Kinetic Model and Parameters Optimization for Tangkou Bituminous Coal by the Bi-Gaussian Function and Shuffled Complex Evolution

In this paper, a new kinetic model for thermal degradation of Tangkou bituminous coal was presented. The pyrolysis process was described by the deconvolution method and global optimization algorithm . The sample was investigated in a thermogravimetric analyzer at the heating rates of 10, 20, 40 and 60 K/min in nitrogen. The reaction curves of each stage and the contribution of each stage to the total reaction were estimated by the deconvolution method with bi-Gaussian function. The total mass loss was explained as the sum of three stages: main pyrolysis, secondary depolymerization and secondary repolymerization. Then, Friedman and Coats-Redfern methods were used to evaluate the kinetic parameters based on the separated thermogravimetric data at 10, 40 and 60 K/min. These possible regions and obtained parameters provided a guide for the search range and initial value of Shuffled Complex Evolution (SCE) algorithm for the optimal scheme. The optimized results showed that the experimental curve was in good agreement with the simulation curve, which indicated the reliability of the new scheme. Eventually, the pyrolysis process at 20 K/min was speculated. The good fitting showed the great potential of the proposed three-stage scheme in describing and forecasting the pyrolysis behavior of Tangkou coal.