Method for refining and reclaiming chloromethane from organic silicon production process

Abstract

The invention discloses a method for refining and reclaiming chloromethane from an organic silicon production process. The method comprises the following steps of: (1) feeding condensate produced by synthesizing methyl chlorosilane into a crude chlorosilane monomer refining tower, obtaining crude chlorosilane at the tower bottom and condensing a gas phase at the tower top to obtain crude chloromethane; (2) delivering the crude chloromethane into a chloromethane refining tower to perform rectification, obtaining chloromethane at the tower bottom and condensing light components at the tower top, then refluxing all liquid phases, mixing the discharged liquid phase and non-condensable gas produced by synthesizing the methyl chlorosilane, feeding the mixture into an absorption tower, condensing partial discharged crude chlorosilane at the tower bottom of the crude chlorosilane monomer refining tower, and then delivering the condensate serving as an absorbent into the absorption tower; and (3) discharging small molecular alkane from the tower top of the absorption tower, discharging the crude chlorosilane and the absorbed chloromethane from a tower kettle of the absorption tower, and then returning the crude chlorosilane and the absorbed chloromethane to the crude chlorosilane monomer refining tower. The method can obtain crude chlorosilane monomer containing less than 0.1 percent of chloromethane and chloromethane with the purity of over 99.5 percent.

Description

technical field [0001] The invention relates to a method for refining and recovering, in particular to a method for refining and recovering methyl chloride in the production process of organic silicon. Background technique [0002] Methylchlorosilane is synthesized by methyl chloride and silicon powder under the action of a catalyst. In order to make the silicon powder react completely, generally there is an excess of 5% to 10% of methyl chloride in the reactor. The reaction products are mainly methylchlorosilane, high boilers, low boilers, small molecular alkanes (methane, ethane, etc.), hydrogen and unreacted methyl chloride. Among them, hydrogen accounts for about 0.2%, small molecular alkanes (methane, ethane, etc.) account for about 0.2%-2%, and methyl chloride accounts for about 30-50%. It can be seen that if these hydrogen, small molecular alkanes (methane, ethane, etc.) and methyl chloride are recovered, the direct economic benefits and indirect environmental benefi...

AI Technical Summary

Problems solved by technology

At the same time, the content of methyl chloride in the discharged gas phase is as high as 20% to 30%, resulting in difficulties in subsequent treatment of tail gas and increased consumption of methyl chloride

[0007] Chinese Patent Application No. 200610113258.8 proposes a method for separating methylchlorosilane and methyl chloride by adding and reducing pressure, which reduces energy consumption, but the final tail gas discharge still adopts gas-liquid separation after cryogenic cooling, and the purity of the obtained methyl chloride is Only 96%

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