Patent ID: 9145527
Filing Date: 2015-09-29
Classification: C07C,C10L,C11B,C11C,Y02E,Y02W

Abstract:
1. A method for preparing biodiesel from crude oils, comprising: 1) providing crude oil raw material, and pre-treating the crude oil raw material to remove impurities; 2) adding the pre-treated raw material into a reaction kettle; 3) pre-esterification step: adding methanol and 0.1-2 wt % concentrated sulfuric acid by the weight of the pre-treated raw material into the reaction kettle, and maintaining at 70-100° C., for 30 min-2 h, wherein the weight ratio of methanol to the pre-treated raw material is (1:11)-(1:6) to provide pretreated material; 4) esterification step of vapor phase: heating the pretreated material to 110-130° C., supplementing vapor phase methanol from the bottom of the reaction kettle under atmospheric pressure, reacting under the temperature until an acid value of liquid phase system is ≦2, and stopping supplementing methanol; 5) ester exchange step: cooling the reaction material obtained in the step 4) to below 70° C., adding mixture of potassium hydroxide and sodium hydroxide with equal weight ratio in the same reaction kettle to maintain pH of the reaction material in the reaction kettle at 8-9, and then reacting at 70-90° C., for 2-3 h; 6) recycling methanol, and separating glycerol via gravity settling, so as to obtain a crude fatty acid methyl ester; and 7) subjecting the crude fatty acid methyl ester obtained in the step 6) to purification and distillation to obtain biodiesel.