Fuel Processing Technology, Vol.191, 202-210, 2019
Behaviors of tetralin and 9,10-dihydroanthracene as hydrogen donor solvents in the hydrogenolysis of coal-related model compounds
During direct coal liquefaction (DCL), an imbalance problem of hydrogen donor solvents (HDSs) occurs, which greatly influences the application of DCL. To explore the imbalance of HDSs, in this work, the behaviors of tetralin and 9,10-dihydroanthracene (DHA) as HDSs were investigated in the hydrogenolysis of coal-related model compounds (CRMCs) at 425 degrees C for 1 h. The derivatives of the HDSs were identified, and the effects of CRMCs, catalyst Fe1-XS and atmosphere were studied. It was found that the conversions of tetralin and DHA changed from 2% to 12.4% and 75.3% to 86.8%, respectively, under the studied conditions. The yields of H-nondonor products in DHA were higher than those in tetralin. Hydrocracking and isomerization of HDSs were the main reasons for the imbalance of HDSs. The free radicals formed by three CRMCs would react with tetralyls to form heavy products. Besides, dibenzyl ether (DBE), one of the three CRMCs, promoted the reaction in tetralyls each other and induced DHA to form condensed aromatic rings (CAS). Fe1-XS promoted significantly the formation of naphthalene from tetralin, while the relative contents of H-nondonor products were reduced. The effective consumption of tetralin was enhanced by Fe1-XS. However, Fe1-XS had no significant effect on the DHA system. In addition, the yields of H-nondonor products in tetralin were promoted by 8 MPa H-2. In the presence of H-2, the yields of H-nondonor products in DHA were greater than those in N-2. Moreover, a high H-2 pressure could increase markedly the hydrogen transfer, hydrogenation, hydrocracking of the HDSs, causing the imbalance of HDSs.