Trichlorosilane Reduction Process-manufacture,factory,supplier from China

The principle is to reduce high purity trichlorosilane with high purity hydrogen on the high purity silicon core at about 1100℃ to generate polycrystalline silicon deposited on the silicon core. On the basis of the traditional Siemens process, the improved Siemens process is equipped with a supporting process of energy saving, consumption reduction, recycling and utilization of a large amount of H2, HCI, SiCI4 and other by-products and a large amount of by-production heat energy.

A high purity trichlorosilane differential pressure coupled distillation process, using the high pressure tower top steam as the heat source of the low pressure tower reboiler, realized the energy integration and process optimization. Chemical simulation software PRO/Ⅱ8.1 was used to simulate the design parameters of two columns of high purity trichlorosilane differential pressure coupled distillation process and three columns of high purity trichlorosilane differential pressure coupled distillation process.

Distillation is the use of SiCl4, and the difference between the relative volatility of impurities components, through several partial gasification and partial condensation process, to achieve the separation of mixed liquid, so as to obtain high purity silicon tetrachloride products.

High temperature hydrogenation of silicon tetrachloride is an important method to treat silicon tetrachloride as a by-product of polysilicon. High temperature hydrogenation is silicon tetrachloride and hydrogen as raw materials, heated by 1200 ~ 1250℃ graphite heater, thermal reduction reaction to produce  trichlorosilane. The advantages of the process are that the whole system is closed circulation, suitable for continuous and stable operation; Trichlorosilane products of high purity, need to distillation links less.

The mixture of trichlorosilane and polysilicon, which is a by-product of the recombination from the bottom of the distillation column in the production of trichlorosilane and polysilicon, was used as raw material to prepare silica by gas phase hydrolysis. The effects of gasification temperature, flow rate and flow ratio of water vapor and chlorosilane mixture on physicochemical properties of the products were investigated.

It is obtained by catalytic hydrogenation of aniline and can be divided into atmospheric pressure method and pressure method. In addition, cyclohexamine can be prepared by catalytic ammonolysis of cyclohexane or cyclohexanol, reduction of nitrocyclohexane, and catalytic ammonolysis of cyclohexanone in the presence of hydrogen.The refining process often contains impurities such as aniline and water.

At present, there are two main synthesis methods of trichlorosilane: one is the traditional synthesis method, that is the silicon chloride method. The other is hydrolyzation of tetrachloride. At present, the mainstream method of polysilicon production is the modified Siemens method, using trichlorosilane reduction method. In recent years, with the continuous decline of polysilicon price, polysilicon production enterprises pay more and more attention to the control of production cost.

Trichlorosilane (TCS or SiHCl3) is generated as follows within a high temperature, pressurized reactor: Si + 3 HCl ➡ SiHCl3 + H2 ，Si + 3 SiCl4 +2 H2 ➡ 4 SiHCl3 .The TCS is then sent to the CVD (Chemical Vapor Desposition) reactor. In the Siemens process, high-purity silicon "starter" rods or hairpins are exposed to trichlorosilane at 1150 °C in the CVD reactor.

Nitrocyclohexane reduction method: This method takes nitrocyclohexane and hydrogen as raw materials, using reducing agent to generate cyclohexylamine, because nitrocyclohexane raw materials are difficult to obtain, this method is basically eliminated. Moreover, the process has some defects, such as low one-way conversion of aniline and poor selectivity of dicyclohexylamine.

The production process of trichlorosilane is mostly prepared by reaction of gold-grade silicon metal powder and hydrogen chloride gas in a fluidized bed reactor. Generally using gold grade metal silicon powder, hydrogen chloride gas by the combustion reaction of chlorine and hydrogen gas. Reaction temperature is 300-400 degrees, most of the pressure using micro positive pressure operation.

Trichlorosilane is mainly used in the manufacture of polysilicon and silane coupling agents, among which polysilicon is the most important downstream application area of trichlorosilane, accounting for 32% of the consumption in 2021, and silane coupling agent consumption accounted for 25%. The market is still in good condition.

Devices that use tail gas to recover cyclohexylamine are characterized in that they include: spray tower, circulating pump, condenser, defogger, photooxygen catalytic oxidizer, ozone treatment device, blower, chimney. Described in the circulating pump and spray the bottom connection, as described in the other side of the circulating pump are connected to the condenser, the condenser and the upper spray tower connection, described in the spray tower are connected to the top of demister, described in the mist bottom and photocatalytic oxidation, photocatalytic oxidation is described, ozone

Trichlorosilane is a higher degree of marketization, competition is more adequate industry. The price of industrial products is easily affected by upstream raw materials and downstream demand. Trichlorosilane production raw materials are mainly industrial silica powder and liquid chlorine, if the raw material prices rise sharply, it profits will be under pressure. The price fluctuation of trichlorosilane has little effect on the profits of polysilicon enterprises. Even if the price is temporarily low, polysilicon prices still have upward momentum. 

Silane coupling agent product price growth is very obvious, compared with the same period last year growth of 118%. Upstream raw material trichlorosilane price rise, silane products for the high price operation provides a strong support. Reporters learned that trichlorosilane is mainly used in the production of polysilicon, silane coupling agent, silane coupling agent is the second largest downstream market of trichlorosilane, in recent years the demand is more exuberant.

Electronic grade trichlorosilane sihc13 is colorless, flammable, corrosive liquid and has a suffocating odor. Hydrolyze rapidly in wet air to produce hydrogen chloride: boiling point 31.9 ':. Melting point 126.5 c:. Liquid density 134ukgi resistance: in the air "}", the flammability limit is B.9% - 7U}'u. Flash point - 28. U}.

Dicyclohexylamine has the chemical properties of a secondary amine. It has a strong base and can form salts with various acids. Acylation may occur. In terms of solubility, dicyclohexylamine is slightly soluble in cold water but almost insoluble in hot water. Dry powder, carbon dioxide, soluble foam and sand are used to extinguish the fire.

It is obtained by catalytic reduction of nickel or cobalt from aniline at high temperature and pressure. Cyclohexanol can also be reduced by phenol, oxidized to cyclohexanone, and then aminated with ammonia to obtain cyclohexanamine.This substance is harmful to the environment, and special attention should be paid to the pollution of water bodies. Acute poisoning may occur by inhalation of vapour. Irritant and corrosive to skin, eyes and mucous membranes, and can cause allergy through skin absorption.

With the rapid growth of downstream PV demand, photovoltaic grade trichlorosilane continues to be in short supply. The application of PV grade trichlorosilane in the production of polysilicon includes a one-time requirement for the first commissioning, which accounts for about 20% of the total capacity. Second, the requirement for chlorine supplementation during continuous production accounts for about 10 to 30 percent of total production. On the supply side, the expansion of trichlorosilane production has been conservative in the past.

The invention relates to a refining method of dicyclohexylamine, belonging to the technical field of organic chemistry.

Since May 2022, trichlorosilane has been sustained upward by the downward trend in silicon metal prices.

Silicon tetrachloride is an important raw material and intermediate product in the process of organic silicon synthesis and polysilicon production. Under different environmental conditions, silicon tetrachloride can react with a variety of substances to produce new substances.

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The process relates to a tail gas refining method, in particular to the hydrogenation of aniline to prepare cyclohexylamine and the deamination of dicyclohexylamine tail gas to refine hydrogen.

Chlorine hydrogenation technology is to add HCl on the basis of low temperature hydrogenation technology to further reduce the reaction temperature and increase the yield of trichlorosilane. Chlorine hydrogenation reaction principle is as follows: 2SiCl4(g)+H2(g)+HCl(g)+Si(s)=3SiHCl3(g). Hydrogen plasma is generated by hydrogen discharge, which is passed into the reactor to react with silicon tetrachloride gas. Since hydrogen is dissociated into hydrogen atoms, the reactivity is greatly increased and it can easily react with silicon tetrachloride to form trichlorosilane.