Method for continuous recovery of by-products from glyphosate hydrolysis tail gas

Abstract

The invention relates to a method for continuously recovering by-products from tail gas obtained by hydrolyzing glyphosate, and belongs to the technical field of the recovery of glyphosate hydrolyzing tail gas. The method comprises the following steps: after alkali cleaning is performed on the tail gas obtained by hydrolyzing the glyphosate, neutral tail gas is obtained, and the neutral tail gas enters a primary rectifying tower to be processed; a liquid phase of the primary rectifying tower enters a dewatering tower, a liquid phase of the dewatering tower is rectified waste water, and a gas phase of the dewatering tower is condensed to obtain finished methanol; a gas phase of the primary rectifying tower enters a methanol rectifying tower to be processed, a liquid phase of the methanol rectifying tower is the finished methanol, and a gas phase of the methanol rectifying tower is pressurized, condensed and decompressed to obtain finished methylal; and noncondensable gas enters a water scrubbing tower to be processed, a gas phase of the water scrubbing tower is dried and compressed to obtain finished monochloromethane, a liquid phase of the water scrubbing tower enters a stripping tower to be processed, a gas phase obtained in the stripping tower enters the primary rectifying tower to be recovered again, and the obtained liquid phase enters the water scrubbing tower to be recycled. Through the adoption of the method disclosed by the invention, the energy utilization rate in the synthetizing process of the glyphosate is increased, and the quality of the by-products in the synthetizing process of the glyphosate is improved.

Description

technical field [0001] The invention belongs to the technical field of recovery of glyphosate hydrolysis tail gas, in particular to a method for continuously recovering by-products from glyphosate hydrolysis tail gas. Background technique [0002] Glyphosate is the herbicide variety with the largest sales volume and the fastest growth rate in the world. At present, the preparation of glyphosate in China mainly includes the alkyl ester method and the IDA method. The alkyl ester method uses paraformaldehyde, glycine, dimethyl phosphite, methanol, and triethylamine as raw materials, undergoes depolymerization, addition, and condensation reactions in a synthesis kettle, and then adds 30% hydrochloric acid solution for hydrolysis reaction . During the hydrolysis reaction, the two methoxy groups on the phosphono group are broken in the presence of hydrochloric acid in the presence of hydrochloric acid, and methyl chloride gas is generated. The main components of the hydrolysis ta...

AI Technical Summary

Problems solved by technology

The disadvantage of the traditional process is: condensing methanol, methylal, water, etc., and then heating and rectifying, which greatly wastes energy. After condensing the materials into liquid, continuous rectification can be achieved

[0003] The invention with the publication number CN101786938A discloses the method of pressurized rectification after alkali washing, all materials are pressurized and condensed, and then heated up step by step, the energy consumption is greater than the traditional recovery method, and due to the discontinuity of the glyphosate synthesis process , so that the operation flexibility of the rectification tower becomes smaller, and the requirements for the rectification tower are high; the invention of CN 103752158A discloses that the operation is carried out by partial condensation, and the energy utilization rate is improved compared with the traditional method, but in the secondary condensation process, Due to the mutual solubility of methylal and methanol, more methylal dissolves in the condensed methanol during the condensation process, which cannot be separated in the rectification process of the methanol rectification tower, which affects the quality of methanol; the publication number is CN101225030A, which discloses the use of tail gas directly into Rectification tower separation, this invention mainly focuses on the utilization of heat, because the synthesis reaction and hydrolysis reaction are batch reactions, this invention is only applicable to the steady state continuous production process, not suitable for the batch glyphosate synthesis reaction, and When the obtained mixed gas containing chloromethane and methylal is condensed to obtain liquid methylal and gaseous chloromethane, since methylal has a certain gas partial pressure, the gaseous chloromethane also contains methylal, which affects the production of chloromethane. quality

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