 10 % lesser than the best achieved.A dedicated technical person for coordinating for utlising this fund will speedup theprocess.

In-house constraints

The plant is on the way of installing the third line and would be focusing on the sametill it is commissioned, the likely date being mid 2010; Decision on the upgradation onthe first line is expected to be taken only after the commissioning of the third line.This plant may be hesitant to allocate sufficient funds for any energy-efficiency workuntil the line 3 is commissioned satisfactorily.

Plant-wide propagation of energy efficiency

Posters and video displays of core parameters like current day's energyconsumption and production may attract staff members to contribute to energyconservation.

Equipment utilization: still room for enhancement

kilnRaw millCoal millcement

millcooler

kilnkiln requiredrequlreme

runningcement runningcaseraw millcapacityrunning capacIty capacity

loadingoutputloading

hours/daynUday hours/daymill hours/day

tpd/m'

tpdtpd/m3tpdtphhours/daytpdtphhours/daytpdtphhours/day

b

c=d=e=fg= elfh=

ij = hlikIm =k11a b x 77.4c/1080ex 1.55 ex 0.1

base46

35603.3551930018.43563011.9373820018.7case 1

4837153.4575930019.23723012.4390120019.5

2

5038703.6599930020.03873012.9406420020.3

3

5240253.7623830020.84023013.4422620021.1

4

5441803.9647830021.64183013.9438920021.9

Nato:77.4 represents the area of cooler in sq.m

1080 represents the inner volume of the kiln (length of kiln is 68 m, dia is 4.5 m , then volume = 1080 m3

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Refer to the above table. The table gives a comparison of the kiln loading withrespect to the loading of all other equipment, both downstream (cement mill) as wellas upstream equipment (raw mill, coal mill). Let us consider the base case: (given inbold italics). The design loading of the cooler is taken as base case. In this case, it is46 tpd/m2 (as per data given by plant). In current day production achievements,cooler loading of 46-50 tpd has become common and achievable, which indicatesthat an immediate target cooler loading can be fixed at 50 tpd/m2. When the coolerloading can be raised 50 tpd/m2 by internal modifications, the kiln volumetric loadingcan become 3.9 tpd/m3 ..

At the base case, the volumetric loading at 3.3 tpd/m3, when compared to presentday conditions, is very low and levels of upto 4.5 tpd/m3 is very common and thelatter is achievable.

At the achievable cooler loading levels of 50 tpd/m2 the required running hours ofraw mill becomes 20 hours/day, while the coal mill running hours will be 13, and thatof cement mill will be 22 hours/day. Thus, reaching a cooler loading level of 50tpd/m2 is achievable, as the upstream and downstream equipment have sufficientcushion in their capacities. Thus the management should take immediate steps toreach a cooler loading of 50 tpd/m2• In such a case, the production will go upto by10%, with a corresponding reduction in the specific energy consumption.

Energy conservation schemes given under Para Nos. 3.2 and 3.3 will facilitateachieving a kiln loading higher than the present.

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3.0 ENERGY COST SAVING MEASURES (ECM) AT HOANG THACH PLANT

3.1 Improve kiln combustion efficiency by reducing the false air ingress atthe preheater section and reducing marginally the sintering level ofclinker

Present system

The 5-stage preheater section, with precalciner matches with the modern well­designed dry process cement plants. Modern dry-process plants typically couldproduce up to 120% of their design capacities, if operated without leaks in thepreheater section. The operating condition of Hoang Thach's line 2-kiln system isshown by the simplified diagram below:

m ..'.SA ••••(n 'Oll'IMt

10 PH Ian-

L.fWJlOr~J'''mmWCh:rn:x.'fdl!lIf •..•01 u..•....10 &C

I Crrlf)l,:h.!I,JI't..'o! Mdt",'u,JI., oc

Simplified schematic diagram ofKILN SYSTEM AT HOANG THACH

(as observed)

Observations of the kiln operating data indicate that the burning intensity of clinker ismaintained at higher levels than the normal requirement. At Hoang Thach, the litreweight of clinker is maintained in the range of 1.30 to 1.40 kg/litre of standard sizeclinker, which is an indicator of the clinker's burning intensity. Typical cement kilnsthat produce and market similar grades of cement maintain around 1.2 kg/litre of·standard size clinker.

Discussion

The preheater fan typically pulls the hot gases from the kiln system typically at 52 ­55 mbar suction pressure. Hence the leaks, especially close to the preheater fan'sinlet reduce the exhaust gas handling capacity of the kiln system. The on-line O2analysers at the kiln inlet and at stage-1 preheater outlet are the indicators of air­leaks into the system. The analyser at the kiln inlet needs more maintenance due to

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the heavy dust loading and high temperature. Also it helps for the combustionmonitoring of only the kiln burner. If the sampling point of this analyser could berelocated to the duct downstream to the precalciner, it could help monitor thecombustion conditions at both the kiln and PC burners. Since the temperature wouldbe marginally lower to help better performance between each sample point cleaning.The field inspection of preheater section by the consultants identified multiple leaksof significant sizes. Many leaks identified were shown to the Hoang Thach engineerduring our field inspection.

The false air entering to the preheater section is calculated as shown below:

False Air quantity estimation

O2 % outlet

If False Air entering the system is X kg. moles,

CYCLONE /'l----, XPREHEATERS~

y 02% inlet

Quantity of gases in the system is Y kg. moles,

from Oxygen balance;

X (02%outlet - O2%inlet )

= --------------------- 0/0

Y (21 - 02%outled

Heat and material balance calculations were ana lysed to evaluate the effects ofincreased Clinker production when the leaks are fixed. About 5 tonnes/hr ofadditional clinker production from the kiln is possible, if the preheater-fan pulls thesame amount of gas from kiln and precalciner, instead of false air.

The heat balance Sankey diagram in the following page shows the present andimproved condition:

Spe<:lflc HeRt ConeUn"lption 870.6kCalslkgof Clinker 854.5

Heat lost withPr.h •• ter

Exhaus·t B'":UOS

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The heat balance calculations with less false air leaks and at equivalent improvedclinker rate are shown in Attachment 3.1.1.

Recommended solution

The following action points are recommended to improve the kiln productivity andenergy efficiency:

1. Fix the all the identified leaks on a priority basis in the next availableopportunity. It is more beneficial to allocate dedicated man-power forpreheater section leak fixing on a regular basis.

2. Relocate the present sampling point for the on-line O2 analyser at the kiln inletto the gas duct after the precalciner, but before it divides towards the fifthstage cyclones. This would enable a better performance for the analyser dueto slightly reduced temperature and dust loading.

3. Maintain the difference between the two O2 analysers (precalciner outlet andpreheater-fan inlet) to less than 1% at any time. The O2 content in preheateroutlet gas stream should be maintained below 5.5%. This would keep thefalse air ingress to the minimum.

4. Reduce the burning intensity of clinker in steps towards 1.2 kg/litre from thepresent levels of 1.3 kg/litre. After each step stabilize the burning intensity fora week and observe the cement properties. Reducing the burning intensity(litre-weight) of clinker should also reduce the specific electricity consumptionin the cement mill.

Estimated benefits

Implementing the above actions is expected to reduce the kiln's fixed energy lossesand also would lower the specific heat consumption by 16.1 kcals/kg of clinker. Theannual energy cost savings to Hoang Thach due to reduced energy losses iscalculated at VND 2420 million ($134,000) for 8400 hrs/yr operation. The savingscalculations are included as Attachment 3.1.2.

Preliminary investment estimate

Fixing the leaks in the preheater section connecting ducts, the preheater-fan inletduct flange seal, many other seals of inspection opening and man-holes at thepreheater cyclones, Relocating the sampling point form kiln inlet to precalciner outletand replacing with a new 02 analyser (if, necessary) are estimated to cost VND 3240million (US$180,000). The recommended actions include the dedicated services ofthree technicians for the leak identifying and fixing job. The cost for this additionalmanpower is estimated at VND 650 million annually, making the total investment asVND 3890 million. The investment is expected to have an attractive simple paybackperiod of 20 months.

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3.2 Improve cooler performance by uniform clinker distribution over thegrate plates

Present system

There are 13-fans that supply cooling air to the clinker cooler. Additionally, 2-boosterfans also supply air into the cooler to the kiln outlet end. The cooler air flow ispresently controlled to achieve the desired clinker outlet temperature of about 100°C.The clinker temperature at the cooler outlet was observed to be high in the range of210 - 240°C. The present reported supply air to the grate cooler based on the meterreading seems to be very low. The temperatures of the secondary and tertiary airthat are recycled back from the cooler are observed at 950°C and aoooerespectively. The cooler vent air temperature was observed at 250°C. Thesimplified schematic diagram of the Hoang Thach cooler is shown below:

CLINKER

Cooler Vent Air toESP & Coal Mill

Primary Air

Uneven clinkerbed thickness

over the grateplates

-200°C

Discussion

A grate cooler require a uniform bed thickness of clinker over the grate plates tomaintain the good heat transfer efficiency. The high clinker temperature at cooleroutlet indicates the heat transfer inside the cooler is not very effective. The videomonitoring of the cooler indicates air flow only at the sides of the clinker bed. Thecenter of the clinker bed seems to be moving without any cooling. The higher outlettemperature of clinker (-200°C) would restrict the efforts to increase the clinkerthrough-put at the kiln.

If the clinker bed is uniformly distributed over the width of the grate bed, betterclinker productivity could be achieved with the same cooling air supply. It is possibleto improve the heat transfer efficiency of the cooler with modified internals anduniform clinker bed thickness.

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Recommended solution

The following actions are recommended to improve the grate cooler efficiency:

1. Review the existing internals and grate plates of the cooler and replace themwith internals and plates that would match with the high efficient design coolers.

2. Modify the refractory wall of the cooler at the kiln outlet side to facilitate betterdistribution of clinker over the full width of the Grate plates. The suggestedconceptual modification for the refractory wall is shown below:

Existing Condition

Cooling Air

Proposed RefractoryInterceptors

Better ClinkerDistribution on Grate

3. Monitor the clinker bed thickness and total air flow to the cooler to maintain the

clinker outlet temperature close to 100°C.

Estimated benefits

By modifying the cooler to maintain better heat transfer efficiency, Hoang Thachcement plant could improve its clinker production from the kiln system to 3500 tpdfrom the present 3200 tpd level. The kiln system's specific heat consumption Isexpected to improve from 854.5 to 834.7 kCals/kg of clinker, as per the heat balancecalculations shown in Attachment 3.2.1. This heat savings of 19.8 kCals/kg ofclinker is expected to yield an energy cost savings of VND 3.07 Billion (US$170,600) annually at the present coal purchased costs. The savings calculation forcooler performance improvement is shown in Attachment 3.2.2.

The Sankey diagram below shows the heat balance indicating the reduction inspecific heat consumption:

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Specific Heat Consumption ~kCal~g of Clinker ~

Preliminary investment estimate

~~H.atabsorb.d by

ClinkBnution

The recommendations to improve the cooler efficiency involve the refractory wallmodifications at the kiln outlet side. Based on our discussion with experts in this fieldwe have estimated the costs for all the above recommendations as VND 2.380 billion

(US$132,000). The simple payback period for this investment is attractive at lessthan 10 months.

3.3 Install a new preheater cyclone at stage-1 and recover additional wasteheat from kiln exhaust gases

Present system

Typical preheater cyclone streams in a modern dry process cement plants aredesigned with twin cyclones at stage-1. Unfortunately the Line #2 at Hoang Thach isdesigned with only one stage-1 cyclone. It was not considered as a big deficiencywhen the energy prices were low. However, when the energy prices have increased,cement plants that spends >35% of their production costs for energy, need tobecome more energy efficient. Otherwise, they cannot survive in the long run withnew energy efficient cement plants. Hoang Thach is no exception to this time bound.necessity. Hoang Thach's line #2 kiln exhaust gases are leaving to atmosphere at380°C, (at least 50°C higher compared to plants built after the year 2000). Theoperating condition of Hoang Thach kiln system is shown by the simplified diagrambelow:

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llo<ln" Thach Ccmcn( Encr' Audi( Rc )011: Sc (cmbcr 2009

Kiln system exhaust gas temperature at 382°C

Simplified schematic diagram ofKILN SYSTEM AT HOANG THACH

(as observed)

ToAtlM....•

"'"

PRf CALCINI:R

ROrARY tOl N

LlJi&.IlIl

Draftntrlll\'\'Cl~ROIC.Il\.,-el..,'of"-'_ • .eotlA_ •••• If' oc

Discussion

Since the existing 5-cyclones already recover the maximum possible heat by them,to recover more heat from the exhaust gases, additional preheater cyclones arerequired. Adding a new preheater cyclone to an existing plant has at least thefollowing challenges:

1. Availability of space for a new cyclone at the existing support structure.2. Availability of pressure head and capacity at the preheater fan

Since the additional recovered heat would increase the clinker rate at the kiln,3. Handling capability of higher clinker rate at kiln and cooler,4. Capacity margins at the kiln burner, PC burner, and at the coal mill5. Capacity margins at the cooler fans.

Our preliminary verification of capacities of burners and coal mill confirm their 10%excess handling capacity. The preheater fan as of now handles at least 12% falseair due to the leaks in the preheater section. The cooler with the suggestedimprovements for uniform clinker-bed distribution can handle an additional 10%clinker. Some of the cooler fans are already operated at partial loads / speeds.

The real challenge is installing the cyclone at the existing preheater structure. Theconsultants observed during their site walk, that enough space for a new cyclone isavailable between stage 1 and stage 2. A good and skilled structural designengineer can successfully complete this challenging job. Hence it is possible to addanother cyclone to the existing preheater stream at Hoang Thach's line #2.

Heat and material balance calculations were analysed to evaluate the effects ofrecovering more heat from exhaust gases and increased clinker production. Sincethis recommendation should be implemented after the cooler improvement, the heatbalance analysis also was carried out in the same sequence to avoid double dipping

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Hoang Thach Ccmclll Energy AudIt Report: Scptember 2009

on savings claims. About 8.5 tonnes/hr of additional clinker production from the kilnis possible, if an additional preheater cyclone is installed at line #2.

The heat balance Sankey diagram of present and improved condition is shownbelow:

HeatLon byKadlation

6.0% I6.0"/.

Specific Heat Consumption ~kCa~/kgofCI nkcr ~

lI.atLost withPreheater

Exhaustl:a.5es

~ H•• t.h,nrhprlhv~ Clinkerisation

The heat balance calculations with additional preheater cyclone and improved clinkerrate are shown in Attachment 3.3.1.

Recommended solution

The following action is recommended to improve the kiln productivity and energyefficiency:

Design and install a suitable preheater cyclone at stage-1 of the existing preheaterstream at line #2. The additional cyclone would recover heat from the kiln exhaustgases and enhance the clinker thru-put in the kiln system.

The proposed schematic arrangement is shown below:

19

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..- -01- 4.0,.

loPH l.:ln•••• 1

..."

Wlflt.IlOrllft In nvn\VC

IcrJ"l,.ll..'lJUi'C 01 0", ...fl'{;.ll'fl~'1dC-.. •..·"lM ••k'lkil.l"C

J IOllng Thach Ccmcnt Encrgy Audit Rcport: Scptembcr 2009

Exhaust gas temperature reduced to 295°CSimplified schematic diagram ofKILN SYSTEM AT HOANG THACH

(as proposed)

Additional preheatel' cyclone at Stage 1

Before moving forward with the additional preheater cyclone project, two criticalaction items indicated below should be completed.

1. The recommended kiln and cooler improvement actions to be completed firstbefore adding the new cyclone at the preheater section.

2. The excess handling capabilities of the preheater fan need to be reviewedand reconfirmed. If necessary additional booster fans capacity should beincluded.

Estimated benefits

Implementing the above action is expected to improve the kiln's energy efficiencyand reduce the fixed energy losses. The action when implemented would lower thespecific heat consumption by 63.8 kCals/kg of clinker. The annual energy costsavings to Hoang Thach due to the improvement is calculated at VND 10.48 Billion($582,000) for 8400 hrs/yr operation. The savings calculations are included asAttachment 3.3.2.

Preliminary investment estimate

Adding a new preheater section at the existing structure would be more challengingthan a new design. However, the available space in the existing structure and thedesign margins in the fan capacities are expected to be fully utilized.

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Iloang Thaeh Cement Energy Audit Repol1: September 2009

The preliminary estimated to cost to add a preheater cyclone is VND 27.0 Billion(US$1,500,000). The investment is expected to have a simple payback period of 31months.

3.4 Utilize cooler vent air as primary air to the kiln burner

Present system

- 201JoC

CUNKER

Fuel(Cool)

Primary Air

At present cold air is supplied as the primary air to the kiln burner and to theprecalciner. The present arrangement is schematically shown below:

12% of total combustionair is supplied as coldprimary air

Discussion

When cold air is supplied for combustion it is heated to the flame temperature usingthe heat of the fuel. If hot air is supplied to the burner instead of cold air, the thermalefficiency of the burner would improve. Also, the flame would be more stablecompared to cold air burners. Near the kiln burner hot air from the cooler is ventedto atmosphere at 250°C.

Recommended solution

It is proposed to connect the suction duct of the primary air fan from the cooler ventduct. This would enable hot primary air supply to the kiln burner. The suggestedschematic arrangement is shown in the schematic diagram below:

-Primaq Air

F .1(011)

Cooler Venl Air toESP & Co<.! Mil

-2OC--e

CLINKER

Hot airsupply ductto primaryair fan

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Iloang Thach Ccment Energy Audit Report: September 2009

Estimated benefits

By supplying hot air as primary air, about 0.365 GCals/hr (2.6 kcal/kg clinker) of heatcould be recycled back to the kiln system, instead of rejecting it to atmosphere. Thiswould save Hoang Thach about VND 685 million (US$ 38,000) annually. Thesavings calculations are included in Attachment 3.4.1.

Preliminary investment estimate

The recommendation to supply hot primary air to kiln burner is to provide aninsulated duct between the existing cooler vent duct and the primary air fan's suctionduct. The preliminary cost to provide this interconnecting duct with its isolation valveis estimated to be VND 740 million (US$ 41,000). The existing fan is expected tohandle the hot primary air.

3.5 Generate electricity from the waste heat of PH exhaust and cooler ventstreams

Present system

At present about 34% of the total heat input to the kiln system is vented toatmosphere through the preheater exhaust gases and the cooler vent air. Only asmall portion of this vented heat is utilized at the raw mill and coal mill. The heatbalance diagram of the Hoang Thach kiln system indicates the heat losses as shownbelow:

RawM&al

Exh. gases toPH fan 19.4% of the total heat

input

CO, IBIs",. fram Gac,natJ(x' 44 kgslkgci Ceca,

Heat of Cimkonzatlon _" " 450 kC81slkg ci Clmk.,-

ROTARY KILN

Primary Air

Fuel

CLINKER COOLER

Cooler Supply Air

14.7% of thetotal heat

input

CLINKER

.-

Discussion

Since the Hoang Thach plant design already incorporates many possible heatrecycling features like the raw meal preheating cyclones and secondary and tertiarycombustion air supply from cooler, any additional utilization of the rejected heat mustconsider converting this into other useful forms of energy. The second largestenergy need in a cement plant is for the electricity. Hence this rejected excess heat

22

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'-

Iloang Thaeh Cement Energy Audit Report: September 2009

would be more useful to the cement plant, if it is converted into electricity. Thoughconventional Rankine cycles are well established for converting high temperatureheat (>800°C) into electricity, they are not very efficient for converting lowtemperature heat «300°C) into electricity.

Organic Rankine Cycle (ORC) power plants have become popular since the recentenergy cost hikes and they are commercially supplied by various manufacturers nowaround the world. For moderate enthalpy heat sources, ORC cycles offer manyadvantages over the conventional steam cycle, primarily due to the simplicity of theturbine, the control system, and the balance of plant. In an ORC plant the turbineand piping sizes are smaller and thus less costly due to the fluid density differences.The condensing pressure in an organic cycle is generally above atmospheric thuseliminating the need for complex vacuum and gas purging equipment that is utilizedin a steam condensing cycle. When the organic vapor expands in the turbine itbecomes superheated or dryer, unlike steam which becomes wetter during theexpansion process. Therefore, superheating of the organic vapor prior to delivery tothe turbine is not required. Since organic fluids have a low freezing temperature,there is no freezing in the condenser, even at extremely low ambient temperatures.The conceptual scheme of the ORC power plant is shown below:

Typical Organic Rankine Cycle Power generation

, -

~, < _ < EliaporalOr

Rejected Heat

Recommended solution

It is proposed to install an ORC power plant near Hoang Thach kiln system that.would utilize the heat from cooler vent air stream and then from the preheaterexhaust gas stream.

More details about the ORC power plant installed in a cement plant in Europe isincluded in Attachment 3.5.1. The proposed heat recovery coils would have suitablesoot blowing provisions to maintain effective heat transfer for longer durations.

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Iloang Thach Ccmcnt Encrgy Audit Rcpoli: SCfltcmbcr 2009

Estimated benefits

The heat balance calculations indicate that an ORC power plant could produce about3.9 MW of electricity at 10% conversion efficiency. By recovering the wasted heatand generating electricity through an ORC power plant, about 10 - 15% of HoangThach Cement plant's electricity needs could be internally generated. The estimatedpower cost savings for Hoang Thach cement plant would be VND 32.18 billion (US$1.79 million) annually at the present power costs. The calculations for potentialpower generation from waste heat recovery and monetary savings are shown inAttachment 3.5.2.

Preliminary Investment estimate

Since ORC power plants are commercially available from many vendors in Europe,Japan and USA, the installed project costs has come down nowadays. However thedust handling in heat recovery is a challenge that has been successfully met throughcareful heat recovery coil designs. The preliminary cost estimate to install a 4.0 MWORC plant is estimated to be VND 187.2 billion (US$ 10.4 million).

3.6 Install variable frequency drive for raw mill fan motor (R2S20)- line 2

Present system

Exhaust from raw mill is done by a fan (R2S20), which is of rating 1700 kW, 6 kV.This fan is regulated by damper control and the fan is highly oversized (damper openjust 30% ) for the present level of operation and requires immediate attention tooptimize power consumption.

The fan has the following design parameters:

Volumetric flow: 77.59 Nm3/sec

Static pressure at fan inletStatic pressure at fan outletPower consumptionMotor rating

Proposed system

= 115 m3/sec at 90°Cc',= 10295 mmwc= -500 mmwc= 1424 bkW= 1700 kW

It is recommended to install variable frequency drive for this fan. Already thepreheater fan (J2J15) upstream of the raw mill fan is retrofitted with a variablefrequency drive and the fan downstream (of raw mill fan) also has a VFD on it. Thus,when this fan is also brought under VFD, then the entire process of exhaust will be·dynamically controlled and hence will result in better process control.

Chart showing the comparison of power consumption of different types of capacitycontrol is given as Chart 3.6.1.

Based on the initial observations, a minimum energy savings of 30 % can bepossible on installing VFDs.

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l!oang Thaeh Cement Energy I\udit Rep0l1' September 2009

Estimated benefits

The annual energy savings will be 2.08 million kWh, equivalent to about VND 2404million.

Preliminary investment estimate

This is expected to be within VND 7200 million (investment figure as per detailsavailable with the plant for another drive). The savings calculation for coolerperformance improvement is shown in Attachment 3.6.1.

Screen shot of raw mill operating parameters

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Hoang Thach Ccmcnt Energy Audit Rcport: Scptembcr 2009

Chart 3.6.1: Chart showing types of flow control vs power requirement

Flow control types vs power

120

100806040200% flow

2040

60 80 100

--+--VFD

_ throttling

cyclic control

3.7 Replaceexisting inefficient equipment· preheater fans in line 1

Present system

Production line 1 was commissioned during 1983 and is still in operation, with manyof the original equipment running now. The preheater fans (2 nos.), J1J01, J1J02,are among of the high power consuming equipment. These fans are rated 1000 kW,coupled through gear to the motor. These fans have the following designspecifications:

FlowHeadFan input

: 5750 m3/min = 95.8 m3/sec: 600 mmwc: 800 bKw

'-

The calculated static efficiency comes to 70 %

(basis: fan efficiency = flow in m31sec x head in mmwcl(102 x bKw)= [95.8 x 600 x100JI(102 x 800) = 70 %

As per details collected from the plant, the fans take a load of 80 % of the ratedcurrent.

Besides inherent low efficiency, the presence of gear drive and damper control,reduce the efficiency further and hence the whole exhaust system suffers from lowefficiency.

Analysis

Production line has been in operation since 1983 and the equipment now operatingare of the older bulkier design. Even though a new line (line 3) is under constructionnow in the plant, the line 1 is expected to continue even after the line 3 iscommissioned. The presence of planetary type of clinker cooler also limits the extentof overloading of the kiln. Cost of operation of older rotating equipment alwaysoverweigh the initial costs and should be a practice to replace them after 10-15 yearsof operation.

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] loang Thaeh Cement Energy Audit Report: September 2009

Proposed system

It is recommended to replace the fans with latest type direct drive fans. Currentcentrifugal fans for heads as high as a 700 mmwc have high efficiency levels of 82­85 % and also help eliminate gear drives. Replacement of fans requires shutdowntime and this kiln has enough downtime and hence can be carried out in phases

Estimated benefits

The annual energy savings will be 1.92 million kWh, equivalent to about VND 1885million.

Preliminary investment estimate

This is expected to be within VND 3000 million. The savings calculation for coolerperformance improvement is shown in Attachment 3.7.1

3.8 Replace existing inefficient equipment - raw mill fan in line 1

Present system

Production line 1 was commissioned during 1983 and still has many of theequipment still running. The raw mill fan R1P09 is one of the high power consumingequipment. This fan is connected to a slip ring motor of 1900 kW, coupled throughgear to the motor. These fans have the following design specifications:

Flow : 6050 m3/min = 100.8 m3/secHead : 1050 mmwc

Fan input : 1540 bKwCalculated static efficiency: 67 %

(basis: fan efficiency = flow in m31sec x head in mmwcl(102 x bKw)= [100.8 x 1050 x100JI(102 x 1540) =67 %

As per details collected from the plant, the fan takes a load of 80 % of the ratedcurrent.

Besides inherent low efficiency, the presence of gear drive and damper controlreduce the efficiency further and hence the whole exhaust system suffers from lowefficiency.

Analysis

Production line has been in operation since 1983 and the equipment now operatingare of the older bulkier design. a new line (line 3) is under construction now in theplant, the line 1 is expected to continue even after the line 3 is commissioned. Thepresence of planetary type of clinker cooler also limits the extent of overloading ofthe kiln. Costs of operation of older rotating equipment always overweigh the initialcosts and hence it should be a practice to replace them after 10-15 years ofoperation.

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Hoang Thach Cemcnt Energy Audit Repol1: Septcmber 2009

Proposed system

It is recommended to replace the fan with latest type direct drive fan. Currentcentrifugal fans for heads as high as a 1050 mmwc have high efficiency levels of 80% and also help eliminate gear drives.

Estimated benefits

The annual energy savings will be 1.49 million kWh, equivalent to about VND 1460million.

Preliminary investment estimate

This is expected to be within VND 3000 million. The savings calculation for coolerperformance improvement is shown in Attachment 3.8.1.

3.9 Install mechanical conveying system for kiln feed in line 1 to eliminateenergy-intensive present pneumatic conveying

Present system

Production line 1 was commissioned during 1983 and still has many of theequipment still running. The preheater is a 4-stage, 2-stream system and the feedingsystem is by a pneumatic conveying consisting of Fuller pump and one air. Thepump has a rated air consumption of 75 Nm3/min at 1.8 atm and is connected to amotor of 130 kW. The air for the conveying is supplied by an air compressor of rating150 kW. Together the system has a connected load of 280 kW, and thus for the 2streams, the total connected load is 560 kW.

Analysis

The transport of kiln feed is normally done through pneumatic conveying systemssuch as air-lifts, in older designs. Conventionally, the pneumatic conveying systemwas being preferred as the mechanical system (particularly the bucket elevator) wasnot very reliable, but many years ago. In the recent years, with the improvement inthe metallurgy, bucket elevators that can operate continuously in a reliable mannerhave been developed. These have been installed in many plants with substantialbenefits. Besides being energy-intensive, the pneumatic conveying system adds(unwanted) cold air to the pre-heater system, thus reducing the thermal efficiency ofthe system.

Production line has been in operation since 1983 and the equipment now operating'are of the older bulkier design. Even though a new line (line 3) is under constructionnow in the plant, the line 1 is expected to continue even after the line 3 iscommissioned. By design, pneumatic conveying is the costliest mode of materialtransport.

Besides being energy-intensive, pneumatic system also adds to the supply ofunwanted air into the system, thus reducing the efficiency of kiln operation. The otherproduction lines, i.e., line 2 and the ongoing line 3 have already mechanicalconveying system incorporated in the original stage itself.

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I !oang Thach Ccmclll Encrgy Audit RCpOl1: Scptembcr 2009

Proposed system

It is recommended to replace the pneumatic system with compact mechanicalconveying. The power consumption of mechanical system is generally 15% ofpneumatic systems. Implementation of this proposal will also facilitate avoiding theunwanted air from entering the kiln, thus facilitating a corresponding increase insecondary air quantity. Increase in secondary air means higher heat recovery andhence reduction in loss.

Estimated benefits

The annual energy savings will be 2.29 million kWh, equivalent to about VND 2250million.

Preliminary investment estimate

This is expected to be within VND 6000 million. The savings calculation for coolerperformance improvement is shown in Attachment 3.9.1.

Note: the present layout of the equipment in line is very complicated and has verylittle free space available for any additions. Thus the proposed system has to bedesigned with experts in the field who can advise suitable layouts keeping intocognizance the present layout constraints

Illustration of conveying systems

"

pre heater Feed

Pneumatic conveyingSimple, but Energy­intensive;Conveying air adds tothe unwanted air

supply into the system

29

Mechanical conveyingEnergy-efficient, butmaintenance-involved

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f10:1Ilg Thach Ccmcnt Encrgy J\udit Rcport: Scptcmbcr 2009

3.10 Install variable frequency drive for coal mill fan (P22)- line 2

Present system

Exhaust from coal mill is done by a fan (P22), which is of rating 530 kW, 6 kV. Thisfan is regulated by damper control and the fan is oversized (damper open just 50 %)for the present level of operation and requires immediate attention to optimize powerconsumption

Proposed system

It is recommended to install variable frequency drive (VFD) for this fan. VFD is themost efficient form of capacity control of rotating equipment.

Chart showing the comparison of power consumption of different types of capacitycontrol is given as Chart 3.10.1.

Based on the initial observations, a minimum energy savings of 20 % can bepossible on installing VFDs.

Benefits

The annual energy savings will be 0.49 million kWh, equivalent to about VND 480.

Preliminary investment estimate:

This is expected to be within VND 600 million. The savings calculation for coolerperformance improvement is shown in Attachment 3.10.1.

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Iloang Thach Ccmcnt Encrgy Audit RCP0l1: Scptcmbcr 2009

ATTACHMENTS

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Attachment 1.1

Typical operating parameters, as seen in the control room

Raw mill process

Coal mill

32

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Kiln process

lloang Thach Cement Energy Audit Report: September 2009

Clinker cooler process overview

33

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Cement mill

Iloang Thach Cement Energy Audit Report: September 2009

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Iloang Thaeh Ccmcnt Energy AudIt Report: Scptcmber 2009

Attachment 2.3.1Heat Balance at existing condition

HEAT BALANCE OF Hoang Thach DRY PROCESS KILNBasis: 3200 tpd Clinker

Reference ambient temp: 25°C

Obse~dCondition

3200HEAT INPUT

Heat input through Raw MealClinker production rateRaw Meal feed rate (@ 0.65 Clinker to Raw meal ratio)

Raw Meal feed temperature (typically around 70 to 100°C)Heat content of the Raw Meal

Share of Heat input by Raw Meal

T/hr

T/hr

°CGCals/hr

133.3

215

752.94

2.5%

116.0997.5%

696416.670.125

119.02

kcals/kgT/hr

GCals/hrTOTAL HEAT INPUT TO THE KILN SYSTEM

Required Heat input from Fuel (from Heat balance based on Heat Output)Heat Input through Coal GCals/hrShare of Heat input by Coal (Fuel)Heating Value of CoalQuantity of Coal fired at both the Kiln & Precalciner

HEAT OUTPUTHeat in Clinker

Temperature of Clinker when coming out of CoolerSensible heat in Clinker

Share of Heat taken out by Clinker

°CGCals/hr

200

4.43

3.7%

Heat of Clinkerization

Typical value of Clinkerization heat in Cement KilnsHeat absorbed by the Clinkerization processShare of Heat consumed by the Clinkerisation process

kCals.kg of CI.GCals/hr

45060.00

50.4%

Heat content of Preheater exhaust gasesPreheater exhaust gases comprises of f1uegases from coal combustion, C02 released from Calcini

False air Ingress in the Preheater sectionsC02 release from Calcination of Raw Meal

CaC03 content in Raw Meal 78%

CO2 release from Raw Meal Calcination T/hr 47.3

Reported Coal/Clinker ratio at Hoang Thach 0.133Amount of Comb. Air requiried to bum this coal T/hr 169.5Stack gas quantity at no excess air (theoretical stack gas) T/hr 175.7

Moles of Fluesgas from combustion of coal kg Moles/hr 6060

Moles of CO2 formed from calcination of raw meal kg Moles/hr 1075

Total quantity of gases passing the PH section in ideal condition: kg Moles/hr 7135

Excess air is added at the burner and through openings in PH/PC/Kiln sections(leaks) to raise the

Oxy content of stack gas as measured at PH outlet (02%) by Vol 5.70%

Oxy content of stack gas as measured at the Kiln Intlet (02%) by Vol 4.30%

Total stack gas quantity at PH outlet (@ the measured O2% le~ls)Excess Air added at Bumer & as False Air 9.2%

'-Moles of air added at Bumer & as False Air up to PH fan

Total quantity of stack gases entering PH fan

Total \.Qlume of stack gases entering PH fan

kg Moles/hrkg Moles/hr

NM3/hr

6537788

174445

35

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Hoang Thach Cement Energy Audit RepOli: September 2009

Heat Balance at existing condition

HEAT BALANCE OF Hoang Thach DRY PROCESS KILNBasis: 3200 tpd Clinker ObseMd

Reference ambient temp: 25°C

Condition

3200Heat content in the Cooler vent air

Total Cooler air supply at the Clinker

NM3/hr280000Total Cooler air supply at the Clinker

kgs/hr362500

Air is suuplied for combustion as Secondary & Tertiary air Total Combustion Air suppliedkgs/hr169522

Estimated share of Primary Air of the total combustion air

12%

Primary Air supplied directly from Fans

kgs/hr20343

Secondary & Tertiary air supply from Cooler

kgs/hr149179

Vented air quantity from the Cooler

kgs/hr213321

Temperature of the Cooler wnt air

°C250Heat content in the Cooler wnt air

GCals/hr16.91

Share of Heat taken out by Cooler wnt Air

14.2%

Heat lost by radiation from the Kiln system

Radiation heat loss at Kiln sectionTotal outside surface area of the Kilnsq.m1356

A-.erage temperature measured at Kiln Radiation heat loss from Kiln @ the Air Velocity of 10m/secRadiation heat loss from Kiln section

GCals/hr

Radiation heat loss at Cooler section Total outside surface area of the CoolerAwrage temperature measured at CoolerRadiation heat loss from Cooler @ the Air Velocity of 2 m/secRadiation heat loss from Cooler section

GCals/hr

Radiation heat loss at PC- PH section Total outside surface area of the PC - PH section (includingducts)A-.erage temperature measured at PC - PH sectionRadiation heat loss at the PC- PH section@AirVelocity of 2 m'secRadiation heat loss from the PC - PH section

GCals/hr

Radiation heat loss from the Kiln system (@6% estimated)

GCals/hr7.14

Share of Radiation Loss in the total heat out from the Kiln system

6.0%

TOTAL HEAT OUTPUT FROM THE KILN SYSTEM

GCals/hr119.02Check on Coal I Clinker ratio

Normal

Specific Heat Consumption

kCals.kg of CI.870.6

36

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•.....

Hoang Thaeh Cemcnt [ncrg} Audit Report: Septcmbcr 2009

Attachment 3.1.1.

Heat Balance at reduced false air ingress at preheater section

HEAT BALANCE OF Hoang Thach DRY PROCESS KILN

I~asis: 3200 tpd Clinker

Obsen.edAt reduced false

Reference ambient temp: 25°C

Conditionair ingress

3200

3200

HEAT INPUT Heat input through Raw MealClinker production rate

T/hr133.3133.3

Raw Meal feed rate (@ 0.65 Clinker to Raw meal ratio)

T/hr215205

Raw Meal feed temperature (typically around 70 to 100°C)

°C7590

Heat content of the Raw MealGCals/hr2.942.80

Share of Heat input by Raw Meal

2.5%2.4%

Required Heat input from Fuel (from Heat balance based on Heat Output)

Heat Input through Coal

GCals/hr116.09113.94

Share of Heat input by Coal (Fuel)

97.5%97.6%

Heating Value of Coal

kcals/kg69646964

Quantity of Coal fired at both the Kiln & Precalciner

T/hr16.6716.36

0.125

0.123

TOTAL HEAT INPUT TO THE KILN SYSTEM

GCals/hr119.02116.74

HEAT OUTPUT

Heat in ClinkerTemperature of Clinker when coming out of Cooler

°C200180

Sensible heat in Clinker

GCals/hr4.433.93

Share of Heat taken out by Clinker

3.7%3.4%

Heat of ClinkerizationTypical value of Clinkerization heat in Cement Kilns

kCals.kg of CI.450450

Heat absorbed by the Clinkerization process

GCals/hr60.0060.00

Share of Heat consumed by the Clinkerisation process

50.4%51.4%

Heat content of Preheater exhaust gases

Preheater exhaust gases comprises of fluegases from coal combustion, C02 released from Calcination andFalse air Ingress in the Preheater sectionsC02 release from Calcination of Raw MealCaC03 content in Raw Meal

78%78%

CO2 release from Raw Meal Calcination

T/hr47.345.1

Reported Coal/Clinker ratio at Hoang Thach

0.1330.133

Amount of Comb. Air requiried to bum this coal

T/hr169.5168.9

Stack gas quantity at no excess air (theoretical stack gas)

T/hr175.7175.1

Moles of Fluesgas from combustion of coalkg Moles/hr60606039

Moles of CO2 formed from calcination of raw meal

kg Moles/hr10751026

Total quantity of gases passing the PH section in ideal condition:

kg Moles/hr71357064

Excess air is added at the burner and through openings in PH/Pc/Kiln sections(leak s) to raise the free Oxygen from.

Oxy content of stack gas as measured at PH outlet (02%) by Vol 5.70% 5.00%

Oxy content of stack gas as measured at the Kiln Intlet (02%) by Vol 4.30% 4.00%

Total stack gas quantity at PH outlet (@ the measured O2°/0 le\els)

Excess Air added at Bumer & as False Air 9.2% 6.3%

Moles of air added at Burner & as False Air up to PH fan

Total quantity of stack gases entering PH fan

Total \Qlume of stack gases entering PH fan

37

kg Moles/hr

kg Moles/hr

NM3/hr

653

7788

174445

442

7506

168131

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Hoang Thach Ccmcnt Encrgy Audit Rcport: Scptcmbcr 2()()9

Heat Balance at reduced false air ingress at preheater section

HEAT BALANCE OF Hoang Thach DRY PROCESS KILNBasis: 3200 tpd Clinker IObsel'\€dAt reduced false

Reference ambient temp: 25°C

Conditionair ingress

I

32003200

Heat content in the Cooler vent airTotal Cooler air supply at the Clinker

NM3/hr280000280000

Total Cooler air supply at the Clinker

kgs/hr362500362500

Air is suuplied for combustion as Secondary & Tertiary air Total Combustion Air supplied

kgs/hr169522174977

Estimated share of Primary Air of the total combustion air

12%12%

Primary Air supplied directly from Fans

kgs/hr2034320997

Secondary & Tertiary air supply from Cooler

kgs/hr149179153980

Vented air quantity from the Cooler

kgs/hr213321208520

Temperature of the Cooler \€nt air

°C250250

Heat content in the Cooler \€nt air

GCals/hr16.9116.53

Share of Heat taken out by Cooler \€nt Air

14.2%14.2%

Heat lost by radiation from the Kiln system

Radiation heat loss at Kiln sectionTotal outside surface area of the Kilnsq.m13561356

A\€rage temperature measured at Kiln Radiation heat loss from Kiln @ the Air Velocity of 10m/seeRadiation heat loss from Kiln section

GCals/hr

Radiation heat loss at Cooler section Total outside surface area of the CoolerA\€rage temperature measured at CoolerRadiation heat loss from Cooler @ the Air Velocity of 2 m/secRadiation heat loss from Cooler section

GCals/hr

Radiation heat loss at PC- PH section Total outside surface area of the PC - PH section (including ducts)A\€rage temperature measured at PC - PH sectionRadiation heat loss at the PC- PH section@ Air Velocfty of 2 m'secRadiation heat loss from the PC - PH section

GCals/hr

Radiation heat loss from the Kiln system (@6% estimated)

GCals/hr7.147.00

Share of Radiation Loss in the total heat out from the Kiln system

6.0%6.0%

TOTAL HEAT OUTPUT FROM THE KILN SYSTEM

GCals/hr119.02116.74

Check on Coal/ Clinker ratio

NormalNormal

Specific Heat Consumption

kCals.kg of CI.870.6854.5

Sal.ings in Heat input

Annual Heat Sal.ings due to the impro\€ment action

Annual Coal costsal.ings

Annual Energy Savings - Kiln Efficiency

38

kCals / kg of CI.GCal/ Yr

1000 VND / Yr

US$/Yr

16.118044

2419541

134419

Page 39: Hoang Th Aches A

Iloang Thaeh ('ement Energy Audit Report: September 2009

Attachment 3.1.2

Energy savings calculation for kiln efficiency improvement

ECM 1a Improve Kiln productivity by reducing false air ingress at the Preheater sectionAt present the Oxygen analyser at the PH exhaust duct is indicating 5.7 - 7.0%.The Oxygen analyser at the Kiln inlet is indicating 4.3 - 5.5%.Visible leaks could be noticed at the Preheater Cyclones, manhole co-.er flanges and other openings.False air ingress between Precalciner & preheater fan inlet seems to be about 10%.By fixing the leaks the false air ingress could be reduced by 0.5 - 1.0% less Oxyegn.As per the Kiln Heat Balance, this reduction in False air ingress wouldImpro-.e the Sp. Heat consumption in the Kiln system from 870.6 to 854.5 kCals/kg of CI.SalAngs in Heat input Y 16.11 kCals I kg of Oinker

Heat Sal.1ngs with less False air ingress @3200 tpd clinker 2.148 GCal1 hrCalculated Heat SalAngs in Kiln system for 8400 hrs/yr operation" 18044 GCals/yrEstimated monetary salAngs $134,419 $Iyr

Estimated monetary salAngs 2,420 million VND/yrReduction in False air ingress could help increase the Kiln productilAty only when the Cooler performance is better.

39

Page 40: Hoang Th Aches A

Iloang Thach Ccmcnt r'ncrg} Audit Rcpol1' Scptembcr 2()(),)

Attachment 3.2.1.

Heat Balance at improved cooler performance

Th h DRY PROCESS KILNHEAT BALANCE OF HoangacBasis:

3200 tpd Cli nker ObservedAt reduced falseImprove.<JCooler

Reference ambi ent temp: 25°C

Conditionair ingressPerformance

3200

3200330(HEAT INPUT Heat input through Raw MealCI inker production rate

T/hr133.3133.3137.~

Raw Meal feed rate (@ 0.65 Clinker to Raw meal ratio)

T/hr21520521~

Raw Meal feed temperature (typically around 70 to 100°C)

°C75909(

Heat content of the Raw MealGCals/hr2.94-2.802.8~

Share of Heat input by Raw Meal

2.5%2.4%2.5%

Required Heat input from Fuel (from Heat balance based on Heat Output)

Heat Input through Coal

GCals/hr116.09-113.94114.7i

Share of Heat input by Coal (Fuel)

97.5%97.6%97-5%

Heating Value of Coal

kcals/kg6964·6964696-1

Quantity of Coal fired at both the Kiln & Precalciner

T/hr16.6716.3616.41

0.1250.1230.12C

TOTAL HEAT INPUT TO THE KILN SYSTEMGCals/hr119.02:116.74117.61

HEAT OUTPUTHeat in ClinkerTemperature of Clinker when coming out of Cooler

°C2001801SCSensibtle he at in Clinker

GCals/hr4.433.933.2i

Share of Heat taken out by Clinker

3.7%3.4%2.8%

Heat of ClinkerizationTypical value ofClinkerization heat in Cement Kilns

kCals.kg of CI.45045045C

Heat absorbed by the Clinkerization process

GCals/hr60.00600061.81

Share of Heat consumed by the Clinkerisation process

50.4%51.4%52.6%

Heat content of Preheater exhaust gases

Preheater exhaust gases comprises offluegases from coal comcustion. C02 released from Calcination andFalse air Ingress in lhe Prehe ater secti onsC02 release from Calcination of Raw MealCaCOJ. content in Raw Meal

78%78%780/.

CO2 release from Raw Meal Calcination

T/hr47.345.146.:

Reported Coal/Clinker ratio at Hoang Thach

0.1330.1330121

Amount of Comb. Air requiried to burn this coal

T/hr169.5168.9167.i

Stack gas quantity at no excess air (theoretical stack gas)

T/hr175.7175.110-173.E

Moles of Fluesgas from combustion of coal

kg Moles/hr60606039599:

Moles of C02 formed from calcination of raw meal

kg Moles/hr1075102610-105E

Total quantily of gases passing the PH section in ideal condition:

kg Moles/hr7135706410-705'

Excess air is added at the burner and through openings in PHlPClKiln sections(leaks) to raise the free Oxygen from zero %.

Oxy content of stack gas as measured at PH outlet (02%) by Vol 5_70% 5.00% 5.00'\1

Oxy contenl of stack gas as measured at the Kiln Intlet (02%) by Vol 4.30% 4.00% 4.000/.

Total slack gas quantity al PH outlet (@ the measured 02% levels)Excess Air added at Burner & as False Air 9.2% 6.3% 63°1.

.-

Moles of air added at Burner & as False Air up to PH fan

Total quantity of stack gases entering PH fan

Total volume of stack gases entering PH fanTotal mass of stack gases leaving the PH fan

Typical temperature of the stack gases leaving PH fan

Heat content in the PH gases

Share of Heat taken out by Preheater exhaust gases

kg Moles/hr

kg Moles/hr

NM3/hr

kgs/hr

°CGCals/hr

653

7788

174445

225844

382­

30.5425.7%

44'

749;

1&781~

21725E

37!28.8L

24.5%

40

Page 41: Hoang Th Aches A

Hoang Thach Cement Energy Audit Report: September 200\)

Heat Balance at optimized cooler supply air flow

HEAT BALANCE OF HOllng Thach DRY PROCESS KILNBasis: 3200 tpd Clinker ObservedAt reduc~c falseImproved Cooler

Referen:e ambi~rt lemp' 25<C

Ccnditionair in£res~Perfo'ma1ce

3200

32003300

Heat contGnl in the Coolar VGnt airTnt'll r.nnlFf ~i, SIIPPY'lt thp. C:link~r

IJM3/hrr

nnnon ,ROnoO?ROnnn

Total Cooler sir supPY at the Clinker

kgs!h,"

JG2!:i00 :G2!:i00JG2!:i00

Ai, i.~ .~rJ(J(l'iF.rlfor r.n'TIh/!!;tim 1M SP.(';onri;ry 8. Tp.rfi:u}' ;;i,"TUlal CUllluu;liuII Ai, :;uppil:!u ky:;!tll1595221749n'7366'

Fs·im;l!P.O Sh'l'P' nf Prim~ry Ai, of thp. !:lt~1r.nmh r~tinn 'I r

'?'In17%1?%

P,illl~11 Ai, ~upliitu uill:!~ly frulfl Fam

ky:;!III"

20343 2099720839

Se:cndClry & Tertiary Lir supply from Cooler

kgs!hr.

1.i9179 153980'52822

Vl:!'II~uoil 4uolllily fIUII' .tl~ Cuu l:!1

ky:;!tll"

213321 208520209678

Tempe'a:ure of the Cooler '/e1t a r

·C250250250

He3t content ir t1E COJler vent airGCalshr

..16.91 16.5316.62

Shsre of Heat taken JLt by Cooler vent Io.ir

"142% 1-1.2'lo~14.1"A

Heet lost by radiation from the Kiln sy",tem

Ra:liation reat loss at Kiln sediQnTotal oJtside sJr'aee ares Jfthe Kiln

"1J~G 1J!:iGlJ!:iGsq.m

Averag~ :emperature measured at <illl Ra~iation I'eat loss from Kin @ :he Air Ve oeity of 10m/seeRajiation ~eat loss from K In sectionGCalshr

RairattOn "ealloo~ el Cooler ~ecli:>r Tnt'll n It~idp.S rr''lr.p. 'lrp.~ 1fthp. r.nnlp."Average :emperature measurnd at :00 err;!;di~tinn ~p.~tInss frnm r.1nJp.r @ nP. A r 'JP.Jrr.ity n:, m/sP.r.RoJi~liulI t l:!~llu:;~ flUl1iCJull:!1 ~l:!~lUII

GCol:;h,P.;di~fl()n "p.~f /()S,~ ~f PC- P!-I.<:p.r:/inn Tulol UJl;idl:! :;J,'o1,;l:!OJl:!~JfU'l:! PC - PH ~l:!1,;liull(nClu~lng~u:t;)AVHag~ :emperature measured at :Ie - PH secti),RoJi~liulI t l:!~llu:;~ cl ,h~ PC- P-l :;~t;tiullilIlAirVeiocly 012 mrsecr;!Cl~iation~eat los~ from the PC - PH section

GCCllshr

Rajiation ~eal loss from the Kiln syslem J@5~o ~slimaledl

GCals/1r"7.14 7.007.0G

Shar~ of RadiCl:icn Loss n the total heat out from the Kiln ~ystem

6.0%6.0%6.0%

TOTAL HEAT OUTPUT FROM THE KILN SYSTEM

GCals/1r119.02116.14111.66Chack on CO:;lIJ ClinJ<H ralio

f\ormalNormalrJormal

Specific Heat Consumption

kCals.kg of CI-HO.D854.5834.1

Sa'ting~ in Heal inputAIl1Lal real SavllQs dUE lJ the impnJ~emEnl ecliont,n1Lal Cool cccl covingc

AnnlJ:lll-np.rJY S:lVInO'> " Kiln I-ttlnF.nq'

kCals J kg JfC.GC31/Yr

1 (00 '1ND I y.lJS$/Yr

16.1

130442419541

n4<11CJ

19.822906

3071499

'70l'i19

'-

41

Page 42: Hoang Th Aches A

'-

J I03ng Thach Ccmcnt Encrgy Audit RCPOl1' Scptembcr 2009

Attachment 3.2.2.

Energy savings calculation for cooler performance improvement

ECM 2 Optimize Clinker bed uniformity over grate plates and improve the Cooler performanceAt present the Clinker temperature leaving the Cooler is observed to be around 200°C.

Due to higher Clinker temperature, the Cooler forces a restriction on Kiln productivity,Uneven distribution of Clinker on the grate plates is also suspected.By refractory wall changes at Kiln end for better clinker distribution andbetter draft control, the cooler performance could be improved by additional 4-Vlu Clinker.Due to 100 tJd improved Clinker production the fixed losses would reduce as per the Kiln Heat Balance.

Reduction in the Sp. Heat consumption in the Kiln system from 854.5 to 834.7 kCals/kg of CI.Savings in Heat input ~ 19.83 kCals/lcg of Clinker

Calculated Heat Savings in Kiln system @4700 tpel clinker 22906 GGalsfyrEstimated monetary savings $170,639 $/yr

Estimated monetary savings 3,()71 million VND/yr

42

Page 43: Hoang Th Aches A

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Iloang Thach Ccment Energy Audit RepOIi: Scptember 2009

Attachment 3.3.1

Heat balance with a new cyclone added at the preheater section

HFAT RAI ANI.F OF Hoanfl Thach nRY PROI.FSS KII N

Basis: 3200 tpd ClinkerIrnprov3d CoolerAfter adding a n3WPH

Reference arrbient temo:

25°C PerfcrmanceCyclone a: stage'

3~00

3500

HI:AIINPUI Heat input through Raw Me31Clinker production rate

T/h137.5145.8

Raw Meal feed rate (@ 0.65 ::linker to Raw meal ratic)

mr212224

Raw Meal feed temperature ~ypica"y aroJnd 70 tJ 100"C)

"C9090

Hoot con:cnt of the Row Mool

GCob/hr289306

Share of -lea: inp.Jt bl' Raw Meal

2.5%2.7%

Required Heat input from Fuel [from Heat balance based on Heat Output)

He••t InpLl throug1 Coal

GCal;/hr114.77112.43

Share of -lea: inp.Jt bi' Ccal (Fuel)

97.5%97.~%

Heating Value of :oakcal~/kg6!.'646964

Quartity of Coal iired at both :he Kiln & Precalciner

TII'r1G.401G 14

0.120O. '11

TOTAL HEAT INPUTTO THE KilN SYSTEMGCal,/hr117.66115.49

HEAT OUTPUTHeat in ClinkerTemperature of C inker when com ng out cf Ccoler

°C150'50Sensible hea: in Clinf:er

GCal,/hr327346

Share of -lea: taken out by Clinker

2.8%3.0~

Heat of ClinkerizaticnTypical value of Qinkerizetion heat in Cement Kilns

kCa s.kg of CI.450L50

H••at absJrbed by the Clinkerization p-ocess

GC••I;/hr61886563

Share of -lea: consumed by tle Clink3risation pro:ess

52.6%56.~%

Htli1ll;UlIltllll ur PI tllltli1ltll tlxlli1usl Yi1StlSPreheate' exhau~t gases comprises of f1u3gases from coal combustion. C02 r31easedfrom Ca cination andFalse air Ingress in :he Preheater sectionsC02 release frorr Calcination of Raw MealCaC03 conte1t in Raw Meal

70%70%

COz '010000 from Row Meal Colci10tion

T/~r46.54~.4

Reported Coal/Clinke- ratio at Hoang Thach

0.1280:20

Amount of Comb. Air requiried to burn thi~ coal

T/~r167.7165.7

:stack ga, quantity at no 3xcess air (theoretical stack gas)

Inr1fHl1fL,tl

Molo:: of Flucogo:: from cJmbuotion of coolkg Moloo/hr5&935959

Mole, of CO, formed from calcination of raw meal

kg Moles/hr1(58l' 2.2

Total quantity of gases pessing the PH SectiOl in ideal condition:

kg Moles/hr7(517081

Excess air is added at the burner and through openings in PH/PC/Kiln secfions(leaks) to raise the free Oxygen from ze1) %.Oxy ;ullltml Jr ~lad<. yaS a~ ITlea;Uleu al PH uull~l (02%:'

by Vul5.00%5.00%

Oxy :ontent Jf stack gas as mea3ured at the I<iln Intlet (0,%)

by Vol4.00%4.00%

Total stack g~s quantity at PH outlet :@ the meaGured ~% lEvels) Excess Air ajded at 3urrer & as False Ar

6.3%6.3%

Mole, of air addej at Burner & as Fal,e ,ojr up to "'H fan

kg fVIolesfhr441L43

Total qU<lntity of ~tack ga;es entEring PH fan

kg Moles/hr74927524

Total volume of stack gases entering PH 13n

r~M3thr167~13168528

Total mass 0: stack gase, leaving the PH fankgsihr217L58218'84

Typical temperature cf the steck gases leaving PI- fan

0<";~75295

Ileat con:ent in the PI I gases

GCals/hr20042270

Share of -lea: taken out by Prehe3ter exh3ust ga~es

24.5%19.7%

43

Page 44: Hoang Th Aches A

Hoang Thach Lemcnt rncrg} AudIt Rcport: Scph':lllbcr 2009

Heat balance with a new cyclone added at the preheater section

Th h DRYPROCESSKilNHEAT BALANCE OF HoanClacBasis:

3200 tpd Clinker Improved CoolerAfter adding a neVi PH

Reference ambent temp: 25°C

PerformanceCyclone at stage 1

3300

3500

Heat content in the Cooler vent airTotal Cooler air supply at the Clinker

NM3/hr2830002fOOOO

Total Cooler air supply a1the Clinkerkgs/hr362500362500

Air i::; :;uuplit:u fur t;ullluu::;liurr <1::; SevUflUiifY & Tf!rli<1ry <1;r Total Combustion Air suppliedkgs/hr173661172674

E~lilll~lt:u ~halt: u· Prilll~IY Air uf lIl~ luLal cU"llJu~liurr air

12%12%

Primary Air supplied directly from Fanskgs/hr23839£0721

Secondary Ii Tertiary air supply from Cooler

kgs/hr1020221[190J

Vented air quantity from the Coolerkgs/hr203678210547

Temperature of the Cooler vent air

·C250250Heat content in the Cooler vent air

GCals/hr16.6216.69

Share of Heat taken out by Cooler vent Air

lL.l%14.L%

Heat lost by radiation from the Kiln system

Kadiation heat loss at Krln sedionTulal Lul~iut ~U1fa~t:art:a uf llit: Kilrr~q_J11

13561356

Average temperature me3sured at Kiln Rauialiurr lit:allu~~ frulII Kil" @ lIrt: Ai, Vt: ucily Jf 10,,1I~t:cRadiation heat loss from Kiln sectionGCals/hr

Radiation heat los~ at Cooler sec;tior Total cutside surfa:e area of the CoolerAverage temperature me3sured at CoolerRadiation heat loss from Cooler @ tte Air 'Jeloci:y of 2 mlsecRadiation heat loss from Cooler sect onGCals/hr

Kad,ation heat loss at PC- PH section Total cutside surfa:e area of the r'C - r'H ~ectior (incluoingducb)Average temperature me3sured at PC - PH sectionR.adiation heat loss at th3 r'C- r'H section@AirVelocity )12 rnI.ecRadiation heat loss from the PC - PH sectionGCals/hr

Rodiotion heot loee from the Kiln ey~tem (@6% cetimcted)

GC~le/hr7.066.93

Share of Radiation Loss in the total heat out frorr the Kiln system

60%6.0%

TOTAL HEAT OUTPUT FROM THE KILN SYSTEM

GCals/hr117.66115.'19Check on Coal I C inker 'atio

NormalNormal

Sppcific Hpat Consumption

kCals.kQ ofC!.834.777C.9

Savings in Heat inputAnllrrJ'li Hp.J'ltSJ'lvin)!'; rlrrp.tn thp. imrmVp.mFnt J'lr.tinnAnllu~ Coal cost savings

Annual Energy Savings Kiln EfficiEncy

kCals I kg of CI. rGr.~11Yr r

1000 VND I '(r r

US$Nr ,.

63.87R1:r1

10475386

581966

44

Page 45: Hoang Th Aches A

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lloung Thach Ccmcnt Encrg} Audit Rcport: Scptembcr 2009

Attachment 3.3.2.

Energy savings calculation for adding a new cyclone at the preheater section

ECM 3 Improve Kiln productivity by adding 0 new cyclone ot 5toge 1 of the preheoter section

At present the Kiln exhau5t Qases are lea'tinQ lhe p-ehe3ters a: about 375 - ~85uC.\/lost modern dry pro:e;s Kiln; have either 6-sta3e prerec.ters or 2.stream, ~-stage preheate·s.

n :he mojern plan:s the exhaust gas temperature is reduced tJ about 235~C, by recovering more heatSince Hoan~ -hach's exi!:tinq Line #2 is performinQ well, adcin=l an addili01a cyclone at stape-1 coulc

mprovl' the ki n ;ystl'm efficie1cy 6. prcductivi1y significantly.

As p:lr the Kiln Ileat DcJalce, th s additional h:lat recJvery from exhaust g3S:lS & 10% addition31 :hru-pu:

'Nould Improve the Sp. He3t con!:um!'Xlon Jt :he Kiln sy!:tem trcm KJ4J :0 110.3 IcC31s/kg ot ~1.~::Nino~in HP';lt np"t ,.. hl 77 ~r.fL••., kry nf rJinh~r-1eat S3vings with ess False air ingress @3200 :pd clinker a.30) Geal/1r

Calculctej Heat Savi1gs in Kil1 system for (400 hrs/yr operation'" 781231 GCals/yr::stimated monetary savirgs $581.965 $Iyr

Estimated menetary savings 10,-175 million VND/yr

-<iii, re~Ll ale 'le~Ll~ lu lJe illt:ft1a:;eu lu iIIaifilaifi .he Kiln ~plelll'~ ltJellllal J,Jluflle,whefl mUle h~a. i~recovered ct staQe 1 prereater.

Attachment 3.4.1.

Energy savings calculation for supplying hot primary air

ECM4 Utilire Cooler vent air as primary airI he 3pproXlmat~ ratle ot Kiln &. fJre:alclJ1er coal trtng IS 40% &. bl%.Tota quartity 0; CJal burnt in the Kiln & Jrecalciner bLrnersQuantity cf Coal burn: al the Kilr burrmQuantity cf Primary air !:u~ly to th~ ~:iln

CJoler \/e1t air temperalure

Arnbiert air temperature

H~at recycld bock to the eyetern by ::ooler vent air

C31culated Heal S~v;ng~ in I{iln system @ 8400 hrs/yr & 60% eff.

Lstima:ed monetary savill9sE~lilrlaleu rnul elal Y ~Cl'/iflY~

45

16.5 Tlhr

6.6 Tlhr7.54 T/Hr

250 °C300C

0.365 SCale/hr

5106 8Cals/yr

~JO,030 li/yr685 Jllilliull VNDly.

Page 46: Hoang Th Aches A

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I !oang Thach Cement hlerg} I\udit Report: September 200l)

Attachment 3.5.1.

Details of the ORC power plant installed at the cooler vent of 2850tpd kilnTechnical Data of the ORC plant installed in an European cement plantPlant dataPlant Production

1 million tpa (2850 tpd Clinker)Heat reco-.ered from the Grate cooler

8.2MWt

Grate cooler air flow

150,000 NM3thr

temperature out (range)

275°C - 125°C

Thermal Oil cycle Thermal oil flow85 t/hr

temperature out (range)

230°C - 85°C

OEC data Rated generation capacity

1.5MW

Vaporiser typeTube and Shell type

MaterialslEMA Class 'C' BEM

Tube and ShellCarbon steel

Cooling side data Cooling media

Ambient airOEC Turbine Turbine Manufacturer

ORMAT

Turbine TypeSpecially designed impulse type

Rotation shaft speed3015 rpm

Generator Rated output

1.5MW

Rated Voltage690V / 50Hz / 3-phase

Type

Induction

Rotation speed at full load3015 rpm

Number of Poles2

Moti-.e Fluid Working Fluid typeHydrocarbon ( N-Pentane)

Electricity generation1300 kW continuous operation varying according to inlet conditions,

due to changes in Grate cooler -.ent temperaturePlant's power sa';ngsThe generated power is equivalent to about 12% of the plant's

own electricity demandMode of OperationUnattended, fully automatic, remote monitoring

Additional effects of the projects

Reduces pollution of CO2 by 7600 tpa.

Equipment deli-.ery time

25 weeks

Erection time

3 weeks

System availability- a\g o-.er 1st 5-years

Abo-.e 98%

Recorded yearly maintenance cost o-.erUS$6,800 (equivalent to less than 0.001 $/kWhthe 1st 5 years of operation (avg)

Source: World cement April 2004

46

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J foang Thach Ccmcnt Encrgy Audit Report: Seplembcr 2009

Attachment 3.5.2.

Energy savings calculation for Waste heat recovery and power generation

Generate Electricity from the waste heat rejected at the Cooler & Preheater exhaust streamsTotal heat rejected at the Cooler vent air & PH exhaL.stgas streams 39-47 GCals/hrTypical station efficiency of Organic Rankine Cycle pRC) power plar 14%Heat recovery by installing an ORC power pant (@ 11)% ConservativeE~ 10%Heat that could b3 converted into Electricity 3.95 GCals/hrEquivale1t generc.ted Electricity by the ORC 3901 kW/hrPotentia electricity generation 3.9 MWReducticn in purchased E ectricity due to the ORC 29493 MWhs/y'Purchas3d cost cf electricity 982.0 VND/kWhPurchas3d cost cf electricity 0.055 U8$/kW1Estimated purchc.sed electricity cost savinqs $1}88,000 $/yr

Estimated monetary savings 32,184 million VND/yr

Attachment 3.6.1

Energy savings calculation for Installation of variable frequency drive for rawmill fan ( R2S20)

Parameter UnitI

ConditionsI

IPresentIExpected with VFDPower

kW1320900**i

;Power savings**

ikWI I350,Annual savings

millionI!

( @ 18 hours/day)

kWh/year2.08

** anticipated power consumption; can vary ± 15 % when actual efficiencyevaluation is done

47

Page 48: Hoang Th Aches A

Iloang Thaeh Cement Energ) Audit Report: September 2009

Attachment 3.7.1

Energy savings calculation for replacing existing inefficient equipment ­preheater fans in line 1

Parameter FormulaUnitValuePresent

New

Design QA1m3/min5,7505,750

A

m3/sec9696

H

Bmmwc600600

Fan input (as given in inhouse technicalC

800data book)

Static efficiency

D=%7082

A x BICMotor power design

EkW1000

Operating Power consumption of existing fan

F=Ax

550/[0.7x

kW870(calculated value)* 0.97xO.85]

Expected power consumption of new fan

G=Ax( at 550 mmwc at fan inlet, and

550/[0.82 xkW 741

assuming same flow as design)

0.85]

Power savings

HkW 129

1= (F-G) x

million

Annual savings/fan0.96310 x 24 kWh/year

No. of fans

J22

Total savings

Kmillion

1.92Wh/year

48

Page 49: Hoang Th Aches A

IIo3ng Thach Cemcnt Energy Audit ReP011: September 2()()9

Attachment 3.8.1

Energy savings calculation for replacing existing inefficient equipment - rawmill fan in line 1

Parameter FormulaUnitValuePresent

New

Design QA1m3/min6,0506,050

A

m3/sec101101

H

Bmmwc10501050

Fan input (as given in inhouse technicalC

1540data book)

Static efficiency

D=%6778

Ax B/C

Motor power design

EkW1900

Oper<:lting Power consumption of existing fan

**F= A x

950/[0.67xkW1606

(calculated value)* 0.97xO.9]Expected power consumption of new fan

G=Ax( at 950 mmwc at fan inlet, and

950/[0.780 xkW1338

assuming same flow as design)

0.9]

Power savings

HkW 268

Annual savings ( 18 hours/day, 310

I=Hx310xmillion1.49days/year)

18kWh/year

** 0.97 represents gear drive efficiency, 0.9 represents motor efficiency, both in decimals

Attachment 3.9.1

Energy savings calculation ling mechanical conveying system for kiln feed inline 1 to replace the present pneumatic conveying

Parameter FormulaUnit ValuePneumatic

Mechanical

Installed loadAkW280

Installed load ( anticipated)

BkW 75

Net power savings ( assuming operating load as 75 % of

C= A-BkW 154

installed load)Annual savings/system

D=CxMillion1.14310 x 24 kWh/year

No. of systems

E22

Total savings

F=DxEMillion

2.29kWh/year

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lloang Thach Ccmcnt Encrgy Audit Report: Septcmber 2009

Attachment 3.10.1

Energy savings calculation for Installation of variable frequency drive for coalmill fan (P22)

0.49

Conditions

P -t-----r-Expected with -resen I VFD

383 300**83

rkWkW

million

kWh/year

Unit-T__Parameter

Power

Power savings**Annual savings

( @ 18 hours/day, 330da s/ ear

** anticipated power consumption; can vary ± 15 % when actual efficiencyevaluation is done

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Hoang Tha<.:h Ccmcnt I:n<.:rgy Audit Report: September 2009

5.0 PATH FORWARD

Engineering System-wide Assessment (ESA) is the first step of our well-provenEnergy Cost reduction program that yielded successful results in the past.

In this first step, a list of Energy Cost Savings Measures (ECM) are developed andpresented. For all ECMs in this report, the following scope is already covered:

• Identification of existing system deficiencies & their possible root causes• Recommendation of an optimum solution that would eliminate the system's

deficiencies.• Benefits estimate, and a preliminary pay-back period range of the

recommended solution(s) is provided. (Preliminary payback range is only to helpjustify investing further time & money on the ECM)

The next steps after this system-wide assessment are listed below:

1. Classify the ECMs that require obvious actions & that require detail engineering.

2. Assign a task force to start taking the Obvious Action ECMs with due priority.

3. For ECMs that require detailed engineering, Basic Design Specification & DetailedEngineering Design (BDS & DED) need to be developed. At this step firm pricequotes and implementation costs could be obtained.

4. Obtain the financial approval, plan with turn-around schedules if applicable,implement the ECMs & establish the results.

Typically in the BOS stage of detailed engineering, the following scope would becovered:

~ Verification & reconfirmation of energy flow estimations & calculations formajor equipment/Units.

~ Reconfirmation & fine-tuning of the recommended optimum solution.~ Changes/modifications in the existing P&I drawings~ 'Tie-in'I'Retrofit' matching with the existing equipment & process

Typically in the OED package, the following scope of work would be covered;~ Collection of vendor equipment details & dimensional drawings, if any

proposedPiping design & preparation of Isometric drawings with Bill of MaterialsVerification of client's design standards for the proposed modifications tocomplyPiping Stress Analysis, where requiredRecommending client to conduct the HAZOP Analysis and participating in itObtaining firm price bids for the proposed scope from client approvedContractorsProvide the 'firm project implementation price' for the approved project scope

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