Method for preparing glycerin from byproduct in manufacture procedure of biodiesel

Abstract

The invention discloses a method for preparing glycerin from a byproduct in a manufacture procedure of biodiesel, which comprises that: phosphoric acid is put into a phosphoric acid storage tank; the byproduct generated in the esterification manufacture procedure of the biodiesel is sent into a blending tank, and clear water in certain ratio is introduced to a temporary storage tank, and mixed and stirred with the byproduct in the esterification manufacture procedure; the stirred byproduct in the esterification manufacture procedure is sent into a homogenizer for conversion treatment through a delivery pump, and simultaneously the delivery pump is started; the phosphoric acid is sent into the homogenizer in specific ratio and is subjected to mixing and conversion with the byproduct in the esterification manufacture procedure, and a mixture of the byproduct in the esterification manufacture procedure after the mixing and conversion is temporarily placed in the material temporary storage tank; and the material in the material temporary storage tank is converted, sticky and thick non-esterified fatty acid, a particle crystalloid potassium phosphate compound, and farrago of liquid crude glycerine, water content and methanol are separated out, and the separated substances are subjected to three-phase separation by a three-phase centrifuge.

Description

technical field [0001] The invention relates to a method for preparing glycerin. Background technique [0002] The process of esterifying animal and vegetable oils to obtain biodiesel produces saponification by-products consisting of animal and vegetable gels, crude glycerin, free fatty acids, methanol (or ethanol), and potassium hydroxide. [0003] Although these saponification by-products have commercial value, if they cannot be handled in detail, they will cause certain harm to the environment. Generally, small and medium-sized biodiesel refineries do not have proper technology and equipment to deal with these by-products. Therefore, most of these by-products are sold at a price ranging from 200 to 250 US dollars per metric ton (the fourth quarter of 2007), and let downstream manufacturers handle them. [0004] Although manufacturers with professional skills have provided technology to refine this crude glycerin to obtain refined glycerin, due to the huge investment, fe...

AI Technical Summary

Problems solved by technology

[0004] Although manufacturers with professional skills have provided technology to refine this crude glycerin to obtain refined glycerin, due to the huge investment, few manufacturers have made this investment; and most downstream manufacturers, after receiving these by-products After that, some of them will be used as raw materials to make soap, and then the residue will be mixed into fuel oil as fuel; or used as raw materials to make feed

However, some manufacturers add these by-products to heavy fuel oil as fuel oil; it is a pity that the added value of the final product is not high.

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