Method for pretreating waste fat, oil and grease and co-producing first-generation biodiesel

Abstract

Provided is a method for pretreating waste fat, oil and grease (FOG) and co-producing a first-generation biodiesel, including: S1, feeding waste FOG, a liquid acid catalyst, and methanol into a pre-esterification reactor, and conducting pre-esterification to obtain a pre-esterification mixed liquid; S2, removing waste residues from the pre-esterification mixed liquid through a filter to obtain a filtrate, and separating the filtrate by a liquid-liquid separator to obtain an organic phase and an aqueous phase; S3, introducing the organic phase into a methanol recovery tower I and conducting separation to obtain a pre-esterification product and crude methanol; introducing the aqueous phase into a methanol recovery tower II and conducting another separation to obtain a liquid acid catalyst and crude methanol; S4, separating the pre-esterification product through a biodiesel refining tower to obtain a first-generation biodiesel product, and a pretreated waste FOG at a tower bottom.