History Of Alcohol Motor Fuel Development

A. Ethanol

A review of the historical development of ethanol usage as a motor fuel is in order before discussion of modern production technologies. The history dates back to the beginnings of the internal combustion engine. In an industrial chemistry book published about a century ago (Duncan, 1907), these statements appear:

One of the most interesting developments of the past decade has been that of the internal combustion engine. . . . The question of profitably substituting in these engines alcohol for gasoline is one enormously controversial, but out of warring testimony there have appeared certain facts that seem unquestionable. . . . Alcohol is reproduced in the cycle of the seasons; it is absolutely inexhaustible; it is made out of sunshine and air; and its composition does not lessen the value of the soil or the energy of the earth. Gasoline, on the contrary, represents a part of the stored energy of the earth; it exists only to the extent of about two percent in petroleum, and its supply, will in the future inevitably fail.

By far, the vast majority of alcohol usage as motor fuel has occurred with ethanol. The invention of the four-cycle internal combustion engine in 1877 by Otto and the two-cycle engine in 1879 by Benz involved the testing of ethanol, other alcohols, and many other organic liquids as potential fuels. Another factor that played a major role in the development of fuel ethanol was the passage of laws that permitted the production of tax-free ethanol for industrial use—England in 1855, The Netherlands in 1865, France in 1872, Germany in 1879, and then the United States (U.S.I. Chemicals, 1981). Farm leaders and alcohol distillers lobbied successfully to have the U.S. federal beverage alcohol tax removed on denatured industrial ethanol during a period of agricultural price decline in 1906 in the belief that vast new markets for ethanol fuels would develop (Giebelhaus, 1980). The enactment of the TaxFree Industrial and Denatured Alcohol Act of 1906 in the United States, however, had little effect on the development of ethanol fuel markets because of the availability of cheap gasoline.

During World War I, various alcohol blends were used by the European military forces as motor fuels because of gasoline shortages. After the war, numerous countries other than the United States began a serious effort to extend their motor fuel supplies by blending ethanol in gasoline (Christensen, Hixon, and Fulmer, 1934). France passed legislation in 1923 which ultimately led to compulsory blending of 25 vol % ethanol in high-gravity gasolines to help reduce agricultural surpluses. A fuel blend called "Monopolin" containing 25 vol % absolute ethanol and 75 vol % gasoline was marketed in Germany from 1926 to August 1930 in open competition with gasoline. After that time, compulsory blending to 10 vol % ethanol levels was required for all gasoline imported or produced within the country. Italian royal decree required that 30 vol % ethanol-70 vol % gasoline blends be used in 1926; this was changed to 20 vol % ethanol in 1931. A fuel blend called "Motalco" containing 20 vol % ethanol and 80 vol % gasoline was compulsory in Hungary for all gasolines over 0.735 specific gravity in 1929. Argentina recommended a fuel containing 30 vol % ethanol and 70 vol % gasoline in 1931, stating that this fuel is superior to gasoline. The Royal Dutch Shell Company marketed a blend called "Shellkol" consisting of 15 to 35 vol % absolute ethanol in gasoline in Australia. A law was passed in Austria in 1931 which compelled the blending of domestic ethanol up to 25 vol % in gasoline during periods in which the price of ethanol was below that of gasoline. A Brazilian law enacted in 1931 required gasoline importers to use domestic ethanol up to 5 vol % of the gasoline imported. Ethanol-gasoline blends containing 10 to 25 vol % domestic ethanol were required in 1931 in place of gasoline, with the exception of aviation gasoline, and sold in Chile. A fuel blend called "benzolite" containing 55 vol % ethanol, 40 vol % benzene, and 5 vol % kerosine was marketed in China. Latvia required all gasoline, kerosine, benzene, or other liquid fuels for internal combustion engines to contain 25 vol % absolute ethanol. In 1931, a fuel blend called "gasanal" was marketed; it contained ethanol, ethyl ether, and gasoline. Beginning in 1931, Sweden used various blends of ethanol with other organic liquids, including methanol, as motor fuels, but recommended 20 to 30 vol % ethanol in ethanol-gasoline blends after World War I. Czechoslovakian law in 1932 required that all mineral oil fuels contain 20 vol % ethanol. In 1932, Cities Service Company began marketing a fuel blend called "Koolmotor" in the United Kingdom; it contained 10 vol % ethanol, 15 vol % benzene, and 75 vol % gasoline. Yugoslavia required all motor fuels to contain a minimum of 20 vol % ethanol in 1932.

Many of the countries that had enacted laws requiring the blending of ethanol in gasolines suspended them in the late 1930s because of the instability of ethanol supplies (Wilkie and Kolachov, 1942). Germany imported expensive foreign ethanol to meet the legal blending requirements and used 63,500 t of the cheaper synthetic methanol in 1937 to meet the ethanol deficiency. Italy and France suspended all regulations during parts of 1937 and 1938 because of crop failures. It is apparent that the use of ethanol as a motor gasoline extender was widespread in many countries after World War I. This was not the case in the United States.

In the early 1920s, Standard Oil Company (New Jersey) marketed a blend of 20 to 25 vol % absolute ethanol in gasoline in the Baltimore area. The program lasted until 1924, although there seems to be a difference of opinion as to why the venture was terminated. One report indicates that high corn prices in 1924 were the cause (Christensen, Hixon, and Fulmer, 1934); another indicates the reason was storage and transportation difficulties coupled with customer complaints (Giebelhaus, 1980). Standard Oil's customers reportedly encountered clogged fuel lines and carburetors with scale and sediment loosened by the solvent action of the alcohol in the gasoline tank, so it is probable that unfavorable economics and operating problems both caused the demise of the first attempts to market ethanol-gasoline blends in the United States. Subsequent efforts to revive an ethanol fuel program in the late 1920s and early 1930s through federal and state legislation, particularly in the U.S. Corn Belt, failed. The American Petroleum Institute opposed the effort and, together with other groups, was able to block federal tax incentive legislation in 1933

and 1934. However, after Henry Ford and several experts on fermentation ethanol joined hands and organized the First and Second Dearborn Conferences to promote science, industry, and agriculture in 1935 and 1936, a fermentation plant to manufacture 38,000 L/day of anhydrous ethanol specifically for motor fuels was announced for construction in Atchison, Kansas. The plant began operation on March 3, 1937 and manufactured Agrol Fluid, a blend of 78 vol % anhydrous ethanol, 7 vol % other alcohols, and 15 vol % benzene. In 1939, 75 million liters of Agrol Fluid was marketed through more than 2000 service stations in 8 midwestern states (Christensen, Hixon, and Fulmer, 1934; Pre-bluda and Williams, 1981). The plant closed near the end of 1938 because the cost of fermentation ethanol could not be reduced to a level competitive with that of gasoline. The plant was started again during World War II to manufacture fermentation ethanol for non-vehicular applications.

In the Midwest, American Oil Company began marketing gasohol containing fermentation ethanol on July 1, 1979, becoming the first major petroleum refiner in recent times to market an ethanol-gasoline blend in the United States (cj Klass, 1980). Several other major oil companies then initiated gasohol marketing programs. Fermentation ethanol was used as a gasoline extender and as an octane enhancer and served to prepare the petroleum and automobile industries for the gradual phase-out of leaded fuels. Gasohol was sold at several thousand retail outlets, and estimates of fuel ethanol production in 1979 ranged from 136 to 227 million L/year (0.86 to 1.43 million bbl/year). At that time, the largest supplier of anhydrous ethanol to the petroleum industry, Archer Daniels Midland Company (ADM), which is located in the U.S. Corn Belt, expanded its production capacity to about 570,000 L/day (1.31million bbl/ year) of 200 proof ethanol from corn. By the mid 1990s, total U.S. fuel ethanol production capacity had increased to over 5.68 billion L/year (35.7 million bbl/year). ADM is still the largest U.S. supplier; it supplied about 38% of the country's demand for fuel ethanol in early 1997 (The Energy Independent, 1997). Gasohol's share of the motor gasoline market in the United States was about 10.8% in the mid-1990s (Bower and Greco, 1997).

The Brazilian fuel ethanol program, called Proalcool, is larger than the U.S. program. It started in the 1930s and was expanded in October 1975 with mandated usage of gasohol (10 vol % ethanol in gasoline) throughout the country (Garnero, 1981). All ethanol-gasoline blends were converted to 20 vol % ethanol shortly thereafter. Ethanol production, primarily from sugarcane, reached a total of 3.41 billion liters in 1980, of which 2.68 billion liters was consumed as vehicular fuel. Neat ethanol-fueled vehicles were introduced to the market in 1979, and by 1982, the percentage of ethanol in blended fuels was raised to 22 vol %. Proalcool was started by government decree and continues today. In 1994, 34.3 million IVday (216,000 bbl/day), or about 12.5 billion L/year (78.8 million bbl/year) of fermentation ethanol was consumed for fuel purposes, accounting for 48.5% of automobile fuel demand (c/. Nastari, 1996). In 1995, 4.2 million neat ethanol-fueled automobiles were on the road, accounting for 35% of the total population of passenger vehicles in Brazil.

B. Methanol

Until the introduction in 1923 to American markets of synthetic methanol manufactured from coal-derived synthesis gas at about one-half the price of wood alcohol, methanol was not given as much attention for motor fuel applications as ethanol (Riegel, 1933). By the early 1930s, when synthetic methanol was well established and had taken over about 75% of the methanol market in the United States, methanol was considered to be a potential alternative fuel for gasoline. But with few exceptions, it was only used as an anti-icing additive, for aircraft injection on take-off, and as a racing fuel where advantage could be taken of the increased power obtainable without regard to economics (Keller, Nakaguchi, and Ware, 1978). The EPA has limited the blending of methanol without cosolvent to a maximum concentration of 0.3 vol % in unleaded gasolines because of phase separation and vapor pressure problems, which will be discussed later.

C. Other Alcohols and Alcohol Derivatives

Many oil companies have blended alcohols such as 2-propanol (isopropyl alcohol) and 2-methyl-l-propanol (isobutyl alcohol) in gasolines as anti-icing additives, but not generally as primary fuel components. Also, neat 2-methyl-2-propanol (t-butyl alcohol, TBA), the corresponding methyl ether (methyl-t-butyl ether, MTBE) and ethyl ether (ethyl t-butyl ether, ETBE), di-isopropyl ether, and t-amyl methyl ether (TAME) are marketed in the United States as oxygenates and octane-enhancing additives for gasolines. Arco Chemical Company has marketed blends of methanol and TBA (Oxinol) since 1969 as a gasoline additive to increase octane. TBA also serves as a cosolvent for methanol to improve phase stability of the gasoline blends.

The butanols and their methyl and ethyl ethers have several advantages as oxygenates over methanol and ethanol in gasoline blends. Their energy contents are closer to those of gasoline; the compatibility and miscibility problems with petroleum fuels are nil; excessive vapor pressure and volatility problems do not occur; and they are water tolerant and can be transported in gasoline blends by pipeline without danger of phase separation due to moisture absorption. Fermentation processes (Weizmann process) have been developed for simultaneous production of 1-butanol, 2-propanol, acetone, and ethanol from biomass and are discussed in Section IV. Product mixtures from these fermentations have been employed as "power butanol." Power butanol refers to fuel blends of the same heating value as dry ethanol and is composed of approximately 17% water and 83% combined 1-butanol, acetone, and ethanol in ratios of 7.8:4:1. This mixture is created by blending 80% l-butanol-20% water, 88% acetone-12% water, and 95% ethanol-5% water mixtures, or the grades of 1-butanol, acetone, and ethanol that can be made by simple distillation. Some of the operating characteristics are different than those of gasolines, but the power output and thermal efficiency data indicate that power butanol and power butanol-gasoline blends function well in standard spark ignition engines with only minor equipment changes (Noon, 1982).

D. Alcohol Racing Fuels

As basic knowledge of combustion and engine designs improved after World War I, racing teams began to use alcohol fuel blends formulated with aviation gasoline. Ethanol-benzene-gasoline blends generally ranged from volumetric ratios of about 20:20:60 to 80:10:10 (Powell, 1975). Ethanol, because of its high latent heat of vaporization and low air:fuel ratio requirements compared to those of gasoline, can be used at higher inducted fuel energy densities than gasoline alone to deliver increased power outputs. In the 1930s, methanol's still higher latent heat of vaporization and lower air: fuel ratio requirement provided better performance and became the main power component of many racing fuel blends. Methanol-benzene-gasoline blends were used to establish land and water speed records, and a fuel containing ethanol and gasoline was used to set a world air speed mark. After World War II, engine compression ratios were increased, and the racing community shifted to neat methanol and methanol-nitroparaffin blends. Neat methanol is now the dominant fuel for many racing events.

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