Abstract:

The quantitative analysis and amplification of the catalytic depolymerization process of low rank coal need a macroscopic dynmaic model to describe the process reasonably. In this work, the chemical percolation devolatilization (CPD) model was used to quantitatively analyze the catalytic depolymerization process of low-rank coal, combining with the corresponding catalytic depolymerization experiment which was carried out with Shaanxi long-flame coal. According to the experimental results, the reaction kinetic parameters were obtained based on the mechanism of the catalytic depolymerization. The simulated results showed a good agreement with the experimental data and can better reflect the difference of different stages of pyrolysis process, i.e., at lower temperature, the yield of catalytic depolymerization was also lower, and with further increasing the reaction temperature, the yield of products will be sharply increased and higher than that of raw coal pyrolysis. In this model, the effect of the catalyst on the yield of pyrolysis tar was reflected by the composite rate constant and the crosslinking reaction activation energy, and the tar yield increased with the increase of these two parameters. For the Fe-based catalysts, it can promote the cleavage of side chain resulting in the increase of gas yield. As for the Zn-based catalysts, it can inhibit the crosslink reaction. However, when the activation energy of the crosslink reaction was too higher, the increase of the tar yield was increased slowedown due to the restriction of reaction temperature.

Key words: low rank coal, catalyst, catalytic depolymerization, chemical percolation devolatilization model, kinetics

摘要：

低阶煤催化解聚过程定量分析和放大需要合理描述该过程的宏观动力学模型，使用化学渗透脱挥发分（CPD）模型结合陕西长焰煤的催化解聚实验，对低阶煤催化解聚过程进行了定量分析。综合对催化剂作用机理的认识，结合催化解聚实验结果确定相应表观动力学参数，所得模拟结果与实验结果趋势一致、吻合良好，其较好地体现了不同热解过程差异，低温下催化解聚产物释放量较少，温度升高后产物量才会高于原煤热解。模型中催化剂对焦油产率的影响体现在复合速率常数、交联反应活化能上，随两者增大，焦油产率均增加；Fe基催化剂有助于促进侧链断裂，提高气体产率，Zn基催化剂可抑制交联反应，但交联反应活化能较大时，受热解温度限制，焦油量增加变缓。

关键词: 低阶煤, 催化剂, 催化解聚, CPD模型, 动力学