PETE KNAPP, JR.
EFFECTIVE TECHNIQUES FOR A MULTI-PRODUCT PILOT PLANT
Three years ago, Industrial and Engineering Chemistry published an article by Richard Fleming on making the most of bench-scale experimentation in process development [51, 48A (November 195911. The following year. an article by C. C. Japs described a pilot plant building for small-scale operation 152, 9 (January 196011 and other articles on similar subjects have appeared [Chem. Ens. Progr. 55, 39 (19591; 56, 71 (196011. Presented here, is still another viewpoint on pilot plant operations, with emphasis on metnodoloav, -. wnicn nos nor r attention in the literature.
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peration of a multi-product pilot plant is not exclusively research, chemical production, or chaos, but usually has the features of all three. Presented here are some techniques that have proved at least partially effective in avoiding chaos, and increasing data and material output in one pilot plant. The unit is used for recipe and Drocess develoDmmt in plastics, elastomers, latices, and special organic chemicals, Since 1949, over 180 promams have been nrocessed. General Tire and Rubber Company has a pilot plant with about 30,000 square feet of working space at Mogadore, Ohio, about five miles from its Akron offices and one mile from its new Research and Development Center. Most of the work done at this pilot plant involves, at some stage, the use of reactors or kettles, ranging in size from 5 to 300 gallons, and generally constructed for moderate pressures and absolute vacuum. Many itrms of auxiliary equipment and services are, of course, necessary. All process effluent passes through a devolatilizing and settlmg sump and is then pumped into the effluent treatment system of the chemical plant.
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-Scale-up laboratory bench technology to plant scale operating procedures
The scale-up function is the one most commonly assigned to pilot plants of this size, and our practice follows the usual pattern. Basically, laboratory information is exnanded until a “transfer reDort” can be issued to the process and a realistic estimate ofthr cost. -Produce plant-trial quantities of experimental materials k r customer acceptance
Each potential customer for a new plastic or elastomer may require as much as 500 pounds of the developmental material in order to determine the “processability” of the product in his equipment. The requirements of
Auxiliary Equipment, Utilities, and Services
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Pilot Plant Functions
The dividing line between the research function and the pilot plant function is necessarily a vague one. Studies involving quantities of material larger than 5 gallons are usually conducted in the pilot plant. The objectives of pilot plant projects are usually better de58
fined and the studies less fundamental than those of the Applied Research Section. ’ The pilot plant has three chief functions:
INDUSTRIAL A N D E N G I N E E R I N G CHEMISTRY
Process Equipment Stills Oven dryers Grinders Spray dryers Filters Meterine ~. . - Dumps . . Measuring and control instruments Utilities (under jurisdiction of pilot plant staff and source generally in pilot plant area) 125-pound steam Dowtherm Well water Treated water Deionized water Refrigerated coolant
Compressed air Inert gas Vacuum
Services Laboratory (on site and at Research Center) Maintenance shop (power tools, welding, etc.; complete machine shop at Research Center) Research library (at Research Center) IBM 610 computer (at Research Center)
a dozen such potential customers total to considerable material by research standards, but are still too small a quantity to justify interrupti% the production plant schedule. This semiworks production, therefore, has become one of the functions of this pilot plant. Sometimes an experimental product catches on quickly and sizable orders begin to come in before the production plant can equip for the transfer. I n these circumstances, activities at the pilot plant are likely to become somewhat frantic. -Develop and evaluate chemical engineering equipment and processes, and trouble-shoot production plant problems
The chemical industry must constantly cvaluatc new equipment, processes, and matcrial rouhinations. The claims (11 the cquipment inhnufacturcr must usually be verified, and perfurmancc under specific conditions with spccitic matcrials m u s t Iic dctcrniined by the purchaser. l ' h e evaluation of sranddrd cquipmrnt on new applications and new equipment on old operations is another function of the pilot plant. The company has chemical and plastic plants at scvcral locations over the cbuntry, and these plants frequcnrly encounter chemical engincerinc: prohlcms requiring assistance IJeyoiid their own staff. This is especially true during plant or unit start-ups. The pilot planr cnh6neers constitute a m a l l reservoir of technical manpower that i b used for special trouble-shooting work when ncedcd. The Pilot Plant StoR
The pilot plant is organized as one of the three major divisions of Central Research, the other two divisions heing Exploratory Research and Applied Research. The rcchnical staff is currently composed of nine project ensincers and a development chemist. The nontcchnical sr;iff totals 23 operators and maintenance men. 'The plant normally operates tiye days a week, 24 hours a day, \,,ith each of the shift qroups working eiqht hours a day. Project lnitiotion ond Assignment
Experimental work in the pilot plant or stalT work by the technical permnnel is initiated by either external or internal request. Extcrnal requests may be submitred by a n y of the divisions or plants in the corporation. External requcsts may also originate from other sections of Central Research -i.e., Exploratury Research and Applicd Research. These requests are submitted in writins to thc proper authority, assigncd priority, and reviewed by the pilot plant staff at the weekly scheduling n.refinss.
Internally initiated projects originate within the pilot plant staff as suggestions for material or process development. These projects total about 25% of the pilot plant work load. Once a proposed project has been approved and priority established, the problem is assigned to one of the project engineers by the Pilot Plant Manager after consultation with his superior. Generally, internally generated proposals are assigned to the engineers who originate them. When the project engineer has been designated, he receives chief responsibility for execution of the project. He makes a patent and literature search, review company reports, and consults with research chemists who worked on the program. He orders raw materials and equipment, if necessary, sets up the experimental program, and writes up the procedures to be followed. The engineer follows the work in the pilot plant, analyzes data as they are secured, and re-slants the program if required. He must, of course, submit the usual verbal and written reports on the progress of his work. I n general, each project engineer becomes an expert in one particular field, but an attempt is made to vary project assignments to the fullest extent practical. The intent is to make each engineer a ''jack of all tradesmaster of one !" Scheduling and Control
If the small multi-product, multi-function pilot plant is to compete successfully with the larger specialized pilot plant, technical competence of the two groups being equal, the smaller pilot plant must be the more flexible and fast-moving. This flexibility and fast response are sought in part through an active scheduling and control system. Key feature of the control program is the weekly scheduling meeting. The Assistant Director of Research for Pilot P l w t attends this meeting, which includes all technical pilot plant personnel. Each project engineer gives a brief verbal progress report on his projects currently active and his plans for future work. New projects are presented and assigned, and from the realignment of priorities, the schedule for the following week is made up.
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AUTHOR Pete Knapp, Jr., is the Pilot Plant Manager at the
Central Research Laboratories, The General Tire and Rubber Co., Akron, Ohio. The material in this article is adapted from a paper presentrd by him last year at the Joint Congress of the A.I.Ch.E. andthe Canadian Institute of Chemistly in Cleveland, Ohia. VOL. 5 4
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Experience has established how much work can be done each week with the equipment and manpower available. Although the program is very seldom followed precisely, the work output exceeds that scheduled about as often as it falls short. Copies of the schedule are sent to all members of research management, each pilot plant engineer, the shift foreman, and the warehouseman. The schedule serves as an effective outline of each week's intended program to all who are concerned. The schedule can be intentionally altered with little notice, and, of course, is often unintentionally altered with no notice at all ! The intent is to secure the benefits of advance planning without losing the flexibility that is so highly valued. Only for a statistically designed program is an attempt made to schedule ahead further than one week. Research management meets monthly with top technical executives of the other divisions of the company, and decisions are made on the initiation, continuance, or termination of major research efforts. The long range research program is fitted into long range company plans at an annual meeting.
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The Check List System
T o standardize certain repetitive operations, detailed procedures have been written up and included in a procedure manual. When it is desired to deviate from the standard procedure, special instructions are prepared by the project engineer as required. One of the most exasperating experiences that any pilot plant supervisor can encounter is that of having some simple, routine item overlooked, with the possible result that expensive equipment is damaged or important data is lost. T o avoid or at least minimize these occurrences, a series of check lists has been set up. These include a start-up check list (for starting up the pilot plant each Sunday at midnight), a shift check list for each of the three shifts, and a shutdown check list for shutting the pilot plant down each Friday at midnight. Points that should be stressed in using check lists: -Provide for the recording of a measurement of some kind whenever possible. The operator is much more likely to inspect the equipment in question if he must take a reading than he is if he can merely check off a statement -Revise check lists frequently to keep them up to date -Make sure the operators know that the check lists are being inspected There has been a surprising reduction in the number of careless mistakes or oversights since the check list system has been introduced. If the question should come to mind-yes, there is a check list to keep track of the check lists ! Each week a pilot plant activity report is issued, giving a brief summary of the work done the previous week on all the active projects. Each engineer contributes the write-up on his projects. A detailed report is issued 60
INDUSTRIAL A N D E N G I N E E R I N G CHEMISTRY
by the project engineer a t the completion of each project or each important phase of a long-range project. The reports all serve as controls on the projects, and on the basis of these reports, projects are continued, postponed, or terminated. Special Equipment Features
Since the pilot plant contains inany units of process equipment and since much of this equipment is portable and is shuffled back and forth between storage and operating areas, a detailed control system is necessary. All major equipment items have been assigned code numbers such as those used in process flowsheets. In fact, flowsheets have been prepared of the systems that might be considered relatively stable in their makeup. Lists have been made of each specific type of equipment. For example, all the metering pumps are shown on one such list, which also shows the rate, range, and materials of construction of each pump. I t can be de-
QENERAL TIRE 8 RUBBER C O M P A N Y CENTRAL RESEARCH
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ABSOLUTE CAPACITY. NWINAL CAPACITY:
DIAMETER: HEIGHT
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each cabinet contains a different assortment of tools. Tools are color-coded for each cabinet, so that they can be returned to the proper cabinet. Only large tools are kept in these open cabinets. The "evaporation loss" of small hand tools is high, so these are kept in a locked tool box and checked out by foremen to the operators as needed. Certain plastics and elastomers have the most annoying property of sticking tenaciously to glass and stainless steel, the two most popular lining materials. Now that the technique of spraying and baking thin coats of Teflon has been perfected, it has been found that Teflon coatings are superior to both glass and stainless steel in many process applications.
PRESSURE CODIKC: None
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termined at a glance what metering pumps are available in the pilot plant. From the item number, one can refer to the proper specification sheet for more detailed information. An individual file folder is maintained for each equipment item, containing manufacturer's literature, parts lists, maintenance history, and other pertinent information. Since much of the motor-driven equipment is portable, Class I, Group D electrical outlets for both 110-volt and 440-volt circuits are provided throughout the operating areas. Motors on portable units are equipped with suitable extension plugs for use with the explosionproof outlets The overload protection for the motor is provided by overload coils in the switchbox mounted on the unit. The supply circuit to the outlet is protected by fuses back at the distribution panel. T o utilize the advantages of hydraulic drives for variable speed applications, 1000-pound pressure oil supply andreturnlines are piped throughout the operating areas. Not only are certain permanent agitators driven by oil motors but portable equipment is also driven from the supply header. Portable air-driven agitators, for example, are gradually being replaced by portable oil driven units, since the oil-driven units can supply higher horsepower at higher torque. Photographs are used to record important features of equipment arrangement. A Polaroid camera is kept at the pilot plant so that temporary installations or fleeting occurrences may be recorded promptly. Since pilot plant equipment is spread over several buildings, and in some cases two or three floor levels, it has been found convenient to install a tool cabinet on each floor in each area. Each cabinet is supplied with those hand tools most frequently needed in that location;
The pilot plant staff is constantly evaluating different types of process equipment. Since makes and models of equipment are increasing almost as rapidly as the technical literature is expanding, it is impossible to justify purchase of even a small cross section of new equipment for such evaluation. Equipment manufacturers will make available either free of charge or at a reasonable rental small-scale or full-size units. In almost all cases, any rental paid can be applied toward the purchase price if the unit is purchased. This arrangement makes it possible for a process development pilot plant to try out several types of equipment under experimental conditions on material, to be processed. Complete engineering data can thus be obtained at reasonable cost. Experience has shown that all process development pilot plants should provide sizable unoccupied floor space, equipped with the standard utilities, for this type of engineering studies on leased equipment. More and more process equipment manufacturers are installing their own customer-service pilot plants; where it is not practical to lease experimental equipment from the manufacturer, it may be ,possible to ship your materials to his pilot plant and arrange for experimental runs through pilot or full scale units. This also is usually done on an equipment-hour fee basis, with all or part of the charges creditable against any purchase made.
Hydraulic motordriven agitator. Special hand-control valves maintain revolutions per minute within 5%. Pressure of the j u i d downstream of the control valve is a function of horsefower drain. Thus, viscosity change during a reaction can be followed by recording the five fluidpressure at the motor VOL. 5 4
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