Low temperature pyrolysates distribution and kinetics of Zhaotong lignite

This paper aims to determine the distribution of all species produced from Zhaotong lignite under low temperature pyrolysis and to derive an appropriate kinetic model. A fixed bed reactor system with no carrier gas is used. For the products (tar, gas and semi-char) distribution determination, experiments are carried out over different operating factors. The characteristics of pyrolysates are analyzed with Gas Chromatograph (GC), Gas Chromatograph/Mass Selective Detector system (GC/MSD), Fourier transform infrared spectroscopy (FTIR), nitrogen adsorption-desorption isotherm analysis and Scanning Electron Microscope (SEM). The kinetic model of Coats-Redfern is used, as a basis, to predict the experimental evolution curves. It is seen here that temperature, heating rate and particle size play a pivotal role in low temperature pyrolysates distribution. Meanwhile, it is suggested that atomic ratios of H/C and O/C have some correlativity with the yield of products. The prediction of Costs-Redfern integral model is discussed with the experimental fractions, which indicates that the model is suitable to explain the reaction mechanism of lignite during low temperature pyrolysis.