Palm biodiesel (palm oil methyl esters) is produced in the continuous
transesterification reaction of palm oil with methanol in the presence of sodium
hydroxide as catalyst. The transesterification reaction takes place in two to three
stages with subsequent washing, drying and polishing of the reaction product.
Refined, bleached and deodorized (RBD) palm oil is thoroughly mixed with excess
methanol and catalyst. The mixture is heated to the reaction temperature and fed
to the first reactor where the transesterification reaction takes place. Glycerol
formed in the reaction is separated from the methyl ester phase.
 Make-up methanol and catalyst are added to the methyl ester phase and the
mixture is fed to a second reactor. In some systems, further conversion to methyl
esters is achieved in a third reactor. The use of excess methanol and the complete
separation of glycerol ensure maximum conversion to methyl esters.
The excess methanol is recovered from both the crude methyl ester phase and the
crude glycerol phase. The recovered methanol is purified in a rectification column
and recycled for reuse in the transesterification reaction. The glycerol is obtained
as a by-product with a concentration of about 80%.
The methyl ester is washed with hot water to remove residual glycerol, methanol
and soap, and dried under vacuum to reduce its water content to within the
specified limits of biodiesel standards. The final product is cooled in a heat
recovery system and additionally with cooling water before it is sent to storage. The
yield of methyl esters is higher than 96.5%.
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Biofuel is an alternative fuel made from renewable resources. Palm biodiesel is a
biofuel and refers to methyl esters of long chain fatty acids derived from palm oil. It
has a high cetane number and can be used in compression ignition engines (diesel
engines) without modification to the engines. The use of methyl esters as diesel
fuel has already achieved widespread acceptance especially in Europe.
