Method for refining crude glycerol as byproduct generated in high-pressure hydrolysis of grease

Abstract

The invention discloses a method for refining crude glycerol as a byproduct generated in the high-pressure hydrolysis of grease. The method comprises the following steps of (a) firstly introducing crude glycerin containing high-pressure hydrolysis byproduct of grease into a thermostatic water bath and then heating to 50-70 DEG C, adjusting pH to 3-4 with hydrochloric acid, and then standing; (2) after standing is completed, removing an upper layer of grease, adjusting pH to 5-6.5 by adding soda ash, then adding sodium metaaluminate, adding a flocculant after a large amount of flocculate is generated, stirring for 5-30 minutes and filtering; and (3) enabling the filtered high-pressure hydrolysis byproduct of grease to sequentially pass through a chromatographic column filled with a cation exchange resin, an anion exchange resin and a cation-anion exchange resin to obtain a purified glycerol. The method for refining crude glycerol as a byproduct generated in the high-pressure hydrolysis of grease is clean and green, the energy consumption of the distillation and rectification section can be reduced and the risk of excessive chloride content in glycerol caused by the liquid-foam entrainment in the distillation process can be reduced.

Description

technical field [0001] The invention relates to the technical field of chemistry and chemical engineering, in particular to a method for refining crude glycerol, a by-product of high-pressure hydrolysis of oils and fats. Background technique [0002] With the continuous development and expansion of the oil processing industry, there is a surplus in the crude glycerin market. According to statistics, in 2006, only in Europe, about 500,000 tons of glycerin flooded into the market, which has far exceeded the carrying capacity of the market. Procter & Gamble predicts that in 2010, the world's glycerin production will exceed 1.2 million tons. The sharp increase in glycerin production will inevitably lead to a decline in the price of glycerin. At present, there are two main sources of glycerin, one is the glycerol by-product of biodiesel, and the other is the glycerol by-product in the production process of fatty acids. Their output accounts for about 10% of the oil raw material...

AI Technical Summary

Problems solved by technology

Due to the addition of chemicals such as hydrochloric acid, soda ash and sodium metaaluminate in the sweet water pretreatment process, there is a certain concentration of inorganic salts in glycerin, which will cause high energy consumption during glycerin distillation and rectification. Especially in the rectification process, if liquid entrainment occurs, the chloride content in glycerin will exceed the standard, and the glycerol rectification residue (also called glycerol pitch) will be very viscous and difficult to discharge. Such glycerin pitch is not good at present. Ways to deal with, bring certain harm to the environment