Indonesia Energy Survey, NIFES

7/28/2019 Indonesia Energy Survey, NIFES

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RESTRICTED COMMERCIAL

Report

on an

Energy Survey

at

PZ CussonsIndonesia

December 2005

Prepared for: Mr. Duncan Wright Contact: Des MurphyPZ CussonsEngineering ExecutivePZ Cussons (International) LtdBird Hall LaneStockportCheshire

SK3 0XN

NIFES Consulting GroupCharringtons House NorthThe CausewayBishops StortfordHertfordshireCM23 2ER

Tel:E-mail

0161 491 [email protected]

Tel:E-mail

01279 [email protected]

Ref: UKE782/DM/DB

Date DECEMBER 2005

Issue DRAFT Rel 1.0


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CONTENTS

Page

1.0 INTRODUCTION 1

2.0 REPORT 3

3.0 HEAT RECOVERY POSSIBILITIES 9

4.0 ENERGY MANAGEMENT 11

5.0 TRAINING 14

6.0 ACTION PLAN 15

APPENDICES

175833807.doc/JRM/DB NIFES Consulting Group


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increases are expected. The figures in the report can easily be adjusted toaccount for any such increase.

Prior to our visit it is understood that considerable efforts were made byMr Kostas Voutiritsas and engineering staff in general to compile records andusage data. This was very worthwhile and has enhanced the quality of the

survey.

We would like to acknowledge the assistance given to Mr Murphy by all staff,and particularly by Kostas Voutiritsas and Suranto, during the survey inJakarta.

175833807.doc/JRM/DB NIFES Consulting Group2


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2.0 REPORT

2.1 Steam System

There are three steam boilers installed. One of these, a new unit rated at 16t/h, is used on its own to supply the full factory demand.

It was suggested that this new boiler may be over sized. However, based onan annual fuel consumption of 3.9 million litres (as advised by local staff), theaverage load factor on the boiler is 60% (Appendix 1). Given the peakynature of many of the steam loads, it is likely that the peak steam load is inthe region of 12 tonnes/hour. If this is the case then the loss due to over-sizing is not very large circa 5,000 pa (APPENDIX 1).

The boilers can burn either residual oil or diesel oil. It is noted that 18% oftotal oil consumption for the past year was diesel oil. Local staff explained thatthis was due to the fact that for a period, diesel oil was cheaper than residualoil (State subsidy distortion). Also, supplies of residual oil are not alwaysavailable.

At present diesel oil is 50% more expensive than residual oil (2.9 p/kWhversus 1.9 p/kWh). The Action Plan advises that oil stocks be closelymonitored to avoid situations were residual oil stocks become low andavailability is a problem. Local staff advised that this is current practice.

The results of boiler efficiency tests were available. These were carried outwhen the boiler was installed (June 05) and no readings have been takensince (no instrument available). The efficiency of boilers does decay with timeand regular checking (monthly) should be carried out.

The retrofitting of a combustion oxygen trim system to the boiler wouldautomatically maintain the boiler efficiency at optimum. This was investigated

during the survey. Such a system optimises the boilers efficiencyautomatically by compensating for fluctuations in fuel consistency (verypertinent in the case of residual oil), atmospheric conditions and boiler fouling.It is estimated that such a system would provide a saving of 2% in oilconsumption which equates to 19,000 pa at present fuel costs. This wouldprovide a payback of less than one year.

A further saving could be realised by fitting a variable speed drive to the boilercombustion fan. At present the output from the combustion air fan is throttledto match the boilers firing rate.APPENDIX 2 calculates the saving as 2,700pa with a one year simple payback.

Another application of motor speed control concerns the boiler feed pump.

The pump (18.5 kW) runs constantly with the output throttled by a modulatingvalve. Installing a variable speed drive unit has the potential to save 1,300pa with a simple payback of one year based on local prices for VSDs. Thisproject would require some more technical analysis given that the pumpoperates against an almost constant head (the boiler pressure).

Because of the risk of contamination of condensate in the various processes,only a small proportion of condensate is returned to the boilerhouse. Thisnecessitates a high use of fresh make-up water which in turn dictates a highboiler blowdown rate (exacerbated by the high silica content of the rawwater). The survey examined the possibility of recovering the heat in theblowdown water to preheat the feedwater. Section examines the case for

blowdown recovery.



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The steam distribution system was surveyed for leaks. The situation here canbe reported as very good but this may be the consequence of a recentmaintenance campaign in this regard. It was advised that prior to thecampaign there were very many leaks.

There is some scope for upgrading of insulation on steam piping and processplant. APPENDIX 5 calculates the cost/benefit for steam pipe insulation andindicates a payback of just one month based on local fuel and insulation costs(rigid pipe insulation with stainless steel cladding).

2.2 Compressed Air System

Compressed air is used throughout the factory. It is generated centrally bythree screw compressors located. A 24 hour consumption test was carried outwhich indicated that the compressed air system is responsible for circa 7% oftotal electricity consumption (APPENDIX 5).A leak survey was carried out.The situation can be described as good but there is scope for improvement inthis respect. APPENDIX 6 quantifies the potential savings from leaks. Thesources of the leaks were notified to local staff. On the basis of electricitycosts pertaining at the site, a 3 mm dia. hole would lose the equivalent of900 pa.

It would be possible to recover the waste heat from the compressors. Thisheat would be available at a temperature of 80 oC hot water. The value of therecoverable heat would be 8,000 pa. The use for this heat is considered inthe Section , Heat Recovery Possibilities.

2.3 Chilled Water System

Chilled water is used in most of the process areas mainly for vacuum pumpwater cooling. This is generated in two chiller packs with reciprocating

compressors. The total electrical rating of the compressors is 200 swathechilled water is circulated in two main circuits to the various processes. Thecirculating pumps have a combined electrical rating of 50 kW.

Based on a chiller load factor of 50% (guesstimate) the system would accountfor some 13% of total factory electricity consumption representing a cost ofcirca 30,000 pa.

With some minor exceptions, the insulation level of the piping is satisfactory.A reliable method of assessing chiller system efficiency is provided by theevaporating and condensing temperatures of the refrigerant. During thesurvey these temperatures were noted for each of the units (APPENDIX 7).Ideally these reading should be compared to the compressors commissioningreadings but such records were not available. However, the followingcomments can be made. The condensing temperatures on Chiller #1 weresatisfactory at 47 oC which was 12 oC above ambient temperature. However,on Chiller #2 the condensing temperature on one circuit was 40 oC (very low)and on the other it was 58oC which is very high. This has significant energyconsumption implications and should be investigated. Each 1 oC of excesscondensing temperature requires 3% more compressor electricity.

Another area of potential saving is to reduce or totally cease the use of chilledwater to sub-cool the tower water supply to the vacuum pumps. Theperformance of ring seal vacuum pumps is dependant on the supply watertemperature but it is possible that acceptable performance will be obtained byusing the cooling tower water without further cooling with chilled water. If the



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operation of the cooling towers is optimised (see section below on CoolingTowers) then this possibility is further enhanced.This was discussed with the local staff who will carry out tests in this regard. Itmay be the case that the chilled water supply is needed only during therainy season when web bulb temperatures are very high and the coolingeffect of the cooling towers is marginal. A 30% reduction in chilled water

would reduce costs by 9,000 pa.

2.4 Cooling Tower Water System

There are five cooling tower water systems supplying cooled water to thevarious processes. Most of this water is further cooled using chilled waterprior to being used in the process.

The cooling towers should be capable of cooling the water very close to thewet bulb temperature of the ambient air.

Tests were carried out to check the effectiveness of the cooling towers. Theresults are summarised in the table below.

Note that the ambient temperature at the time of test was 35 oC (dry bulb).

Cooling Tower ServiceReturn

oC

TowerSump

oC

Evaporator 41 34

Talc Steriliser 48 34

Bleaching 36 28

Drier 34 27

Distillation 38 34

All of the cooling towers should have been producing water at 27 oC (if one ofthem was capable of this then they all should). The reason why this is not thecase is due to fouling of the cooling tower packing which results in short-circuiting of the water as it falls through the tower. The fouling is a problem forsome of the towers due to product carry-over. Given that practically all of thiswater is subsequently cooled with chilled water, any loss of cooling in thetowers must be made good by chilled water cooling - at significant cost usingthe mechanical refrigeration equipment.

It is noted that the circulating pumps for these cooling water circuits have arating of 225 kW. The tower fans constitute another 64 kW. Both the fans andthe pumps run continuously once the plant is operation. On this basis thecooling tower system is responsible for some 22% of total electricalconsumption at the factory. The cost at present rates is 50,000 pa. (SeeAPPENDIX 13).

This is a key cost and it is recommended that:

Renewed efforts are made to ensure that the towers are

optimally maintained.

A review is undertaken of the need for cooling water throughout

the plant including the quantities per item of plant.



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Following the above, a study should be carried out to ascertain if

the use of variable speed drives on the circulating pumps wouldbe cost effective.

2.5 Split Air Conditioning Systems

There are approximately 70 split air conditioning systems spread around the

site. The total rated load of these units is 120 kW.Based on the hours of usage per day and applying a reduction factor foractual consumption versus rated consumption, the annual electricityconsumption is estimated at 190 MWh. At current site electricity costs thisamounts to 6,000 pa. This represents 2.6% of total site consumption(APPENDIX 12).

Spot checks were made on a sample of units to check the quality ofmaintenance. For these the internal filters were clean. However the outsidecondenser heat exchangers were partially blocked. This has the effect ofincreasing the required condensing temperature (and pressure) therebyincreasing the power consumption. Equipment was not available to check the

condensing pressures. Each 1o

C increase in condensing temperature resultsin 3% additional electricity consumption. It is estimated that there is scopehere for reducing consumption by 15% by improving maintenance in thisarea.

Most of the units should operate from 08.00 17.00 but it was not possibleduring the survey to verify if this regime is being adhered to. The operation ofa Monitoring and Targeting system as advised elsewhere in this report willhelp to flag significant excessive usage.

2.6 Processes

The individual processes were examined in some detail for energy reduction

possibilities. The findings are summarised as follows.

Process Energy Saving Possibility

Bleaching: During the cooling downstage of the process the batch is cooledfrom 140 oC to 90 oC using chilledwater.

This is high grade heat and thepossibility of recovery and useelsewhere is explored in Section .

If it is decided that heat recovery isimpractical then consideration should begiven to using cooling tower waterinstead of chilled water. It is appreciatedthat this would extend the process cycle

time but local staff have advised the thisis not a critical issue.

Also, the cooling of this vessel withchilled water places a very high shockload on the chiller system and affectsother processes.

Bleaching: The vacuum pumps arerequired for only a portion of the cycletime.

It was not clear during the survey ifnormal practice is to switch off thesevacuum pumps when they are notrequired.

This should be followed up and anappropriate operating procedure put inplace.



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The proposed Monitoring & Targeting(M&T) system will pick up on this issue.

Bleaching: Barometric condensers are

used on the vacuum lines even thoughthere is no moisture being drawn fromthe oil vessel. Kostas Voutiritsasadvised that on another similar plant inAfrica these were removed with noadverse affect.

A small saving might result due to less

cooling tower water pumping but thiswould be very small. Not furtherconsidered.

Lye Treatment: Heat is removed fromthe product in a downstream heatexchanger using cooling tower water.The temperature is reduced from 80oC

to 50o

C.

The possibility of recovering this heat isexamined in Section - 3.0 HEATRECOVERY POSSIBILITIES.

Soap Dryer: Here the neat soap isdried in a flash dryer. The dryeroperates under strong vacuum therebydictating a low exit steam condensingtemperature.

No energy reduction opportunitiesidentified on this process.

PCC Liquids: Batch sterilization. Thebatch (mostly DI water) is first raisedfrom 30 oC to 95 oC and held for 15minutes to ensure sterilization. It is thencooled down to 60 oC using chilledwater in the jacket.

If sterilisation of the DI water could beeffected using an alternative method(e.g., UV) then a saving would be madeby not having to heat and then cool thewater (double saving).

APPENDIX 11 Calculates the savingsas 9,000 pa based on current fuel andelectricity prices.

PCC Liquids: Vessel Sterilization iscarried out after each batch. It consistsof filling the vessel with heated DI watervia a spray ball. The water in the vesselis then maintained at 95oC and

circulated for 30 min to ensuresterilization of the vessel.

It may be possible to sterilize using anon-thermal method (e.g., chemicals inthe spray water). This would reduceenergy consumption and perhaps evenspeed up the process (the sterilization

process currently takes about an hour).

APPENDIX 11 Calculates the savingsas 1,800 pa based on current fuel andelectricity prices.



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Soap Finishing - Glycol Chillers: Thereare four glycol chillers on the lines usedfor mould cooling. These are each ratedat 6.4 kW electrical.

The glycol flow temperature variedacross the four units from 10 oC to 18 oC. If 10 oC is adequate for theprocess then all units should be set atthis temperature.

The air cooled condensers on theseunits are quite badly fouled whichinvariably results in higher thanneeded condensingtemperatures/pressures andexcessive electricity consumption.

APPENDIX 9 calculates the annualoperating cost at 3,600 pa. It is likelythat a saving of at least 10% (360pa) could be made by cleaning of thecondenser heat exchanger. Besides

the energy implications, it is likely thatthe fouled condensers will result inpremature failure of the compressors.

Evaporator: There is one 3-stageevaporator and one single-stage unit.

The process design information wasnot available to allow an analysis ofthis process.

It is recommended in the Action Planthat the present operational regime bereviewed against the design

parameters for the evaporators. It ispossible that operational changeshave been made over the years tofacilitate production but at theexpense of energy consumption.

Distillation: There is one distillationprocess.

Comment as per Evaporators



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APPENDIX 4 shows the saving to be 11,000 pa. It was beyond the scopeof the survey to obtain capital costs but the installation is unlikely to costmore than 11,000 giving a one year payback.

3.2 Heat Recovery from Chillers and Air Compressors to SAP Water Supply

In the Sap process there is a requirement for 55 tonnes of water at 80o

C perday. At present this is heated in the pans using steam.

It is understood that, from a process viewpoint, there is no reason why thewater could not be supplied heated to the pans.

Assuming this to be the case then this water could be preheated by firstpassing it through heat exchangers in the chillers (to recover heat from thecondensing refrigerant at ~ 47 oC and then to pass it through a heatexchanger (oil cooler) in the compressors. Because the flows are notconstant, it is expected that the design would have to incorporate a hot waterbuffer tank.

Based on current fuel costs, the saving would be circa 17,000 pa. (SeeAPPENDIX 14) The capital cost cannot be estimated until preliminary designis carried out but a payback of ~3 years is expected.

3.3 Bleaching Process

During the cooling down stage of the process the batch is cooled from 140 oCto 90 oC using chilled water. If this heat could be used to preheat the nextbatch then a double saving would be made; the steam saving in heating thenext batch, and, the chiller saving. APPENDIX 15 estimates the saving as18,000 based on current fuel and electricity prices.

The technical feasibility of this should require further investigation which isbeyond the scope of this survey.



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4.0 ENERGY MANAGEMENT

Our review of the plant has indicated that operator diligence could have asignificant effect on energy consumption. Many energy using operations areunder the control of the operator. Examples are the heating of vessels,

switching of pumps, etc.

It would not, from an energy saving viewpoint, be cost effective to automateall of these processes. A different approach is called for. We propose a twopronged approach:

Operation of a Monitoring & Targeting system (M+T). Essentially, thisallows, each week, the actual consumption of energy in each process to becompared to a target.

Checklist system for tracking problems such as leaks, damagedinsulation, fouled refrigeration condensers, etc.

Both of these systems are relatively low cost yet provide an effective methodof energy management.

4.1 Monitoring & Targeting System

As an example of this technique, the total production at the facility was plottedagainst the fuel oil used (last 20 weeks only were available). Using regressionanalysis, the best fit line was drawn, as shown below.

It can be seen that for a production of ~ 700 tonnes/wk the fuel consumption

varied between 56,000 litres and 95,000 litres.

Even neglecting these extreme points (weeks) there is still a wide spread(deviation) for similar production outputs. The question arises as to why thefuel consumption should vary so much for the same product consumption. Itis possible that these variations can be explained by differing product mixes,but unlikely.

An M&T system uses this technique to obtain a Target Line for eachprocess. Weekly consumption is then compared to the target. Significantdeviations then have to be investigated.



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Production versus Fuel Oil Regresssion

0

100

200

300

400

500

600

700

800

900

0 10,000 20,000 30,000 40,000 50,000 60,000 70,000 80,000 90,000 100,000

Fuel Oil (litres)

TotalProduction

(tonnes

)

It is appreciated that at present there are only main meters, i.e., oilconsumption and total electricity. In the short term this is sufficient tocommence the M&T system. Correction factors can be used to adjust forchanges in production mix compared to the mix used to form the target line.

The above analysis chart is for oil versus production. A separate analysisshould be set up for electricity versus production and another for productionversus air compressor run time.

Ideally meters should be fitted to each main process and the regressioncarried out for that process and also for the facility overall. However, it maytranspire that acceptable results will be obtained using the existing meters.Ten weeks of analysis should determine this.

Specialist software packages are available for this but there can be expensiveto purchase, to set up and to modify.

We would recommend using a simpler but equally effective approach usingsuch data sources as are available on site and using spreadsheets andtargeting analysis that is easy to follow and could be modified by site staff.

4.2 Checklists

The M&T system can be described as a Indirect approach to energymanagement by ensuring that overall performance is maintained on target. Itwill not identify any problem but merely flag that a problem exists. This isimportant given that many causes of excessive energy consumption are notalways obvious.

The Checklist system can be described as a more Direct approach and willsupplement the M&T system.

It involves, for each energy using process, making a list of the indicators ofexcessive energy consumption. These will be checked regularly (e.g., weekly)and will highlight problems with equipment.



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Taking the steam boiler as an example, the checklist would comprise thefollowing.

Checklist item: Information provided:

Flue gas temperature Fouling of the boiler heat transfer surfaces.

Oxygen concentration in flue gas Excessive combustion air beingprovided to the burner.

Boiler chamber water total dissolvedsolids (TDS)

Excessive blowdown being used.

Once these few parameters are within limits it can be concluded with a highdegree of confidence that the boiler is operating efficiently. Similar check listscan be set up for all utilities (compressed air, chillers, air conditioning units,etc) and for the processes.

The test equipment needed to operate the checklist system would be minimal.

4.3 Energy Management Strategy

To ensure an effective drive at reducing energy use there needs to be anenergy management system in place that is structured, planned and wellintegrated into overall management objectives.

Energy management at the moment is slightly informal and dependent as the

drive of a few individuals. It lacks structure, policy, strategy planning anduseful reporting.

The reporting can be taken care of in the M&T systems discussed above.There are a series of actions identified here that form the basis of an actionplan. There is a need to identify a suitable structure, assign responsibilitiesand to set objective with a company policy and site strategy.



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5.0 TRAINING

A full compendium of energy efficiency Good Practice Guides was handedover to local staff during the survey.

In setting up and operating the M&T and the Checklist systems recommended

above it would be very useful for the local staff to have access to a handholding advice from energy specialists. The need for on-the-job trainingshould be reviewed.



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6.0 ACTION PLAN

The site spends over 1m on energy per year and they are anticipatingfurther price rises. There is an informal approach to energy management andcommitment from senior management. The site has recently made good

progress in reducing energy use by undertaking leak surveys, etc. However,the positive benefits from such energy actions are difficult to maintain over thelong-term, without a systematic approach to energy management.

In this report, based on a very brief survey, possible savings of over 100,000or 10% of the energy bill have been identified. A list of these are given belowand rough details are given in supporting appendices. We would recommendthat the site:-

1. Initiate an energy management system and integrate energy reportinginto normal management responsibilities.

2. Install an M&T system to allow proper tracking of projects.

3. Adopt a check-list approach to help operators maintain efficiency ofsignificant energy using operations. This could be combined with hand-holding assistance. Possible on-the-job training should be reviewed.

4. Correct some obvious faults identified.

5. Look in detail at the list of projects and select those that areimplementable and show worthwhile savings.

6. Further develop M&T. Provide steam and electricity meters to showperformance of key areas.

7. Track progress of energy saving projects.



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List of Possible Actions

Process Action

Set up M&T system. At this stage no capital cost is required. Somedegree of consultancy could be required to set upthe system but site visits would not be necessary.

Later, it may transpire that metering of some of theprocesses proves necessary to provide adequatecontrol.

Set up Checklist System No capital cost required. Some small degree ofconsultancy may be required.

Bleaching Process heatrecovery

Investigate the possibility of recovering thecooling heat as outlined in Section 3.

Heat Recovery fromChillers and AirCompressors to SAPWater Supply

Carry out detailed analysis of this energy savingoption as described in Section 3.

Boiler BlowdownRecovery to FeedwaterHeating

Carry out detailed analysis of this energy savingoption as described in Section 3.

Distillation process The current operating parameters of this processshould be reviewed against the original design tocheck for drift in practices which could adverselyaffect energy consumption.

Determine Checklist items for the process.

Evaporators As per Distillation process.

Soap Finishing - GlycolChillers

Further investigate the operation of these units:evaporating temperature, condensing temperature.Compare to commissioning data. Take action asappropriate (which will definitely include cleaningof the condenser coils).

PCC Liquids: VesselSterilization

Investigate the possibility of carrying out thesterilisation using a non-thermal process.

PCC Liquids: Batchsterilization.

Investigate the possibility of carrying out thesterilisation using a non-thermal process.

Soap Dryer The current operating parameters of this processshould be reviewed against the original design tocheck for drift in practices which could adversely

affect energy consumption.

Determine Checklist items for the process.



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Bleaching: Control ofvacuum pumps

Check that the optimal regime is in place forcontrol of these pumps. Can they be switched offwhen not required during the cycle?

Bleaching: Batch cooling Examine the technical feasibility of using coolingtower water instead of chilled water. Also examinethe possibility of heat recovery as outlined inSection 2.

Split Air ConditioningSystems

Set up a regime for regularly (every three months)checking the operation of these 70 units. Preparechecklist.

Cooling Tower WaterSystem

Renewed efforts should be made to ensure thatthe towers are optimally maintained. It is

appreciated that the carryover from the processcan make this difficult.

A review is undertaken of the need for coolingwater throughout the plant including the quantitiesper item of plant.

Following the above, a study should be carried outto ascertain if the use of variable speed drives onthe circulating pumps would be cost effective.

Chilled Water System Clean the condenser coils on unit 2. This maysolve the current low efficiency problem. If notfurther investigate the problem.

Review the need for using chilled water on vacuumpumps. Optimal operation of the cooling towers isvital in this respect.

Compressed Air System Continue with the leak checklist system.

Steam System Give strong consideration to installation of anoxygen trim system and combustion fan variable

speed drive.

If this system is not being installed, than an oxygentest instrument should be purchased (circa1,000).

Further investigate/confirm the technical viability ofinstalling variable speed drive (or soft start)control on the feedwater pump.

Maximise use of residualoil

Put in place a formal system for logging residual oilstocks to ensure that stocks are sufficient to allowfor short term unavailability.



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Energy monitoringequipment

The company should invest in equipment to assistwith energy use tracking and problem solving.Cost circa 5,000.

Equipment required: portable data logger withprobes/sensors, boiler efficiency tester, ultrasonicleak detector.

Details can be provided on request.



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APPENDIX 1 STEAM BOILER CALCULATIONS



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APPENDIX 2 BOILER COMBUSTION FAN SPEEDCONTROL



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APPENDIX 3 BOILER FEED PUMP VSD CONTROL



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APPENDIX 4 BOILER BLOW DOWN HEAT RECOVERY



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APPENDIX 5 STEAM PIPING COST/BENEFIT



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APPENDIX 6 COMPRESSED AIR



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APPENDIX 7 CHILLERS



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APPENDIX 8 LYE HEAT EXCHANGER HEAT RECOVERY



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APPENDIX 9 SOAP FINISHING LINE GLYCOL CHILLERS



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APPENDIX 10 COMBUSTION AIR PREHEATING



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APPENDIX 11 PCC WATER HEATING



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APPENDIX 12 SPLIT AIR CONDITIONING SYSTEMS



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APPENDIX 13 COOLING TOWER COSTS



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APPENDIX 14 HEAT RECOVERY TO SAP PAN WATERPREHEATING



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APPENDIX 15 BLEACHING PROCESS HEAT RECOVERY

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