Energy & Fuels, Vol.26, No.1, 511-517, 2012
Catalytic Hydropyrolysis of Five Chinese Coals
Five Chinese coals were subjected to pyrolysis by thermogravimetry (TG). The investigated pyrolysis conditions included pyrolysis atmospheres (N-2 and 10% H-2/N-2) and catalysts (MoS2 and ZnCl2) with different amounts (0.5, 1.0, 2.0, 5.0, and 10%). The existence of hydrogen improved the final conversion and reduced the reaction temperature by different degrees. With the addition of catalysts, the maximal reaction rate in the hydropyrolysis process was increased for all coals, except Shaotong coal. The optimal catalytic amount for each coal was determined by the final conversion. MoS2 was more effective on the increase of the total conversion than ZnCl2,, while ZriCl(2) was more effective on reducing the peak temperature of secondary devolatilization. Finally, the kinetics results showed that the activation energy would be lower in the catalytic hydropyrolysis process than that in the non-catalytic run. Tongchuan coal was subjected to pyrolysis in a fixed bed. The results showed that ZnCl2 and MoS2 improved the conversion in different ways. ZnCl2 increased the yield of liquid but has little effects on the yield of benzene, toluene, and xylene (BTX), while MoS2 increased the yield of BTX obviously in hydropyrolysis.