Method for separating and recycling chloromethane with chloromethane mixture gas

Abstract

Disclosed is a method for separating a mixed gas of methyl chloride to recover methyl chloride, and the method at least has two absorption tower systems filled with adsorbents, and obtains the methyl chloride gas separated and removed of impurities from discharge ports of the absorption towers through temperature swing adsorption processes of both adsorption and desorption to the mixed gas containing methyl chloride in the absorption towers respectively by means of interlock of time sequence; the adsorbent is at least one of allochroic silicagel, active carbon, aluminum silicate salt zeolite molecular sieve or alumina zeolite molecular sieve; and the method adopts the dry separation and recovery of temperature swing adsorption, one set of apparatus can remove water, methanol, methylal, methyl oxide and air simultaneously, and the methyl chloride product is obtained relying on high purity and / or high rate of recovery, the flow is simple and operation costs are low; and the method can realize the zero discharge of waste sulfuric acid and waste desiccant and green and environment-friendly production compared with the traditional treatment method.

Description

technical field [0001] The invention relates to a method for separating and recovering methyl chloride from a mixed gas containing methyl chloride, more specifically from the production and purification of glyphosate acid, dimethyl phosphite, trimethyl phosphite, etc. In the exhaust gas, after removing impurities such as methanol, methylal, water, etc., it is a method for recovering methyl chloride with high efficiency and pollution-free, and the method does not produce secondary pollution. Background technique [0002] Glyphosate is the fastest-growing herbicide with the largest sales volume in the world. It has excellent herbicidal performance and less residue in the soil and has been widely used around the world, opening up prospects for the development of glyphosate. The production of glyphosate acid mainly contains two kinds of methods at present, and a kind of is IDA method, and it is the IDA method with diethanolamine generally adopted by companies such as U.S. Monsan...

AI Technical Summary

Problems solved by technology

The cycle period of pressure swing adsorption is generally very short, generally several seconds to several minutes. In such a short period of time, it is difficult for methyl chloride and other gases to penetrate the adsorbent in an orderly manner. Most of the methyl chloride is adsorbed, and the yield is relatively low. Low, and the desorption of the adsorbate in this literature is through nitrogen purging at room temperature, it is difficult to desorb, the adsorbent cannot be reused, and it does not have the conditions for industrialization

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