Glycerin purification method

Abstract

This invention provides a cost-effective method for removing impurities from waste glycerin generated in the process of biodiesel production, so as to prevent a supercritical water reaction tube from clogging, when synthesizing acrolein by allowing supercritical water and acid to react with glycerin. The method for purification of glycerin of the invention comprises steps of: heating glycerin containing alkali metal, alcohol, organic fatty acid, and water under reduced pressure, so as to remove alcohol and water; adding sulfuric acid to glycerin from which alcohol and water have been removed, so as to neutralize glycerin; subjecting neutralized glycerin to centrifugation, so as to separate and remove a sulfate of alkali metal and organic fatty acid; adding a sulfate of alkaline earth metal to glycerin collected via centrifugation; and subjecting a mixture of glycerin and a sulfate of alkaline earth metal to centrifugation, so as to separate and remove a sulfate of alkali metal and an alkaline earth metal salt of organic fatty acid.

Dependencies are inferred from the claim text.