Method for recovering tail gas of trichlorosilane production

Abstract

The present invention discloses a recovery method of the tail gas produced by the trichlorosilane, which is characterized in that after the synthetic gas of the fluidized bed reactor is condensed, the noncondensing gas(tail gas) is sent to a compressor to be compressed, and then came into a hydrogen membrane separator to separate the hydrogen, the impervious gas in the hydrogen membrane separator is sent to a recycle condenser, via the further condensation by the recycle condenser, obtaining the trichlorosilane and the silicon tetrachloride, the incondensable gas is the chlorine hydride, reused in the fluidized bed reactor as the raw material again, the trichlorosilane and the silicon tetrachloride are the recycling productions. The separated hydrogen is capable of being used for fuel or raw material used for producing other productions, and is also capable of directly injecting into the atmosphere.

Description

technical field [0001] The invention relates to a process in the technical field of chemical industry, in particular to a method for recovering tail gas from trichlorosilane production. Background technique [0002] Trichlorosilane (HSiCl 3 ) is a very versatile organosilicon monomer, mainly used as raw materials for the production of semiconductor silicon, single crystal silicon and polycrystalline silicon, and widely used in various fields of national defense, national economy and even people's daily life. In recent years, my country's demand for trichlorosilane is increasing. There are more and more trichlorosilane units under construction or proposed. However, in view of the increasing environmental protection requirements in various places, in order to make the production of trichlorosilane meet the environmental protection requirements and meet the national energy conservation and emission reduction requirements, the recovery and utilization of tail gas is also becom...

AI Technical Summary

Problems solved by technology

It is generally understood that the boiling points of trichlorosilane and silicon tetrachloride under normal pressure are 31.8°C and 57.6°C respectively. In theory, all trichlorosilane can be condensed as long as it can be cooled below its minimum boiling point. But in fact, due to the presence of hydrogen in the mixed gas, even if it is cold to -30°C, it cannot be condensed completely. This part contains about 13% of the mixed gas of trichlorosilane and silicon tetrachloride. In traditional or In the current existing production process, this part is directly sent to washing, and this part of gas is not further recovered (mainly recovering trichlorosilane, silicon tetrachloride and hydrogen chloride), resulting in high raw material consumption, uneconomical, and Conducive to environmental protection

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