Non-isothermal pyrolysis kinetics characteristics of ZhaoTong lignite using thermogravimetric analysis

In this study, the effects of heating rate and ash content on the pyrolysis kinetic characteristics of ZhaoTong lignite were investigated by using thermogravimetric analysis (TGA) method. The non-isothermal pyrolysis process of lignite was strongly affected by the heating rate and ash content. Raw lignite was treated by demineralization method, indicating that with increasing the demineralizing time, carboxyl groups content of lignite increased, while hydroxyl content and minerals content of lignite decreased, respectively. The pyrolysis kinetics characteristics of lignite such as the activation energy (E) and frequency factor (A) were discussed by Coats–Redfern method. The first-order reaction kinetics model had the higher linear fitting correlation on the non-isothermal pyrolysis reaction of lignite. The activation energy of lignite pyrolysis increased with increasing heating rate, but decreased with increasing ash content. The study can provide the theoretical foundation for large-scale pyrolysis of lignite.