Process Optimization Of Trichlorosilane Synthesis And Post Treatment Unit

SiHCl₃ is an important silicon based monomer material,widely used in the field of electronic substrates,photovoltaic panel materials and silicone production.At present,the most commonly usedSiHCl₃ production technique is direct chlorination,which involves gas-solid heterogeneous phase reaction in fluidized bed reactors using industrial grade silicon powder and HCl.The performance of the reaction is affected by reaction temperature,pressure,ratio of hydrogen to silicon,hydrogen content in HCl gas,silicon particle size,pressure difference and catalyst,and so on.A small amount of solid impurities,such as small particles of silica powder and metal chloride,are carried out in the synthetic gas produced by the reaction,such as small particle silica powder and metal chloride impurity.The dust removal method combined dry and wet process is widely used in the process of production at present,which is used to remove solid impurities in synthetic gas and to purify synthetic gas.Because of the technology secrecy and other reasons,there is a big gap between the technical level of enterprises produced by direct chlorination method in China and the international advanced enterprises.There are many problems in the operation process of most enterprises,which lead to the increase of production cost and the decline of quality.Firstly,this paper analyzes the affections of the reaction temperature,pressure,ratio of HClto silicon,H₂content in HClon the equilibrium content of trichlorosilane to get the optimized parameters of the process and to provide guidance for optimizing the process.Secondly,characteristics of different kinds of cyclone dust removal process and its influence on the running effect of dry dust removal system are analyzed,which suggested that for direct chlorination process,the parallel built-in cyclone dust removal process is optimal,which not only improves the automation level of the system,but also reduces the production cost.According to this,a scheme for the transformation of dry dust removal system is put forward.Thirdly,a variety of working conditions,including reflux ratio,number of tower plates and inlet location,are simulated on scrubber of the wet dust removal system,which has been used to analyze the sensitivity of the purification effect of the washing tower.The results show that the optimal number of tower plates is 15,the optimal feeding position is10th plate and the optimal reflux ratio is 1.Under the optimal operating conditions,the load of the reboiler is reduced by 61.90%,the load of condenser is reduced by33.55%and the manufacturing cost of the washing tower is reduced by 33.33%.The reform scheme of the washing tower is designed according to the calculation results.In the end,aiming at the problem of resource waste in the process of washing tower residue treatment,by analyzing the deficiency of the existing chlorosilane waste liquid treatment technology and the characteristics of the related components in the waste liquid of the washing tower,this paper proposed to remove the solid impurities such as silica powder and metal chloride in the waste liquid of chlorosilane by hydrocyclone and to recycle chlorosilicon from residue by catalytic cracking technology.According to this,a new techlonogy for recycling chlorosilane from residue,suitable for direct chlorination process,is designed,which realizes the effective recovery of the valuable elements of silicon and chlorine in the waste liquid,reduces the production cost and improves the economic benefit.