The invention relates to a method for preparing
biodiesel by mixing waste
edible oil with mineral diesel oil and hydrogenization. The method comprises the steps as follows: pretreatment of waste
edible oil, a first stage of hydrogenization process, a second stage of hydrogenization process, and a product
fractionation process. The method adopts the waste
edible oil and the mineral diesel oil as raw materials for preparing high-quality
biodiesel and biological
aviation kerosene components which have low
polycyclic aromatic hydrocarbon contents, high cetane values, low
sulfur contents and
low nitrogen contents, effectively solves the problems of blockage of a catalyst
bed caused by the settlement of
metal and gelatine in the animal and vegetable hydrogenization process, influence on the activity of catalyst from H2O, CO2 and CO produced in reaction,
sulfur supplement of a hydrogenization
system, and influence on the service life of the catalyst caused by centralized release of reaction heat, can realize the continuous hydrogenization and industrial production of materials containing animal and vegetable oils, and has practical significance.