Problems Facing Dave S oping Countries inOperating Large Ammonia Plants

Several developing countries have invested heavily in the construction of large ammonia plantswith severe impacts on their economies due to high technologies involved. What are the causes

of plant shutdowns and solutions to the problems ?

M. BoumazaUniversity of Constantino, Constantine, Algeria

INTRODUCTIONA most urgent global problem is to provide

adequate food for the world's hungry andmalnourished people. In the long run, the mostfeasible method of expanding food productionin developing food deficient countries is toraise crop yields through modern farmtechnology, plant protection, adequate financialcredit, appropriate motivational incentives andmarket demand for the output baked bypurchasing power are all essential forincreasing crop yields. Fertilizer however is abasic input in the food production cycle,andtherefore is a major ingredient in the foodexpansion production.

The use of fertilizer in the developingcountries is currently low. However agonornicresearch (1,2,3) indicates a substantial potentialfor expanding its use. Thus Stängel (4)estimated that by 1994, additional nitrogenrequirements for rice production in 20 majorrice-growing countries will be about 6.3 milliontonnes. Therefore, for the world as a whole,49% of NPK (Nitrogen, phosphate, potassium)Consumption was accounted for by nitrogen,whereas, for developing countries, it was 63%

About the author :

Dr M, BOUMAZA holds a bachelor, a Master and a PhDdegree in Chemical Engineering from BRADFORD University,U.K. He spent several years investigating the performanceand the reliability of ammonia plants operating in developingcountries. Dr BOUMAZA is presentely a senior lecturer in theDepartement of Engineering, at the University of ConstantineAlgeria,

Ammonia is the key input for manufacturingnitrogen fertilizer. Even though ammonia is alsoused for other industrial pruposes, trends inproduction to a great extent, reflect trends infertilizer production. With world ammoniademand growing at about 4% per annum, thissuggests the need for an additional 200 largeammonia plants to be built around the worldduring the next 15 years.

During the last thirty years ammoniaproduction worlwide hase gone through animportant step change.The change from the1950 's technology to the large single-streamammonia plant has demonstrated thatsignificiant changes can rarely be affectedwithout difficulty and the need for a heavyproblem solving effort, These unforseenproblems could result in low plant availabilitythereby frustrating the realization of theireconomic advantages. In effect therefore, therealiability of these plants plays a vital role intheir capital budgeting decisions.

There js.a direct relationship between theprofitability and realiability of large ammoniaplants. The large capacity of such units permitsa considerable reduction in capital andoperating cost per unit of output. However theeconomic advantages depend on havingcontinuous uninterrupted production and can benullified if a plant does not operate with a highdegree of reliability from the time of start-up.Several researchers(5,6,7) have studied theeconomic effects of large capital projects, suchas ammonia plants, of change in the primeeconomic and physical factors, which affect

254

these projects and have found that thepn-stream process availability is of crucialimportance.

In certain circumstances, the economicimpact of a reduced plant availability can bemore severe than that indicated by thesestudies. In the case of developing countries e,g,a shortfall in ammonia production would resultin balance of payment problems and shortagesof hard currency as a result of importing theproduction shortfall. In effect therefore largesingle-stream ammonia plants will only beprofitable if they are designed and constructedon time, reach budget output early in their livesand maintain a high on-stream factor.

The basic aim of this paper is to evaluatethe availability and reliability of ammonia plantsand locate the main difficulties encountered bydeveloping countries in operating these hightechnology ammonia plants. The second aim ofthis paper is to propose some methods ofavailability improvements of these plants inparticular and process plants in general indeveloping countries.

DESCRIPTION OF THE PERFORMANCE OF THEALGERIAN PLANTS

Algeria developed its ammonia industryin order to provide the agricultural sector withthe required quantity of fertilizer to reach selfsufficiency by substituting the importation ofthis product and eventually exporting thesurplus of The production thereby providing thecountry with sources offoreigncurrency.

In this aspect, Algeria constructed three1000 tonnes per day ammonia plants, of which,one started ooeration in 1989. and is notconsidered in the present study.

PLANT I.

This plant was constructed by the Frenchcontractor Technip ans uses the Chemicoprocess. The plant started operation in late1966. but was withdrawn from productionduring 1976, due to frequent unscheduledshutdowns, and it is now still being refurbished.During the period 69-76, the performance ofthis plant was only 34,5%. Thus since itscommissioning, the plant experienced a seriesof operational problems. Many of these arosefrom original design déficiences and resulted infrequent shutdouwns, low productivity andconsequent high production costs. In additionunsafe and hazardous conditions were oftencreated. During 1975, the plant operated foronly 2. 5 months. At this juncture, it wasdiscovered that most of the major equipmentwere badly designed and constructed. Theother factor contributing to this poor

performance was the lack of appropriateexperience shown by the local operating andmaintenance staff.

Table 1 indicates the total productionduration in each year between 1970-75 whiletable 2 shows the major sections of the plantwhich have caused the downtime andshutdowns of the unit. It can be seen that themajority of the downtime is due to the failure ofthe synthesis and primary reforming sections,which account for 60% of the total douwntime.Most of the i equipment in these sections(whichare considered to be the most important andsensitive sections of the plant) wereinadequately designed. The ammonia converterexperienced frequent failures with sometimeshazardous and unsafe condition which led tofires. The synthesis compressor failed on manyoccasions due to the excessive vibration,faulty sea! oil system and maloperation of theprobes. Most of the downtime in the purificationsection were attributed to the failures of heatexchangers, which did not resist the corrosionproblems caused by the circulation of the M.E.Asolution in this area of the plant.

PLANT II.The construction of this plant started in

1974, adjacent to the first plant. This plant wasconstructed by Creusot-loire. Entreprise anduses the Pullmann Kellogg process. Engineersform P.K.P.S were originally contracted tocommission and operate this plant between1981-84.

After its commissioning in October 81, Theplant started operation on the 11 th November81. Table 3 gives the production and the designcapacity during 1981-87, while figure 1represents the cumulative target andachieved production during this period. It canbe seen that the plant started operating wellbelow the design capacity and thus slowlyprogressed to reach an average of 74% ofthe design capacity in its 5 th year ofoperation.

The objectives of the study, were toanalyse the data collected, where they weresufficient and locate the actuel sources of theshutdowns and the downtime and determine itsreliability and maintainability. It was thenintended to compare these results with otherdata reported in the literature (8,9,10,11,12) witha view to making recommendations for theimproved performance of the plant. The failuredata were provided by the production andmaintenance départements.

Table 4 shows the total performance of theplant and includes all downtime regardless ofthe reasons,even that beyond the control ofthe plant.

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The causes of the plant shutdowns anddowntime are shown in table 5. It can be seenthat the rotating section caused most of thedowntime, as it suffered frequent failures withlong outages particulary in the first and secondyear of operation . The static section hascaused an average of 35 downtime days/year,most of them were attributed to the failures ofsome exchangers. The miscellaneous sectionhas also caused a great number of downtimes;mainly due to operator error and failures ofauxilliares equipment such as the feed watertreatement unit which operated for a longperiod at reduced rates, most of the electricalfailures were due to the unavailability of thepower; as the turbo-generators which supplythe power to the plant were out of services,thereby causing the plant to be fully dependenton the external source.

Table 6 gives a detailed list of the majorequipment causing a high frequency of

shutdown, and lenghty downtime. Both thesynthesis gas compressor (103 J) and aircompressor (101 J) caused a total of 216 daysshutdown time during the period investigated.Most of the failures associated with thesecompressors were due to the malfunction ofthe governor, axial thrust probes, vibrationprobes, excessive vibration and problems withthe lube oil system. In fact these problemspersisted until the remplacement of some itemswere carried out.

The refrigeration/compressor condensers(127-CA:CB) have contributed to a total loss of50 days. This was due to the inadequatedesign of these exchangers which had tooperate at reduced rates during the summer.The demineralised water units had to operatefrequently with reduced rates, forcing the plantto operate at reduced rates.

Tables 7 shows a detailed comparisonbetween the performance of the Algerian plantII and the average performance of ammoniaplants worldwide. The data provided byWilliams et al (9,1O,11,12) enabled this comparison.

The distribution of the downtime andshutdowns into the major section is shown ontable 8. It can be seen that although the path ofthe causes of the failures is the same for thealgérien plant and the rest of the world plant(R.O.W), accounted for nearly all that difference.

ACTUAL CAUSES OF THE SHUTDOWNS ANDDOWNTIME .

PLANT I.

The on-stream availability of this plantduring the period 1969-1976 was 34%. This is apoor performance, as compared with the

average performance of similar plants whichranged between 75-90 %. Due to this extremelypoor performance,the plant owner carried outseveral investigations to identify the actualreasons of these frequent shutdowns. It wasdiscovered that most of the equipment wasbadly constructed and designed, thecontractor while admitting some design andconstruction errors, identified other factorssuch as lack of skillsshown by local operatorsand technicians and improper operatingprocedures.

Such problems of this magnitude shouldhave been anticipated especially when oneconsiders that such large tonnage plants hadonly just been introduced into the U.S.A and theUK, where the technology had actually beendeveloped and skilled personnel were readillyavailable to ensure the best possibleperformance of these plants. By contrast,Algeria did not possess skills in operating andmaintaining this process and not havingammonia plants, previously, did not haveadequate trained source of skilled managersand technicians.

PLANT II.

A total of 194 failures were reported duringthe period studied (1981-1907), of which 125failures caused a complete halt to theproduction and led to a total loss of 620downtime days and 69 failures forced the plantto reduce its throughput, contributing to 136downtime days.

It is on record that the plant owner claimsthat most of these problemshave been causedby incorrect design and improper installation ofdifferent equipment. Other causes such asimproper operating procedures and low qualityof maintenance have also been implied but notstressed by the owner. However, the author isconfident that the two latter, causes havebeen important contributing factors to theplant's low performance. In this aspect, threemain sources were identified as the origins ofall failures. These were :

EQUIPEMENT RELATED FAILURES

The investigation on the nature of thedifferent failures revealed a number ofcontraints for achieving respectableproduction rates as well as for high on-streamfactors. These equipment failures wereclassified as follows :

Incorrect design : Several cases ofincorrect design were discovered in this plant.These were due to the improper assumptions

256

concerning basic design and to the int̂design of the equipment.

- Manufacturing and construction faults : Someequipment was found to be badly

manufactured, therebly failing frequently andcausing shutdowns of the plaint.

- Improper installation and system integration :In some cases,the . équipement was correctlydesigned and constructed and yet failed onseveral occasions. The investigation revealedthat this equipment was inadequately installed,thereby initiating several shutdowns of theplant.

MAINTENANCE RELATED FAILURES.

A lower than designed quality ofmaintenance can be one of reasons for theplant shutdowns. If plants are not maintened tothe standard recommendations by themanufacturerSjthey may deteriorate fasterthan normal.

In the plant under study, the maintenancedepartment contributed to a great number ofshutdowns by not respecting certain importantregulations and rules such as preventiveactions and continuous monitoring ofequipment. Whereas a normal maintenancestrategy would have involved a mixture ofcorrective, preventive and opportunity, mostof the time, this department operated on thebasis of corrective maintenance only withdisorganised methods of intervention resultingin frequent forced-outages having and adverseeffect on the plant's availability. The pccurenceof such maintenance can be minimised byensuring that the operator and maintenancepersonnel possess the appropriate skills andhave been properly trained so that their jobswill be undertaken proficiency. In the caseunder study a total of 15 (3/year) unscheduledoutages had been initiated by lack of propermaintenance and low quality of maintenance.The forced outage for similar plants operatingin the U.S.A. would be 1.5 shutdowns / year.

OPERATION RELATED FAILURES

Improper operating procedures can result indamages to major components in the equipmentand lead to a considerable loss of product. Inthis study on many occasions operator errorsinitiated a shutdown of the plant, and hence,contributed to a total loss of 30 shutdownsinvolving 30 days lost in production during 1981- 1987. The major sources of these outageswere , lack of attention, unfamiliarity with theequipment and lack of skills to re-start theplant.

REASONS OF THE DOWNTIME .

As shown in table 4, the plant availabilitywas 63 % as compared to the averageavailability of worldwide plants of S0%.

The plant contractor claims that much ofthis extented downtime was due to a lack ofspares on site and shortages of qualifiedpersonnel with a third factor, namely the poorcoordination between different departments .Two main factors extented the repairsprocedures, these were.

LACK OF SKILLED ENGINEERS

In this plant , several delays in thecompletion of some repairs resulted from a lackof skilled engineers and specialists , requiringthe presence of foreign assistance . Thisprocess involved different steps, contactingthe specialist , waiting his arrival and repairingthe failed item.

LACK OF SPARES PARTS

The reliability of a plant is affected by theavailability of spare equipment . In the plantstudied , a few delays of repairs wereobserved as a result of the unavailability ofsome spare parts, which had to be orderedfrom abroad. The ordering is an awkwardprocess since it involves .different steps andis subject to local regulations ranging from theapproval of the plant manager through theclearance by local customs offices.

SUMMARY OF THE INVESTIGATION

Several factors have affected theperformance of both plants studied. These canbe classified as follows :

(i) The lack of experience in many of thechemical plants has allowed the acceptance ofsome deficient equipment.

(ii) The shortage of qualified and skilledengineers led to poor quality maintenance andfrequent shutdowns, and alternatively thiscaused the plant to be dependent on foreignassistance.(Hi) Improper training of operators andtechnicians caused several unscheduledoutages o the plants.

(iv) The lack of spare parts on site extendedthe actual repair time.

(v) The absence of any failureanalysis, as itwas discovered that no proper work studyhad been carried out to determine thestandard time or repairs and to analyse thenature of certain failures.

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In fact these failures could be interpretedas symptoms of ineffective system planning. Inthis respect the author wishes to interpretthese symptoms as a global failure of notconsidering the philosophy of technologytransfer during the planning of a project. Thisimplies that the planners not only failed toconsider the barriers to technology transferbut also failed to consider such factors astechnology forecasting, research anddevelopment and learning curve theory whichcan help to promote the transfer of technology.

PROPOSED METHODS OF AVAILABILITYIMPROVEMENTS.

Several methods are available toincrease the reliability of a system during thedesign, fabrication and operation stages.However, since the present study is mainlyconcerned with existing process system, themethods applied during the design andmanufacturing stages will not be consideredhere.

The outages and unavailability observed inthe Algerian plants were mainly originated fromhuman factors (operator error, poormaintainability, poor coordination betweendifferent departments and a disorganisedwarehouse) and thus could be improved byconcentrating mainly on the following

BETTER MANAGEMENT OF THE MAINTENANCEDEPARTEMENT

The investigation of the Algerian plantshas revealed the absence of proper

maintenance policies and the underestimate ofthe role of this department.. maintenance workshould raise the level of equipment

performance and availability butatttiesame timeit adds to running costs. The objectives of anindustrial maintenance should be theachievement of the optimum between theseeffecte.There are a number of maintenancepolicies that can be specified individually or incombination for each unit of a plant. Thenationalized sum of such specified policies forthe whole manufacturing plant for a plan shouldbe built by selecting for each unit, the bestcombination of the existing policies (preventive,condition based, corrective opportunity anddesign out maintenance) in order to make thebest use of ressources and time. The plannedsystems are essential if maintenance is to betruly controlled and cost effective. It is simplya rationalised approch to managing the

maintenance function. Thus high managementshould be aware of the benefits of a plantmaintenance system in terms of long terms oflower unavailability and better plant conditions.

IMPROVED SPARE PARTS STOCK HOLDINGPOLICIES

Availability of spare parts often makes thedifference between a successful project and adisastreous one. This is true anywhere in theworldjbytfndeveloping countriesaremagnified athousandfold.

A significant step towards reducing suchproblems can be taken at the time of contractnégociation by providing for important quantityof spares. The contract should ordirnarilyinclude the provision that original equipment isto be procured by the contractor at itsdiscretion. At the same time, the local companyshould develop its own spare parts program inorder to ensure continuous operation of theplant. This requires the need to study scientificallyinwentoryiy : control - policy whichconsistsmainly ot balancing the costs of holdingstock against the cost of running out (15, 16).Thus it is of paramount importance to ensureimmediate availability of spare parts.

TRAINING OF TECHNICAL PERSONNEL

This study has revealed that more than30% of the shutdown experienced by theplants studied were initiated by operator error,through lack of attention, improper operationprocedures and lack of training and know-how.Similar problems have been reported byseveral researchers (11,12,13) namely thatdeveloping countries suffer lack of skills.

The operation of an ammonia plant hasalways required highly developed operatorskills. These skills depend upon a deep insightinto the process and into the dynamicoperating characteristics of the plant. Thus aplant facing the start-up of a new ammoniaplant must address the question of operatortraining techniques. Slmllator training asreported by some researches (14,17) is gainingever increasing use as part of a moderntraining program and can be very useful todeveloping countries. Thus in order to limit theoutage caused by operator errors, it isrecommended to provide efficient andorganised training program.

FAILURE ANALYSIS

In the present study, the production losseswere generally more serious than th actualequipment damage or losses. There are steps,however, that may be taken to minimize theseunscheduled outages, the most important beingthe establishment of reliability and failurestudies.

The term reliability engineering should berecognised as a new dimension to the

258

traditional maintenance engineer duties. In thepresent study, it was found that repairs aremade to damaged parts but little time is givento analysis and diagnosis of the symptoms toarrive at the cause of failure. The reliabilityconcept should place more emphasis on causeidentification and development of permanentsolutions. Reliability engineering is not expectedto solve problems, but act as a coordinatingagent to identify the problem and see thatpriority is set to prevent it from being lost inthe maze of daily emergency jobs. Through thisapproch it is possible to roughly categorizefailures into equipment types and failuresmodes. This provides an indication of the typeof equipment requiring special attention and inparticular the prime cause of concern.Therefore, it is strongly recommended tocreate a continuous failure analysis and failuredata control system through careful records,adequate monitoring system, attention todetail of critical components and adequateplant personnel.

CONSIDERATION OF TECHNOLOGY TRANSFER

Several developing countries have littleexperience of the chemical industry, a factwich can make a relatively simple processappears sophisticated. An operating companyin a developing country must be very carefulin the selection of the technology andequipment for a new plant. It is desirable that aplant wich is going to operate in thesecountries, is simple reliable, flexible andprofitable. In order to achieve these aims, it isdesired to consider carefully and seriously thetechnology transfer when planning suchprojects. Therefore it is desired to studyimportant topics such as technologyforecasting, research and development andlearning curve theory wich can help to

promote positively the transfer of technology,They must not be considered at the industrylevel just to satisfy the industry interest butthey must also be the concern of thegovernments and other related bodies in thecountry.

CONCLUSION

Over the last three decades, there hasbeen a marked tendency for manufacturingplants in general and ammonia plants inparticular to become both large and complex.To a large extent, both of these features haveresulted from a conscious corporate search ofways of obtaining economic advantages.However the operational flexibility of suchammonia plants has been reduced andbreakdowns often, resulting irishutdowns ofsignificant reduction of The plant's profitability.If these trends in increasing unreliability wereto continue, the advantages of large andcomplex plants would be eroded rapidly. This isparticulary important for large ammonia plantsoperating in the developing countries.

The investigation of the Algerian plantsshowed that these plants had frequentshutdowns during their operation period.Detailed investigation of the failure datarevealed the existence of enormouspossibilities to increase their performance ifserious attention were given to the humanfactors as most of the outages were due topoor maintainability, lack of skilled personneland a disorganised management.

ACKNOWLEDGEMENT

The author wishes to thank the Algerian'national oil company which made its ammoniaplants available for analysis over the period1981 - 1988.

REFERENCES .1- international Food Research institute (IFPRI): 'Food needs of developing countries,Projections of production and consumption to 1990, Washington DC, 1977,

2- Trilateral Food Task Force (TFTF): 'Expanding food productivity in developing countries,rice production in south and south East Asia, Bonn, 1977.

3- UN Industrial development organisation :, Worldwide study of the fertilizer industry1975-2000 ' UNIDO,Vienna,1976.

4- St angel, P:! Nitrogen requirements and adequacy of supply for the major rice growingareas in the world'lnternational fertilizer development centre, Muscle Schoals Ala, 1978.

5- Holroyd, R: ' Ultra large single - stream chemical plants their advantages anddisadvantages chemistry and industry August 1977,PP 1310-20.

6- Finneran J.A Sweeney N.J, Hutchinson T.C: ' S tart-up performance of large ammoniaplant's, ehern Eng Prog, 64,8,1968, PP 73-79.

259

7- Leblanc J.B, Shah M.N, Buividas, L.J : 'Reliability key to NH 3 plants profits, Hydroc Proc,April 1980.

8- Williams G.P, Sawyer J.G : ' Causes of ammonia plants shutdown's Safety of ammoniaplants, AlChe Puplication N.Y, 16,1974,PP 4-9.

9- Williams G.P : ' Causes of ammonia plant shutdowns ' Safety of ammonia plant, AlChePublication, N.Y, 20,1978, PP 122-128

10- Williams G.P : ' Causes of ammonia plant shutdowns ' Pullam Kellogg Ammonia Club,Annual meeting, los Angeles, 1982.

11- Williams G.P : ' Causes of ammonia plant shutdowns ' Safety of ammonia plant, AlChePublication, N.Y 98. 1987, PP 72-85.

12- Zakariah Z.A.B : ' Electrical generating capacity management in developing countries,Ph.D. thesis, University of Bradford, 1986.

13- Stipho N.A : ' Reliability and availability studies of chlorine plants P h.D thesis, Universityof Bradford 1979.

14- Solommon S.M : ' Real time dynamic simulation : the GIL ammonia plant simulator, Safetyof ammonia plant, 25, 1984, PP 129-135.

15- Kelly A,Harris M.J : ' Management of industrial maintenance, Butter worths, London, 1978.

16- Lewis C.D : Scientific Inventory control' Butterworths, London, 1970.

17- Madhavan S: ' Ammonia process simulator', Safety of ammonia plant, AiChe publication,N.Y, 24, 1982, PP 167-171.

18- EL-KHADI H.T : ' Studies on the process availability of chemical plants with particularreference to developing countries, PhD thesis, University of Sheffield, G.B 1976.

Table 1. Total production duration Plant I 1970-1975

M, Boumaza

Year

1970

1971

1972

1973

1974

1975

Averageper year

ProductionDurationMonths

2

6

7.5

5.5

0.30

2.50

3.90

Downtime

Months

9.5

6

4.5

6.5

11.7

9.50

8.10

On- streamEfficiency

Z

17.40

50

60.8

47.8

8.70

21.75

34.4

260

Table 2. Major sections causing downtime andshutdown In Plant I. (Period 1970-1975)

Table 4. Overall performance of Plant II.

Classification

Synthesis &Refrigeration

PrimaryReforming

SecondaryReforming

Purification

FeedstockPreparation

Z of TotalDowntime

30

26

17

15

12

Z of TotalShutdowns

30

30

13

17

10

Downtime Days

No of totalshutdowns

Frequencyof reducedthroughput

On- s t reamfactor (Z)

Periodllth Nov 198125th Dec 1986

756

164

68

62

AnnualAverage

151

32.8

13.6

62

Table 3. Production capacity of Plant II November81-January 1987.

Year

1981-1982

1982-1983

1983-1984

1984-1985

1985-1986

ActualProduction1000' s tonnes

196.29

175.46

170.51

224.1

250.1

Z Of designCapacity

59.45

54.05

52.08

68.03

75.80

TargetProduction1000' s tonnes

250.0

280.0

330.0

330.0

330.0

Table 5. Classification of downtime (days/year)and shutdowns (no./year) Plant II, 1981-1987.

Classification

Rotatingimo'nirifiry

Static erniipruent

rtir.csllaniäous

Turnarounds

M.-rket InventoryControl

Instrument

Electrical

tatrl

DountimeDays / year

51

32.5

31.4

19

a. 36.8

6.2

156

ShutdownsNo / year

8.2

7

6.4

0.3

1.2

S

4.2

32.8

261

Table 6. Major equipment failures in Plant II(1981-1987).

Table 8. Classification of downtime andshutdowns Plant II, ROW, average world,(days/year/plant) and (no/year/plant).

Equipment

Synthesis GasCompressor

Air compressor

DemineralisedWater units

Refrigerant/compressorcondensers

Primary shiftconverter heatexchanger

Strong solutionMEA/ weaksolution MEAexchanger

Total

Downtime Days

135

81

80

50

33

12

391

No of failures

22

9

25

24

3

9

92

Table 7. Overall Performance, Plant II, Worldwideplants (11).

Da/»/rr

Nu / rrOn-air b.*factor 'f>

NorthAmerica

71.1

0.7

Bd.iiZ

Curop.

Wrf

6.^

ao.63

R. a .u

Ü4.S2

,(.6.

vs. sa

Uorld

7O.11

Ü.J3

30.79

Plant 11

156.1

Ï2.»

62.8

Classification

Rotating machines

Static equipment

Miscellaneous

Turnarounds

Market inventory

Instrumentation

Electrical

Total

R.O.U1978-1381(25 plants)

8.8

(3.5)

8.6(6)

4.1(1)

36(1)

4.3

(0.5>

1.3

(1.5)

3.7

(1.5)

67

C15)

Worldwide1978-1981( 88 plants)

8.4

(2.4)

9.4(4-8)

2.5(0.7>

27.1(o.a)

8.5

(0.3)

1.7

(1.7)

1.6

(1)

59.2

(11.6)

II1981-198

51

Cfl)33.5

(7>

31.4(6.4)

19(o.a)

8.3

(1.2>

6.8

(5)

6.2

(4.2*

156.2

f 32. 6)

Figure 1. Cumulative production In Plant II (1981-1986).

262