Glycerine refining method

Abstract

The invention discloses a glycerine refining method which comprises the following steps: adding alcohol and an inorganic acid into crude glycerine to form a fatty acid, first glycerine and an inorganic acid salt, and separating the first glycerine by using a first phase splitter; adding ferric trichloride into the separated first glycerine to form second glycerine, an iron soap and impurities, and separating the second glycerine by using a second phase splitter; distilling the second glycerine to form the refined glycerine. According to the scheme, the crude glycerine is preprocessed by using different auxiliaries before the step of distilling the glycerine, the substances like the fatty acid, salt, soap and ester in the glycerine are removed, so that the distilling and purifying steps lead the glycerine to a higher purity degree; in addition, the technological process in the scheme is simpler in comparison with an existing refining method, and is suitable for continuous commercialized batch production.

Description

[0001] technical field [0002] The invention relates to a method for refining glycerin. Background technique [0003] In oil production, such as oil cracking, saponification, and oil alcoholysis, in addition to obtaining natural fatty acids, fatty acid salts, and fatty acid methyl esters, about 10% of sweet water will also be produced. Glycerin sweet water is the main source of natural glycerin, and more than 90% of natural glycerin production comes from oil products. As another example, in the mass production of biodiesel, 1 ton of biodiesel produces about 100 kilograms of glycerol. In many industrial productions, glycerol often exists in the form of by-products. For example, in soap production, glycerol is produced when oils are saponified to produce fatty acid salts (alkali soap). Therefore, rational development and utilization of these by-products is in line with the concept of green environmental protection. [0004] Pure glycerin is a colorless, sweet-smelling visc...

AI Technical Summary

Problems solved by technology

[0005] Due to the high viscosity and poor fluidity of glycerol, in order to obtain high-purity glycerin (above 99.5% purity), it is not feasible to purify glycerin by heating and evaporating by traditional heating methods. However, in various purification technologies, when the source of glycerol comes from a fermentation tank, Crude glycerin contains olefin polymers, ketones, double bond carbides, and other unsaturated organic pollutants. Using ion exchange, membrane separation, and vacuum distillation methods to purify glycerin, the above pollutants must be removed before glycerin can be processed. refining

When the source of glycerol comes from biodiesel, in order to increase the reaction conversion rate during the production of biodiesel, excess methanol and alkali catalysts are often added. These alkalis and methanol are all dissolved in the by-product glycerin. If vacuum distillation, membrane separation, or ion exchange methods are used to purify glycerin, glycerin polymerization and ion exchange particle failure will easily occur during production, the purity of glycerin is unstable, and the purification efficiency is not high. and high operating costs