the COME was slightly higher than those of animal fat methyl
esters. The fuel properties of produced methyl esters were close
to each other. The most apparent differences in the fuel properties
were the sulfur content and cold flow properties of the COME,
which were lower compared to animal fat methyl esters.
Especially, the cold property of the FOME was unacceptable to
use in winter climate. The cold flow properties of the FOME should
be improved with cold flow enhancers or it may be mixed with
petroleum diesel fuel which has better cold flow properties. Experimental
results showed that the sulfur content of the biodiesel
feedstock is very important to get low sulfur content biodiesel after
transesterification. The sulfur content of COME was much lower
than those of animal fat methyl esters. On the other hand, the first
sulfuric acid catalyzed pretreatment reaction increased the sulfur
content of pretreated fat. However, second pretreatment reaction
had almost no effect on the sulfur content of pretreated fat. Nevertheless,
the animal fat methyl esters fitted the ASTM D6751 (S500)
biodiesel fuel standards. According to the economic analysis, the
costs of biodiesels produced from corn oil, chicken fat and fleshing
oil were 1.62 €, 1.40 € and 1.13 €, respectively.