Page 462 - Advances in Eco-Fuels for a Sustainable Environment

Eco friendly biofuels for CI engine applications 415

Source of biomass Feedstock Conversion process Product

Chemical
Transesterification Biodiesel or
Oilseed crops Fats and oils Hydrotreating renewable diesel
First generation Grains Starches Biological

Conventional alcohol
fermentation Ethanol, butanol
Sugar crops Sugars
Enzymatic hydrolysis
and fermentation
Anaerobic digestion
Methane
Second generation Trees and hemicellulose and Thermochemical
Novel approaches
Agricultural
residues
Cellulsoe,
lignin
Pyrolysis
grasses
Gasification Hydrocarbon and
natural oils
Algae
Catalysis to liquid
fuel
Third generation
Fig. 15.5 Production of biodiesel [16].

Fig. 15.6 Transesterification
RCOOR¢ + R²OH R¢COOR² + ROH
reaction.
Ester Alcohol Ester Alcohol

1 1
COOR CH OH R COOCH
2 3
CH 2
2 2
CH COOR + 3CH OH CHOH + R COOCH
3 3
3 3
CH COOR CH OH R COOCH
2 2 3
Vegetable oil Alcohol Glycerol Methyl ester
15.3.4 Performance characteristics of biodiesel
Various performance characteristics such as BTE, brake specific fuel consumption
(BSFC), and brake specific energy consumption are used to study the properties of
biodiesel under various conditions.

15.3.4.1 Brake thermal efficiency

The BTE is the ratio of power output by the engine to the amount of heat supplied by
the fuel. Therefore, BTE is an indication of fuel conversion efficiency. Various studies
have indicated that biodiesel gives an increase in the BTE as the engine load increased.