The catalytic performance of MoCl3-LiCl-KCl and NiCl2-LiCl-KCl salts in coal hydroliquefaction with the H donor tetralin was studied. Yilan subbituminous coal impregnated with the above catalysts and with LiCl-KCl at different loading levels (weight ratios of salts to coal of 0.1-1.0) was hydroliquefied at 400 °C for 1 h with an initial H2pressure of 4.9 MPa. Increased loading of the MoCl3salt increased oil yield (up to 50 wt %), coal conversion, and H2consumption, decreased the net hydrogen transfer from tetralin, and lowered the heteroatom content of oil. Addition of the NiCl2salt below a weight ratio of 0.2 led to more pronounced increases in oil yield, coal conversion, and H2consumption and decreases in net hydrogen transfer from tetralin than with the MoCl3system. Higher loadings (>0.2) led to a small decrease in H2consumption in spite of a further increase in oil yield (up to 50 wt %), implicating contributions of in situ formed H donors. The use of a LiCl-KCl mixture slightly improved coal conversion while considerably suppressing H2consumption. The relation between coal conversion and hydrogen consumption suggests that the action of the MoCl3and NiCl2catalysts led to enhanced but selective hydrocracking reactions that contribute mainly to oil production. 1H NMR analysis of the oil revealed that hydroaromatic compounds increased and the average ring sizes of aromatics decreased with increased loading of the catalysts.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Fuel Technology
- Energy Engineering and Power Technology