Pyrolysis of a typical low-rank coal: application and modification of the chemical percolation devolatilization model

Tong Lv; Mengxiang Fang; Huaixiang Li; Jiqing Yan; Jianmeng Cen; Zhixiang Xia; Jianglei Tian; Qinhui Wang

doi:10.1039/d1ra01981c

Pyrolysis of a typical low-rank coal: application and modification of the chemical percolation devolatilization model

RSC Adv. 2021 May 18;11(29):17993-18002. doi: 10.1039/d1ra01981c. eCollection 2021 May 13.

Authors

Tong Lv^{1

2}, Mengxiang Fang^{1

2}, Huaixiang Li^{1

2}, Jiqing Yan^{1

2}, Jianmeng Cen^{1

2}, Zhixiang Xia^{1

2}, Jianglei Tian^{1

2}, Qinhui Wang^{1

2}

Affiliations

¹ State Key Laboratory of Clean Energy Utilization, Zhejiang University Hangzhou 310027 P. R. China mxfang@zju.edu.cn.
² Energy Research Base, Zhejiang University Qingshanhu, Lin'an Hangzhou 311300 P. R. China.

Abstract

The chemical percolation devolatilization (CPD) model can simulate the formation of various products during the coal pyrolysis process and predict the products composition relatively accurately. In this study, the pyrolysis products of a typical low-rank coal were calculated using the CPD model, and several model improvements were proposed by combining the experimental results in a lab-scale pyrolysis system. The chemical structural parameters calculated from the Genetti correlations were verified by adjusting the initial fraction of char bridges (c ₀) from 0.098 to 0.25. A yield difference (Δf _tar) was defined in this paper to analyze the consumption of tar fragments in the model, and it was found that the deviations between experiments and calculations resulted from the weak influence of crosslinking. A modification expression was adopted to amplify the tar consumption: , which improved the accuracy of the model on the tar yield with errors of less than ±0.5 wt%. Furthermore, this paper also developed a correlation in an exponential form about gas composition, which attempted to extend the application of the CPD coalification reference mesh for the coal away from interpolation triangles. The improved model by the correlation predicted CH₄, CO, and CO₂ yields for this typical low-rank coal accurately in most cases. Compared with the original CPD model, the modified model showed better agreement with the experimental results and predicted 71.4% and 88.6% of the data points in this work within ±10% and ±20% errors, respectively.