![]() ① The industrial silicon is crushed and reacted with anhydrous hydrogen chloride in a fluidized bed reactor to produce trichlorosilane to be dissolved. ![]() The equipment used for the modified Siemens process to produce polysilicon mainly includes: hydrogen chloride synthesis furnace, trichlorosilane fluidized bed pressurized synthesis furnace, trichlorosilane hydrolysis gel treatment system, trichlorosilane crude distillation, distillation tower purification system, silicon Core furnace, energy-saving reduction furnace, phosphorus inspection furnace, silicon rod cutting machine, corrosion, cleaning, drying, packaging system equipment, reduction exhaust gas dry recovery equipment others include analysis, testing instruments, control instruments, thermal energy conversion stations, compressed air The main reactions of power stations, circulating water stations, substations, purification plants, etc. The raw and auxiliary materials for the production of polysilicon are trichlorosilane, hydrogen chloride, hydrogen, calcium oxide, hydrofluoric acid, nitric acid, and hydroxide. Most of the existing polysilicon factories at home and abroad use this method to produce electronic grade and solar grade polysilicon. The purified trichlorosilane Hydrogen silicon undergoes CVD reaction in an oxygen reduction furnace to produce high-purity polysilicon. Hydrogen chloride and industrial silicon powder synthesize trichlorosilane at a certain temperature, and then separate and purify the trichlorosilane. The modified Siemens method uses chlorine and hydrogen to synthesize hydrogen chloride (or purchased hydrogen chloride). In terms of cost, the international Siemens method costs 30 US dollars per kilogram of polysilicon. h per kilogram of polysilicon, while China’s power consumption per kilogram of polysilicon is 200~250kW.h.At present, the international Siemens method consumes about 150kW The toxic liquids and gases emitted by the hydrochlorination of silicon and the reduction of trichlorosilane not only pollute the environment, but also increase the cost of the enterprise. Compared with the traditional Siemens method, pollution is controlled and the environment is protected.Īt present, the modified Siemens method is generally used-the closed-loop trichlorosilane hydrogen reduction method. Since the improved Siemens method is a closed loop system, various materials in polysilicon production are fully utilized and discharged There is very little waste. ![]() In addition, the improved Siemens method adopts large-diameter reduction furnaces and other measures, which can effectively reduce the power consumption of the reduction furnace and reduce pollution. The improved Siemens method recycles all the various components in the tail gas, which can greatly reduce the consumption of raw materials. ①Energy saving and consumption reduction. The advantages of the improved Siemens method over the traditional Siemens method are mainly as follows. The polysilicon produced accounts for 70% to 80% of the world’s total production today. This method reduces the energy consumption per unit product by adopting a large reduction furnace: the SiCl4 hydrogenation and dry exhaust gas recovery process are used to significantly reduce the consumption of raw and auxiliary materials. In 1955, Siemens successfully developed the process technology of using H to reduce SiHCl3 to deposit silicon on a silicon core heating element, and built a factory in 1957 for industrial-scale production, which is commonly referred to as the Siemens method.īased on the Siemens process, it was further improved later, adding a reduction tail gas dry recovery system and SiCl4 hydrogenation process to achieve a closed loop and form an improved Siemens process that is widely used today.
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