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 H-2 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 H-2 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 H-2. The kinetic parameters in L-H equations were obtained. Interactions of char gasification by steam and CO2 in the presence of H-2 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. (C) 2010 Elsevier B.V. All rights reserved.