and unburned THC. Biodiesel also has enhanced biodegradability,
reduced toxicity and improved lubricity compared with
conventional diesel fuel. However, biodiesel is portended to increase
NOx emissions [8]. On the other hand the use of biodiesel
may lead to engine durability problems including injector cocking,
filter plugging and piston ring sticking, severing deposits, failure of
engine pump, softening of fuel system seals and unusual characteristics
of engine wear [9,10]. According to Silitonga [11] and Atabani
[12], globally, annual biodiesel production increased from 15 thousand
barrel per day in 2000 to 289 thousand barrel per day in 2008,
and acceptance of Kyoto protocol and clean development mechanism
(CDM) will lead to more biodiesel production around the
world and it is anticipated that this policy will lead to a total
bio-fuel demand in EU of around 19.5 and 30.3 million tons in
2012 and 2020 respectively. Biodiesel production is expanding rapidly
around the world, driven by energy security and other environmental
concerns. Biodiesel is most commonly made from
soybean oil in Europe using methanol, which has to meet EN
14214 standard [1]. A lot of valuable research has been conducted
on soybean biodiesel and other types of biodiesels and their blends
with conventional diesel fuel.