Kinetics of NO-Char Reaction at Temperatures of 1073-1573K

Two Chinese coals (YB lignite coal and SH bituminous coal) were used to prepare the chars. The chars were obtained in an entrained flow reactor which can simulate the temperature and gas composition of a true pulverized coal combustion environment. The kinetic characterization of NO-char reaction was performed by isothermal thermogravimetry in the temperature range 1073-1573 K. It was confirmed that the reactions were under chemical kinetic control in the low- temperature regime (1073-1273 K) for SH char. The discrete random pore model was applied to describe the NO-char reactions. The model can predict the data at 1073 and 1173 K very well, but underestimate the reaction rates at high carbon conversions, which can be attributed to the catalysis of inherent minerals in chars. However, the influence of the catalysis on reactions of SH char is moderate. Ultimately, the determined intrinsic activation energy of NO-char is 111 kj/mol.