用热重法研究大同煤焦的CO_2加压气化动力学

Kinetics of the Pressurized Gasification of Datong Coal Char

用快速升温和在高温高压下用热重分析装置和 ST-03表面孔径测定仪在1203～1423K 的温度和0.1～0.3MPa 的压力范围内研究大同煤焦的 CO_2气化反应动力学和其孔结构在反应中的变化。结果表明,Arrhenius 关系可以描述不同压力下气化反应速率随温度的变化;在实验的压力范围内,反应速率随压力的变化低压时变化明显;气化过程中煤焦的微孔表面积与转化率的关系出现一极大值.经理论分析和实验证实建立了包括煤焦孔结构参数的动力学方程。

The kinetics of CO_2 pressurized gasification of a char prepared from Datong medium volatile bituminous coal is studied by using a unique high temperature/pressure thermal gravimetric analyzer system at a range of the temperature from 1203 to 1423K and the pressure from 0.1 to 3.0MPa. The system is able to achive a heating rate as high as about 10~2K/sec. Microstructural properties of the char during gasification are investiga- ted by a Type ST-03 surface meter.The results indicate that the effect of gasification temperature on the char reactivity could be described by Arrhenius law and the effect of CO_2 pressure by an expression of (K_oPCO_2/A+PCO_2). The data for specific surface area of the char at different conversions are well fit withBhatias random-poremodel.Based on the experimental results of reactivity and other kinetic properties investigated a rate equation is built up as follows: r=467.6exp(-(92966/8.314T)(1-x)(PCO_2/PCO_2+0. 0532))1-3.55ln(1-x)^(1/2)