Characteristic of the Shenfu coal char gasification with steam and carbon dioxide

The effects of the heating rate of pyrolysis, the different reaction agents (steam and carbon dioxide) and temperature on the gasification of Shenfu coal char at ambient pressure and 850 ℃～1 000 ℃ by TGA were investigated. The initial structure of coal char was analyzed by SEM and N2 physisorption apparatus. The pore volume of the pore size of 2 nm～170 nm accounts for above 90% of the total pore volume. The BET surface area of SP (slow pyrolyze char) is 1.077 7 m2·g-1, and the BET surface area of FP (fast pyrolyzed char) is 1.893 9m2·g-1. The reactivity index of the fast pyrolyzed char gasification with steam is 4.16 times higher than that of slow pyrolyzed char, which is resulted from the destruction of the structure of pore and retarding of secondary reaction because of the higher escaping rate of volatile from fast pyrolysis . The gasification reactivity index of the SP char and the FP char with steam is 9.94 and 7.15 times higher than with carbon dioxide respectively, because steam can come into wider range of pores and be dissociated easier than carbon dioxide. The experimental data was fitted by the random pore model and the kinetic parameters were obtained. Gasification temperature has a similar effect on the gasification reaction rate of the SP char with steam and carbon dioxide and the FP char with steam, however, a smaller effect on the FP char gasification with CO2 is found.