METHOD FOR PREPARING BIODIESEL

摘要

A method for preparing a biodiesel, comprising: reacting a feedstock oil, a short-chain alcohol, water, and a liquid lipase in a single-stage or multi-stage enzymatic reactor; separating the reaction fluid into an enzyme-containing heavy phase and light phase; recycling and reusing the enzyme within the heavy phase; using the light phase in a subsequent immobilized enzyme conversion; pouring the light phase and the short-chain alcohol into the single-stage or multi-stage enzymatic reactor containing the immobilized lipase, performing online dehydration during the entire reaction process or during a stage of the reaction process. The method obviates the need for any preprocessing of the feedstock oil in the early stage of liquid enzyme catalysis during the reaction process, and allows for a feedstock oil-to-biodiesel conversion rate greater than 90%. In the later stage of immobilized lipase catalysis process, online dehydration is performed during the entire reaction process or a stage of the reaction process, thus allowing for a biodiesel yield of greater than 98%, and product acid value of less than 0.5 mgKOH/g oil.