关键词: 低阶煤, 催化剂, 催化解聚, CPD模型, 动力学

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