(1. 昆明理工大学 冶金与能源工程学院，昆明 650093；
2. 云南冶金集团总公司 技术中心，昆明650031；
3. 昆明冶研新材料股份有限公司，昆明 650031)
摘 要: 应用有关热力学数据研究了与多晶硅主要生产工艺即西门子法相关的“Si-Cl-H”三元系的复杂化学反应，研究SiCl4氢化转化为SiHCl3过程中可能发生的15个反应，给出15个反应的 —T图；并确定5个独立的反应，给出这5个独立反应的 —T图；高温时主反应(1)的 增长较慢，而反应(2)和(5)的 快速增大，1 373 K时，主反应(1)的 较小，为0.157 1。进一步研究温度、压强和进料配比 对SiCl4氢化率的影响，并绘制出SiCl4氢化率随这些因素的变化曲线。结果表明：当压强和进料配比一定时，SiCl4的氢化率随温度的升高先增加后降低；增大压强或增加进料配比 都会提高SiCl4的氢化率；SiCl4氢化转化为SiHCl3过程的最佳操作条件为温度为1 000 ℃，压强为0.3 MPa，进料配比 为4，在此条件下，SiCl4的氢化率为25.78%。
关键字: SiCl4；SiHCl3；热力学；转化
（1. Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology,
Kunming 650093, China;
2. Technology Center, Yunnan Metallurgy Group Co., Kunming 650031, China;
3. Kunming Yeyan New-Material Co., Ltd., Kunming 650031, China）
Abstract:Based on the thermodynamic data for the related pure substances, fifteen possible chemical reactions in the SiCl4 hydrogenation system of Siemens process that is one of the main process for the polysilicon production were studied. The curves of the fifteen chemical reactions in the system versus temperature were fitted by the assistant of computer. The values of for most reactions are greater than zero at the range of 973K to 1 773 K. That is to say that the value of equilibrium constant is small. Therefore, the small degree of the reactions was carried on. Five independent reactions in the process were decided and the relation between and temperature was fitted by the assistance of computer based on the thermodynamic data for the related pure substances. The value of for main reaction (1) increases a little at high temperature, but the value of for side-reactions (2) and (5) increase quickly. Besides, the value of for main reaction (1) is low at low temperature, for example only 0.157 1 at 1 373 K. Therefore, the transformation ratio of SiCl4 to SiHCl3 being low is a objective fact which can not be changed. Furthermore, the influencing factors, such as the temperature, pressure and feeding mole ratio, on the transformation ratio from SiCl4 to SiHCl3 were studied. The diagrams of η—transformation ratio are presented as function of temperature, pressure and feeding mole ration, respectively. The transformation ratio of SiCl4 to SiHCl3 decreases with increasing the temperature, and the pressure have a positive effect on the transformation ratio. Furthermore, the excess of H2 is necessary in SiCl4 hydrogenation system of the modified Siemens process. From the thermodynamic above, The results show that the optimum operation parameters are at 1 050 ℃, 0.3 MPa and feeding mole ratio of 4. Under this condition, the transformation ratio from SiCl4 to SiHCl3 is 25.78%.
Key words: SiCl4; SiHCl3; thermodynamics; transformation
