1 Production and Use

Among the lower alcohols, the two prime candidates for replacing petroleum fuels are methanol and ethanol. Although both are now manufactured largely from petroleum sources, processes for their production from biomass are available.

Butanol, a four-carbon alcohol, can also be produced from nonpetroleum sources. It is, however, a less likely contender for broad use as a fuel because of its comparatively high cost.

In Table 3, some characteristics of these alcohols are compared with those of gasoline and diesel oil. Several differences are obvious:

· Alcohols are essentially pure chemicals, boiling at one temperature, while the petroleum fuels are mixtures of many different chemicals with wide boiling ranges.

· Alcohols contain oxygen, whereas the petroleum fuels do not.

· Heating values for the alcohols are significantly lower than for the petroleum fuels.

Each of these differences has its consequences in the use of the fuels. The wide boiling range of gasoline is an advantage; the lower boiling components are sufficiently volatile to allow engine starting even at low temperatures. Unmodified engines powered by pure methanol or ethanol will not start below 10°-15°C.

The presence of oxygen in the alcohols gives them compatibility with water. Neither gasoline nor diesel fuel has any significant solubility in water, but methanol and ethanol are completely miscible with it. These two alcohols have an affinity for water sufficient to draw it from the air, a characteristic that can cause problems in their unprotected use and storage.

TABLE 3 Liquid Fuel Characteristics

	Fuel
Characteristic	Gasoline	Diesel	Methanol	Ethanol	Butanol
Formula	C4-C12	C14C20	CH3OH	CH3CH2OH	CH3CH2CH2CH2OH
	hydrocarbons	hydrocarbons
Boiling point
°C	32-210	204-343	65	78	118
°F	90-410	400-650	149	173	244
Lower heating valuea
MJ/kg	44.5	43.0	19.6	26.9	33.1
Btu/gal	114,800	140,000	55,610	76,100	96,100

^a Lower heating value = heat of combustion at 25° C and constant pressure to form H₂O (gas) and CO₂ (gas).

TABLE 4 Alcohol and Hydrocarbon Heating Values

Fuel	Formula	Lower Heating Value (MJ/kg)
Methanol	CH3OH	19.6
Methane	CH4	50.0
Ethanol	CH3CH2OH	26.9
Ethane	CH3CH3	47.5

The energy produced when any of these fuels are burned depends on the heat-generating reaction of oxygen with carbon and hydrogen Since the alcohols already contain oxygen, their heating values are less than their parent oxygen-free hydrocarbons. Table 4 illustrates this point for methanol and ethanol.

The oxygen content of the alcohols means that less air is required for their combustion. Compared with gasoline, methanol requires only 44 percent as much air for combustion and ethanol only 66 percent as much.

Each of these differences affects the ways in which alcohol fuels can be used or substituted for petroleum fuels.

PRODUCTION OF ALCOHOL FUELS

Ethanol, methanol, and butanol can all be produced from biomass. The manufacturing methods used, however, are quite different for each and are described below.

Ethanol

One of mankind's first biochemical activities was the preparation of wine. The earliest records of many societies describe the fermentation of grains and fruit juices for beverages. In time, the technique of distillation was developed to increase the ethanol concentration, and ultimately almost pure ethanol was produced.

Currently, both fermentative and synthetic methods are used to produce ethanol. The primary synthetic route is the catalytic hydrolysis of ethylene derived from petroleum:

CH₂ = CH₂ + H₂O ---> CH₃CH₂OH
ethylene........water....®........ethanol

Synthetic ethanol plants range in size from 40 million liters to 450 million liters per year.

A wide variety of crops have been used for the production of ethanol by fermentation. These include sugar-containing raw materials such as sugarcane; starch-containing raw materials such as cassava, potatoes, maize, and barley; and cellulosic materials such as wood and crop residues.

For crops like sugarcane, sugar beet, and sweet sorghum, the juice is expressed and fermented directly. The primary sugars converted to ethanol are glucose and fructose (from sucrose):

C₂H₁₂O₆ ---->2CH₃CH₂OH + 2CO₂
glucose..................ethanol.......... carbon dioxide

Starch-containing crops must be pretreated with acid or enzymes to convert their starch to glucose. Enzymatic pretreatment of potato starch and various grain starches is routinely practiced in alcoholic beverage manufacture.

Like starch, cellulose is a polymeric form of glucose, but cellulose containing raw materials are not as readily degraded to glucose, principally because of cellulose crystallinity and the naturally occurring binding material, lignin, which gives wood its structural strength. Since cellulose comprises almost 50 percent of all biomass, it is an almost universally available, renewable, and inexpensive raw material. Throughout the world, a great deal of research is under way to find economic ways to convert cellulose to glucose. Although there are wood-to-glucose acid process plants operating in the Soviet Union, data on economics are unavailable.

The technologies for producing ethanol from sugar and starch are well known and widely practiced. In contrast to methanol production, small-scale ethanol manufacture (I ton per day) from sugars or starches (but not from cellulose) is feasible.

A process for converting cassava to 95 percent alcohol is shown in Figure 3. Typically, the raw material is ground to a paste, slurried in water, and heated. Enzymes are then added to convert the starch to sugars. The mix is transferred to a fermentation tower, and nutrients and yeast cultures added. The yeasts convert the sugars to ethanol and carbon dioxide. Fermentation are usually run to give a 10-15 percent ethanol concentration. In addition, solids consisting of yeast cells, undissolved or unconverted starch, and fiber and protein from the raw material are present.

Generally, this complete mix is passed down through a stripping column, counter current to steam. A solution of approximately 50 percent ethanol in water is taken from the top of the column and the spent solids from the bottom.

The alcohol stream is next distilled, first to give a 95:5 ethanol: water mix and, if required, redistilled with a water-entraining agent such as benzene or cyclohexane to give anhydrous ethanol.

Figure 3. Conversion of cassava to 95 percent alcohol.

Methanol

The original process for the production of methanol was from the dry distillation (pyrolysis) of wood. The process was expensive, the yields poor (about 30 kg per ton of hardwood), and the product impure. Synthetic methods have completely replaced this route to methanol. Current processes use synthesis gas, a mixture of carbon monoxide (CO) and hydrogen (H2) usually derived from natural gas.

This mixture is reacted under pressure at high temperatures to yield methanol:

CO.............. + 2H₂ ---->CH₃OH
carbon.......... hydrogen..........methanol
monoxide

Although natural gas is the predominant source of carbon monoxide and hydrogen for this reaction, it is possible to generate this mixture from coal, wood (including wood wastes), peat, or urban solid wastes, although no commercial plants use this process. Several countries, however, including Australia, Brazil, Canada, the United States, and New Zealand, have done extensive engineering and economic studies on wood-to-methanol processes.

A drawback to any biomass-to-methanol scheme is the size of the plant required and, therefore, the amount of raw materials needed to keep it operating. The minimum practical plant size (about 200 tons per day of methanol) requires about 500 tons per day of ovendry wood or equivalent biomass. Such volumes of biomass are not usually available at a given site without extensive gathering and transportation costs.

Whether biomass, natural gas, coal, or peat are used as a source of carbon monoxide and hydrogen, the final reaction is the same. The gases are mixed and compressed to 50-100 atmospheres and reacted over a catalyst at about 250°C.

The methanol-containing gases leaving the converter are cooled to condense the methanol and the unreacted gases are recycled. The methanol is then purified by distillation. Only a small amount of byproducts are obtained, including dimethyl ether and higher alcohols.

Butanol-Acetone

Butanol-acetone mixtures can also be produced by fermentation of starch- and sugar-containing raw materials. At one time second only to ethanol production by fermentation, the commercial use of the butanol-acetone process diminished sharply with the increased availability of petroleum raw materials.

The process, based on molasses, is still used in South Africa. In a 90,000-liter fermenter, about 5,850 kg of sugars yield approximately the following amounts:

Butanol	1,050 kg
Acetone	525 kg
Ethanol	175 kg
CO2	2,900 kg
H2	117 kg

Unlike ethanol fermentations, which can yield a 10-15 percent product concentration, the butanol-acetone fermentation gives only about a 2 percent product concentration because the organism used, Clostridium acetobutylicum, cannot tolerate higher levels of the products. Recovery of the butanol and acetone is therefore more energy intensive. Clostridial fermentations are also more susceptible to bacteriophage contamination, requiring scrupulous plant hygiene.

If some of the innovative techniques for ethanol concentration that are currently in development could be applied to butanol-acetone, the process could gain greater use. In addition, clostridial fermentations will be particularly useful for the conversion of sugars from cellulose hydrolysis. In this process, both C5 and C6 sugars are produced. While organisms used for ethanol production can utilize only the C6 sugars, clostridia can convert both C5 and C6 sugars.

ENERGY VALUES

For any biomass-to-fuel project to be viable, the energy in the fuel produced (and the attendant by-products) should exceed the nonrenewable energy required to produce and convert the biomass.

Energy inputs can be divided into those needed for crop production and those needed for crop conversion. Crop production includes the energy required for machinery, fertilizer, herbicides, and insecticides involved in culture, harvest, and transportation of the biomass. Crop conversion involves the energy consumed in equipment manufacture and the chemical or biochemical processes, separations, and purifications required to generate the fuel.

One calculation of the distribution of energy required in crop production for ethanol is summarized in Table 5.

Clearly, the machinery, transportation, and fertilizer components are controlling factors for crop production energy.

Total energy requirements for both production and conversion to ethanol for these same crops are shown in Table 6.

Although each of these crops shows a positive energy return, many other factors must be considered. These include the amount of water required for high crop yields, the length of growing and harvesting seasons, the practicality of storage, capital and processing costs, and the potential for yield improvements. Energy balances alone do not provide the basis for investment decisions. The reasons for using alcohol fuels may include increasing rural employment and stimulating agricultural development as well as replacing imported petroleum fuels.

Energy form and versatility are also important. No amount of wind energy, for example, will help propel a farmer's tractor. Electricity probably has the most versatile range of applications, and liquid fuels are usually more readily transported, stored, and used than solid or gaseous fuels.

The Brazilian national oil company, Petrobras, has a 60,000-literper-day cassava-to-ethanol plant in Minas Gerais. This plant, in its first 3 years of operation, produced alcohol on a stop-and-go basis, since deliveries of cassava were not sufficient to keep the plant in operation. A technical team in Brazil concluded that cassava alcohol would only be economic if the cassava were plantation grown and mechanically harvested. The cost of collecting cassava from small growers is probably too expensive.

TABLE 5 Approximate Distribution of Total Energy Required in Ethanol Crop Production (Percent)

Crop	Machinery and Transportation	Manual Fertilizer	Labor	Seed	Insecticides and Herbicides
Sugarcane	63	28	3	5	1
Cassava	59	29	5	5	2
Sweet sorghum	63	33	1	0.5	3

SOURCE: DaSilva et al., 1978.

TABLE 6 Energy Balance for Ethanol Production

	Alcohol		Energy (Mcal/ha/yr)
	Crop Yield,	Produced,	Expended		Produced
Crop	tons/ha/yr	liter/ha/yr	Agricultural	Industrial	Alcohol	Residue	Balance
Sugarcane	54	3,564	4,138	10,814	18,747	17,500	+21,345
Cassava	14.5	2,523	2,573	8,883	13,271	-	+ 1,815
Sweet sorghum	62.5	5,165	8,021	16,500	27,168	19,110	+21,757

SOURCE: DaSilva et al., 1978.

USES IN TRANSPORTATION

The use of alcohol and alcohol-gasoline blends in motor transport is almost as old as the automobile itself. In England before 1900, an internal combustion engine was designed to run on ethanol. Alcohol powered vehicles were common in Europe during World Wars I and II. Alcohols, particularly ethanol, have been used in many other countries as motor fuel.

Considerable applied research on the use of alcohols and alcoholgasoline blends is being conducted both by major automobile manufacturers and government agencies in the United States, Europe, the Philippines, arid Brazil. Past experience shows that few performance problems are encountered with blends of up to about 20 percent alcohol in gasoline. The most efficient use of straight methanol or ethanol requires significant engine modification, including replacement of alcohol-sensitive components. Problems of retrofitting cars to use alcohol fuel and the cost and subsidy of the fuel production have been the subject of intense debate in the Brazilian press.

Automobiles will operate satisfactorily on alcohol-gasoline blends or on pure methanol and ethanol. Currently, the cost per mile traveled is higher than gasoline using these alternatives, but benefits in terms of balance of payments, local employment generation, and use of renewable resources must be included in decision making.

OTHER FUEL USES

Cooking and Lighting

Ethanol and methanol can be used for cooking and lighting. A variety of simple stoves are commercially available or can be easily fabricated for use with alcohols. The flame is clean, relatively smoke- and odorfree, easily controlled, and readily ignited and extinguished.

For lighting, neither alcohol has a luminous flame when burned with a wick. This can be overcome by adding a small amount of an illuminant such as kerosine, vegetable oil, or animal fat. Use of alcohols in thorium mantle lamps is also a possibility.

Utility Boiler Fuel

In Brazil, Jones has examined the use of ethanol as a utility boiler fuel. Because the Brazilian government is committed to purchase all ethanol produced, its use as a boiler fuel could be an equalizing factor in balancing increasing production with automotive use; electrical generation is an alternative that avoids the necessity of new storage facilities for temporary surpluses.

Further, oil-fired boiler conversion costs for ethanol are modes compared with those required for coal or charcoal, and ethanol ha a low atmospheric pollution factor.

The boiler used in the Brazilian trial was a 135-MW unit in the Piratininga Power Station in Sao Paulo. After atomizing tests, burne modifications, and combustion trials, boiler load tests were conducted A maximum load of 110 MW was reached. This limit was impose by the capacity of the fuel pump, however, rather than any inherer problem with ethanol use. Flue gas analysis showed traces (1.8 ppm of aldehydes, but lower levels of nitrogen oxides than would be found foul fuel oil.

Duhl and Boylan tested methanol and fuel oil in a utility boiled designed for use with natural gas. The test was conducted at the' Patterson Station of the New Orleans Public Service Company in, boiler delivering steam to a 50-MW generator. Methanol use resulted in a loss of boiler efficiency of about 3 percent compared with nature gas, while maintaining the rated load and final steam temperature Nitrogen oxide emissions from methanol were less than those from natural gas and much less than those from fuel oil.

Von Kleinsmid et al. have compared methanol and distillate fuel use in gas turbines for Southern California Edison. A 26-MW gas turbine was run for 523 hours using methanol, and a second turbine' using distillate fuel was run in parallel. Lower nitrogen oxide emis signs as well as fewer internal deposits were found with methanol.

Fuel Cells

Methanol has also been used in fuel cells, devices in which the chemical energy of the fuel is converted directly to electrical power. Fuel cell are capable of high efficiencies because they are not limited to the efficiency of the Carnot Cycle, as are heat engines. Fuel cells, however are still in the development stage. If proved practicable they could provide a significant market for methanol.

SOLVENT AND CHEMICAL PRODUCTION

Johnston has outlined some of the uses of ethanol as a solvent and as a basic building block for chemical production, the potential for these uses is included here because it affects ethanol's cost and avail ability for fuel use.

About half of the ethanol sold in the United States is used as a solvent. Printing inks, shellacs, varnishes, nitrocellulose coatings, cosmetics, pharmaceuticals, and foods all utilize ethanol in varying amounts. Paints, brake fluids, lubricants, herbicides, pesticides, and explosives all consume ethanol at some point in their manufacture.

For use as a chemical building block, ethanol can be readily dehydrated to ethylene. By using a fixed or fluidized catalyst bed at about 300°C, a yield of 85-90 percent can be obtained-about 1.7-2.0 tons of ethanol per ton of ethylene are required. Some of the simple derivatives of ethylene are shown in Table 7. Ethanol has also been used to produce acetaldehyde, which is a precursor for acetic acid, acetic anhydride, butanol, DDT, ethylhexanol, and butadiene. The bulk of Indian production of several of these chemicals is now based on ethanol. In Brazil, facilities are being planned to produce lowdensity polyethylene and vinyl acetate from ethanol.

Palsson and coworkers have suggested that the raw materials and technology exist for basing a major fraction of the United States chemical industry on four biomass-derived fermentation products: ethanol, isopropanol, butanol, and 2,3 butanediol. The route for introduction of these fermentation products is through their dehydration to olefins. Existing processing facilities can then be used to convert these olefins to other commercial chemicals. Figure 4 illustrates some of the possible routes and chemicals. Figure 5 compares the costs of ethanol, ethylene, and butanol from sugar and petroleum.

TABLE 7 Ethylene Derivatives and Uses

Reaction	Product	Uses
Polymerization	Polyethylene	Plastics
Oxidation	Ethylene oxide	Intermediate for solvents,
		plastics, surfactants, synthetic
		fibers, textile chemicals,
		corrosion inhibitors
Chlorination	Ethylene dichloride	Intermediate for plastics,
		lacquers, explosives, rubber

CONCLUSION

Ethanol and methanol can both be produced from biomass and can be used as transportation fuels as well as for heating, lighting, and electricity generation.

In addition, both alcohols can be used as chemical intermediates. Ethanol is particularly versatile. It can be used to produce a wide variety of chemical derivatives, including solvents, plastics, and detergents.

Figure 4. Some of many possible chemical and biochemical derivatives of glucose.

Figure 5. Break-even costs between petrochemistry.

REFERENCES AND SELECTED READINGS

Alcohol Fuels for Motor Vehicles

General

Goodrich, R.S. 1980. Alcohol cars in Brazil's future: a technological forecast. In: IV International Symposium on Alcohol Fuels Technology. Guaruja, Sao Paulo, Brazil.

Joyce, C. 1981. Can aircraft fly on alcohol? New Scientist September 24:790-793.

Keller, J.L. 1979. Alcohols as motor fuel? Hydrocarbon Processing May:127-138.

Klass, D.L. 1980. Alcohol fuels for motor vehicles: an overview. Energy Topics: A Periodic Supplement to Institute of Gas Technology Highlights. Institute of Gas Technology, Chicago, Illinois, USA.

Leng, I.J. 1980. Fuel systems for alcohols - corrosion and allied problems. In: IV International Symposium on Alcohol Fuels Technology. Guaruja, Sao Paulo, Brazil.

LePori, W.A., and Davison, R.R. 1980. Ethanol as a fuel for internal combustion engines - spark ignition and diesel. In: Proceedings of the Alcohol-Fuel Symposium, July 12, 1980. Texas A&M University, College Station, Texas, USA.

McCallum, P.W., Timbario, TJ., Bechtold, R.L., and Ecklund, E.E. 1982. Alcohol fuels for highway vehicles. Chemical Engineering Progress August 1982:52-59.

Pleeth, SJ.W. 1949. Alcohol: A Fuel for Internal Combustion Engines. Chapman & Hall, Ltd., London, United Kingdom.

Schrock, M.D.1980. Using alcohol in engines. In: Proceedings of the AlcoholFuel Workshop. Sponsored by the Great Plains Agricultural Council Energy Committee, Kansas State University, Manhattan, Kansas, USA.

Seiffert, U. 1979. Mid-Term Prospects for the Use of Alcohols as Motor Vehicle Fuels. In: III International Symposium on Alcohol Fuels Technology. Asilomar, California, USA.

U.S. Department of Energy. 1980. Internal Combustion Engines for Alcohol Motor Fuels: A Compilation of Background Technical Information. National Technical Information Center, Washington, D.C., USA.

U.S. Department of Energy, Assistant Secretary for Conservation and Solar Energy, Office of Transportation Programs. 1981. Alternative Fuels Utilization Report. U.S. Department of Energy, Washington, D.C., USA.

VITA. 1980. Converting gas and diesel engines to use alcohol fuel. In: Energy Fact Sheet. Volunteers in Technical Assistance, Mt. Rainier, Maryland, USA.

Wiebe, R., and Nowakowska, J. 1949. The Technical Literature of Agncultural Motor Fuels, Including Physical and Chemical Properties, Engine Performance, Economics, Patenk, and Books. U.S. Department of Agriculture, Washington, D.C., USA.

Spark Ignition

American Petroleum Institute. 1971. Use of Alcohol in Motor Gasoline-A Review. American Petroleum Institute, Washington, D.C., USA.

Anonymous. 1982. New engine revives plans for alcohol fuel. New Scientist October 14:96.

Deardorff, T. 1979. Operation of a Spark-Ignition Engine With a Range of Ethanol and Water Mixtures. Agricultural Engineering Department, Iowa State University, Ames, Iowa, USA.

Hill, R. 1980. Alcohol fuels can they replace gasoline? Popular Science March:25, 28, 30, 32, 34.

Hunt, D.R. 1980. Alcohol in a spark ignition engine. In: Proceedings of the Alcohol Fuel Workshop. Sponsored by the Great Plains Agricultural Council Energy Committee, Kansas State University, Manhattan, Kansas, USA.

Kirik, M. 1981. Conversion of engines to run on fuel alcohol. Gasohol USA 3(6):17-20, 42.

McCormack, M.C., Overbey, J.K., and Pefley, R.K. 1979. Hardware/Software Strategies for Fuel Economy Optimization With Exhaust Emission Constraints in Methanol Fueled Automobiles. In: III International Symposium on Alcohol Fuels Technology. Asilomar, California, USA.

Ministry of Energy, Philippines. 1979. Alco-Tipid: A Gasoline-Saving Device. Center for Nonconventional Energy Development, Fort Bonifacio, Metro Manila, Philippines.

Pinto, F.B.P. 1980. Aspects of the design, development and production of ethanol powered passenger car engines. In: IV International Symposium on Alcohol Fuels Technology. Guaruja, Sao Paulo, Brazil.

Rajan, S. 1979. Factors Influencing Cold Starting of Engines Operating on Alcohol FueL In: III International Symposium on Alcohol Fuels Technology. Asilomar, California, USA.

Sladek, T.A. 1978. Ethanol motor fuels and "gasohol." Mineral Industries Bulletin, Colorado School of Mines 1978:1-16.

Vann, L.G., Jr., and MacDonald, J.T. 1979. Alcohol Blend Use in Stratified Charge Engines. In: III International Symposium on Alcohol Fuels Technology. Asilomar, California, USA.

Compression Ignition

Bacon, D.M., Bacon, N., Moncrieff, I.D., and Walker, K.L.1980. The effects of biomass fuels on diesel engine combustion performance. In: IV International Symposium on Alcohol Fuels Technology. Guaruja, Sao Paulo, Brazil.

Boruff, P.A., Schwab, A.W., Goering, C.E., and Pryde, E.H. 1982. Evaluation of diesel fuel-ethanol microemulsions. Transactions of, the American Society of Agricultural Engineers 25(1):47-53.

Cruz, J.M., Ogunlowo, A.S., Chancellor, W.J., and Goss, J.R. 1980. Biomass-based Fuels for Diesel Engines. Paper prepared for the Pacific Regional Annual Meeting, American Society of Agricultural Engineers, Hilo Lagoon Hotel, Hilo, Hawaii, March 18-20, 1980.AmericanSocietyo fAgricultural Engineers, St.Joseph, Michigan, USA.

Fahlander, S., and Walde, N. 1980. Ethanol fuels with ignition improver for turbocharged diesel engines. In: IV International Symposium on Alcohol Fuels Technology. Guaruja, Sao Paulo, Brazil.

Goering, C.E. 1980. Ethanol and diesel fuel. In: Proceedings of the Alcohol Fuel Workshop. Sponsored by the Great Plains Agricultural Council Energy Committee, Kansas State University, Manhattan, Kansas, USA.

Hunt, D.R. 1980. Converting a diesel engine to run on alcohol. Agricultural Engineering December 1980.

Kaufman, K.R. 1980. Carbureting alcohol into diesel engines. In: Proceedings of the Alcohol Fuel Workshop. Sponsored by the Great Plains Agricultural Council Energy Committee, Kansas State University, Manhattan, Kansas, USA.

Mori, M. 1980. Ethanol blended fuels for diesel engines. In: IV International Symposium on Alcohol Fuels Technology,. Guaruja, Sao Paulo, Brazil.

Moses, C.A., Ryan, T.W. and Likos, W.E. 1980. Experiments with alcohol/diesel fuel blends in compression-ignition engines. In: IV International Symposium on Alcohol Fuels Technology. Guaruja, Sao Paulo, Brazil.

Pischinger, G., Clymans, F., and Fernandes, F. 1980. Consumption data and considerations on three approaches to diesel-oil substitution. In: IV International Symposium on Alcohol Fuels Technology. Guaruja, Sao Paulo, Brazil.

Singh, A.K., Pundir, B.P., and Singh, A. 1980. A fuel system for dual-fuel operation of an automotive diesel. In: IV International Symposium on Alcohol Fuels Technology. Guaruja, Sao Paulo, Brazil.

Starke, K.W. 1980. Ethanol: an alternative fuel for diesel engines. In: IV International Symposium on Alcohol Fuels Technology. Guaruja, Sao Paulo, Brazil.

Sugiyama, H. 1980. Utilization of alcohol as a fuel in diesel engines. In: IV International Symposium on Alcohol Fuels Technology. Guaruja, Sao Paulo, Brazil.

Wrage, K.E., and Goering, C.E. 1979. Technical feasibility of diesohol. Agricultural Engineering October:34-36.

Butanol-Acetone

Noon, R. 1982. Power-grade butanol. Chemtech 12:681-683.

Spivey, MJ. 1978. The acetone/butanol/ethanol fermentation. Process Biochemistry 13:24,25.

Walton, M.T., and Martin, J.L. 1979. Production of butanol-acetone by fermentation. Pp. 187-209 in: Microbial Technology, Vol. I, edited by H. J. Peppler and D. Perlman. Academic Press, New York, New York, USA.

Weizmann, C. 1919. U.S. Patent 1,315,585.

Energy Balance

Chambers, R.S., Herendeen, R.A.,Joyce,J.J., and Penner, P.S. 1979. Gasohol: does it or doesn't it produce positive net energy? Science 206:789-795.

Da Silva, J.G., Serra, G.E., Moreira, J.R., Concalves, J.C., and Goldemberg, J. 1978. Energy balance for ethyl alcohol production from crops. Science 201:903-906.

Harding, J. 1981. Ethanol's balance sheet. Soft Energy Notes 3(6):18-19, 21.

Hopkinson, G.S., and Day, J.W. 1980. Net energy analysis of alcohol production from sugarcane. Science 207:302-303.

Hyman, E.L. 1980. Net energy analysis and the theory of value: is it a new paradigm for a planned economic system? Journal of Environmental Systems 9(4):313-314.

Jenkins, D.M., McClure, T.A., and Reddy, T.S. 1979. Net Energy Analysis of Alcohol Fuels. American Petroleum Institute, Washington, D.C., USA.

Khan, A.S., and Fox, P.W. 1982. Net energy analyses of ethanol production from sugarcane in northeast Brazil. Biomass 2(3):213-222.

Leppanen, O., Denslow, J., and Ronkainen, P. 1980. Energy consumption in the distillation of fuel alcohol. In: IV International Symposium on Alcohol Fuels Technology. Guaruja, Sao Paulo, Brazil.

Lewis, C.W. 1980. Energy consideration of biofuels production. Pp. 209-226 in: Biochemical and Photosynthetic Aspects of Energy Production, edited by A.G. San Pietro and A. Gordon. Academic Press, New York, New York, USA.

Lewis, C.W. 1977. Fuels from biomass-energy outlay versus energy returns: a critical appraisal. Energy 2:241-248.

Perez-Blanco, H., and Hannon, B. 1982. Net energy analysis of methanol and ethanol production. Energy, 7:267-280.

TRW, Inc. 1980. Energy Balances in the Production and End-Usc of Alcohols Derived From Biomass. NTIS, Springfield, Virginia, USA.

U.S. Department of Energy. 1980. Report of the Energy Research Advisory Board on Gasohol. Department of Energy, Washington, D.C., USA.

Wayman, M., Lora, J., and Gulginas, E. 1979. Material and energy balance in the production of ethanol from wood. In: Chemistry for Energy, edited by M. Tomlinson. ACS Symposium Series 90. American Chemical Society, Washington, D.C., USA.

Weisz, P.B., and Marshall, J.F.1979. High-grade fuels from biomass farming: potentials and constraints. Science 206:24-29.

Wettstein, P., and De Vos, J. 1980. The net energy balance of ethanol production from wood. In: IV International Symposium on Alcohol Fuels Technology. Guaruja, Sao Paulo, Brazil.

Wettstein, P., and Domeisen, N.1981. Production of ethanol from wood: energy balance of the process starting with weak acid hydrolysis. Paper presented at the First International Energy Agency Conference on New Energy Conservation Technologies and Their Commercialization, April 6-10, 1981, Berlin, Germany. International Energy Agency, Paris, France.

Other Uses for Alcohols

American Petroleum Institute. 1976. Alcohols in non-automotive fuel uses. In: Alcohols: A Technical Assessment of Their Application as Fuels. American Petroleum Institute, Washington, D.C., USA.

Anonymous. 1982. Ethanol fuel cells seen as promising for transportation, cogeneration. Synfuels June 18:6.

Duhl, R.W., and Boylan, J.W. 1976. Use of Methanol as a Boiler Fuel. Symposium of the Swedish Academy of Engineering Sciences, March 23, 1976, Stockholm, Sweden.

Johnston, PJ. 1979. Ethanol-an alternative to its use as fuel. In: Workshop on Fermentation Alcohol for Use as Fuel and Chemical Feedstock in Developing Countries. Vienna, Austria.

Jones, E.C. 1980. The utilization of ethanol as a fuel in utility size boilers. In: IV International Symposium on Alcohol Fuels Technology. Guaruja, Sao Paulo, Brazil.

Palsson, B.O., Fathi-Afshar, S., Rudd, D.F., Lightfoot, E.N. 1981. Biomass as a source of chemical feedstocks: an economic evaluation. Science 213:513-517.

Pearson, R.K., and Hirschfeld, T.B.1980. Minimally refined biomass fuels: an economic shortcut. In: IV International Symposiumon Alcohol Fuels Technology. Guaruja, Sao Paulo, Brazil.

Salazar M., H. 1980. Ethanol: One of the Most Important Renewable Raw Materials for Chemicals. Paper prepared for the Inter-American Seminar/Workshop on Materials for the Future: Renewable Resources, November 18-21, 1980, Kingston,Jamaica.

Von Kleinsmid, W.H., Schreiber, H., and Klapatch, R.D. 1981. Methanol combustion in a 26-MW gas turbine. Gas Turbine Conference, March 9-12,1981, Houston,Texas, USA.