Research On Trichlorosilane Production Process By Hydrogenation Of Silicon Tetrachloride

Domestic polysilicon industry has suffered from cold snap and been seriously challenged due to overcapacity since 2008. In addition to the competition effect of foreign polysilicon giants, the fundamental reason is that our core technology is not mature enough, resulting in high production costs. Reducing energy consumption, and recycling byproduct to production process, is crucial to sustainable development of domestic polysilicon industry.Modified Siemens process is the mainstream of polysilicon production, however, about 15 tone of silicon tetrachloride is generated with 1 tone of polysilicon capacity, Reasonable treatment with huge amount of silicon tetrachloride, is a constraint to the development of polysilicon industry. Preparation of trichlorosilane by hydrogenation of silicon tetrachloride began to get more and more attention, which achieve material closed-loop circulation, and reduce the production cost to a large amount. High-temperature hydrogenation process and cold hydrogenation process have the problem of high-energy and low reaction conversion. How to improve the conversion rate of silicon tetrachloride, and decrease energy consumption has become a hot topic. Aiming at the problem, silicon tetrachloride hydrogenation process in DBD plasma was explored, and Supported nickel catalyst was tested in this paper.The main research work and results are as follows:?1? Silicon tetrachloride hydrogenation process in DBD plasma was initiatively proposed. Plasma generator and quartz tube reactor were designed to carry out the feasibility test. In DBD low-temperature plasma, silicon tetrachloride is reduced to trichlorosilane. With the increase of plasma power, the yield of trichlorosilane increases, and the maximum yield is 12.1%.?2? Due to bad control of reaction extent in the DBD plasma hydrogenation process, silicon tetrachloride are deeply reduced to silicon, forming conductive smoke. The conductive smoke changes the original structure of the discharge, discharge gap decreases greatly, resulting in bad discharge uniformity.?3? In the last part, different nickel catalysts were prepared by impregnation method for hydrogenation of silicon tetrachloride. The comparison of catalytic activity among the catalysts was investigated, and the results revealed that Ni/HZSM-5 displayed the best performance. The optimum reaction condition is nickel loading of 10%, reaction temperature of 850 ?, pressure of 0.3 MPa, molar ratio of H₂:SiCl₄=4:1, reaction space of 5000 h^-1, which gives the highest silicon tetrachloride conversion of 16.69%.