From 30 to 100 gallows
...
Laboratory Bench
- Gian
Monsanto Chemical Co.'s new organic engineering research laboratory at Nitro, W. Va., will permit duplication of virtually any laboratory bench setup, using 30- to 100-gallon equipment, with essentially no changes in service piping and very little change in process piping, although equipment locations may be changed in a matter of minutes. The building and equipment design and layout are the result of the A. Kapnicky, pilot plant combined efforts of three men-James group leader (now on the teaching staff of the University of West Virginia), Walter G. Canham, chief design engineer at Nitro (now located in the divisional engineering department of the organic division at St. louis), and Earl 1. Walk, design engineer in that department, who authored this article.
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HIS new engineering research laboratory was designed to demonstrate feasibility of proposed new processes; to investigate processes from a n engineering point of view, studying process variables important in future plant designs; and to prepare limited quantities of neiv materials for sales development. The most important and valid design considerations for building and equipment were derived from estimates of the minimum establishment necessary t o carry out the most probable research and engineering assignments. Based on previous experience and foreseeable assignments, exhaustive equipment lists were prepared and then cut extensively before the last estimate was prepared. Less than half as niang reactors, pumps, receivers, and columns were retained as were first requested. On the other hand, flexibilit'y was considered t,oo important to sacrifice. Reactors control layout
The bulk of organic pilot operations in the laboratory centers around the use of reactors and receivers. This equipment, then, controls the entire building layout. Three major facilities for the reactor areas were considered-utilities, control and instrumentntion, and operating. It was necessary t o provide as quickly and easily as possible the utilities of electrical power, stenin and condensate, hot and
cold water, brine and brine return, vacuum, and, on occasion, Aroclor heating for higher temperature processes. Control and instrumentation had to include such things as agitator speed adjustment, drive power input, recording and control of vessel temperat,ures, miscellaneous recording control, vessel pressure and vacuum regulation, vessel safety relief devices, utility inlet and outlet temperature indicators, utility flow totalizers, water and brine flow regulators, and steam metering. 1 lie operating layout had to provide access to all utility valves, with due consideration to automatic control; access to all vessel valves; access t o vessel openings for solids feed and observation; proper sight glasses; and forced and induced draft ventilation. This area also had to he provided with adequate heat and ventilation facilities, lighting, and stairs. Safety showers, eye bathe, fire estinguishers, fire escape, sprinkler system, etc., had to be provided for safe operating conditions. An elevator was held desirable for movement of materials and equipment from level to level. The only equipment design concept that seemed worthy of serious consideration is based on modular units. This idea begins Lvith a repetitive space allotment of reactor stations, both in the horizontal and vert,ical plane. I t then provides a standardized supporting frame for reactors of 100-gallon capacity or less, each adapted to carry a given reactor a t an optimum location and elevation. All agitation provisions, primary instrument elements, and valve connections, including safety valves, are a permanent part of each of these units. Each of the reactor stations is furnished with modular piping terminals--i.e., all corresponding nozzles are equipped with extensions to a selected location and elevation a t each of the stations. For a 100-gallon maximum reactor size, a 4-foot-square reactor station ie adequate. This size st'at'ion iits in very n ~ l with i the 20-foot modular building bays.
Striking night photo shows clearly aluminum walls and glass-reinforced plastic windows. Note contrast (left) of new building construction to standard brick buildings beyond
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I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
Vol. 48, No. 2
PILOT P L A N T Building construction represents n e w approach The building itself represents an entirely new approach for buildings in a Monsanto organic plant area. To reduce the cost of maintenance and t o obtain a building of maximum utility at a lower first cost, several radical departures from Monsanto’s standard buildings were made, and considerable use was made of new building materials and construction techniques. The building consists of an office section and a n operating section. The operating section consists of four 12-foot levels with nine bays, each 20 feet square. Center bays on the second and third level contain the 4foot-square reactor stations. The fourth level, intended primarily for feed and weigh tanks and equipment storage, is for the most part completely floored. The ground level is completely floored with the floors draining t o two, acid brick-lined, trough type sewers. Open wells, 6 feet 8 inches by 20 feet, are provided through the entire height of the building a t the northeast and northwest corners. These wells are equipped uTith Unistrut framing firmly attached t o the struclural steel to permit easy erection, in the future, of equipment not adapted to the reactor station openings. Since future changes are provided for by flexibility in design of the building concrete floors were feasible. High cost of acid brick eliminated its consideration as a resistant floor finish, and finally a floor topping containing iron filings was selected. I n addition to a hard, smooth, nonslip surface, this floor provides a reasonable amount of resistance t o caustics and acids; it is a nonsparking static conducting floor of extremely hard surface.
Four design factors proved predominant..
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Adaptability. An organic research pilot plant must accommodate a theoretically unlimited variety of batch and cont inuo us processes involving t he whole range of unit operations. Capital Cost. Fixed limitations on proiect ex pendit ures, from whatever source they arise, will always dictate the exclusion of some adaptability. Operating Costs. Like the capital cost, operating costs must be held within limits. In spite of increasing labor, service, and utility costs, engiFebruary 1956
Exterior building malls are coi iugated aluminum sheets of 61s alloy construction. Flashing, gravel stops and facias, roof and floor thimbles, etc., are fabricated from either 545 or 61s aluminum alloy. Windows have long been a source of high maintenance costs, not only within Monsanto, but throughout the chemical industry. T o reduce these costs and t o further the use of plastic as a material of construction, Fiberglas-reinforced panels of polyester resins were used. Since the plastic panels are not transparent, fixed alumirium sash was used in the office section.
neering research or pilot plant investigations must not become too expensive. Allowance for idleness of other parts of the facility was a prime consideration. A larger installation could provide better and more useful types of equipment, but its greater depreciation rate would raise operating cost unduly. Flexibility. The factors above dictated the greatest possible flexibility in equipment and layout to enable a minimum number of units to operate at maximum efficiency.
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ENGINEERING, DESIGN, AND EQUIPMENT Finished service piping manifold: Unioned spool-piece (foreground) can be replaced with a flow regulator. In f right foreground is one of the portable pumps
T o provide process venk through the built-up bonded roof (without the services of a roofing contractor), an aluminum roof scuttle was designed with a removable insulated aluminum top through vhich mechanics can run vent pipes and provide the flashing t o accommodate changing equipment layouts. The fume exhaust system serving the reactor stat'ions conEists of a dual-duct netiyork, with ducts running from each reactor station to a single exhaust blower on the roof. .211 rigid ductworli, inst,alled just below t,he ceilings, is fabricated from protected metal sheeting with links of flexible hose running from the rigid duct t'o the reactor or other equipment. Four-inch, full-blast gate valves control the flow of air a t each station. The interior surface of the steel exhaust fan housing and the fan blades are coated with a phenolic resin for corrosion resistance. To overcome the moat, common causes of sen-er failure-thermal shock, crystallization and gelling blockages-two separate seiyer ~j-stemshave been installed in this building. -4 cast-iron service s e w x carries waste from floor vr-ashing, safety showers and eye hathe, and stcam condensate. -4 l'ermanite process semw carries waste from the st,eam-jet, hot n-ells and process vessels. Since all the processing equipment is portable, an adaptahle fewer system is required. Process s w e r inlets were provided on the ground floor only, directly under the rcaction stations. These inlets, flush with the floor, have Haveg plugs tapped and fitted with 2-inch brass ferrules. This provides each piece of process equipment v d h an almost direct discharge route t o the sen-er. A cantilever type electrical elevator was used for the first time in place of the hydraulic tvpe elevators used a t the Nitro plant in the pa.st. This elevator does not require a penthouse as do most electrical elevators, although somei.i.hat greater floor space is requiied. A savings of over $4000 was realized in the use of this elevator versus the hydraulic type. The electrical system consists of a 220/110-volt, single-phaae system for lighting and convenience wiring and a 440-volt, threephase system for the power miring.
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With the exception of the permanently installed equipment such as the elevator and the brine system, all power supplied t o equipment is handled by means of plugs and receptacles. The receptacles, delayed action Arlrtite type, are conveniently distributed throughout the building t o supply both 110, singlephase, and 440-volt, three-phase power. All electrical equipment includes cords and plugs for these receptacles. T o permit the use of more than one 440-volt motor (as many as five) on a single circuit, all frequently used apparatus such as reactors are provided with circuit breaker-starter combinations. These starters are plugged directly int'o the 440-volt receptacles. On intermittently used equipment such as grinders, pumps, centrifuges, etc., manual starters have been provided. These equipment items are fitted with plugs that will not directly connect int'o the 440-volt receptacles; instead t'hey connect into one of three separate circuit breakers which, in turn, are fitted with plugs that will connect to the 440-volt receptacles. Thus, any violation of code-approved safe operating procedures is prevented. Service connections are through umique manifolds
T o maintain flexibility it was necessary t o bring all service facilities t o two points on the reactors-jacket inlet and jacket outlet. In essence, the manifold system devised t o accomplish this consists of two sections controlled through a three-way valve with lines going t o the top and bottom reactor connections. Controlled in this nianifold are brine and brine return, steam and condensate, water, and air for purging of jackets. Through this manifold steam mag be routed into the top jacket connection m ith the condensate returned through the lower Pection of the manifold and discharged into the condensate header, which in turn runs t o the steam pigs located on the east and west side of the building. Similarly, brine may be furnished t o the bottom jacket connection and returned from the top jacket connection through the upper manifold into the brine return line. Cold water, and hot water provided through a water-zteam mixer, are similarly handled through the manifold. All jacket connections have been extended to the same relative point in the cantilever sections. Just above the manifold takeoffs in the service risers, connections have been provided to supply any of these services directly to the process vessels and other equipment or through the automatic controls. The brine is maintained a t a temperature of -20" C. in a 20ton-capacity system utilizing an ammonia booster in conjunction with the plant ammonia system. The brine, 28% calcium chloride solution, is pumped a t the rate of 200 gallons per minute
INDUSTRIAL AND ENGINEERING CHEMISTRY
Vol. 48, No. 2
PILOT PLANT by means of a vertical sump pump of all-iron construction. This type pump eliminates the maintenance required on packing glands or rotary seals in a conventional centrifugal type pump. Vacuum facilities are on the east and west sides of the fourth level-a singlestage Karbate and a three-stage condensing Karbate steam ejector. The s i n g l e - s t a g e e j e c t o r s are intended primarily for transferring material from drums to process or vice versa. The three-stage ejectors are primarily for process purposes. The ejectors provide vacuums of approximately 100 mm. on the single-stage and 1.5 mm. on the three-stage ejectors. Borosilicate glass pipe with Teflon envelope type gaskets having corded neoprene inserts are used t o distribute the vacuum facilities throughout the building. As with the service piping, Unistrut was used almost exclusively in hanging of the glass pipe. A wire-reinforced suction hose made of Permanite has been used for the atmospheric leg of the condensing jets with the hot wells on the ground level. Instruments control flow or measure and record process variables
The instrumentation facilities provided in this building will make it possible for the engineering-research group t o provide more reliable information t o the engineering design group. lnstruments have been provided t o maintain a fixed flow or temperature or t o measure and record temperatures, pressures, flow, and humidities. I n the service piping manifolds, i t is highly desirable to measure the flow of water, steam, and brine t o the reactor jackets. However, as the size and cost of available meters was prohibitive, the flow is regulated and the time period for the known flow rate recorded. Water flow is controlled by a Teflon-packed regulator having a bronze case with stainless steel trim; it is calibrated for 1 t o 12.5 gallons per minute of water. The calcium chloride brine flow regulator, calibrated for 1 to 12.5 gallons per minute of brine, has Teflon packing, a cast-iron case, and stainless steel trim. Purchase of only two each of these regulators made it necessary t o provide spool pieces t o replace them when they are not in use in any particular manifold. Changing these regulators is facilitated by the use of handlebar O-ring unions. Steam flow is regulated through a pressure reducing valve and metered through a totalizing Shuntflo steam meter. These meters are also made to interchange in the different manifolds with spool pieces replacing them when not in use. Records of power consumption from agitation and grinding studies will be available through the use of a two-element alternating current wattmeter, for use on balanced three-phase, three-wire, 440-volt, 60-cycle loads consisting of 2- or 5-hp. motors. This meter will record consumptions in two ranges-0 t o 4 and 0 t o 8 kw. The initial purchase of process instruments consisted of one temperature recorder with two ranges from -30" to 0' to 150" C. and from 100" t o 300' C.; two temperature recording controllers with ranges of -30' t o 0' t o 150' C. and 100' t o 300' C.; one temperature difference recorder with a range of -10' to 0' to 10' C.; one recording absolute pressure controller with a range of 0 t o
February 1956
200 mm. absolute; and one dewcell element to be used in conjunction with the temperature recorder and controller. The electric meter and the temperature and pressure instrun e n t s are mounted on portable three-wheel racks and are provided with a n air purge system required for use of these instruments in the Class I, Group D, Division 2 area. The racks are eqaipped with a swivel wheel in the rear and two fixed wheels in the front which can be adjusted t o level the instrument. The water supply t o the building is metered through a 4-inch compound water meter located in a pit on the east side of t h e building. The main steam flow into the building is measured b y a 4-inch orifice type indicating and recording meter. Equipment provides for pilot studies of unlimited scope
Having previously decided to limit the size of the reactors t o be used in this building t o 100 gallons or less, the problem of choosing the equipment was reduced to deciding what would best serve for pilot studies of unlimited scope. Four reactors were moved from existing facilities. Two were 75-gallon capacity, one 50-gallon, and one 30-gallon. Since these reactors were t o be mounted in movable frames, 4 feet square, it was necessary t o maintain their center of gravity as near the center as possible. New 50-gallon glass-lined reactors with clamped on glass-lined covers were purchased, without drives, t o be used as receivers; these can be converted t o reactors a t a later date. A special 50-gallon jacketed reactor vessel, shaped very similar t o a thermos bottle, was built with 20% nickel-clad construction t o secure the maximum heat transfer area from the jacket. T h e vessel has a flanged top with a l b i n c h opening and 1-hp. driveand-shaft seal mounted directly on the top flange. Removal of
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ENGINEERING, DESIGN, AND EQUIPMENT keeping with the idea that the equipment should be as. versatile
as possible, the normal condenser-receiver combination was not
Typical process hookup making extensive use of plastic tubing. Note column installation and use of portable instruments
this flange and drive unit eimultaneousl~permits easy changing of the turbine type agitator purchased with the unit. These reactors are mounted in 4-foot-square frames constructed of 13/r X 3 inch aluminum box channels, with aluminum tread plate fixed to the top of the channel frame. With the yield point of 61s alloy aluminum very close to the ultimate strength of the material, it was necessary to design a special pickup hook assembly for lifting these loaded platforms. Even with the special pickup hook it was necessary to counterweight the reactor platforms t’o ensure balance and safe pickup and movement; in some instances it, is necessary to “pickup” by attaching the hook directly to the vessel. An all-glass scrubbing tower, 0 inches b y 10 feet, a packed all-glass distillation column, 6 inches by 20 feet, and a bubble cap distillation column, G inches by 20 feet, are installed in this building. Since they are more or less permanently located, these columns are supported from two 2-inch Schedule 80 aluminum pipes running from the third level ceiling through reactor stations to within 9 feet of the first floor. Parallel to these pipe columns are two other pipe columns used for mounting the reflux controller and reflux condensers. One Type 316 stainless steel condenser and two graphit.e cubic heat exchangers are mounted under three of the 4-foot-square floor-plate sections, for easy posit,ioning of the equipment, These will be used in conjunction with the reactors and rrceivers in the reactor area. The west drying room on the second level is equipped with a vacuum shelf dryer. The interior of the drying chamber, including the door, has been coated with phenolic resin as a safeguard against corrosion failure and for ease of cleaning. I n
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purchased for this dryer. Instead, a separate Type 316 stainless steel heat exchanger was purchased and mounted on the dryer proper, and a 30-gallon, two-piece, unjacketed standard glasslined steel vessel was purchased for use as a receiver. Both these pieces of equipment may be used elsewhere in the building when the vacuum tray dryer is not in use. Vacuum for the dryer is provided through a single-stage Karbate steam ejector with glass piping used for the vacuum lines. As the bulk of the heavy drying operat’ions will be accomplished in the vacuum tray dryer in the west room, the drying room on the east side can house smaller atmospheric type dryers that will be used to determine drying characteristics of various materials and to establish the type equipment best suited for the purpose. This room d l also house a Mikro-pulverizer, The pulverizer is of Type 302 stainless steel construction, mounted on wheels, aiid has complete electrical switchgear mounted on the unit. Although primarily intended to be used in the drying room, it can be used anywhere in the building. I n addition to existing pumps, two new pumps have been added to provide a minimum of pumping facilities---a two-feed proportioning pump with a capacity of 5.8 gallons per hour minimum and 58.0 gallons per hour maximum a t a maximum pressure of 500 pounds per square inch gage and a Iiarbate centrifugal pump, of monoblock construction, with a capacity of 40 gallons per minute a t a head of 40 feet. These punipa and a vacuum pump are mounted on four-wheel trucks with lock-type casters; they have manual starters to be used in conjunction with the circuit breakers as described earlier. The base of one pump has been drilled t o receive a small pressure filter of Type 316 stainless steel construction. A small drum dryer and a small sigma blade mixer were moved from the existing pilot plant, fitted with wheels, and furnished with manual starters t o be used in the same manner as the pumps. Portable platform scales have been provided for various usee. A 20-inch standard centrifuge of all-nickel construction is mounted on a special wooden pallet equipped with vibration Pliminators; it can be moved to the various locations by means of a fork-lift truck. The foyk-lift truck is the hand type commonly used in warehouses and foundries. Flow rates and process setups will be measured by flowrators moved from existing facilities. Insulation
Steam and condensate piprlines are insulated with a preformed tvpe of Fiberglas; polyethylene tape and/or galvanized steel Staples hold the insulation in place. This insulation is finished lvith a vinyl paint that forms an effective vapor seal. Cold lines (brine and brine return) are insulated with preformed roamglas. The vapor seal for the Foamglas insulation consists of one application of white vinyl mastic. Main manifold lines were given a two-layer application of the Fiberglas type insulation with a vapor seal applied to each layer. Process vessels are insulated with foamed glass blocks, in accordance ~ i t h standard procedures for hot and cold applications, with the exception of two vessels. On these two vessels Monsanto’s Santocel (finely divided silica) insulation was poured into a jacket made of light gage stainless steel welded over the vessel jacket. This type ineulation, comparable in cost t o the foamed glass insulation with protective cover, is expected to be cheaper on vessels larger than 300 gallons and also to virtually eliminate insulation maintenance. This laboratory incorporates many new ideas and modifications of old ideas representing Monsanto’s contribution, as stated on the dedicatory plaque, “TO FURTHER T H E Eh-GINEERISG STUDY OF CHEMICAL PROCESSES *4SD TO PROT‘IDE A LABORATORY FOR T H E PURSUIT AND ADVAKCEAIENT OF CHEbIICrZL E S G I N E E R I N G TCCHKOLOGY.”
INDUSTRIAL AND ENGINEERING CHEMISTRY
Vol. 48, No. 2
