Polycrystalline silicon cold hydrogenation method adopting gas-solid parallel flow downer reactor

Abstract

The invention discloses a polycrystalline silicon cold hydrogenation method adopting a gas-solid parallel flow downer reactor. The method comprises the following steps: adding silicon powder, a solidcatalyst, preheated H2 and preheated and vaporized SiCl4 gas from the upper portion of a reactor, reacting to obtain a gas-solid mixture containing SiHCl3, extracting the gas-solid mixture from the bottom of the reactor, and separating in a gas-solid separator; and obtaining SiHCl3 gas carrying impurities, and sending to a downstream separation and refining section, and introducing a mixture of silicon powder obtained through separation and the solid catalyst into the reactor again from the upper portion of the reactor. According to the invention, the gas-solid ring core structure of the ascending fluidized bed reactor is eliminated, the reaction is sufficient and uniform, and the efficiency is high; the silicon powder and the catalyst are taken out less during reaction and are recycled, so that the utilization rate of the silicon powder is high, and the yield of the slurry is greatly reduced; the single-pass yield of SiHCl3 is increased to 30% or above; and the method has the advantages of simple operation, high efficiency, energy saving, economy and environmental protection.

Description

technical field [0001] The invention belongs to the technical field of polysilicon manufacture, and specifically relates to a polysilicon cold hydrogenation method using a gas-solid co-current down-bed reactor. Background technique [0002] With the increasing consumption of traditional fossil energy, today's energy is becoming increasingly tense, and environmental pressure is increasing. It is increasingly urgent and important to find a new type of alternative energy. Due to its advantages of safety, cleanliness, richness and high efficiency, solar energy has gradually received more and more attention from people. Polysilicon is the basic raw material of crystalline silicon photovoltaic materials, and its price has a great influence on the cost of crystalline silicon photovoltaic materials. The traditional polysilicon production process is mainly the improved Siemens method. For every ton of polysilicon produced, the by-products produced are about 15 tons of SiCl 4 , by-p...

AI Technical Summary

Problems solved by technology

The gas-solid fluidized bed reaction is easy to produce a ring nucleus structure, which is easy to form a gas short circuit, which reduces the conversion rate of SiCl4 and affects the single-pass yield of SiHCl3

In addition, the fluidized silicon powder and catalyst are easily carried out of the reactor, resulting in a large amount of slurry

The loss of a large amount of slurry not only pollutes the environment, but also brings serious economic losses

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