Kinetic model and parameters optimization for Tangkou bituminous coal by the bi-Gaussian function and Shuffled Complex Evolution

Abstract

In this paper, deconvolution procedure coupled with Shuffled Complex Evolution (SCE) algorithm was employed to fit the thermogravimetric curve for Tangkou bituminous coal in nitrogen atmosphere. The kinetic model and parameter optimization of detailed stages of coal pyrolysis were studied to simplify and characterize the thermal degradation process with complex behavior. The reaction rate curve of Tangkou bituminous coal was separated into three stages: primary pyrolysis, secondary depolymerization and secondary repolymerization. Based on the deconvolution results of bi-Gaussian function, the kinetic parameters were determined by Friedman and Coats-Redfern methods. The results showed that the reaction order model was responsible for each individual stage. Then, SCE algorithm was employed to optimize the obtained parameters to get more accurate results. The optimization results showed that the experimental curves can be well characterized by the parameters obtained by the deconvolution procedure and SCE algorithm. Eventually, the accuracy and applicability of the reaction model and optimization parameters of Tangkou bituminous coal were verified by blind prediction of the experimental curve at an extra heating rate. Good fitting indicated that the three-stage reaction model has great potential in describing and predicting the pyrolysis behavior of Tangkou bituminous coal.