Catalyst And Mechanism For Direct Liquefaction Of Shenhua Coal

In this paper, DCL was carried out to investigate the effect of catalyst on productdistribution of coal liquefaction, the role of catalyst and hydrogen transfer in coal liquefactionand kinetics of Shenhua coal liquefaction.The results show that at experiment condition, Ni-based catalyst presents high catalyticactivity in Shenhua coal liquefaction than iron-based catalyst, when catalyst loading being0.50 wt%, Ni-based catalysts can improve oil yield from 33wt% to about 49.5 wt% andiron-based catalyst only improve oil yield to 43 wt%. The mass of loading catalyst exist anoptimum value, which is 0.50 wt%. When reaction time increases, the oil yield increases,meanwhile the gas yield also increases appreciably.In coal liquefaction process, perfect result comes from the mutual effect of catalyst,strong donation hydrogen solvent and H2. The major role of iron-based catalysts on DCL is topromote the hydrogen transfer from molecular hydrogen to solvent and from solvent to coal.That is, it promotes the formation of active hydrogen and accelerates the secondarydistribution of H in the whole reactive system, which includes gas, liquid and solid phases.A kinetic model of Shenhua coal liquefaction with iron catalyst was developed. Theestimated rate constants of both heating-up and isothermal stages showed that the model isvalid for both stages of coal liquefaction perfectly. Significant reaction occurs at theheating-up stage for the direct coal liquefaction. Lower temperature is favored to the reactionof coal converting to PAA, while higher temperature is more appropriate for the reaction ofPAA to (O+G). The rate dominated process for coal liquefaction was the reaction of PAA to(O+G), and the oil is mainly from coal at heating-up stage and PAA at isothermal stage,respectively.