Approximately 18% in mass of vegetable oil is generated as crude glycerol from base-catalyzed biodiesel production. Crude glycerol is a waste mixture of methanol, glycerol, lye catalyst, soap, water, and glycerides and requires appropriate disposal. To recover valuable chemicals from crude glycerol, the waste was processed by a series of fractionation and purification procedures. Phosphoric acid was added to crude glycerol at 30/1000 v/v and the mixture was centrifuged to obtain three layered fractions. The top brown liquid was identified as glycerides, biodiesel, methanol, and free fat acids and was recycled in biodiesel production. The middle yellow liquid was distilled at 80 degree Celsius to recover methanol and at 150 degree Celsius to remove water. The glycerol residue was decolored with activated carbon and filtered for purity. The bottom precipitate was mainly potassium phosphate and could be used as a fertilizer. In each step, mass balance was determined.

Fractionation and purification of crude glycerol from biodiesel production

244th National Meeting (2012)

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