Refining production method of glycerin

Abstract

The invention provides a refining production method of crude glycerin. Byproducts of grease ester exchange or hydrolyzation are used as ingredients, and byproducts of biodiesel can also be used as ingredients. The method comprises the following steps: acidizing treatment, decolourization, alkali return for neutralization, concentration for salt removal, ion exchange and concentration treatment, wherein the ion exchange step comprises the substep of sequentially using cations, anions, cations, anions and zwitterions to exchange resin posts in a mixed way, the operation temperature of the resin posts is controlled between 40 and 60 DEG C, the flow rate is 15 mL / min, and finally, the pure glycerin solution is collected. The process of the invention has the advantages of simple operation condition, low temperature, little pollution and high yield, and can avoid the deterioration of the glycerin at the high temperature, the yield is higher than 97 percent, and the product purity is higher than 99.2 percent. The invention also provides a multiplex mixed type anion-cation exchange resin post combination device applicable to the method.

Description

technical field [0001] The invention relates to a production method for refining glycerin, in particular to the by-product glycerin in the biodiesel production process and the glycerol produced by the hydrolysis process. Background technique [0002] Along with the mass production of biodiesel, the output of its by-product glycerol (according to 10% of biodiesel output) is also increasing sharply. However, the current research on the recovery and utilization of glycerin is still lagging behind, especially the research on the refining of high-purity glycerin and high value-added products of glycerin is far from enough. Therefore, the refining and comprehensive utilization of glycerol, a by-product of biodiesel, is a new topic and a severe challenge for scientific and technological workers. With the current development of my country's market economy, glycerol has always been in short supply, especially high-purity glycerin (99.5%) is almost entirely dependent on imports. The...

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Problems solved by technology

However, the main disadvantages of these methods are high vacuum, high energy consumption, and the temperature is still too high, and the glycerol in the kettle is easily polymerized to produce side reactions, which affects the purity, color and yield of glycerin; and these methods cannot be used for impurities. Crude glycerin with high content (such as waste oil, crude glycerol produced by transesterification of feed oil), and with the continuous gasification of glycerin during the vacuum distillation process, the residual organic impurities are continuously concentrated and coked, and finally the glycerin is wrapped in It cannot be gasified inside, and the residual organic impurities are tightly bonded to the wall of the still and the heating coil after coking, which not only reduces the distillation yield, but also makes it difficult to remove the residue after coking

[0007] In addition, in some glycerin refining methods, in order to reduce the salt or impurity concentration in crude glycerol during the separation process, or use esterification to introduce chemical agents, or add other separating agents, or use expensive reagents, These not only increase the energy consumption of separation, but also produce new impurities, which cannot be effectively decolorized, thus affecting the actual yield

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