Method for preparing trichlorosilane by plasma hydrogenization of silicon tetrachloride

Abstract

The invention discloses a method for producing trichlorosilane from silicon tetrachloride through plasma hydrogenation. The method is characterized in that through induction of a high-frequency coil, hydrogenous plasma is produced to treat a gaseous silicon tetrachloride raw material added to a plasma region; two raw materials participate in reaction in a plasma state; and the silicon tetrachloride is hydrogenated into the trichlorosilane. In a high-frequency coil inducted plasma rector, a gas circuit is divided into three circuits of axis central gas, central main gas and protective gas; hydrogenous gas is subjected to plasma arc starting to form a hydrogenous plasma flame region; the gasified silicon tetrachloride is added through an axis center, reacts in the hydrogenous plasma flame region, and is converted into the trichlorosilane; after the reaction, mixed gas is subjected to heat exchange, condensation, cooling and distillation procedures to obtain a trichlorosilane liquid, a silicon tetrachloride liquid, chlorine hydride, hydrogen gas and argon gas respectively, wherein the silicon tetrachloride, circulating hydrogen gas and the argon gas are in the reactor; and the trichlorosilane and the chlorine hydride enter the polysilicon production procedure. The method can concisely treat the silicon tetrachloride as a byproduct of polysilicon with high efficiency and environmental protection, simultaneously obtains raw materials needed by the polysilicon, and greatly reduces the output of waste and production cost for the polysilicon.

Description

technical field [0001] The invention belongs to the chemical process of hydrogenation and circulation of silicon tetrachloride, a by-product of polysilicon, and particularly relates to a method for treating silicon tetrachloride with radio frequency induction plasma hydrogenation. Background technique [0002] In recent years, with the rapid development of the solar photovoltaic industry, the demand for polysilicon, the raw material of solar cells, has been greatly stimulated. The supply of polysilicon raw materials is the bottleneck restricting the current solar photovoltaic industry. The analysis of the cost composition of photovoltaic power generation shows that more than half of the cost of photovoltaic cells is the cost of polysilicon. Therefore, reducing the production cost of polysilicon through technological innovation is an inevitable prerequisite for the global popularization of photovoltaic power generation in the future. [0003] According to statistics, more th...

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Problems solved by technology

[0009] The disadvantages of this method are: the reaction conditions are high temperature and high pressure, the reactor preparation cost is expensive, and the equipment corrosion problem makes the industrial application of this process not as wide as the heating furnace hydrogenation method.

However, the speed of mixing and soaking of feed gas is still limited

[0016] 3. From the preparation of hydrogen plasma to the generation of trichlorosilane, there are three steps in this method, that is, hydrogen gas is first made into hot plasma flow gas, then mixed with silicon tetrachloride gas for soaking, and then sent into the reactor to react to form trichlorosilane. Chlorohydrosilane has a long process flow, and it is very difficult to meet the requirements of response time in milliseconds, and the prospect of industrial scale development is not great.

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