Purification of glycerol as a by-product of biodiesel based on palm oil and castor oil

Abstract

The government program requires the use of biodiesel B35, which is 35% fatty acid methyl ester and 65% diesel oil from petroleum, which would impact the rise of biodiesel production and is accompanied by an increase in the by-product of crude glycerol. Crude glycerol requires purification to increase its selling value. This product still contains a lot of impurities such as methanol, soap, catalyst, fatty acids, and water. Crude glycerol, a by-product of making biodiesel based on palm oil and castor oil, has a purity of 39.10 and 37.30%. In this research, purification of crude glycerol was carried out using 10% w/v activated carbon. The results of glycerol after purification were 64.90 and 66.90%, it shows that the addition of activated carbon can absorb impurities contained in glycerol. The increase in levels from 37.30 to 64.90% and 66.90% due to the loss of water, alcohol, residue base (KOH), soap and fatty acids. It can be concluded that activated carbon is quite effective for the glycerol purification process with an addition of 10% (w/v). A further process is required, namely separation by distillation, to obtain glycerol with a purity above 80% to comply with SNI 7182-2015 standards.