162
INDUSTRIAL AND ENGINEERING CHEMISTRY
A continued shifting of usages according to supplies and including animal, vegetable, and marine oils. Increased attempts to develop a substitute for coconut oil. Increased use of fatty acids as raw materials. Increased competition from petroleum derivatives and cellulose derivatives. The fats and oils, however, will continue to be used in large quantities for a wide variety of industrial purposes and will retain the major portions of their present markets.
Literature Cited (1) Baughman, W. F., and Jamieson, G. S., J . Am. Chem. SOC.,43, 2696-2702 (1921). (2) Ibid., 44,2947-52 (1922). (3) Brown, W. B., and Farmer, E. H., Biochem. J.,29,631-9 (1935). (4) Bur. of Census Bull., “Animal and Vegetable Fats and Oils” (1937). ( 5 ) Ibid., “Fats and Oils Subjected to Sulphonation during 1937” (1938).
VOL. 31, NO. 2
(6) Collin, G.,and Hilditch, T. P., J. SOC.Chem. Ind., 47, 261-9T (1928). (7) Collin, G.,Hilditch, T. P., and Lea, C. H., Ibid., 48, 46-50T (1929). (8) Hilditch, T. P.,“Industrial Chemistry of Fats and Waxes,” p. 25,London, BailliBre, Tindall and Cox, 1927. (9) Jamieson, G. S., and Baughman, W. F., J. Am. Chem. Soc., 42, 1197-1204 (1920). (IO) Jamieson, G. S., and Baughman, W. F., Oil Fat Industries, 4 131-3 (1927). J . SOC.Chem. Ind., 48,41-6T (1929). (11) Lea, C. H., (12) Milligan, C. H.,Knuth, C. A., and Richardson, A. S., J. Am. Chem. SOC.,46, 157-66 (1924). (13) Shriner, R. L., and Adarns, Roger, Ibid., 47,2727-39 (1925). (14) Statistical Abstract of U.S., p. 771 (1936). (15) Toyama, Y., and Tsuchiya, T.,Bull. Chem. SOC.Japan, 10,53943 (1935). (16) Twitchell, E.,J. IND. ENG.CHEM.,6,564-9 (1914). RECH~IVED September 12, 1938.
ALCOHOL FROM FARM PRODUCTS P. BURKE JACOBS Industrial Farm Products Research Division, Bureau of Chemistry and Soils, U. S. Department of Agriculture, Washington, D. C.
ECAUSE of the paramount importance of motor fuels in modern civilization, numerous efforts have been made in recent years to develop substitute fuels with which to supplement petroleum resources. The greatest activity in this movement has been i n f o r e i g n countries whose natural petroleum resources are inadeauate. * , emeciallv for defense needs. Since certain chemical compounds prod;cible by chemical or bacteriological processes from saccharine, starchy, or cellulosic vegetable materials, particularly ethyl alcohol, can be used with comparative success as fuel in the modern type of internal combustion engine, much of the experimentation for the production of such substitute motor fuels has been based on the use of agricultural products as raw material. In some cases this activity has been interrelated with a national agricultural program, This foreign experimentation with agricultural materials as fuel sources has aroused great interest in the United States, since here, as well as abroad, disturbed agricultural conditions have been experienced, as well as variations in farm crop prices resulting from over- or underproduction, fluctuating demand, etc. But the situation here differs from that obtaining in most of the foreign countries, since many of the countries which have resorted to the expedient of diverting crops to alcohol fuel as a means of raising farm prices or stabilizing agriculture have been mainly actuated by a need of fuel.
Means for Petroleum Conservation I n this country we had originally a considerable part of the world’s supply of petroleum, and therg has as yet been little
indication of approaching shortage or need for replacement fuels. Prices of petroleum products are extremely low, in contrast to the foreign situation. However, a t the present rates of consumption eventually the supply will diminish, with corresponding price advances, and some thought should be given to the situation then to be faced. Whether our petroleum supply will last ten or twenty years is immaterial. The supply is irreplaceable, and conservation should be practiced up to the time when a better source of motive power is developed to the commercial point. But actually the use of alcohol motor fuel has been advocated in this country mainly as a farm-relief or crop-price-raising expedient rather than as a conservation measure. Such proposals bring complications into the problem. If high prices are paid to the farmer for alcohol materials to increase farm income, the cost of the alcohol becomes impractical. Any increase in farm income from alcohol fuels, therefore, must rather come from such portions of crops now unsold or unusable which could be utilized industrially without disturbance to the price structure.
Potential Sources of Farm Income The problem of uncontrolled production of crops and of unsalable surpluses which remain on hand to depress prices has recently been countered by governmental measures tending to restrict crop raising. But besides crop surpluses, for which present markets are lacking, great quantities of unmarketable culls and wastes are also produced each year and represent further loss of potential farm income. But these materials are scattered over the 6,800,000 farms of the country and are largely uncollectable for industrial use. Another loss of potential farm income attends the production of quantities of relatively perishable crops which by reason of geographical location or temporarily glutted markets cannot be sold before they deteriorate. I n addition, the various crops are classified into several standard grades according to quality, and usually there is difficulty in disposing of the poorer grades. In normal production years crops are usually produced in excess of food market requirements, and some form of industrial utilization to use up any surplus above the normal carry-over should be found, es-
FEBRUARY, 1939
INDUSTRIAL AND ENGINEERING CHEMISTRY
pecially since export markets have fluctuated. All these constitute an important part of the agricultural problem. in addition, vast quantities of cellulosic materials, such as cornstalks, straws, sugar cane bagasse, corncobs, hulls, and shells, which might serve as raw materials for industrial purposes and for motor fuels, are annually produced and largely wasted each year. Attempts to control or stabilize agricultural prices by maintenance of a fairly constant surplus would necessitate a means of economically utilizing or disposing of any additional surplus, over the normal supply, in such manner that food or feed prices are not adversely affected. Such use would, however, be necessarily limited by the possible market for the chemical or industrial products made from such crops. Decreased crop production means a relatively larger unit overhead, and increased production might be more desirable if a proper market outlet existed. Agricultural materials should not be substituted in industry uneconomically and at theexpense of raw materials now used, nor should such substitution disturb present operations unduly. And yet a large market must be found. Because of the vast quantities of motor fuel now required annually for the operation of automobiles, tractors, and other mechanized forms of power in the United States, and the limit to petroleum resources, it seems logical to use such agricultural products or surpluses as a means of partially supplying this required motor fuel. The chemical feasibility of doing this has long been established, but theeconomics of price are not as yet in satisfactory adjustment, although future advances in petroleum prices may eventually partly offset the present disadvantage. Consideration can be given to the problem both on the present situation and on the future. At present alcohol will cost more than gasoline, and this relative differencein cost must be met. Furthermore, use of considerable portions of present crops will advance raw material prices. This may or may not benefit the farmer in the long run, but a t any rate large-scale use of farm materials for alcohol production will probably keep the cost of the alcohol up, because present cropP are inadequate for such a motor fuel program. OF ALCOHOL TABLEI. PRESENTCROPSAS SOURCES
Material Barley Corn Grain sorghum Rice (rough) Rye Wheat Jerusalem artichokes Potatoes, white Potatoes, sweet Sugar beets Sugar cane (U.S.) a
b
Gal. of Alcohol Producible from Total Cropa 280,158,800 3,593,918,450 122,542,200 84,299,400 56,218,800 1,628,798,600
. . . . . .. . . .
230,997,900 60,295,360 202,811,700 75,908,800
% of Requirements (for 10% Blend,with Gasoline) Supphed by Present Cropa 14.26 182.87b (275.5) 6.24
;:%[
7:4) 82.88b 91 6) .,‘5. b. . ~ ’4’ b)
.,
3.07 10.32 3.86
6,335,950,010 322.40 1936 basis, 19,653,142,000gallons gasoline used. Poor crop year; normal figure shown in parentheses.
The use of alcohol in motor fuel can be visualized either on the basis of national use of a standardized blend of definite high percentage (10-15 per cent) as one extreme, or by the localized production and irregular use of blends of varying and low concentration as the other. In the latter case the alcohol will probably be produced from such inconstant local supplies of crops as may be securable, in which much of the culls, by-products, or temporary surpluses will be absorbed. The amount and the cost of such alcohol will both vary widely. As the other alternative, the production of alcohol in large quantities sufficient to make a 10-15 per cent concentration blend of national scope is not yet possible because, on the
163
TABLE11. COMPARISON OF QUANTITIES OF ALCOHOL OBTAINABLE FROM CROPSPRODUCED IN THE UNITED STAT~S 15% of U. 8. Production (1935)
u. s.
Material Apples Apricots Artichokes, Jerusalem Barley Buckwheat Carrots Corn Dates, dry Figs all Grain sorghum Grapes, all Oats Peaches Pears Plums, all Potatoes, Irish Potatoes, sweet (includes yams) Rice, rough :%hum cane Sugar beet Sugar cane (for sirup) Sugar cane (for sugar) Sugar molasses (blackstrap) Wheat
Unit
Bu.
Ton Bu. Bu. Bu. Bu. Bu. Ton Ton Bu. Ton Bu. Bu. Bu. Ton Bu.
Production in 19350 167,283,000 216,000
..........
Units 25,000,000 32,400
.........
Equivalent in gal. of 99.5% alcoholb 8,750,000 440,000
.........
285,774,000 42,750,000 81,250,000 8,332,000 1,250,000 2,620,000 13,138,000 1,965,000 491.000 2,303,747,000 346,500,000 777,500,000 3,230 470 37,100 35,790 5 375 113 000 54,634,000 8,200:OOO 18,200:000 2,454,615 368,000 5,550,000 1,194,902,000 179,000,000 182,500,000 52,808,000 7,920,000 2,220,000 22,035,000 3,300,000 955,800 124,540 18,700 204,000 386,3SO,OOO 58,000,000 40,000,000
Bu. Bu. Bu. Gal. Ton Gal. Ton
83,128,000 38,784,000 58,597,000 13,350,000 7,908,000 25,982,000 4,573,000
Gal. Bu.
28,906,000 626,344,000
12,490,000 5,820,000 8,~00,000
2,000,000 1,185,000 3,900,000 685,000
11,740,000 10,420,000 19,350,000 ~20,000 26,200,000 1,600,000 10,400,000
4,300,000 1,774,000 94,000,000 241,500,000
Total gal. of 99.5% alcohol obtainable from 15% of the above crops produced in 1935 1,444,634,900 a Agricultural Statistics U. S. Dept. of Agriculture 1937. b Based on the average termentable oontent of the ;espective materials.
basis of present crops, the diversion of any great quantity of our crops would result in price increases which would not only raise the cost of the alcohol to impractical levels but would likewise affect food and feed costs. Table I illustrates the present crop situation in the United States, and demonstrates the impossibility of making a national 10 per cent blend. The corn and wheat crops are the only ones large enough to merit consideration. Any large-scale alcohol production operation will require crop increases. On the local production scale, if we assume that 15 per cent of all the crops might be available for alcohol production as annual culls or surplus, the alcohol potentiality of the country’s present crops might be illustrated according to the figures in Table 11. Since the use of an entire crop is impractical, and since this hypothetical 15 per cent would actually not all be available because of geographical distribution in respect to the location of the probable small number of alcohol plants, it is evident that some compromise will have to be effected. An alcohol motor fuel program must have a source of raw material which will be adequate during a long period of years. In poor crop years plant, personnel, and capital charges will have to be carried.
Industrial Crops There has been some discussion on the growing of “industrial” crops, or crops grown in unlimited quantities directly for industrial use. Such crops would perhaps net a lower unit price return but would permit farm overhead to be distributed over more production units. Whether this will be practical remains to be demonstrated. Experimentation has indicated that the average production of various crops might be considerably increased by improved farming methods. New developments with hybrid corn, sweet potatoes, and other crops have indicated that it is possible to increase acre production of these raw materials, at least in the more suitable areas. Raising more crops on the same acreage would mean proportionately increased
164
INDUSTRIAL AND ENGINEERING CHEMISTRY
costs for labor, seed, and fertilization; the last item would perhaps be the principal one. On a properly equipped farm, machinery capital expense should not greatly increase, but the machinery would work more hours per year. Crop failures, however, would represent a heavier investment loss than under the present system. The compromise program, if ever started, will therefore have to be that of a slow development of alcohol motor fuel production. It will be based on the use of such crop surpluses, culls, and wastes as may be suitable and available to produce irregular amounts of alcohol, and will necessitate the sale of a blend of varying concentration, which must then be sold in direct competition with cheaper gasoline. Such production may later advance through stages of larger crops or industrial crops on a more and more definite use of motor blends on an enlarging scale. Once the alcohol-fuel producing system existed, the utilization of present culls and wastes would become far more practicable and these present losses would become virtual assets. Use of culls and wastes as motor fuel raw material will partly reduce required crop acreage increases, although it might slightly increase the alcohol production costs. The reduction of crop surpluses to alcohol for storage might be possible, if storage charges do not become too serious. Despite some proposals that have been made, an alcohol fuel industry on a large scale could not be brought about for many years, particularly because of the lack of processing plants. The present annual production capacity of the industrial alcohol plants of the United States is around 250,000,000 gallons, and the capacity of the alcoholic beverage industry is about the same. The industrial alcohol induitry has operated a t around 50 per cent of its capacity, and the beverage industry has recently rather reached a standstill. Assuming both of them to operate at 50 per cent of their capacity, if the combined excess capacity w3re directed to motor fuel alcohol production, only about 250,000,000 gallons could be produced annually. Since this is about one tenth of the alcohol which would now be required for a national 10 per cent blend, the present impossibility of a national motor fuel alcohol program becomes even more apparent. Without entering into detailed discussion of the behavior of alcohol in an automobile engine, it may be considered that a 10 per cent blend would function about as efficiently as a straight gasoline. There are advantages and disadvantages, and the general statement becomes more accurate with modern motors using high compression ratios. The crop figures shown have been stated in terms of a 10 per cent blend, because with higher concentrations not only would the mileage return decrease proportionately because of the lower heat values involved, but the obvious impossibility of producing sufficient alcohol for such blends prevents consideration of such concentration. On the other hand, blends of low percentage-e. g., 2 per cent-would be so diluted as to lose the inherent value of the alcohol in increasing the octane number; at the same time practically no conservation of petroleum would be effected. The 10 per cent blend, therefore, represents more largely a compromise than a scientific optimum. With engines designed to operate on alcohol blends, a 10 per cent blend should be generally satisfactory. Any replacement fuels must be of such character and price as to be immediately adapted for use with present automotive equipment, but a mutual adjustment between the engine and the fuel would probably be made eventually. The costs of producing any replacement fuels which can be visualized today are higher than present gasoline costs. Probably the cheapest source of supplementary fuel in the immediate future will be from waste gases (particularly cracking gases of the petroleum industry) There is, however,
VOL. 31. NO. 2
a limitation to the present supply of such gas, and in the future such limitations would depend on the number of cracking plants and the duration of the petroleum reserves. Water gas and natural gas provide other sources. A point of advantage of gas as a source lies in the fact that either alcohols or hydrocarbons may be obtained from the same starting materials by process variations. Polymerization, hydrogenation and other process adaptations are possible. It has been claimed that alcohols from this source can be produced more cheaply than fermentation alcohol. Synthetic ethyl alcohol is now being made commercially from gases in amounts of about 16 per cent of our national industrial alcohol output. Methyl, isopropyl, and amyl alcohols, acetone, and similar potential fuel blend constituents are also being produced synthetically.
Sources of Alcohol The fermentation process, using the annually replaceable carbohydrates produced by the interaction of water, sunlight, air, and soil, will probably be the next logical source, both from the standpoint of quantities available and of production cost. The advantage here lies in the fact that the supply is relatively endless, the process is simple and requires a relatively small plant investment, and the use of farm products would indirectly benefit a considerable portion of our population. As the next practical source, the chemical conversion of wood may be considered, although such chemical conversion may be cheaper or more practical when accomplished as a charcoal-steam blue gas whereby carbon monoxide and hydrogen are obtained. At present, the wood supply in the United States would be inadequate to meet the needs of a replacement fuel supply. Under a program of reforestation, particularly of land inferior for crop raising, some future possibilities may be visualized since wood is replaceable. I
TABLE111. FARMCROPSCOMPARED WITH BLACKSTRAP MOLASSES AS ALCOHOL SOURCES‘ Tons
Material Molasses cane, blackadrap Corn Jerusalem artiahoke Potatoes, white Potatoes, sweet Sugar beets
Sugar cane Grapes Apples
Probable
By-
ConProdRaw version uct. Net Material Cost Credits Costb Unit Cost Material, 1.42 $ 8.50 8 8,OO $1.90 $18.34 50.05/gal. 11.90 1.90 23.24 0,07/gal. 1.19 9.27 10.8OC 3.49 18.34 0.26/bu. 20.00 5.91 28.69 0.56/bu. 26.78 7.76 34.91 0.75/bu. 6.00 1.91 10.80c 2.00 18.34 10.00 3.50 57.30 .... 4.37 2.25 11.15c 2.66 18.34 0.07/bu. 10.00 2.66 52.19 0.30/bu. 2.92 3.22 10.60C 1.65 18.34 0,09/bu. 8.55 1.65 31.93 0.25/bu. 4.52 2.51 9.00 2.00 18.34 3.25 43.42 8.33 6.58 1.47 9.20 0.50 18.34 3.50 0.50 31.73 6.62 1.71 10.00 1.75 18.34 5.00 1.75 31.35 7.00 1.53 9.50 1.90 18.34 5.00 1.90 42.60 Raw
Price
’ ! :
. . . . .. .. ..
The next possible source would be shale, of which tremendous deposits exist. In this case the cost of extraction would probably be too high in comparison with present motor fuel costs, and a relatively large amount of coal would be r e quired for distillation. The hydrogenation of coal has also.
FEBRUARY, 1939
INDUSTRIAL AND ENGINEERING CHEMISTRY
been advanced as a possible source because of the relatively large, world-wide coal deposits. At present, however, the capital cost of hydrogenation plants runs from ten to fifty times the cost of an alcohol plant, but these may be somewhat reduced as development proceeds. When to the capital cost thus incurred is added the cost of the raw material, especially of the hydrogen, and the operating or processing costs, a total delivered cost of perhaps 35 cents a gallon will be indicated. How far such cost may be reduced in the future cannot now be stated. Coal is being hydrogenated in England, Italy, Germany, and Japan, but under government subsidy. As far as a national conservation of fuel is concerned, the use of a large portion of our present liquid fuel petroleum supply for heat purposes might be considered uneconomic if it forced us later to create other liquid fuels from coal by an expensive process. About half the thermal energy of the original coal is lost. By using alcohol as a motor fuel, some petroleum conservation can be achieved since the date of exhaustion of the reserves will be thus deferred. As far as the petroleum industry is concerned, this may be an actual benefit, since the life of the industry would be extended. In the last analysis, true conservation of petroleum resources may not consist in holding a reserve below ground untouched for future use. Engines developed in the years to come may use some other form of motor power. Conservation a t its best seems to be largely a matter of regulation of output to avoid waste and uneconomic prices, and stretching the supply to the farthest degree compatible with national use requirements.
ever, certain misconceptions should be clarified. Assuming large-scale alcohol production, possibilities of utilizing more than a small percentage of the carbon dioxide must be discounted for a long time to come. Markets must be developed and distribution perfected. It is not fair, therefore, to generalize a return from carbon dioxide beyond the possibilities in a particular locality. I n the matter of by-product feed, assuming large production, we do not believe that in the long run such feed can constantly command prices greater than the original raw material price, less the cost of handling. On a localized scale and in the absence of much competition the prospects may be better, pending growth of the industry, but our studies have necessarily enbraced a more general and national viewpoint. Based on the present situation in regard to crops, conventional alcohol production process, and present by-product markets, some figures can be stated as to the probable returns to the farmer from crops sold for alcohol purposes. These are shown in Table 111in which blackstrap molasses is used as an index, although figures are also given for returns on the basis of a cent a pound for the raw material. In Table I11 assumption has been made of present average crop yields per acre, present average starch or sugar content of crops, 85 per cent plant efficiency, and dehydration by means of the benzene azeotropic process. There are two aspects to the use of crops for alcohol. The manufacturer is interested in the amounts produceable per ton of the material, whereas the farmer is more interested in the amounts produceable per acre. The relative status of the several crops in this respect is as follows:
Economics Alcohol today costs too much in comparison with gasoline. However, present costs of alcohol production can probably be decreased. All experimentation on motor fuel alcohol to date has been done in plants designed for the production of pure or industrial alcohol. Alcohol motor fuel requires no degree of purity beyond that necessary t o prevent engine corrosion; odor and taste as well as contamination can be ignored, and therefore production may perhaps be simplified and low-grade materials used. At present anhydrous alcohol is being used in motor fuel because of the necessity of maintaining complete miscibility with gasoline. Even in this case it is desirable to add blending agents for protection against accidental admission of water, and a considerable volume of denaturing material must be present to prevent illegal diversion. A suitable denaturant might be evolved, which would also be an effective blending agent or would add other desirable qualities to the fuel blend, and which might be made available in sufficient quantities and at low enough price so that the necessity of producing anhydrous alcohol might be omitted. At present the anhydrous alcohol step costs perhaps 2 cents a gallon, and the cost of using present available blending agents with 95 per cent alcohol might be estimated at 3 cents. Incidentally, this problem of suitable denaturant is one of the present severe handicaps to a large-scale alcohol motor fuel program. As further examples of possible alcohol cost reduction, it may be possible to saccharify starch by diluted acid or by the action of molds, and thus eliminate the present expensive malting process. Simplification of plant equipment and reduction of capital cost can be visualized, and combinations of steps to reduce steam conshmption and required labor are possible. All of these points must be studied, and this is the type of research which is contemplated in the proposed studies on the production of agricultural motor fuels. The utilization of the by-products from the alcohol production is of great importance in the final alcohol cost. How-
165
Raw Material Sugar beet Sugar cane (La.) Jerusalem artiohokes Potatoes, white Potatoes, sweet Apples Raisins Grapes Corn Rice (rough) Molasses (blackstrap) Grain sorghum FVheat
Alcohol Yield G'al./acre G'aZ./ton 287.0 22.1 268.0 15.2 180.0 20.0 178.0 22.9 141.0 34.2 140.0 14.4 102.0 81.4 90.4 15.1 88.8 84.0 65.6 79.5 45.0 70.4 35.5 79.5 33.0 85.0
Time does not permit presentation of all angles of this somewhat perplexing problem of national economics. Much experimentation to secure basic costs must be done before real visualization of the future situation can be achieved. Any agricultural motor fuel program will involve agricultural, legal, social, technical, and economic aspects, and the various interrelations and possible effects on our industrial structures must be carefully considered. Any such program should evolve on merit rather than by forced legislation. The figures and assumptions given here represent compilations of data from various sources rather than actual research findings. No recent work on the technical aspects has been done, and no funds have been heretofore available for such work. It is hoped that a bulletin will shortly be ready for distribution,'in which the general problem of motor fuels from agriculturalmaterials in the United States is discussed in great detail. Here only a somewhat inadequate review has been given of the material contained in this more comprehensive compilation. R ~ C E I V ESeptember D 12, 1938.
1 Jaaobs, P B (1938).
and Newton, H. P., U. 6. Dept. AD., Misc. P&.
327
