高变质程度无烟煤热天平二氧化碳加压催化气化动力学——热天平等温热重法

Pressurized catalytic gasification kinetics of high rank anthracites with CO_2 by TGA

以碳酸钠为催化剂,在加压下用热天平等温热重法研究了四种高变质程度无烟煤(挥发分Vad=2.69%~4.35%)二氧化碳催化气化反应动力学,考察了0.101MPa^3MPa对二氧化碳催化气化反应的影响。结果表明,压力大于2.0MPa,增大压力不再加快反应速率。在2.0 MPa、750℃~950℃测定实验无烟煤的转化率与时间的关系,用缩芯模型进行较好地拟合。按反应速率常数判定煤样活性大小顺序为:永安丰筛煤>永安加筛煤>永定煤>上京煤,活化能为:157.21 kJ/mol^185.89kJ/mol,要比相同煤种常压二氧化碳催化气化时具有更大的反应速率常数、活化能和指前因子。850℃及较低压力0.101MPa^2.0 MPa下,给出永安加筛煤气化动力学方程中的压力修正指数为0.347 44,与文献报道一致。

Using sodium carbonate as the catalyst, the carbon dioxide gasification kinetics of the four high rank anthracites （ Vad = 2.69 % -4.35 % ） was investigated by isothermal thermo-gravimetric analysis under high pressure. The range of pressure from 0. 101 MPa to 3.0 MPa was tested. The results show that when the pressure is higher than 2.0 MPa, the increase of pressure has no effect on the reaction rate. The coal conversion as a function of reaction time was measured at the temperature from 750℃ to 950℃ and at 2.0 MPa, which could be preferably correlated by the shrinking-core model （SCM）. According to the reaction rate constant determined by SCM, the reactivity order of the four anthracites is： Yongan Fengshai coal 〉 Yongan Jiashai coal 〉 Yongding coal 〉 Shangjing coal. The activation energies, ranging from 157.21 kJ/mol to 185.89 kJ/mol, are obtained. The reaction rate constant, activation energy and pre-exponential factor under high pressure are larger than those of the gasification in CO2 at atmospheric pressure. At 850℃ the power of CO2 partial pressure for Yongan Jiashai coal is 0. 347 44, which agrees well with the literature.