IEEE TRANSACTIONS ON INDUSTRY AND GENERAL APPLICATIONS, VOL. IGA-6, NO. 5, SEPTEMBER/OCTOBER 1970

Interesting Features of Ciments Lambert-Lafarge'sLe Havre Plant

H. W. WIDMER AND HERBERT A. EGGER

Abstract-The subject of modern plant design as related to auto-mation and integration as experienced in the realization of the firstfully automated cement plant is discussed. The philosophical andpractical aspects of advanced plant conception are analyzed in thelight of such new technologies as the straight-line flow, the computer-controlled equipment and process sequencing, the gearless ball milldrive, etc.

INTRODUCTIONC IMENTS Lambert-Lafarge was formed as a partner-

ship between Lambert Freres, a major Frenchcement, gypsum products, and building materials manu-facturer, and Ciments Lafarge, one of the largest cementmanufacturing companies in the world. The completeengineering of the plant was done under the responsibilityof Prospective Engineering Gestion (PEG).

Besides Le Havre, the company owns two cement plantsin the Paris area: Cormeilles, with a yearly production of850 000 short tons, and Limay, with a yearly production of500 000 short tons.The Le Havre plant is located on the Seine river delta

approximately 10 miles east of the city. Its constructionwas decided in 1967, and it has been in operation since themiddle of December, 1969. Some of the features of thisproject are rather different from the conventional and haveresulted in setting new trends in design and conception ofmodern cement manufacturing plants.

1) The plant is conceived as a straight-line flow.2) The plant is fully automated with direct digital

control (DDC) process control.3) Process starting and stopping is computer controlled.

Paper 70 TOD 40-IGA, approved by the Cement Industry Com-mittee of the IEEE IGA Group for presentation at the 1970 IEEECement Industry Technical Conference, Indianapolis, Ind., May12-14. Manuscript received June 1, 1970.H. W. Widmer is with Ciments Lambert-Lafarge, Le Havre, France.H. A. Egger is with Prospective Engineering Gestion, Geneva,

Switzerland.

4) Quarrying is done by the ripping technique.5) A new process for separation of the flint (silex) from

the chalk, never used in the cement industry before, wasdeveloped.

6) The plant is equipped with one of the largest Dopolsuspension preheater kilns ever installed.

7) The world's first gearless mill drive is mounted ontothe shell of the 15- by 50-foot 6.400-kW cement mill.

8) The 21-inch diameter semistatic Wedag classifiers ofthe raw and finish grinding circuits are the largest everbuilt.

9) The plant does not contain raw material crushers.The quarry run material is preground and dried (kilngases) in a semiautogenous aerofall mill.

10) All electrical equipment including the 90-kV trans-former and switchgear equipment are located in a specialbuilding.

11) The plant does not feature a clinker storage hall.The clinker is stored in 10 000-ton capacity concrete siloswith gravity discharge.

12) The efficiency of flint (silex) separation in the aero-fall is continuously measured by an automatic Holderbankon-line titrator.

13) Cement fineness is continuously controlled by anautomatic Holderbank on-line permeabilimeter.

14) The chemical composition of the raw mix is con-tinuously analyzed by a General Electric XEG on-lineX-ray analyzer.

15) The clinker drop between kiln and cooler is less than10 feet.

GENERAL PLANT DESCRIPTIONThe raw material used for cement manufacturing con-

sists of three different types of chalk: pure, low silica, andhigh silica. Ripped off on benches of 150 by 150 feet, thematerial is pushed by bulldozer to the quarry bottom.

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WIDMER AND EGGER: FEATURES OF CIMENTS LAMBERT-LEFARGE S LE HAVRE PLANT

Reclaimed by a 17-foot diameter bucket wheel, the quarry-run material is transferred to the plant by a 1.2-mile longconveyor and discharged onto a 70 000-ton capacity open-air polar stockpile. Again reclaimed by an automaticallycontrolled bucket wheel, it is fed over a 50-ton capacityvariable-speed storage belt to a 27-foot diameter 250 shortton per hour aerofall mill.

In the kiln gases swept aerofall, the minus 20-inchquarry-run material is dried and preground to minus '/4-inch size, with approximately 50 percent passing 170 mesh.With the help of the kiln gases, the 25-percent moisturecontent of the chalk is at the same time reduced to lessthan 1 percent.The flint (silex) is separated from the chalk by a com-

bined process of semiautogenous grinding, cyclone re-cuperation, and screening. The efficiency of flint (silex)separation is continuously measured by an automaticHolderbank on-line titrator.

After the aerofall treatment, the different types ofchalk are stored separately in three silos from where theyare fed into the raw-finish grinding circuit which isequipped with a 21-foot-diameter 275 short ton per hourcapacity Wedag semistatic classifier.The composition of the raw mix is continuously analyzed

by a General Electric XEG on-line X-ray spectrometerlocated between the classifier and the two homogenizationsilos.The 3300 short ton per day capacity Dopol clinkerization

unit consists of a 265-foot high 4-stage suspension pre-heater and a 18- by 270-foot oil-fired rotary kiln. From thekiln, the clinker first passes into a Fuller grate cooler.The cooler-kiln combination is conceived in such a wayas to limit the height of the clinker drop to less than 10 feet.After discharge from the cooler, the clinker is transferredby vibrating conveyor and bucket elevator to six 10 000-ton capacity (each) concrete silos.The 200 short ton per hour capacity cement mill is

driven by a 6400-kW Brown Bovery wrap-around motor(gearless drive) mounted directly onto the shell of this 15-by 50-foot two-compartment mill. The cement grindingcircuit is equipped with a 21-foot diameter 250 short tonper hour capacity Wedag semistatic classifier. After grind-ing, the cement is conveyed by air slide and bucket eleva-tor to a group of eight 10 000-ton capacity (each) silos.Fineness of the cement is continuously measured by anautomatic Holderbank on-line permeabilimeter.The plant is located on a deep-water shipping canal. It

features its own dock for boats of up to 25 000-ton capacity.The packhouse is conceived so as to permit the shipment ofbulk and bag cement by road, rail, and water.The office-service building compound is located next to

the plant and comprises the production staff quarters, thecentral control room, the laboratories, the work shop, thespare parts store, and the locker rooms.The 7 000 000-barrel capacity plant is operated by a

staff of 125. Included in this number are management,laboratory, and office personnel, supervision, quarry, pro-duction, packhouse, and maintenance crews.

GENERAL PLANT SPECIFICATIONSThe location of the Le Havre plant and its general speci-

fications were practically decided before process possibil-ities with flint (silex) containing raw materials were known:

1) plant location on the deep-water shipping canal nearLe Havre;

2) chalk with high flint (silex) content to be used as rawmaterial;

3) plant to be equipped with a single 3300 short tons perday capacity kiln;

4) plant to be completely automated;5) clinker storage in silos with gravity discharge;6) no outdoor electrical transformers and switchgears;7) cost price not to exceed a specified limit.

As a consequence of this rather ambitious and to acertain extent arbitrary approach by management, theengineers charged with the technical realization of theproject had to face up to some definite facts.

1) The Le Havre material is composed of chalk and hardlimestone and contains up to 12 percent of pure silica (flint,silex).

2) Previous industrial wash-mill separation tests in-dicated insoluble residues of up to 50 percent (flint plushard limestone).

3) No large dry process operation with chalk as a rawmaterial had ever been realized.

4) There was no dry process flint (silex) separation sys-tems in existence at the time.

5) No 3300 short ton per day capacity suspensionpreheater kilns were in operation anywhere.

6) In 1966, fully automated cement plants were few.7) Due to the high silica and moisture contents, the

raw material was known to be difficult to crush with con-ventional equipment.

8) Test drillings on the preselected plant site revealedextremely difficult building ground conditions.

ENGINEERINGThe Le Havre plant is fully integrated with the dis-

tinction between departments less accentuated than inconventional nonautomated installations. It constitutes ahomogeneous assembly with work functions articulated andto a certain extent interconnected.

In the development of Le Havre, it has been experiencedthat integrated plants demand a higher degree of engineer-ing. Integration implies a complete analysis and cleardefinition of objectives; it asks for a thorough examinationof all methods and prodution systems. Integrated plantscan be designed so as to be mostly free from restrictionswhich considerably hamper installations designed with theconventional approach. The designer's freedom in seekingthe most advanced and efficient solutions has-led to manysimplifications. In deciding to build a plant such as LeHavre, the owner invests important sums not only for thepresent but especially for the future. Therefore, to conceivea new plant based on past experience only may beequivalent to building a plant with the latest features that

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IEEE TRANSACTIONS ON INDUSTRY AND GENERAL APPLICATIONS, SEPTEMBER/OCTOBER 1970

others are already using. By the time that such a plant isready for operation, it could already be several years be-hind the times. People who do not look ahead in anticipa-tion of new developments will run the risk of having themost modern obsolete plant in their hand the day it goesinto production.

All this leads to the question of what is necessary inengineering studies, and who should participate in thedevelopment of a new plant. It is absolutely essential thatthe engineers charged with the design keep close contactwith the future operating personnel and give the chemistsand the process and systems engineers an important voicein the determination of plant conception and operatingphilosophies.

It is not exaggerated to state that there are few projectswhich have been studied more carefully than Le Havre.All possible efforts have been made in order to answer allquestions raised and to resolve a multitude of problems.Mathematical simulations have served to determine thecapacities of equipment and storage facilities. The problemsand influence of automation were analyzed in detail.Hundreds of tons of raw material were processed throughsemi-industrial and industrial Aerofall and wash-mill in-stallations. Raw-mix calculations were performed with thehelp of computer-programmed mathematical models.Hundreds of tons of clinker were burned in pilot, semi-industrial, and industrial kiln installations.

RAW-MATERIAL PROCESSINGThe raw material used by cement plants located along

the Seine river between Paris and Le Havre consists mostlyof chalk. Closer to Paris, the silica content (flint, silex)seldom exceeds 5 percent, and few traces of hard lime-stone inbeded in the chalk are found.For many years, both Lambert and Lafarge have been

operating plants in the Paris area. Due to the low silica andhard limestone contents of their raw materials, these wetprocess operations use the wash-mill method for flint(silex) separation. However, raw material deposits locatednear Le Havre contain a higher percentage of flint (silex)and hard limestone. With up to 50 percent of the materialinsoluble in a wash-mill process and the preference ofmanagement for a dry process operation, new methods forsilex separation had to be found. Drying of chalk to lessthan 1.0-percent moisture content, hardly ever done before,was a second obstacle Lambert-Lafarge was faced with.Some acquaintances in the French cement industry had

successfully dried limestone containing a high percentageof clay. Through them, the engineers working on the LeHavre project were informed about the existence of a semi-industrial aerofall test-grinding installation in France. Itwas interesting to learn that in 1966 there were alreadythree or four such semiautogenous mills being used forcrushing, pregrinding, and drying of raw materials inEurope.

In cement-plant application, an autogenous grindingcircuit normally consists of a kiln-gases swept aerofall mill,

followed by a multistage static cyclone system for separa-tion of the material from the drying gases.

Tests conducted in a 5-foot diameter pilot installationequipped with a 3-stage cyclone group gave positiveindications as to the feasibility for pregrinding and dryingof the Le Havre material. Already during the first testruns, it was observed that the flint (silex) due to its higherdensity was ground to a lesser fineness than the chalk. Asa consequence, the major portion of the flint (silex) wasseparated from the gases in the first cyclone, whereas mostof the finer ground chalk was recuperated in the second andthird cyclone stages. Extensive tests with a semi-industrialaerofall installation brought confirmation of the pilot re-sults and certitude of the feasibility of flint (silex) sep-aration in an industrial aerofall circuit. Large quantitiesof the Le Havre raw material were tested for their clinker-ization characteristics in semi-industrial and industrialkilns.

EQUIPMENT CAPACITY AND SIZETo equip cementplantswith single high-capacity kilns and

clinker coolers seems to be an accepted principle and withinthe last decade has led to the development of very largeunits of the conventional type. This trend is, however,very much reversed when it comes to the choice of grindingmills and classifiers. Operational security, seasonal sales,fluctuations, high-power peaks, and the need for specialcement types are most often given as justification for theselection of smaller and multiple units. Whatever thereasons, there is little doubt that operational and mainte-nance problems are more accentuated by the number ofgrinding units than by their size.The development of the semistatic classifier for capaci-

ties of up to 300 short tons per hour, the availability ofvariable speed gearless drives, and the feasibility of grind-ing mills equippedwith slide-shoebearings are certainly con-tributing factors in the direction of large raw- and finish-grinding mills. In order to prevent excessive equipmentsize and operational complexity, it becomes rapidly neces-sary to look for new production methods and systems, suchas autogenous grinding, gearless drives, preheater kilns,automation, etc. It must be recognized that the cementindustry has had its share of difficulties with high-capacitykilns of the conventional design. It must also be admittedthat the reasons for some of the failures can easily be recog-nized and should not be taken as proof against the feasi-bility of large kilns. The same reasoning applied to grindingmills where difficulties with mechanical gear-reductionunits and mill heads have discouraged many operators fromventuring into higher capacity equipment. However, thedevelopment of the gearless drive and the slide-shoe bear-ing seems to open up new possibilities.

PROCESS AUTOMATIONCiments Lambert-Lafarge wanted to realize a plant

which would not only be recognized for its size but also forits all-out approach in process control.

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WIDMER AND EGGER: FEATURES OF CIMENTS LAMBERT-LEFARGE 'S LE HAVRE PLANT

In automation, one has to choose between two basicsystems: optimization and regulation-stabilization. Forthe purpose of this paper "optimization" is considered asystem of advanced automation programmed for auto-regulation by computer of which the goal is to attain andmaintain the optimum limits of the operations. Within thesame context, "regulation-stabilization" is considered asystem of automation which permits the regulation andmaintenance of an operation within the limits determinedby the operating staff.The Le Havre plant is equipped with the regulation-

stabilization system which permits changing of set pointspractically at will. The computer, inside the chosen limits,is capable of maintaining process and equipment stability.However, it must be added that a certain number of partoptimizations are included in the system and providefor the minimization of the cost of the raw mix, the maxi-mization of mill loads, and the maintenance of properbalance between raw-millcapacity and raw-meal silo levels.Le Havre is probably the most automated plant pres-

ently in operation. Practically all nonmanagement func-tions are computer programmed. In its larger lines, thisautomation system has been conceived so as to preventall equipment redundance, to permit the application ofprocess operations which are too complex for manual con-trol, to assure the security of the different operations, andto increase the availability of controls and process opera-tions. Its different functions can be distinguished asfollows:

1) logging of process information and execution of thenecessary calculations;

2) regulation and supervision of equipment and processoperations;

3) stabilization of the different operations which con-stitute the production line;

4) programmed start-up and shutdown of equipmentand process, including computer manipulation of regulatingloop set-points and algorithms during the transient condi-tions.The system which assures the logging is of the classical

type; it does not permit for cost-price calculations. How-ever, periodic performance information on certain opera-tions are provided.The system relative to process and equipment super-

vision is very complete. Mainly due to the size of theequipment and the large quantities of material to behandled, it appeared necessary to exercise a permanentsupervision over all major installations and operations.Also included is a permanent control and evaluation ofthe validity of the values measured; the possibilities forserious operating errors due to defective sensors are prac-tically ruled out.The automation system for regulation and stabilization

covers all process operations including:1) pregrinding and drying of raw material; flint (silex)

separation with continuous control of separation efficiency

2) finish grinding of raw material with continuouscontrol of chemical composition by an on-line X-rayanalyzer;

3) preheater, kiln, and cooler operation;4) clinker grinding with continuous control of cement

fineness by an automatic on-line permeabilimeter.Separate systems not connected to the central computer

provide automatic control for operations such as stock-piling and reclaiming of raw materials, and truck and rail-car bulk loading.

Finally, the programmed start-up and shutdown ofprocess and equipment assures for proper coordination andreduces the need for manual interventions to a minimum.

PLANT LAYOUTIn discussing the future layout and conception of the

Le Havre plant with management and the automationengineers, it was recognized that some of the traditionalprinciples, still largely applied in cement plant design,had to be abandoned.

It is often maintained that the most efficient layout isthe one which provides for the grouping of the main pro-duction units around a central control room. This permitsthe central operator to physically see the production unitsand practically be in shouting distance of the operatingpersonnel on the floor. This principle is easily adaptablefor small installations (less than 1200 tons per day) withlittle outlook for future expansion. The problem is some-

what different for plants of the size of Le Havre, where theinitial production line capacity was fixed at 3300 shorttons per day and where management wanted to preservethe possibility to eventually quadruple production.

In order to satisfy these specifications Lambert-Lafargeundertook extensive studies of layout possibilities includingthe analysis of a considerable number of existing plantsall over the world. The result was the straight-line flowconcept. The ideal straight-line flow concept would consistof single production units for raw grinding, clinkerization,and cement grinding with the clinker and cement-storagesilos and the packing loading facilities also being part of it.If for capacity reasons, it is, for instance, necessary toinstall two cement mills, the straight-line flow concept isstill possible. In case of an extension, a new and againindependent production line is simply added along side theexisting line(s).As mentioned in the plant description (see Figs. 1 and 2),

the central control room in Le Havre was not placed in theproduction line but is located in the service building on thesame floor as the laboratories and the production offices.The central control room is of sufficient size to house thehardware for a second line.Some of the more important advantages of the one-line

conception are shorter internal material transports, no

crossing of material flows, a greatly reduced number ofequipments and drives, easier expansion possibilities, moreefficient use of plant site, and easier ground-floor access

by an automatic on-line titrator;

433

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Fig. 2. West view of Le Havre plant.

AEROFALL MILLThe 27-foot diameter gas-swept mill is the key to the

Le Havre process. It is the basic tool for the raw materialand at the same time allows for efficient pregrinding anddrying of the chalk. Without the aerofall, the feasibilityof the Le Havre project would have been doubtfull.The mill is fed with minus 20-inch size quarry-run mate-

rial and its capacity is guaranteed at 250 short tons perhour of minus '/4-inch size material with 50 percent offinished raw meal passing 170 mesh.

Aerofall mills are designed for feed sizes of up to 1 cubicyard, and capacities exceeding 400 short tons per hourcertainly are feasible. This autogenous mill was developedin Canada, and its application in the mining and metal-lurgical industry is rather wide spread. However, thecement industry has been reluctant to accept the idea, andonly one machine is operating in North America. Euro-pean cement people have been more interested in its fea-tures, and approximately ten of these mills can now befound in plants on this continent. Another three or fourare presently under consideration, and one was recentlypurchased for installation in a new plant in Algeria.

Together with the suspension preheater kiln and thegearless mill drive, the aerofall mill must be consideredone of the foremost developments in the field of cementmanufacturing equipment. Some excellent results obtainedin actual operation and with various types of raw materials(limestone, clay, and chalk) have established its efficiency,and many cement people already consider the aerofall as apossible replacement for the conventional high-maintenanceprone and low-availability primary, secondary, and tertiarycrushing systems.

SUSPENSION PREHEATER KILNS

The initial clinker capacity for the Le Havre plant wasset at 3300 short tons per day. After extensive investi-gations and in the face of numerous successful applicationin Europe and Japan, a clinkerization unit consisting of a4-stage Polysius Dopol suspension preheater and an 18- by270-foot rotary kiln was chosen.

For operators and engineers who have had experiencewith the conventional and suspension preheater kilns, it isdifficult to conceive that some cement people still acceptthe installation of wet kilns which for a comparableproduction (3300 short tons per day) would measureapproximately 25 feet in diameter and up to 700 feet inlength.

One of the principal reasons often given in favor of longkilns is the alkali problem. In fact, experience shows thatpreheater kilns are vulnerable to high alkali contents in theraw material. However, the manufacturers of the suspen-sion preheater kilns have not been inactive, and they arenow willing to guarantee trouble-free operation with rawmaterials whose alkali contents exceed 1 percent. The firstsuch kiln has been in operation at the St. Lawrence CementCompany's Clarkson, Ont., plant for almost 2 years.As described by Coles [8], the Clarkson preheater is

equipped with a by-pass system for alkali control. Up to25 percent of the kiln exhaust gases are removed at thebottom stage of the preheater and are quenched to ap-proximately 800°F. The solids, high in alkali and chlor-ides, are removed in a wet scrubber.Another development which puts a different light on

the problem are the more frequently appearing restrictionsof the alkali contents in the cement. These restrictions,combined with the more rigid air-pollution laws, forcemany conventional dry and wet process plants to eitherdispose of large quantities of precipitator dust or to takerefuge in dust leaching.The difference in favor of the suspension preheater kiln

is even more accentuated by the fact that material reten-tion time in a 3300 short ton per day capacity conventionallong kiln is approximately 3 hours, whereas in a compa-rable preheater kiln material, retention time is reduced toless than 1 hour. Btu consumption, refractory life, andoperational availability are other factors which shouldinfluence cement people to carefully compare before decid-ing on a giant size conventional kiln.

It seems safe to conclude that the trend in the industry,especially in Europe, Japan, and Russia, is developing moreand more in the direction of very large suspension pre-heater plants with their inherent low-cost price, theirsimplicity, and their superior operating availability.

REFRACTORIESThe desire of the cement industry to increase production

efficiency has led to the development of larger and largerkilns. With few exceptions, an average increase in diameterby more than 6 feet has been noted within the last decade.The refractory industry has been hard pressed to adapttheir technology to this new trend in kiln size. Develop-ment is advancing in the direction of new installationmethods using more efficient devices or techniques. This,combined with the selection of the most suitable brick

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IEEE TRANSACTIONS ON INDUSTRY AND GENERAL APPLICATIONS, SEPTEMBER/OCTOBER 1970

quality and shape, will lead to reduced installation time,improved stability of the lining, and lengthened refractorylife.For the installation of refractory linings, principally three

different working procedures can be distinguished:

1) bricks are glued onto the kiln shell;2) screw thread or hydraulic jacks are used to hold the

bricks in place;3) the bricks are installed with a special brick-installa-

tion machine.

Methods 1) and 2) require turning of the kiln during in-stallation, whereas method 3) allows execution of the wholelining work with the kiln in fixed position.

In order to reduce the hazards of lining failures causedby faultly installation to a minimum, such a special brick-installation machine was used for the Le Havre kiln. Thismachine was developed by Didier Werke, Wiesbaden,Germany, which also supplied the totality of the refrac-tories for preheater and kiln. The results of this new methodof installation are very satisfactory, and after severalmonths of kiln operation, there are no traces of liningdeterioration. The Didier brickwork erection machine con-sists of a supporting framework, a working car with plat-forms and boarding trestle, and a circle conveyor for liftingthe bricks to the platform level. The machine is adjustableto different kiln diameters.Another novelty in the field of refractories applied in the

Le Havre kiln is the so-called interlocking brick, a brickwhich cannot work loose easily and is especially suited forlarge-diameter kilns with small tapes.

BURNERFLOOR AND CLINKER COOLER

The concrete burnerfloor, sufficiently strong to support amovable kiln head, still is a requisite in most new plants.The massive concrete beams of such a structure can easilymeasure 6 feet or more in height. With the kiln hood placedon top of the floor and the clinker cooler underneath it, theclinker drop between kiln and cooler for an installationlike Le Havre would have amounted to approximately20 feet. Some of the ill effects caused by high clinker drops,such as wear on cooler grates, rebounding of the fine clinkerinto the secondary airstreams, and the double burning ofclinker reentering the burning zone are all too well known.Another important consequence of such a kiln hood-burner-floor-cooler conception is the height of the kiln aboveground level. In order to reduce this height, coolers areoften placed in pits. In the Le Havre plant, the kiln hoodsits in fixed position on two separate concrete structureswith the cooler inlet placed in between. Two sliding doorson the hood allow for easy access to the inside of the kiln.The burnerfloor consists of a frame structure covered withremovable light-weight concrete slabs for access to thecooler roof in case of necessity. This conception made itpossible to limit the clinker drop between kiln and coolerto less than 10 feet. Placement of the cooler bottom 6 feetabove ground level permits easy access to discharge gatesand transportation equipment. An added feature is the

location of the burnerpipe only 5 feet above the burner-floor level as against 10 to 15 feet in some of the largerconventional plants.

CEMENT MILL GEARLESS DRIVEThe cement mill of the Le Havre plant is equipped with

a 6400-kW Brown Bovery gearless drive (wrap-aroundmotor). The rotor of this variable-speed motor is mounteddirectly onto the shell of the 15- by 50-foot mill. Besideseliminating problems and worries which are often experi-enced with large mechanical gear reduction units, the appli-cation of a gearless drive brings added advantages such as

1) reduced surface area requirement for the mill-driveunit;

2) variable-speed driving from zero to maximum;3) adjustment of the mill speed up to full hp load on the

motor;4) spotting of the mill without the help of an auxiliary

drive;5) turning of the mill in either direction;6) possibility to adjust mill speed to actual cement

grinding conditions.

An unexpected benefit has been found to be the possibilityto drop the mill speed with simultaneous reduction of thefeed rate in case of plugging condition on the elevators orother equipments. The resultant time to clear such plug-gings is much less than that experienced by the conventionalmethod of reducing or cutting off mill feed, or even shuttingdown the mill itself.

It is not intended to ride shot gun against mechanicalgear-reduction systems, but there is no doubt that thefuture belongs to the gearless drive, especially for capaci-ties exceeding 5000 kW. It might even be predicted thatdespite a considerable price difference, there will be cus-tomers for units of less than 5000 kW. A German cementcompany has recently decided on a 4800-kW gearless driveand three 6000-kW units have been ordered for a 4000 shortton per day capacity cement plant in Italy.

INFLUENCE OF START-UP CONSIDERATIONS ONPLANT CONCEPTION

The initial start-up is an important phase in the develop-ment of a new project. It must, however, be kept in mindthat this phase is of relative short duration, and that theoperators will practically never again encounter the sameproblems and difficulties as during the start-up.

Despite this, the operators and engineers responsible fora project, especially if it is situated in a new location andcomprises new process methods and equipment, will alwaysbe faced with the question of to what extent the plant andespecially the control systems should be conceived in orderto allow for a so-called easier start-up. One who builds aplant which is equipped with a computer-control systemhas to accept the fact that start-up procedures for such aninstallations are quite different from the manual approach.The Le Havre plant is equipped with a control system

which restricts manual operation possibilities to a mini-

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WIDMER AND EGGER: FEATURES OF CIMENTS LAMBERT-LE FARGE S LE HAVRE PLANT

mum. The goal was to prepare the installations in such away as to allow for a minimum start-up and debugging pe-riod. It was foreseen to try to operate from the beginningwith the computer system without going through too manyintermediate stages. The operating personnel was tofamiliarize themselves immediately with the new controlsystem and methods thus avoiding the necessity for retrain-ing at a later date. A detailed manual specifying procedurefor the different start-up phases was established, and it wasadmitted that no pressure for the purpose of shorteningstart-up procedures was going to be applied by manage-ment.

It is quite possible that in practice the actual outcomemight be somewhat different. However, this type of start-up planning will lead to careful preparation of the opera-tion and to extensive training of the future operating per-sonnel. In Le Havre it has again been demonstrated thatthe success of a start-up, no matter if the plant is of theconventional or the automated type, still depends to thelargest extent on such things as

1) sufficient engineering time;2) selection of experienced equipment suppliers;3) properly executed mechanical and electrical erection;4) completion of plant installation before start-up is

undertaken;5) proper start-up planning;6) no top-management interference during start-up;7) familiarization of the personnel with the new installa-

tions during erection;8) careful training of future operators;9) qualified assistance from supplier engineers;

10) closed buildings in areas with adverse climaticconditions.

On the raw-material preparation side, the Le Havre plantmust be considered one of the more complex installationsever realized, and some problems were encountered duringthe start-up period. Interestingly enough, these problemswere not created by difficulties in flint (silex) separation,autogenous grinding or drying of the chalk, but wererather a consequence of improper mechanical and electricalerection, adverse weather conditions accentuated by openbuildings, and to a certain extent ignorance of regulationslisted in the start-up manual.

Designing a plant in order to facilitate the initial start-upis not necessary if the previously listed conditions are met.Based on the Le Havre experience, there is every indicationthat operating people as well as equipment supplier engi-neers are learning quickly and are getting used to theimaginary lack of large numbers of push buttons in thecentral control room.

PERSONNEL TRAINING

Complete mechanization combined with modern auto-mation contribute in reducing the number of operatingpersonnel. This number, although production capacitieshave risen considerably, is now approximately one third ofthe total strength needed not very long ago.

The development of large plants equipped with processautomation has had a considerable effect on the qualifica-tion of the managerial and technical operating staff.Cement plant operation was formerly an art based onimponderable criteria and on the experience acquired inlong years of operation. Systems engineering is now anapproach with which plant operation has become ascientific knowledge one can learn in a classroom. Systemsengineering allows this thanks to problem objectivationand systematic analysis of the functional relations of theprocess. The development of mathematical models permitsnumerical or analog simulation of the process, and thissimulation, in turn, makes it possible to train personnel onhow to act or react when faced by the different operationalcases.

Personnel recruitment and interchangeability are greatlyfacilitated by these formation and training possibilities.The required skill for computer use and standard mainte-nance can easily be acquired in training courses organizedby equipment suppliers. The relatively high operationalavailability of industrial computers and of their peripheralsrequire few specialized interventions. Since routine tasksare executed by the computer, operational personnel havemore time for analytical and provisional activities. Thisimplies on their part a new mentality, a new spirit, charac-terized by excellent confidence in computers. Except for alimited number of operators, the training of the futurepersonnel for a modern and automated plant is not essenti-ally different from that for a conventional one. The differ-ence affects, however, key people and though involvingfew, the importance of such training must not be min-imized. The personnel which should be considered forspecial training includes systems engineers, process en-gineers, programmers, X-ray chemists, central controloperators, and electronic servicemen.For Le Havre, almost all of the operating personnel were

hired from the outside. Only three key people have hadprevious cement plant experience (operations manager,process engineer, and production-maintenance engineer);all the others were formed for their future tasks in theLafarge operating school, in supplier training courses, inclasses organized on-site during the erection, and by partic-ipating in the actual erection and the start-up of the plant.The personnel considered for this special training werehired between 1 and 2 years ahead of the scheduled start-update. The operations manager, the process engineer, andthe systems engineer did participate actively in the en-gineering phase and in the discussion with equipmentsuppliers and contractors.

How THE FUTURE LOOKS

The technical evolution in the cement industry hastaken on accelerating proportions. Despite earlier difficul-ties with large plants, many cement operators have re-versed their opinions and are now considering 3000 to 4000ton per day kilns, suspension preheaters, 7000 to 10 000-kWgrinding mills, autogenous grinding, gearless drives, com-plete automation, etc.

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In order to prevent costly failures, it might be prudentnot to exceed the speed limit. It must be realized thatengineering and design of large automated plants takemore time than that required for conventional drawer-type installations. Repeatedly it has been demonstratedthat time gained by cutting short the engineering anddesign phases of a project is in most cases more than thatlost during construction, start-up, and the initial operatingperiod.

In looking ahead there seems to be no doubt that 5000-ton suspension preheater kilns will be realized before verylong. 10 000-kW grinding mills with gearless drives arealready under serious consideration. Automation in oneform or another is here to stay. Conventional long wet- anddry-process kilns will slowly disappear from the scene.Less complex clinker cooling equipments are in the develop-ment stage, and some operators are again attracted by thesimplicity of the planetary cooler. Equipment-availabilityconsiderations will outrank certain outdated an overvaluedefficiency requirements. The availability of reliable chem-ical on-line analyzers, combined with careful geologicalevaluation of raw material deposits, new process methods,mathematical simulation of raw-mix design possibilities,etc., will allow utilization of more marginal quality rawmaterials. Objective evaluation of the technological possi-bilities in cement manufacturing combined with more con-certed efforts by the industry as a whole could lead to themore general application of new and highly efficient con-cepts and methods. Manufacturing equipment and automa-tion systems suppliers will eventually get together in orderto combine their efforts in the interest of the industry.Modern plants of high capacity are already being built inindustrially underdeveloped countries. If some leadingcement manufacturing companies or nations continue tohold back; in the development of efficient and automatedcement plants, they could one day be relegated to backseats.

RECAPITULATION OF PLANT DATA

Plant Capacity7 000 000 barrels of cement1 200 000 short tons per year, 3300 short tons per day.

Raw Materials2 300 000 short tons per year chalk, average mositure

content 80 percent, average silex content 10 percent20 000 short tons per year alumina20 000 short tons per year iron ore30 000 short tons per year fly ash.

QuarryExtraction of chalk by ripping50 000 short tons per week, 10 000 short tons per day.

Barge and Boat Loading1100 short tons per hour of bulk cement1100 short tons per hour of clinker110 short tons per hour of bags.

Surge Capacities (Live)Polar stock pile chalkPreground chalkAluminaIron oreFly ash (raw side)Homo kiln feedClinkerGypsumFly ash (finish cement)

70000 short tons2 X 2750 short tons1 X 1000 short tons1 X 1000 short tons1 X 700 short tons2 X 2750 short tons6 X 10000 short tons1 X 1000 short tons2 X 700 short tons.

Quarry, Raw Material, Transportation, and StorageBucket wheel for chalk 17 foot diameter, 1600

reclaiming short tons per hourBelt conveyor 48 inches in two sections,

total length 1.2 milesPolar stockpile 450 foot diameter,

70 000 short tonsRaw-material staker 1600 short tons per hourBucket wheel for stockpile 15 foot diameter, 350

reclaiming short tons per hour.

Raw GrindingAerofall semiautogenous

mill

Raw-finish mill

Air separator

27 by 6'/2 feet, 250 shorttons per hour, 1050 kW,12.4 r/min

12 by 24 feet, 275 shorttons per hour, 2000 kW,15.5 r/min

21 foot diameter, 275 shorttons per hour, variablespeed, fan 450 kW,separator 300 kW.

Clinker Burning4-stage Dopol suspension preheater

height 265 feetRotary kiln

17 feet 6 inches by 270 feet, pitch 3 percent, 1.8 r/minmaximum, 3300 short tons per day, motor 400, kW

Fuller clinker cooler12 by 73 feet, three sections, first section inclined,second and third sections horizontal

Electrostatic precipitors2 X 100 000 ft3/min, 2 X 40 000 ft3/min

Conditioning tower for kiln gases26 by 100 feet, 165 000 ft3/min.

Cement GrindingCement mill

15 by 50 feet, 200 short tons per hour at 3000 Blaine,6400-kW gearless drive, variable speed up to 16r/min

Air separator21 foot diameter, 250 short tons per hour, variablespeed, fan 450 kW, separator 300 kW.

Packhouse4 truck bulk-loading stations 275 short tons per

hour each

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439WIDMER AND EGGER: FEATURES OF CIMENTS LAMBERT-LEFARGE S LE HAVRE PLANT

4 truck bag-loading stations

1 railcar bulk-loading station

1 barge and boat bulk-loadingstation

1 barge and boat bag-loadingstation

110 short tons perhour each withrotary packers

275 short tons perhour each

1100 short tons perhour

110 short tons perhour.

Automation1 GEPAC 4020 process computer1 XEG on-line X-ray fluorescence spectrometer (GE)1 Holderbank on-line titrator for silex separation1 Holderbank on-line permeabilimeter for fineness

control1 GE operators console4 typewriters1 GEMAC, instrumentation system1 GE-type XRD-6V5 laboratory X-ray analyzer forcement-mix control and general purpose chemicalanalyses.

REFERENCES[1] E. A. E. Rich, "Cement automation-1965," presented at the

1965 IEEE Cement Industry Conf., Allentown, Pa.[21 J. R. Romig and W. R. Morton, "Application of a digital com-

puter to the cement making process," presented at the IFAC-IFIP Conf., Stockholm, Sweden, September 1964.

[3] R. Anderson, "A new concept of management," North AmericanRockwell Corp., American Club of Geneva, March 14, 1969.

[4] G. Pralle, "Lining technique of large rotary kilns," Conf. Warmeand Energie, Dusseldorf, Germany, 1967.

[5] M. Kumecke and H. Naefe, "Improved refractory life in largerotary kilns through application of high-burnt magnesia andinterlocking bricks," Zement-Kalk-Gips, vol. 22, November 6,1969.

[6] J. P. Piguet and M. Cuenod, "Automation control of a cementplant-why? how?" presented at the 26th Conf. Swiss Assoc.for Automation, Lausanne, Switzerland, April 1970.

[7] H. A. Egger, "Design and conception of integrated automatedcement plants," IEEE Trans. Ind. Gen. Appl., vol. 1GA-5,pp. 752-758, November/December 1969.

[8] C. W. Coles, "Interesting features of St. Lawrence Cement'sClarkson Plant," presented at the 1969 IEEE Cement IndustryConf., Toronto, Ont., Canada, May 13-15.

[9] B. Homassal and H. Jakouloff, "Concepts for full cement plantautomation at the Lafarge's Saint-Constant plant," presentedat the 1969 IEEE Cement Industry Conf., Toronto, Ont.,Canada, May 13-15.

[10] M. R. Hurlbut, D. L. Lippitt, and E. A. E. Rich, "Application ofa digital computer control to the cement manufacturingprocess," presented at the Internat. Seminar, Brussels,Belgium, 1968.

[11] F. Le Bel, A. Guy, and D. E. Hamilton, "Computer direction ofquarry operations," Rock Products, March 1967.

H. W. Widmer was born in Switzerland in 1925. He received his education in Switzerland.After several years with electrical equipment manufacturers both in fabrication and en-

gineering, he joined the Holderbank Group in 1953 in view of their projects in Canada. Hewas employed by the St. Lawrence Cement Company from 1953 until 1962 and participatedin the design, erection, and start-up of their Quebec and Clarkson Plants. In 1967, after fouryears as Production Manager with the Atlantic Cement Company, Ravera, N. Y., he joinedLambert Freres, Paris, France. He is Operations Manager of the Le Havre Plant, CimentLambert-Lafarge.

Herbert A. Egger was born in Bern, Switzerland, on March 14, 1923. He studied mechanicalengineering in Switzerland followed by studies in the United States.He started his career in the cement industry with the Holderbank Group. In 1953 he was

transferred to Canada, where he was initially employed by the St. Lawrence Cement Com-pany. He has held various engineering and management positions in the Canadian andAmerican cement industry. He is Technical Director of Prospective Engineering Gestion,Geneva, Switzerland, a consulting engineering firm specializing in the design of moderncement manufacturing plants.