from vegetable oil, algae or fat were transesterified to Biodiesel
(Fig.1). The transesterification of vegetable oils produced of fatty
acid alkyl ester and glycerol. Several process of catalyst that
used in Biodiesel production will be discussed below.
by sulfonic, sulfuric acids, phosphoric acid and hydrochloric acid.
These catalysts give high yields in alkyl ester, but the reactions
are slow. This process suitable for oil which many free fatty acid
and high water content.
by sodium hydroxide, potassium hydroxide and potassium carbonate.
This process is faster than acid-catalyzed reaction. And it is cheaper
so, it popularly process to produce Biodiesel.
However, acid and basic
catalyzed process have disadvantages such as hard to separate glycerol
from product, interferences of free fatty acid and water in the
reaction, elimination of the catalyst.
can solve the problems from acid and basic catalyzed process. This
process is easier derived glycerol from product and complete reaction.
But important factor is more expensive cost of enzyme.
Super critical fluids
process, vegetable oil was heat to 350OC then reaction with supercritical
methanol 240 minutes. From the research, Rapeseed oil produced by
this method gives higher yield than conventional production.
the production of Biodiesel industry used basic-catalyzed process
In the process produced a mixture of fatty acid alkyl ester, glycerol, and intermediates; monoglyceride, diglyceride, methanol. So, the product will determine of FAME and other components before use in the engine.
Vegetable oil and animal fat composed difference saturated and unsaturated triglycerides that effect to Biodiesel properties. The perfect Biodiesel must be from monounsaturated fatty acid, found in palm oil, peanut canola. However, it must test other properties such as cold flow properties, cloud point.
Biodiesel 100% called B100 can not used in diesel engine because it is a good solvent, destroy rubber part. In Thailand, Department of Energy Business, Ministry of Energy decided a quality standard of Biodiesel (Fatty acid methyl ester) for used in diesel fuel not more than 5%. That is accepted from Car Company to use in normal car, not necessary adaptation.