After decreasing the FFA level of the feedstock below 1%, transesterification
reaction was completed with alkaline catalysts for the
fleshing oil and chicken fat. Because of the low FFA level of corn oil,it was directly used in transesterification reaction to produce biodiesel.
For transesterification reactions, potassium hydroxide and
methanol were used. The transesterification processes were the
same as those of pretreatment experiments except for catalyst.
After the transesterification reaction, the reaction mixture transferred
to the settle tank. The mixture was settled overnight and
the glycerin layer was separated. The ester layer was transferred
to the washing tank and it was washed with warm water. After
washing process, the methyl ester was sent to the main reaction
tank and it was subjected to a heating under vacuum to remove
excess alcohol and water as stated above, and then it was filtered
with 10-micron filter.