Page 463 - Advances in Eco-Fuels for a Sustainable Environment

416 Advances in Eco-Fuels for a Sustainable Environment

Oil

Alcohol Catalyst

Phase seperation

Crude glycerin Crude biodiesel
(glycerol/alcohol/catalyst)

Refining
Glycerin
wastewater

Prerefining Biodiesel

Alcohol + Catalyst
Glycerin
(80% glycerol)
Fig. 15.7 Transesterification process employed to obtain biodiesel.

Table 15.2 Viscosity, density, cetane number, and flash point measurements of six oil methyl
esters

2 3
Viscosity mm /s Density kg/m Cetane Flash
Methyl ester (at 313K) (at 288K) number point (K)
Soybean oil 4.29 855 51.8 432
Corn vegetable oil 4.5 880 52.5 439
Palm oil 5.7 880 62 431
Sunflower oil 4.16 880 49 439
Fish oil 4.45 881 52.4 428
Chicken fats 4.35 876 54.8 440

The BTE is determined by the calorific value of the biodiesel, and higher calorific
value betters the BTE. The calorific value of biodiesel is fairly high and varies among
different biodiesels. But compared to diesel, the fuel calorific value of biodiesel is less.
Hence, the BTE of biodiesel is lower than that of diesel. The BTE characteristics can
also be affected based on the oxygen content present in the biodiesel, and the more