October, 1028
INDUSTRIAL A N D EN@lNEERIh% CHEMISTRY
1063
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Peoria, Ill., P h n t
Butanol Fermentation Process‘ C . L. Gabriel CoMMHRcihL SoLvmn CoEPonATroN, TBRxI: H*UTB,
T
HE industrial development of the production of butanol and acetone by fermentation has been exceedingly rapid
but the initial impetus was probably given almost sixty years before the fermentation process was placed on a manufacturinr scate. Development of Process
To follow the story properly from the beginninb, u-e must temporarily digress from the discussion of our fermentation products and go back to about 1860, when history tells us rubber was &st synthesized. At that time thisdiscoverynw of more scientific than practical interest, since the demand for rubber was relatively small and could be easily met. In the early part of the present century considerable interest was again aroused in synthetic rubber as a result of the increase in the price of the natural niaterial due to its use in automohiile t.ires. Plantation production soon increased, however, so that the price fell, and interest in the synthetic product was maintained only for the purpose of attempting to take care of the rubber needs of various nations during the World War, or for scientific value alone. The consensus of most of the research workers was that isoprene, dimethylbutadiene, and butadiene were the most suitable materials from which t.o synthesize rubber. Isoprene was obtainable from amyl alcohol, dimethylbutadiene from acetone through pinacone, and butadiene from norma.1 butanol. The attention of various investigators was therefore focused on methods for obtaining sufficient quantities of amyl and butyl alcohols and acetone at low prices. Amyl alcohol was of course on the niarket as an ingredient of fusel oil obtained as a by-product in alcoholic ferment,ation, but the a;orld production in 1912 probably approximated 4000 tons, with demand equaling supply and the price around 30 cents per pound. Acetone was being manufactured from acetate of lime at a Pr-ted at the General Conference relntinb- to “The Utilisafion of Corn Grain other than for Food and Clathixzg,” held at %heInstitrite of Chemistry of the Arnericnn Chemical Societs, Evanrton. Ill., July 24, 1928.
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fairly high cost. Butanol had never been made commerciall,v. However, the biochemical production of normal butanol, as uwll as acetone, had been known even though the discovery of a satisfactory fermentation process is of relatively recent date. The older workers in this field include Fitz. Grimbert. h c laux, Beijerinck, and Bredemann. In 1910 the firm of Strange and Graham, Ltd., in England, undertook to make s.ynthet,ic rubber and hired Perkin, Weizm a t s , and subsequently Fernbach t o work on developing processes for the production of higher alcohols. In 1011 Fernbach isolated a culture, to which he gave the namc “PB,” which fermented potatoes but not corn. After hydrolysis of the starchy maierkl of corn to sugar only indifferent results were obtained. Weizmann left the group in 1912 and undertook a personal study of the fermentation problem and continued his experiments for two years, isolating and studying numerous cultures and, among others found: was one which he called “BY.” About the time of the out,break of the World War, Weizmann had satisfied himself that BY had fermentative qualities not possessed by any other bacilluswhich he had studied. Meanwhile, Strange and Graham had filed English Patent Application 21,073 covering Fernbach’s bacillus B F and begun production at %%inhamabout the middle of 1913 using potatoes as raw materials. Afror about a year this plant was closed and operations were transferred to a plant which had been established at Xing’s Lynn. During the preliminary operations at Rainham it was discovered that acetone in considerable amount.s, as well as butanol, was formed during the ferment,ation. At this point fate took a hand and added impetus was given to the new fermentation process. The World War broke out in August, 1914, and England shortly required huge quantities of acetone, which was used as the solvent in making that important explosive cordite. The chief source of acetone up to this time was acetate of lime produced chiefly in Austria and our country. Acetone
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INDGSTIZIAL AND ENQI NEERINQ CHEMISTRY
Vol. 20, No. 10
from Austria was of .course not available to England, asid the Armistice witnessed the closisig of each of thesc plants in production capacity in the United States was almost negligible which operations had just begun. compared with the large and sudden demand. Strenuous It must be borne in mind that all the war-time operations attempts to increase the supply of acetone were made and were for the purpose of producing acetone, and butanol was many potential new processes were investigated, among these considered a white elephant. At Toronto, to supply an adthe hacteriological, with the result that early in 1915 Strange junct to acetone, a plant was erected and operated to convert and Graham contracted to supply acetone to the British normal butanol to ethylmethyllcetone with butylene and secGovernment. Their production averaged 970 pounds a week ondary butyl alcohol as intermediate products. The cessafor several months, when the Government took over the plant tion of operations in America found the fermentation plants and increased the average weekly production to 2340 pounds. with large quantities of that useless material “butanol” in Weismann had intended to publish the results of his re- their storage tanks. Efforts were made to salvage it. Some search as a scientific contribution. However, the exigencies small amounts had previously heen used in place of fusel oil, of war made it apparent that his discoveriesregarding the pro- when the latter became almost unavailable owing to prohiduction of acetone might be helpful to England. Accord- bition in Russia and the United Stat.es. As a result of the ingly, a confidential demonstration was given before the head intensive study of butanol and it,s derivative, butyl acetate. of the chemical department of Nobel’s Explosives Company, chemists found that, among other uses, these products who had previously looked into the Strange-Graham process. could be sstisfactorily substituted for fusel oil and amyl sceThis man appears to have been very much impressed with the tate. In fact, the purity of butanol actually gave it consideradvantage of Weizmann’s process and suggested the advis- able advantage over fusel oil-a varying mixture of higher ability of applying for a patent. As a result English Patent alcohols. ‘When this was discovered, the accumulated by4845 was issued to Weizmann in March, 1915. product was disposed of to several manufacturers of nitroThe favorable report on Weizmann’s process resnhed in cellulose lacquers. undertaking further research work under his direction a t The potential use of butanol, thus developed, resulted in the Lister Institute and larger scale development work a t Messrs. Eorniation of the Commercial Solvents Corporation of MaryKicholson’sdistillery. The results were so promising that the land which took over from the Allied War Board the two Admiralty decided to erect a plant for the production of ace- plants at Terre Haute which had been operated by it under the tone a t the Royal Naval Cordite Factory. Good manufactur- name of the Commercial Solvents Corporation of New York. ing results were obtained in this plant and the Ministry of This was late in 1919 and the start of operations a t the MaMunitions therefore decided to adapt six distilleries in Great jestic Distillery in Terre Haute early the following year repreBritain for Weizmann’s process. Two were operating satis- sents the real beginning of the industrial gowth of the Wekfactorily when a shortage of grains made it necessary to aban- mann process. However, the purpose of operations was comdon the idea of operating in that country on a large scale. pletely reversed. No longer was “butanol” to he disdainHowever, Weizmann’s process was substituted for that of fully regarded as a useless by-product. Now the process was Strange and Graham a t their plant in 1916, with a resultant to produce but.anol as its chief material and acetone was rele increase in output. gated into the by-product class, though of course it could not The British Government then decided to put plants in be considered useless. Canada where raw materials were available, and in India so The new company originally operated only under a United that it would have an independent source of acetone supply States license, but later obtained the world-wide patent for its cordite requirements. The plant in India was not rights to the Weizmann process. Still later the world rights completed unt,il after the close of the war and was subse- to a similar process of Eloi Ricard were also acquired. quently sold to the Bombay Government for conversion into a My contact of more than eight years with the industry has distillerv. In Toronto, Canada, however, Gooderham and enabled me to watch and marvel at its growth and to speak Wort’s iistiilery w a s from personal obadapted totheWoiss e r v a t i o n . Even m a n n process and t h o u g h its growth began operations in has been at an exAugust, 1916. The tremely rapid rate, plant operated sucit was not a mushcessfull~~for about room g r o w t h , f o r two years and prothat implies danger duced 3000 tons of of collapse. On the acetone and twice contrary, it was a that a u a n t i t v of steady forging ahead butan& based on the careful After tho United t h o u g h t a n d reS t a t e s entered the s e a r c h of business war: the British War and technical men. Mission purchased Of course, t h e r e the CommercialDiswere ups and downs, tillery a t Terre t h e l a t t e r due to H a u t e , I n d . , foi business depressions carryingout the aceor technical difficultone fernentation ties. Thegreatgenprocess, and shortly era1 business slump afterwards our Govof 1920 forced a nine ernment bought the months’ shutdown Majestic Distillery of the plant. Raclocated in the same teriological troubles city. The sibpingof encountered in 1923 Part of Mefhanol Plant
October, 1928
INDUSTRIAL AND ENGINEERING CHEMISTRY
resulted in fermentation yields being cut in half for about a year. Many specialists conducted investigations but were unable to cure the trouble. However, it was finally completely overcome and the knowledge obtained from the experience assured against any recurrence of the difficulty. The forty fermenters in the Terre Haute plant were increased to fifty-two during 1923 in the hope of increasing production in spiteof bacteriological troubles. Asaresult of the discovery that butanol and its derivatives were especially suited for use in the manufacture of nitrocellulose lacquers for finishing automobiles, interest in these materials developed at a rapid rate, and the supply of but.ano1had to he increased before tlienewfinishcouldbemarketed. In order to supply the great.ly increased demand, the Majestic Distillery, located at Peoria in the heart of the Illinois corn belt, was next acquired, additions made, and the plant put into operation in December, 1923. The original completed plant had thirty-two 50:000-gallon fcrinenters and the remainder of the equipment was adjusted to the output of those fermentation vessels. A year later the capacity of this plant rras incrr:nsed 50 per cent by t,he addition of sixteen more fermenters. During 1926 work was started on doubling the entire Peoria plant. This meant increasing the size of buildings and amount of equipment. The already large power house was doubled in size and like additions were made to the still house and mill. Kew buildings were construcbed and equipped for cooking, wuling, culture propagation, aiid fermentation. New centrally located laboratories for bacteriological and chemical control work were erected. Concrete elevators were also constructed, addiiig 200,000 bushels to the grain-storage capacity. To s u n up, toward the end of 1927, ninety-six fermenters were in operation at Peoria, making a total of 148 for bot,h plant,s. To prepare t.he mash and culture and to put the
1065
First Plant Stage Culture Preoaratlon
products of the fermentation into finished fonn requircs 2s agitated pressure cookers, 15 large double pipe coolers, 148 culture vessels of 100 gallons capacity, 132 culture vessels of 1000 gallons capacity, 7 continuous stills, and 22 stills with 11,000 to 35,000 gallon kettles. As corn is the chief raw material and as it had been found iineconomical to work up the residue in the fermented mttslr for feed or fertilizer after removal of the solvents by distillation, equipment for degerminating the corn was installed at Terre Haute last year and at Peoria this year. In the past, bran had alvays been scalped from the corn and sold to feed manufacturers. Now the germ is also removed, crude oil expelled from the germ, and the oil cake ground to produce a high-prot,ein cattle feed. This procedure has greatly reduced the amount of valuable products wasted in the “slops,” which is the name given to the watery fermentation residue after the solvents have been removed. Outline of Process
Second Plant Stage culture Preparation
The processisdivided into four chief steps -the preparation of meal and mash, the building up of cultures, the fermentation, and the distillation. Shelled corn is cleaned and run to the mill, where the bran and germ are removed and a meal of 10 to 20 mesh prepared. This is dropped into horizontal agitated pressure cookers into which water has previously been admitted. Live steam is then allowed to enter until the desired pressure is reached, and this is maintained for several liours. The smooth, cooked mash is then forced through double pipe coolers directly into the fermenters,. where it arrives a t a temperature of approximately 98” F. Meannrhile, the culture has been built up in the laboratories and cult,urc rooms. A few drops of bacilli in the spore form have heen activated by heat and used to inoculate a test tube of corn mash; this in turn forms the inoculant for a small flask, then comes a lnrgor flask. All the operations u p
CATRIAL A X D EXGlNEERING CIIE~MlS'TIz Y
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tothis&&gehave &en c
elaboratory incubators.
4 plant,culture rooms and
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and million gallons of water would be required daily. It makes uk.wonder if the laboratory workers attempting hut a few y w s ' a g o to produce butanol and acetone for the synthesis of rnhher could, even in their wildest dreams, have thought that an industry could grow so without the demand fromrubber makers.
onsofmasli ineach vesselrthe are used as inoculant er. are then run into vesseli fermenting contents of. ash. These are termed containing 1000 gallons ise the seed or inoculant "seed tanks," as their con for more than 40,000 gallons of corn mash in each fermenter. Other Developments Each step in building up the culture has required about 24 hours and the operations have been carried out under abso: m i l e the progress of the true fermentation end has been lutely sterile conditions. Selection of active and elimination told, mention of ot,her developmcnts cannot be omitted. If a of sluggish cultures have been in progress during each step, the few years ago a cliemist were asked how wood alcohol might be control work G i g in the hands of trained bacteriologists and made from corn, he probably would have replied that the cobs chemists. and stalks might possibly be subject,ed to destructive distillaThestace where40.000 crallonsof mash have been inoculated tion and some m o d alcohol thus obtained tocether with other wood p r o d u c t s . with an active culHowever. that is not ture has now the manner in which been reached. Gas pure methanol is beshortly begins to be evolved from the ing obtained f r o m corn. mash, its volume inIt has previously creasing u n t i l i t literally pours o u t been mentioned that large quantities of t h r o u g h a &inch gas were e v o l v e d pipe a n d s t e r i l e during the fermenwater seal. T h e t a t i o n . Each feracidity of tile mash mentation gives off is observed to be rising. I t reaches a more than 150,000 cubic feet of a mixpeak aud begins to ture approximately diminish. The conhalf hydrogen and t r o l meii know by half carhon dioxide this that the BY orb y volume. The ganism is properly weight of the gas doing its work and produced exceeds that solvents are beoneand a half times ing formed at a rate that of the fermene v e n more r a p i d than the lowering of t a t i o n solvents. These figures give t h e acid c u r v e . Upper L e v 4 of Still Tower some idea of t h e Laboratory tests on samples from the fermentors verify this conclusion. The cul- large quantities of gas which have been wasted. Tho questures rapidly progress in their task of changing starch into sol- tion of utiliaing a t least part of the gases was studied by vents, hydrogen, and carbon dioxide. Forty-eight hours our Rezearclr Department. Synthetic ammonia was apparsees their job completed. By this time the gas evolution has ently the most logical manufacture to undertake, as this ceased, the acidity curve has flattened out a t the minimum, would utilize all the hydrogen. Semi-plant equipment proved the concentration of solvents no longer increases, and the that pure hydrogen could easily be made from our gases and bacilli have returned t,o the spore stage, their food supply that synthet,ic ammonia could he produced from i t without undue difficulty. Arrangements were then made with the having been exhausted. Tlic short but useful lives of the cultures are now about Sitrogen Engineering Corporation of New York to design and ended and the completely fermented mash or beer is dropped install a plant a t Peoria capable of producing 12 tons of anhys run through continuous beer or drous ammonia per day. into reservoirs, from which it i direct steam stills a t the rate of niorc than 50,000 gallons per Meanwhile, our Research Department had begun intensive hour. Whereas the beer entering tliese stills contained but a work on the production of methanol by the passage of hydrosmall percentage of solvents, the distillate contains a t least 50 gen and carbon dioxide over catalysts a t super-high pressure. per cent, while a t the lower end of the still, slop free from sol- Hundreds of possible catalysts were prepared and t a e d and Trent6 is being discharged. Process storage tanks receive t.he the high-pressure catalyst-testing bombs were in use 4 .7 hours mixture containing, say, 50 per cent of water, 30 per cent of each day over a period of many months. The best catalysts butanol, 15per cent of acetone, and 5 per cent of ethyl alcohol. were then tested in a larger plant which could produce 50 galKettle stills now undertake the work of separation and pnri- lons per day. fication. The water is eliminated, and anhydrous butanol and The erection of the ammonia plant and the development of acetone, together with 9.5 per cent ethanol, are obtained. mctlraool certainly ran a close race. However, the ammonia Storage tanks await the newly produced solvents until they plant was run for a month to prove that it was satisfactory. hecome the contents of tank cars and drums to fill the demand Its capacity was found to he almost double its 12-ton NIL, of users located in various corners of the globe. rating. A t the end of the test period necessary changes were Adding the capacity of the Terre Haute plant to that a t made in the equipment, the catalyst was changed, and methPeoria, the plants are capable of using more than 30,000 anol operations hegnn just a little over a year ago. The plant bushels of corn per day, and in converting this amount of raw clos~lychecked the development work as to production per materials into solvents probably more than 600 toils of coal unit of catalyst per hour. Synthetic methanol manufacture I
October, 1928
INDUSTRIAL A N D E.VQIA’EERI.VG CIIEXISTR Y
1067
contains several had been established thousand volumes in the United States of technical books b y a process proand bound journals t e c t e d by patents in addition t o a distinctly American. rather complete colThe procedure is rellection of legal and l a t i v e l y simple. patentbooks. There The fermenter gas is are also hundreds of run through a solpamphlets and privent recovery plant vate reports. The to a gas holder, after a b s t r a c t files conwhich it is scrubbed tain about 15,000 with water under cards covering varipressure to remove ous subjects of inpart of , t h o carterest to the combon dioxide. The scrubbed gas is furpany. ther compressed to Commercial Value about 4500 pounds of Butanol Upser Level of One of the Fermenter Rooms Industry and run over catalysts xt an elevated temperature. Three volumes of hyI have endeavored to point out. the history and development drogen combine with one of carbon dioxide to form a mole- of the fermentadion proccss for butanol and acetone. The cule of methanol and one of water. The crude reaction corn-consuming rapacity of the plants would replace that used nroduct is thcn distilled and viclds a material containine ._ by the old distilleries for t.he production of over fiO million practically one hundred per cent methanol. Owing to the proof gallons of alcohol in various forms. The market for our availability of the gas, successful operation of the plant, and corn crops has been expanded. Lower grades of corn, often demand for the products, the meibanol plant is at present difficult to dispose of, earl be used, thus reducing the country’s being enlarged. waste and increasing the value of such material to the farmer. It is a lcnowii fact that only about 16 per cent of the maize Activities at Terre Haute grown leaves the farm and that the law of supply and demand Little mention has been made of the Terre Haute plant prevails. The price which corn brings is detenuined to a since its early development for tlie reason that most of the grezit extent by tlie mall surplus above the demand. So the recent expansion has been at Peoria. However, while Peoria butanol induslry, tending to decrease or eliminate the surplus is devoted to the large-scale manufacture of butanol, acetone, increment, increases the value of all corn marketed. Thus the et,hanol, methanol, and the by-products obtained, Terre butanol iiidirsiry affects tlic farmer by tending to increase the Hau!e omrations are considerablv more varied. In addirion orice of corn: the coal miner by creating an additional demand to the production of fermentafor coal which alone requires tion products, there are plants mm one hundred men to mine; for making b u t y l a c e t a t e , tile lacquer industry by supplybutyl aldehyde, dibutyl phthaing a necessary raw material; late, butyl stearate, and diacrand tlie automobile industry by tone alcohol. nraking available t,he excellent The Development D i visi on qii i c k-d r y in g lacquer &ish is also concentrated at Terre rrliich greatly speeds up proHaute. This consists of wellduction and reduces to an enore q u i p p e d and well-manned IIIOUS extent the number and Bacteriological and Chemical value of cars in the finishing Research Department.s toI’OONIS. gether with a large technical library wherc our Patent and Research Information Department,s are also housed. In I. G. AcquiresNew Magnesium addition to four research IaboCatalysts-Accordins t o tht. ratories, the Bacteriological ReDcpartment oi Commerce, it is search Department has a comreported in Frankfurt that the plete fermentation unit consistI. G. has acquired, on a Ions ing of t,wo fermenters and all lease. the rights of exploitation accessory e q u i p m e n t oneoi processcs for the production of magnesium alloys owned by quarter full plant size. There the Aluminum and Magnesium are eight chemical research 1:abrik A. G. Aside from the l a b o r a t o r i e s , a chemical enI. G.’s well-known interest in gineering lahorat.ory and misinngnesium through the pmcellaneous individual huildduction of its magnesium alloy ings housing such apparatus as Elektron metal, it appears that a complete small-scale wateran alloy of chromium and maggas producer, complete distilncsium possesses valuable catalytic activities. lation unit, etc. The library Lower Level of One of the Fermenter Rooms
