Page 211 - Biofuels Refining and Performance

194 Chapter Seven

TABLE 7.1 Comparative Properties of Ethanol with Petrol and Diesel
Sr no. Property Petrol Diesel Ethanol
1. Specific gravity (at 15 C) 0.73 0.82 0.79
2. Boiling point ( C) 30–225 190–280 78.3
3. Specific heat (MJ/kg) 43.5 43.0 27.0
4. Heat of vaporization (kJ/kg) 400 600 900
5. Octane number (Research) 91–100 NA NA
6. Cetane number Below 15 40–60 Below 15

Any new fuel that is going to be introduced should be evaluated from
the aspect of availability, renewability, safety, and cost adaptability to
the existing engines’ performance, economy, and finally emission. A mas-
sive research effort has been put into the study and analysis of all these
aspects for ethanol, which is now an established, viable alternative fuel
for IC engines. The comparative properties of ethanol with petrol and
diesel are shown in Table 7.1.

7.2.2 Production of ethanol
Ethanol is the most appropriate fuel for India to replace petrol, and the
utmost of efforts have been made to increase alcohol production in the
country. India is in an extremely happy position in this regard as it is
the world’s largest producer of sugarcane, a major source of alcohol.
India topped the world in sugar production with 181 Mton (in 1978),
followed by Brazil (130 Mton) and Cuba (67 Mton).
Alcohol is derived not directly from sugarcane but molasses–sugar-
cane by-products. All starch-rich plants like maize, tapioca, and potato
can be used to produce alcohol; cellulosic waste materials can also be
used. Production of ethanol from biomass involves fermentation and
distillation of crops. India has a vast potential to produce ethanol, and
only 2.5% of the country’s irrigated land is used to produce sugarcane.
This can be raised to a much higher level without adversely affecting
the production of food-bearing crops.
At present, Brazil is the only country that produces fuel alcohol on a
large scale from agricultural products (mainly sugarcane). Other coun-
tries, especially those with an substantial agricultural surpluses, such
as the United States and Canada, are also bound to enter into this field
of so-called energy forming. The area of land required is substantial. A
medium-sized car with an annual run of 15,000 km needs 2000 L of
ethanol. To produce this amount, the crop areas required are given in
Table 7.2. To provide enough sugar beet alcohol to fuel 20 million cars
in Germany requires half the area of the entire country.