Plant Adaptation in Organic Chemicals Manufacturing W. S. COE AND G. A. ANDERSON Naugofuck Chemical Division, United States Rubber Co., Naugatuck, Conn.
The many problems connected with the applicability of adaptation in a highly diversified plant are presented. Several specific plant problems in adaptation are discussed, pointing out unique change-overs to produce new chemicals. In each case, substantial savings in both time and capital were effected while producing sizable quantities of new material for rapid and extensive commercial evaluation.
T
HE chemical industry has well earned its reputation of being an active, aggressive, and rapidly growing field. It is expand-
ing a t the average rate of approximately 10% per year compared t o 3% for all industry. It has likewise earned a less enviable reputation for having a high rate of technical obsolescence. This is a natural consequence of the dynamic forces that provide its very lifeblood, namely an insatiable demand for new products. Chemical producers have learned many hard lessons by having large investments tied up in ventures that a t one time seemed to be secure but quickly changed their status. The accelerated tempo of our excellent competitive free enterprise system has merely increased the risk of putting major capital funds in a new venture before it has withstood the competitive test of field usage and adoption by the trade as a desirable and semistablc article of commerce. Rapidly rising cost of building new facilities has been a concurrent aggravating factor in this chain of events. A criterion commonly used in this connection is the Tuttle index which shows approximately 185% increase in construction costs since 1939. Time is the other major factor confronting the chemical manufacturer who is interested in producing a new product. There is often critical necessity for immediate production of sizable quantities of a new product to satisfy demand or to obtain extensive commercial evaluation. This must be accomplished before interest diminishes or before a customer is forced to adopt a competitive product. Therefore, the basic problems of a rapidly changing field of chemical technology are:
1. Cost of new facilities is high, and there is the risk of technical obsolescence. 2. Time is required for construction, and the market may not r a i t . Adaptation-An
Alternate Course
of Action
The principle of adapting existing facilities to meet a new production requirement is often a lifesaver from the standpoint of both cost and time. Plant adaptation, in effect, often provides an alternate course of action for varying technical and economic circumstances. The fact that existing facilities may be available is another story. There may be several basic reasons: 1. The former product may have outgrown its original facilities to the point where further expansion in the same location is impractical; it may have finally justified that bright shiny new building, that chemical engineer’s dream, which the research chemist had in his mind when the product was first developed. 2. An entirely new and cheaper process may have been dis-
December 1954
covered which made a new plant more feasible than revamping the old. 3. By no means least probable, the product may have become a commercial casualty of technical obsolescence. Without a doubt, any organization of appreciable size or diversity of products has experienced numerous cases of this type. Plant adaptation or the ability to make a new product in an obsolete or only partially scheduled facility has obvious attraction from the standpoint of regaining earning power on an inactive investment. Flexibility Desirable
There are certain features of plant design which, if given consideration at the time of original construction, may serve to make potential future plant adaptation much more feasible. First of all, it is frequently desirable to include flexibility with respect to materials of construction, usually by way of using somewhat more corrosion resistant equipment than might be specifically dictated for the process step immediately anticipated. Glass-lined equipment with glass-lined, porcelain or plastic piping is often a desirable expedient in this connection, even though there are certain potential disadvantages such as increased repair and maintenance. Other features of flexibility may include overdesign of pumps, lines, condensers, charge tanks, holding tanks, and other auxiliary equipment, These can often be oversized originally for a small fraction of what it would cost for complete replacement later to remove bottlenecks or to accommodate process improvements. Another reason for using overdesign is the fact that sufficient detail of exact requirements may not be available to allow exact sizing before the plant is in operation. Increased flexibility may actually be cheaper than waiting for completely adequate process and equipment design information. Obviously, considerations such as these require a lot of “engineering horse sense” and it is not intended to imply that one should use excessive overdesign. limitations
Plant adaptation certainly has many limitations and cannot always be expected to give magic answers for any problem at hand. Plant adaptation may not be feasible where plant facilities were originally constructed for rather unusual processing conditions. These may include particularly high pressure, high temperature, very low temperature using special refrigeration, particularly hazardous reactions requiring excessive safety considerations, or very unusual material handling problems. A special case of unusual processing conditions might require certain unit processes that have little in common with others. For instance,
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ENGINEERING, DESIGN, AND PROCESS DEVELOPMENT nitration nornially requires abnormal heat exchange and agitation. Practical adaptation in this case might be limited to other nitration? of similar materials.
aCohE*ISER 1 SODIUM
HYDROKiLFiCE
B -
LAURYL BROMIDE
LaURYL BROh4l.E REACTOR
REACTW
VERTER
SEPMATOR
WASHER
CRUDE DODECYL MERCAPTAN WASTE ACID
Dodecyl Mercaptan Flow Sheet
Figure 1.
.hother example might be continuous process units 7vlier.e integrated design throughout is closely tied to a specific type of operation in its ent,irety. In these cases the original plant invcstmerit will have been quite high and i t may not be feasible to carry the high investment over to a subsequent operation unless it in turn actually requires many of the same special design features.
some chemicals, such as tetramethylthiuram disulfide, are both rubber and agricultural chemicals. Chlorinated quinone fungicides, a complex sulfite miticide, and growth regulating materials, such as maleic hydrazide, have been added over the years. A broad study of polymerization chemistry and plastics n-as initiated during the 1920's. This came to fruition in a line of resins and specialty plastic product's. This varidy certainly justifies the terminology of diversified organic chemicals manufacture. I t covers approximately 300 chemical products or formulations in several differentfields of end use. l I a n y of these are of comparat,ively small volume produrtion covering the range froiii 10,000 t,o 1,000,000 pounds per month. This range of productivity often made it necessary or desirable t,o produce more than one product in a given unit for optimum equipment and manpower utilization. Several products may be made alternately in the Same basic unit employing different process auxiliaries. It has often been found desirable t o use somewhat standardized equipment to make best use of t h i p phase of intermittent adaptation, as well as for more draytic: change-over adaptations later. In giving specific exaniplea of plant adaptation, the first serics ot' t,hese concern one part,icular building and its evolution. OE some interest is the fact that the building was originally built when the plant was founded 50 years ago and its early career included everything from storehouse and boilerhouse t o machine shop, hefore graduating into chemical process usage prior to 1940.
OFF-GAS
Type of Plant Before going into numerous examples of plant adaptation accomplished at Xaugatuck Chemical over the past 10 or 15 Seals, it i i desirable to outline briefly what type of plant we are considering. The Taugatuck plant had its inception just 50 yeals ago in 1904. The original facilities were provided to make acid for an adjoining reclaimed rubber operation. Acid reclaiming has long since ceased to be an important factor, but sulfuric acid ir still produced for captive use and for local markets.
3WI I
REACTOR
c
MCB RECOVERY*
I
PRODUCT
DISTILLAT
LPRODUCT
PLCOhOL
Figure 3.
WASHER
FLTER
Miscellaneous Chemical Flow Sheet T?? = Triphenyl phosphite DCDS = Dicresyl disulfide DAF = Diallyl fumarate P Q L = Terpolymer
Examples
ALCOHOL RECOVERY
Figure 2. DDT Flow Sheet T o i l d V a r I cut off the boui ce of many products of the German organic chemical industry. h plant was built in Naugatuck t o produce aniline which T T - ~used S briefly in the rubber industry as a vulcanizing accelerator. Rapid subsequent development of greatly improved rubber chemicals found aniline occup\ ing a unique role as the basic raw material for many accelerators and antioxidants. Saugatuck expanded with this field into inany specialty pioducts for the entire rubber industry. Organic agricultural chemicals came into their o7vn prior to World \Tar I1 and Kaugatuck initiated its first real step toward diversification in the organic field. Of interest is the fact that
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PROWCT
WASH
BLEND
s s.
KID
DAF OR POL REACTOR
REACTOR
@
fi, CONDENSER WATER
REACTOR
VAC
Just before our entry into Korld War 11, the United States Government had launched a program for the production of eynthetic rubber. A vital project in connection Tvith this prograni vias the production of a chain modifier to be used in the polymerization of GR-S. To Chain Modifier. For an expenditure of $25,000 limited production of dodecyl mercaptan rias accomplished in one month, and after six months the production was in excess of 100,000 pounds per month by adapting: existing equipment t o produce this chemical. The process entailed the production of hydrogen bromide, and reacting this material with lauryl alcohol. The lauryl bromide thus formed vias converted to dodecyl mercaptan by treating with sodium hydrosulfide in equipment shown i11 Figure 1. It is estimated that the cost of a new plant to produce material by this process would have been approximately $150,000 and moreover would have required 15 months to construct. illthough a new plant was built for the manufacture of dodecyl
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PLANT ADAPTATION mercaptan by a cheaper process, it was necessary to operate the interim unit until late in 1944 to satisfy the wartime demand. Chain Modifier to DDT. Interest in a new insecticide, namely DDT, had risen sharply about this time, and the equipment was adapted to produce this material for the armed forces. In Figure 2, the addition of a glass-lined reactor and other minor changes are indicated for the unit to produce DDT. The reaction of chloral and chlorobenzene and subsequent washing were carried out in reactors A and B which formerly produced lauryl bromide. The crude, washed DDT was melted in the new vessel marked D and then sprayed into alcohol for final purification. The alcohol was removed and recovered from the white crystalline
Polymer to Agricultural Chemical. The terpolymer PQL and its intermediate diallyl fumarate had moved into a new unit. This facility is shown in Figure 5.
CONDENSER ( S S I
YSS
RAW MAT " L
DDT. DDT to Rubber Chemicals and Polymer. As World War I1 neared an end, several new chemicals were developed and an indicated economic advantage of these materials justified the termination of D D T production. The adaptation of equipment to produce three different products is indicated in Figure 3. Reactor A was converted to the production of triphenyl phosphite. This material, a nondiscoloring stabilizer for GR-S, was produced by reacting phenol with phosphorus trichloride. The by-product hydrogen chloride evolved was absorbed in water and the product then stripped to remove traces of unreacted phenol. A blend tank, triple stage vacuum jpt, and receiver were added to the original equipment. Reactor B n a s set up to produce dicresyl disulfide, a black viscous liquid, used as a devulcanieing agent for rubber reclaiming operations. This material mas a reaction product of cresylic acid and sulfur monochloride. Vessels C and D were converted to the production of a terpolymer known as PQL. This material was used in making enamels curing a t 400" F. To produce this material it was necessary to prepare the ester of allyl alcohol with fumaric acid. The diallyl fumarate was purified by distillation, and the polymerization of this material with allyl alcohol and styrene took place in the presence of xylene. These operations were carried out intermittently in the same reactor. Polymer to Rubber Chemical. As production of diallyl fumarate and the terpolymer expanded, operations were transferred to larger facilities and the vacated equipment again became available for adaptation. At this point, an alkylphenyl phosphite had been developed to replace triphenyl phosphite as a stabilizer in GR-S. To produce this material it was necessary to alkylate phenol with an olefin in the equipment formerly used to manufacture the triphenyl phosphite. This is shown in Figure 4 as well as the conversion of the diallyl fumarate-terpolymer equipment to the alkylphenyl phosphite reactor and blending unit. The adaptation to this product was simple with only minor piping modifications being necessary.
6
CONDENSER (G L I
REACTOR
STILL
PRODUCT
Figure 5. Terpolymer Flow Sheet DAF = Diallyl fumarate PQL = Terpolymer
The life of this plastic was short-lived. Fortunately, a new agricultural chemical had been developed and was ready for plant production. The equipment was adapted in place to produce p-chloroethyl-p-(p-tert-butylphenoxy)or-methyleth~l sulfite and one of the required intermediates. Briefly, ethylene oxide was reacted with thionyl chloride and the reaction product was distilled to yield P-chloroethyl chlorosulfinate. This was accomplished in the diallyl fumarate reactor and distillation equipment. In Figure 6 the minor changes required can be noted. The distilled p-chloroethyl chlorosulfinate was reacted with p-(p-tert-butylphenoxy)-2-propanol,prepared in another unit, t o produce the miticide. Since then a large scale, more efficient plant has been constructed to make this material.
SS
?iOi.D TANK
JL L
Figure 6. Aramite Flow Sheet CECS = 6-Chloroethyl chlorosulflnate
CONDENSER
BPI
VACUUM
,-I::---,+
General Comments
a
t BLEND
PRODUCT
Figure 4. Alkylphenyl Phosphite Flow Sheet
December 1954
= P-(p-tert-Butylphenoxy)-2-propanol
Practical plant, adaptation does not necessarily require any siniiIarity of raw materials, intcrmcdiates, or finished products. On the other hand, there should he some degree of basic similaiity as to processing conditions in the primary reaction vessels. These and many other cases have shown b y experience that plant adaptation can often be accomplished in 5 to 10% of the time and for 5 to 15% of the cost for new facilities. These considerations have sometimes been the determinant factors in discontinuing an old product to provide facilities for a nex- one. There has been no intent to imply that the principle of plant adaptation, as applied to organic chemicals manufacture, is unique and novel or used only b y Xaugatuck Chemical. Rather, some of the basic principles and Naugatuck's methods of applying
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ENGINEERING, DESIGN, AND PROCESS DEVELOPMENT them to a few specific problems have been outlined in order to encourage others to tap resources t h a t may have gone unnoticed. llmost every chemical manufacturing plant has probably made rather major adaptations in some form a t one time or another. To illustrate this point, it is possible to quote two such cases through the courtesy of Hercules Powder Co. ( 2 ) which show a remarkably close similarity as to application of the same general principles. Hercules Examples
Thanite to Toxaphene. The insecticide, Thanite, is used in household and livestock sprays in combination with pyrethrins and other toxicants. The basic steps in the manufacture of Thanite are reaction of a terpene with chloroacetic acid to form terpene chloroacetate, which is reacted in turn with a thiocyanate to form terpene thiocyanoacetate. Because of the extremely corrosive nature of chloroacetic acid, glass-lined reactora are used. Following Korld War 11, toxaphene, a chlorinated terpene, was developed for use as an agricultural insecticide. Dominating other engineering considerations in its manufacture was the corrosiveness of by-product hydrogen chloride. It was quite logical to convert the former Thanite plant to the initial production facilities for manufacturing toxaphene. By then, Thanite was being made in a larger plant. Adaptation required changes in agitation, transfer lines, and pumps, but most auxiliary equipment, including makeup, holding, and storage tanks, was usable, although in some cases relocation was necessary. An off-gas system was added for treatment of effluent hydrogen chloride and chlorine. Capacity of the first commercial toxaphene plant was later enlarged, first by addition of two glass-lined reaction vessels formerly used for DDT, and later by addition of new vessels. Parlon to Chlorobs. Parlon is a chlorinated natural rubber, and Chlorofins are chlorinated paraffins. When the natural rubber shortage developed during World War 11, Parlon production was curtailed. Coincidentally, Chlorofins were needed for military use as flameproofing and waterproofing materials. The Parlon plant used glass-lined vessels for the chlorination reaction rrhich was followed by precipitation and drying of the product. Scrubbing and absorbing equipment was used for treatment of chlorine and hydrogen chloride exit gases. Most of this equipment n-as suitable without change for Chlorofins production. Both processes employed liquid phase chlorination, thus not only the reactors but also liquid and gas handling facilities, as well as the solvent recovery system, could be used with minor changes. This is a case of drastically different major raw materials being treated by basically the same operation to end up with entirely different products with minor equipment modifications. Since the war the plant has been reconverted to Parlon and can now make both products. People
One of the most important phases in taking advantage of plant adaptation is the attitude and resourcefulness of people in the organization. Of course, people hold the key to success or failure of almost any problem confronting an organization and in this light the statement is a broad one. However, it seems to apply particularly well to the subject of plant adaptation. Experience has indicated that novel ideas in this respect may originate from many segments of the organization covering the range of management, development, engineering, production supervision, and operating personnel. Ideas have often come from one of these groups after other groups had considered a new problem quite thoroughly but had tentatively concluded that no suitable facilities were available. KOone group of experts has a monopoly on bright ideas in this field. In other words, a complete organizational consciousness of the problems connected with plant adaptation is perhaps even more fruitful in yield of good ideas than in the case of many other operating problems. 2478
Safety
Plant adaptation is something that cannot be handled on a quick and haphazard basis. It is necessary to emphasize that safety considerations must a h a y s be completely investigated before equipment and facilities are used for something other than that for which they were primarily designed. This is extremely important to avoid the serious consequences of which any chemical reaction is capable if not properly handled and controlled. Every step of the new operation and the specific suitability of every equipment item, including all piping, lines, safety valves, and other processing auxiliaries must be individually checked each time a process change is contemplated in just as thorough a fashion as would be the case in design of entirely new facilities. Plant Adaptation--A
Tool far National Preparedness
A recent publication, “The Chemical Industry-Facts Book” ( I ) gives an excellent statement of the general position of the chemical industry with respect to national preparedness. The essentiality of chemicals in any picture of national preparedness has dictated great increases in productive capacity since 1950 for dozens of industrial chemicals. By 1955 the chemical industry will have about one third more capacity than in 1950. The American chemical industry today stands far above that of any nation in the world. America’s chemical might is a deterrent to aggression and a powerful factor in the domestic economy. The same booklet gives much interesting information with respect to present size, magnitude, and complexity of the chemical industry and allied products with gross sales in the magnitude of t w n t y billion dollars per year. This does not include the socalled chemical process industries which raise the figure to approximately fifty billion dollars per year. In recent years the chemical industry has become more and more closely associated with several other major fields, such as petroleum, synthetic fibers and textiles, plastics and synthetic rubber. These evpanding interrelationships are increasing in complexity and interdependence one on the other. However, a t the same time they are building a larger field of flexibility and alternate sources of raw materials. This is also increasing outlete and demand for their ovn finished products. I n future cases of necessity for rapid defense mobilization there will be many lese cases where a, whole industry is critically dependent on one plant or even one key industry for its source of critical raw materials. For instance, the phenomenal strides in petrochemical developments and expansions are a tremendous safeguard against the critical shortage of many coal tar chemicals, such as the basic product benzene. In previous emergencies two basic principles have been widely used in the chemical industry which are closely related to plant adaptation. They are:
1. Diversion of critical basic raw materials to produce essential intermediates or end products, and 2. Diversion of intermediates or products t o essential end use applications rather than less essential normal peacetime outlets I n the future it should be possible, by broader application of the principle of plant adaptation, to extend this thinking one step further back to produce essential new raw materials in existing facilities to a much greater extent than has heretofore been practiced. Every case where this principle is applicable will have the same advantages in terms of cost and time as for normal private operation. In this case, reduced cost Rould take on its true perspective in the light of less usage of critical construction materials and equipment which would certainly be urgently needed for other projects. The importance of time is self-evident. I n other words, our rapidly growing chemical industry, in the course of servicing a normal domestic economy and its increasing
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PLANT ADAPTATION complexity of interrelationships with other industries, is actually giving us a vastly important degree of flexibility for any future requirement for rapid national preparedness.
Summary The major advantages for plant adaptation are lower cost and shorter time to produce new products in sizable quantities for extensive commercial evaluation. Also earning power may be regainedon otherwise obsolete facilities. Plant adaptation provides an important alternate course of action for varying technical and economic circumstances. Practical adaptability requires flexibility of original design which is also advantageous from the viewpoint of making process improvements after initial plant operation. Several examples illustrate that adaptation usuallyinvolves some similarity of basic processing conditions but not necessarily any similarity of raw materials, intermediates, or final product.
Very abnormal processing conditions may impose limitations on the applicability of plant adaptation. The attitude and resourcefulness of people is a particularly important factor in plant adaptation. Safety considerations must always be given careful attention in making adaptations. The principle of plant adaptation can be used more extensively in any future national emergency to save time in producing vital materials.
Literature Cited (1) Manufacturing Chemists’ Association, Inc., Washington, D. C., “The Chemical Industry-Facts Book,” 1st ed., 1953. (2) Thompson, W. D., Paper Makers Chemical Research Division,
HerculesPowder Co., private correspondence, W. D. Thompson, February 26, 1954. RECEIVED for review March 26, 1954.
ACCEPTED -4ugust 26, 1954
Conversion from Coke to Natural Gas as Raw Material in Ammonia Production R. 6. BURT Tennessee Volley Aufhorify, Wilson Dam, A l a
W h e n the TVA ammonia plant was built semiwater gas produced from coke was the most practical source of hydrogen. However, when natural gas became available the plant was converted to use this cheaper raw material. The conversion from the use o f coke to natural gas was a major problem in plant adaptation and required numerous engineering and economic evaluations both of processes and of equipment. Studies were made concerning the choice of reformers, the retention of existing heat-recovery equipment, the use of by-product gases from other processes, the need for sulfur removal equipment, and the limiting capacities o f other units in the original plant. Two separate trains of two-step reformers and additional gas compression facilities were installed. Minor changes were made to other parts o f the orginal plant to ensure their efficient performance at the expanded rate of production with natural gas. These changes increased the capacity of the plant from 160 to 250 tons o f ammonia per day. The change-over from use of coke to natural gas was made one train at a time; the first was out of production only 29 days, the second only 26 days, and both simultaneously less than one day.
W
HEN TVB was created in 1933 it inherited the nitrogen fixation facilities of Nitrate Plant No. 2 a t Muscle Shoals, Ala., which had been built during World War I. However, in its initial fertilizer development program, TVA did not utilize these facilities to produce nitrate fertilizers. They depended on the calcium cyanamide process for the production of ammonia and t h a t process had become obsolete, primarily because many new plants had been built during the 1920’s which utilized the pressure-synthesis ammonia process (1). With the advent of World War 11, rapid expansion of the national production of nitrates for munitions was necessary. Therefore, TVA investigated the possibilities of utilizing its facilities to augment the national program. As a result of its studies on the best way of contributing to that program, TVA concluded that a new pressure-synthesis ammonia plant should be built to supplant the old cyanamide facilities. It recommended t,his step t o the War Department in July 1940 and coordinated the TVA program with that of the War Department. Initially, the plan was t o get the necessary hydrogen from semiwater gas produced from coke. The fact that a national emergency existed, and that the nitrate plant December 1954
could be made operable in a relatively short time, led to the choice of the semiwater gas process. Greater efficiency and economy could be obtained through the use of natural gas as a source of hydrogen, but the natural gas was not available a t Muscle Shoals. The TVA plant was among the first of the plants sponsored by the Ordnance Department to start operation and has remained in continuous operation since 1942 while supplying ammonium nitrate for munitions and fertilizers ( 2 ) . The demand for nitrate fertilizers increased steadily during the years immediately after World War 11,and the operation of the TVA plant was continued in order t o help meet this demand. However, maximum economy in nitrate fertilizer production could not be obtained with the continued use of the semiwater gas process. This situation grew worse because of the steady rise in the cost of coke and the increased operating costs associated with the use of the variable-quality coke available for plant operation. Therefore, u-hen a supply of natural gas became available t o the Rluscle Shoals plant through development by private companies, TVA re-exnmined its position and decided t o utilize this more economical raw material. TVA’s aid to the private interests who developcd
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