SiCl4氢化转化为SiHCl3过程的热力学

来源期刊:中国有色金属学报2011年第12期

论文作者:侯彦青 谢刚 陶东平 俞小花 李荣兴 宋东明

文章页码:3202 - 3210

关键词:SiCl4;SiHCl3;热力学;转化

Key words:SiCl4; SiHCl3; thermodynamics; transformation

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△GmΘ—T图;并确定5个独立的反应,给出这5个独立反应的KpΘ—T图;高温时主反应(1)的KpΘ增长较慢,而反应(2)和(5)的KpΘ快速增大,1 373 K时,主反应(1)的KpΘ较小,为0.157 1。进一步研究温度、压强和进料配比nH2/nSiCl4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nH2/nSiCl4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nH2/nSiCl4为4,在此条件下,SiCl4的氢化率为25.78%。

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 △GmΘ curves of the fifteen chemical reactions in the system versus temperature were fitted by the assistant of computer. The values of △GmΘ 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 KpΘ and temperature was fitted by the assistance of computer based on the thermodynamic data for the related pure substances. The value of KpΘ 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 KpΘ 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 nH2/nSiCl4 of 4. Under this condition, the transformation ratio from SiCl4 to SiHCl3 is 25.78%.

相关论文

  • 暂无!

相关知识点

  • 暂无!

有色金属在线官网  |   会议  |   在线投稿  |   购买纸书  |   科技图书馆

中南大学出版社 技术支持 版权声明   电话:0731-88830515 88830516   传真:0731-88710482   Email:administrator@cnnmol.com

互联网出版许可证:(署)网出证(京)字第342号   京ICP备17050991号-6      京公网安备11010802042557号