Distillation and deodorization method for production of biodiesel

Abstract

The invention provides a distillation and deodorization method for production of biodiesel. The distillation and deodorization method is characterized in that raw oil is reacted with methanol to generate coarse methyl ester containing glycerine soap; the coarse methyl ester containing glycerine soap is subjected to water washing and then transferred into a disk centrifugal separator to quickly separate coarse methyl ester and a glycerine soap water mixture; then the centrifuged coarse methyl ester enters a falling film dehydrating tower to remove residual moisture; the distillation product is taken out from a distillation column in two parts; a cycle oil cooling system is arranged at the upper part of the column; a distillation cooling substance taken out from the upper part of the column is the finished product of biodiesel; another distillation cooling substance taken out from the top part of the column is an odor substance (light-component oil); the afterheat is comprehensively recycled, thus over 20% of the production cost on heat exhaustion can be decreased; a vacuum cold well used for protection is provided for a distillation system, so that the yield of the odor substances (light-component oil) can be increased, and a vacuum set is able to work smoothly; the yield of the biodiesel can reach more than 92%; the acid value is not greater than 0.5mgKOH / G; no foreign odor is generated.

Description

technical field [0001] The invention belongs to the technical field of biodiesel preparation, in particular to a biodiesel production distillation and deodorization method. Background technique [0002] At present, the preparation of biodiesel mainly adopts an acid-base two-step method, that is, the reaction of waste oil and methanol, an esterification reaction occurs under the action of an acidic catalyst, and then a transesterification reaction is carried out with an alkali as a catalyst to generate a crude fatty acid methyl ester, which is then washed, Distillation and other processes to obtain biodiesel. [0003] The traditional process of distilling crude methyl esters to produce biodiesel is to wash the crude methyl esters containing glycerin soap and then let it stand for stratification naturally, take out the upper layer of crude methyl esters containing water, perform flash dehydration and heat the crude methyl esters to 260 °C with heat transfer oil °C, enter the ...

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Problems solved by technology

This method mainly has the following problems: ① Due to the high water content (0.5% to 1%) of the crude methyl ester entering the distillation tower, a partial reverse reaction occurs in the distillation tower (reduction of water and fatty acid methyl ester to methanol and fatty acid). The acid value of the finished biodiesel product is relatively high (2-4mgKOH / g); ②During the distillation, the biodiesel is collected by cooling the distillate at the top of the tower, resulting in an odor in the finished biodiesel product; ③There is no heat recovery in the distillation system , leading to high heat energy consumption in the production cost of biodiesel; ④The vacuum device of the distillation system has no cooling well protection, resulting in low vacuum efficiency of the vacuum unit, poor vacuum stability of the distillation system, and a decrease in the yield of biodiesel products

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