Method for extracting fatty acid methyl ester from vegetable pitch

Abstract

The invention discloses a method for extracting fatty acid methyl ester from vegetable pitch. The method comprises the following steps: (1) adding methanol into the vegetable pitch for the first time, and esterifying fatty acids in the vegetable pitch at the temperature of 60-100 DEG C under the action of an acid catalyst; and (2) adding methanol into the solution in the system for the second time for diluting after the esterification reaction is finished, performing centrifugal separation, collecting light components, steaming to remove the solvent to obtain crude fatty acid methyl ester, and regulating the acid value of the crude fatty acid methyl ester to be 1mgKOH/g below, thus obtaining the fatty acid methyl ester. According to the method for extracting fatty acid methyl ester from vegetable pitch, the esterification reaction and the centrifugal separation are combined, the reaction temperature and the reaction difficulty are greatly reduced, and the method is low in equipment requirement, simple in after treatment and suitable for industrial production.

Description

technical field [0001] The invention belongs to the technical field of fine chemical products processing, and in particular relates to a method for extracting fatty acid methyl ester from plant asphalt. Background technique [0002] Vegetable asphalt, also known as black foot, is the leftovers left in the production process of fatty acid, oleic acid or fatty acid methyl ester. It is mainly used in the fields of foundry adhesives and waterproof asphalt, or directly burned as a heavy oil filler. Preliminary analysis shows that it also contains 60% to 70% of mixed fatty acids (methyl esters), 5% to 10% of phytosterols and about 5% of natural vitamin E. Fatty acid methyl ester, also called biodiesel, is a renewable diesel fuel that can replace petrochemical diesel. It is currently produced in large quantities in the world, thus producing a large amount of vegetable asphalt. [0003] For example, the patent document with the publication number CN 102776067A discloses a process ...

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Problems solved by technology

[0006] However, at present, the yield of refined fatty acid methyl ester obtained by esterifying acidified oil to obtain crude fatty acid methyl ester through acidification method is about 80% to 90%, that is, about 10 to 20% of high boiling point fatty acid methyl ester remains in the Plant asphalt, causing a lot of waste of resources

And because the plant asphalt itself is obtained through a high-temperature distillation process, the viscosity is high and the color is deep, so when the rectification process is used for further processing, on the one hand: most of the fatty acid methyl esters extracted from the plant asphalt are left behind during distillation. Higher substances require a higher rectification temperature. If this part of methyl ester is distilled, higher requirements will be placed on temperature and equipment; on the other hand, too high temperature will easily lead to the decomposition of fatty acid methyl ester, reducing the Yield of ester

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