Kinetic studies of char gasification by steam and CO2 in the presence of H2 and CO

Char–CO2 gasification reactions in the presence of CO and char–steam gasification reactions in the presence of H2 were studied at the atmospheric condition using a thermogravimetric apparatus (TGA) at various reactant partial pressures and within a temperature range of 1123 K–1223 K. The char was prepared from a lignite coal. The partial pressure of H2 and CO varied from 0.05 to 0.3 atm. The experimental results showed that Langmuir–Hinshelwood (L–H) kinetic equation was applicable to describe the inhibition effects of CO and H2. The kinetic parameters in L–H equations were obtained. Interactions of char gasification by steam and CO2 in the presence of H2 and CO were discussed. It was found that the kinetic parameters determined from pure or binary gas mixtures can be used to predict multi-component gasification rates. The results confirmed that the char–steam and char–CO2 reactions proceed on separate active sites rather than common active sites.