Process and device for treating tail gas during producing trichlorosilane

Abstract

The invention relates to a process and device for treating tail gas during producing trichlorosilane. The process provided by the invention comprises: the tail gas generated from a trichlorosilane synthesizing workshop section and a trichlorosilane fractionating workshop section is compressed by a diaphragm compressor in a pressuring way, then condensed by a rear water condenser, deeply condensed by a rear deep condenser, and finally absorbed by a circulating absorption tower to recover the chlorosilane; and the hydrogen chloride in the tail gas which is absorbed by the circulating absorption tower is absorbed by a secondary falling film absorption tower to be made into 30% hydrochloric acid, and the tail gas which is absorbed by the falling film absorption tower is directly discharged to the air after being checked out. The device provided by the invention consists of the diaphragm compressor, the rear water condenser, the rear deep condenser, the circulating absorption tower and the falling film absorption tower which are connected with the one another in series by pipelines, wherein the diaphragm compressor is provided with a tail gas inlet, and the falling film absorption tower is provided with an outlet and an emptying port. According to the invention, the 99.5% of chlorosilane and hydrogen chloride can be recovered; the great mass of the chlorosilane and hydrogen in the tail gas not only can be recovered, but also can be reused, so that the process and device provided by the invention are favorable for environmental conservation.

Description

technical field [0001] The patent of the present invention relates to a tail gas treatment process and device of a trichlorosilane synthesis section and a trichlorosilane fractionation section. Background technique [0002] The tail gas of the trichlorosilane synthesis section and the trichlorosilane fractionation section contains 5.4% chlorosilane, 30% hydrogen chloride gas, 0.2% nitrogen and 64.2% hydrogen, and other gases account for 0.2%. The direct evacuation of this part of the tail gas will cause pollution to the environment, so it is necessary to design a tail gas treatment process and its device. Contents of the invention [0003] The purpose of the present invention is aimed at above-mentioned present situation, aims to provide a kind of tail gas treatment process and its device in the trichlorosilane production that can recover most of chlorosilanes and hydrogen chloride in the tail gas, carry out reuse. [0004] The realization mode of the object of the presen...

AI Technical Summary

Problems solved by technology

The direct evacuation of this part of the tail gas will pollute the environment, so it is necessary to design a tail gas treatment process and its device

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