Portal de Periódicos da CAPES

Catalytic activity of alkali and transition metal salt mixtures for steam-char gasification

1995; Elsevier BV; Volume: 74; Issue: 9 Linguagem: Inglês

10.1016/0016-2361(95)00081-f

1873-7153

Woon Jae Lee, Sang Done Kim,

Metal Extraction and Bioleaching

The catalytic activities of pure and mixed catalysts of alkali and transition metal salts in steam-char gasification at 700–850°C were measured with a thermobalance. The effects of catalyst loading (0–35 wt%) and composition, coal rank and steam partial pressure were determined. The initial rate increases with increasing steam partial pressure in non-catalytic gasification but is almost independent of it in catalytic gasification. The catalytic activities of single salts are in the order K2CO3 > Ni(NO3)2 > K2SO4 ≈ Ba(NO3)2 > FeSO4. The gasification rate with K2SO4 can be enhanced by addition of other salts and the order of catalytic activity of the salt mixtures tested is K2SO4 + Ni(NO3)2 > K2SO4 + Ba(NO3)2 ≈ K2SO4 + FeSO4. The char reactivity increases with increasing catalyst loading for K2SO4 + Ni(NO3)2 and with gasification temperature. The catalytic effectiveness of K2SO4 + Ni(NO3)2 decreases with increasing coal rank. An equimolar mixture of K2SO4 and Ni(NO3)2 exhibits the highest catalytic activity and a synergistic effect.