Value Addition of Crude Glycerol – A Co-product from Biodiesel Production Process

Abstract

The crude glycerol obtained as a co-product from biodiesel production process had soap, alcohol, water and catalyst. It contained 8.9% soap, 4.6% ash, 3.7% free fatty acid and had pH of 11.8. More than 21% methanol was recovered from the neutralized glycerol at 65 degree C. The glycerol, after alcohol recovery, was distilled at 100 degree C to remove moisture. The moisture-free glycerol was distilled under vacuum at 0.4 mbar for 140 degree C. The recovery of distilled glycerol was 40.5% of the crude glycerol, and 19% residue was obtained. The distilled glycerol was further purified by filtration using Whatman No.22 filter paper and activated carbon to remove odour and color, respectively. The purified glycerol had 0.77% soap, 0.03% ash and pH of 3.5.