Thermal degradation of bituminous coal with both model-free and model-fitting methods

• Published in: Applied thermal engineering 2019-04, Vol.152, p.169-174
• Main Authors: Du, Wenzhou, Wang, Gang, Wang, Yue, Liu, Xuelin
• Format: Article
• Language: English
• Subjects: Activation energy; Bituminous coal; Coal; Energy conversion; Energy efficiency; Heating; Kinetics; Mathematical models; Oxidation; Parameter estimation; Pyrolysis; Reaction kinetics; Shuffled Complex Evolution; Thermal degradation; Thermogravimetric analysis; Thermogravimetry
• ISSN: 1359-4311; 1873-5606
• DOI: 10.1016/j.applthermaleng.2019.02.092

•Pyrolysis kinetics of bituminous coal is studied at various heating rates.•Both model-free and model-fitting methods are applied.•Shuffled Complex Evolution method is first used in the coal pyrolysis.•The predicted results by SCE agree well with experimental data. A series of thermogravimetric experiments was conducted to study the thermal degradation of bituminous coal at various heating rates in both nitrogen and air atmosphere. Both model-free and model-fitting methods were applied simultaneously to explore the reaction kinetic parameters. The activation energies were estimated in the range of 194.7–348.0 kJ/mol at different conversions by two typical model-free methods (Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose methods). Shuffled Complex Evolution method (SCE), as the representative of model-fitting method, was firstly used in the coal pyrolysis process. By comparison, the predicted activation energy (199.2 kJ/mol) by model-fitting method was just within the range of values obtained by the model-free methods, validating the applicability of this model-fitting method. Furthermore, the effect of char oxidation and its kinetic parameters are analyzed by SCE based on the difference of nitrogen and air atmosphere. These optimized parameters can be coupled with the pyrolysis model and applied in the following energy conversion processes.