Effects of Ba and Mg promoters on gas release from Fe catalyzed coal pyrolysis: Effects of different precursors

Abstract

The effects of Fe, Fe-Ba and Fe-Mg catalysts with different precursors on the catalytic pyrolysis of brown coal were studied in a fixed-bed reactor. The results show that Fe, Fe-Ba and Fe-Mg catalysts prepared by Fe(OH)3, Mg(OH)2 and Ba(OH)2·8H2O as their precursors increased the yields of H2 and CO. When 0.6 wt% Mg was added to 5 wt% Fe, the yield of H2 was increased to 104.36 mL/g, while the yield of H2 was 79.06 mL/g when 5 wt% Fe was added, and the yield of CO2 was lower than that of the Fe(NO3)3·9H2O as precursor. Fe(NO3)3·9H2O, Ba(NO3)2, Mg(NO3)2·6H2O as the precursors of Fe, Fe-Ba, Fe-Mg catalysts showed slight inhibition of H2, CO, CH4 production, and increased CO2 production. The results showed that Ba and Mg could promote the cracking of C–H, O–H and C=C bonds, improve the H2 yield and coal conversion. Ba promoter can inhibit the reaction between Fe and silicate in coal, thus improving the catalytic activity of Fe. This study compared the influence of external promoter on the pyrolysis of Fe catalyzed coal, and lay a theoretical foundation for the research and development of the process of coal catalytic hydrogasification to produce methane.