Catalytic Activity of Iron and Matal Salts for Steam-Char Gasification

Abstract

The catalytic activity of five different binary mixtures of alkali (K2CO3, K2SO4, Na2CO3) and iron salts (FeSO4, Fe(NO3)3) on steam-char gasification at 700-800-degrees-C was measured in a thermobalance reactor. Under the same experimental conditions with 3 wt% catalyst loading, the catalytic activity of the pure salts is in the order K2CO3 > Na2CO3 almost-equal-to FeSO4 > K2SO4 > Fe(NO3)3. For K2SO4 and Na2CO3 the gasification rate could be enhanced by addition of iron salt. A synergistic effect of alkali and iron salts on the gasification rate was observed and the mixtures K2SO4 + FeSO4 and K2SO4 + Fe(NO3)3 exhibited better catalytic activity than K2CO3 at 800-degrees-C. A kinetic parameter is proposed as a simple measure of activity of various catalysts based on the grain model. On the basis of the kinetic parameters and melting behaviour, K2SO4 + FeSO4 in the temperature range 700-800-degrees-C is an effective catalyst for steam-char gasification.