Performance and synergistic effect of oil-coal co-hydrogenation with hydrogen-donor solvent enhancement

The synergistic effect of oil-coal co-hydrogenation and the relationship between H2 consumption and hydrogenation performance of heavy oil and low-rank coal were investigated. The feasibility of oil-coal co-hydrogenation with hydrogen-donor solvent (HDS) enhancement was studied. Results show a matching between the hydrogenation of CG residue and HS coal. H2 consumption is closely related to the severity of reaction, and positively related to the conversion of raw material and oil yield, which could be an essential index for evaluating and predicting the effectiveness of hydrogenation reactions. HDS, rich in partially hydrogenated polycyclic aromatic hydrocarbons, can enhance the synergistic effect of oil-coal co-hydrogenation, effectively inhibit coke formation and improve product distribution because of its ability to supply and transfer hydrogen. Compared to the superimposed product yield of single hydrogenation of residue and coal, the oil yield increases by a maximum of 9.18 wt%, while the gas yield and asphaltene yield decrease by a maximum of 2.72 wt% and 3.55 wt%, respectively, in the oil-coal co-hydrogenation with HDS enhancement. Under the condition of suitable H2 consumption, that is, suitable reaction severity, the synergistic effect of oil-coal co-hydrogenation with 35 wt% HDS is the optimum, and the best raw material conversion and oil yield can be obtained, which are 89.78 wt% and 67.46 wt% respectively.