Page 210 - Biofuels Refining and Performance

Ethanol and Methanol as Fuels in Internal Combustion Engines 193

with conventional engines, the modifications required in the engine if
used in practice, and their environmental pollution characteristics.

7.2 Alcohols as Substitute Fuels
for IC Engines

Due to the global energy crisis and continuous increase in petroleum
prices, scientists have been in search of new fuels to replace conventional
fuels that are used in IC engines. Among all the fuels, alcohols, which can
be produced from sugarcane waste and many other agricultural products,
are considered the most promising fuels for the future. There are two types
of alcohols: ethanol (C H OH) and methanol (CH OH). Many other agri-
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cultural products (renewable sources) also have a vast potential for alco-
hol production, and it is necessary to tap this source to the maximum level
in national interest. The use of alcohol as a motor fuel is itself not a new
idea. Nicolas Otto, the pioneering German engine designer, suggested it
as early as 1895. But, as long as crude oil was plentiful and inexpensive,
petroleum gasoline was the most economical fuel for the IC engine.
Due to the global energy crisis, many countries that used to export
molasses to be used as cattle feed are now setting up distilleries to man-
ufacture ethanol.

7.2.1 Ethanol as an alternative fuel
Ethanol (ethyl alcohol) as a transport fuel has attracted a lot of atten-
tion because it is seen as a relatively cheap nonpetroleum-based fuel.
It is produced to a large extent from biomass, which aids agricultural
economies by creating a stable market. Ethanol, being a pure compound,
has a fixed set of physical as well as chemical properties. This is in con-
trast to petrol and diesel, which are mixtures of hydrocarbons [3].
The use of alcohol in spark ignition (SI) engines began in 1954 in
countries like the United States, Germany, and France. During World
Wars I and II, gasoline shortages occurred in France and Germany, and
alcohol was used in all types of vehicles, including military planes.
Nowadays, it is used with gasoline (a mixture) in the United States and
has become a major fuel in Brazil.
Ethyl alcohol can be produced by fermentation of vegetables and plant
materials. But in countries like India, ethanol is a strong candidate
since they possess the agricultural resources for the production of ethyl
alcohol. It is a more attractive fuel for India because the productive
capacity from sugarcane crops is high, of the order 1345 L/ha. Earlier,
this fuel was not used in automobiles due to low energy density, high pro-
duction cost, and corrosion. The current shortage of gasoline has made
it necessary to substitute ethanol as fuel in SI engines.