Numerical analysis and research on coal pyrolysis characteristics in BGL gasification process

Abstract

Research on the patterns of the internal temperature change and volatile analysis on the law of coal particle pyrolysis are essential to optimizing the furnace structure and operating parameters, while further improves the economy of BGL coal gasification.Based on the analysis of BGL coal gasification pyrolysis process, this study established the coal particle pyrolysis model.The decoupling algorithm was sadopted in solving the model, in which the heat transfer model adopted the chasing method, the pyrolysis kinetic model adopted the fourth-order single-step push-up method, and the ambient temperature was calculated by the moving bed one-dimensional model.The rationality of the model was verified by experimental data in literature.The simulation results show that the final pyrolysis temperature of BGL coal gasification is higher, and the temperature gradient inside the particles changes greatly.The particle size is 10 mm, the calculated final pyrolysis temperature is 1 372 K, and the calculated peak temperature difference between the surface and center of coal particles is 338 K. Taking the particle size of 40 mm, the corresponding calculated values are 1 412 K and 381 K respectively; The process of coal particle volatilization is similar to that of gas-solid non-catalytic condensation reaction, which proves that the coal pyrolysis process is controlled by heat transfer process.Pyrolysis kinetics is described by FZ general pyrolysis model, which has better adaptability than distributed activation energy model.When the moving bed one-dimensional model predicts the height of BGL coal gasification pyrolysis layer, the pyrolysis evaporation model is superior to FZ general pyrolysis model.The predicted height of pyrolysis layer is 0.616 5 m, which is consistent with the operation of agitator.

Keywords

• bgl coal gasification
• coal particle
• pyrolysis
• numerical simulation