In the two stage liquefaction of Wandoan subbituminous coal it was found that the coal was effectively converted into THF-soluble products with high conversion and low hydrogen consumption by pyrolytic procedures in a N2-tetralin system, using relatively low heating rates, high temperature and short-contact-time conditions. Runs carried out at 440 °C (with 2.5 MPa N2) showed better efficiency as regards higher conversions and SRC yields, and lower consumption of hydrogen from tetralin. Comparative examination of these short contact-time runs with other runs under different conditions suggested that coal pyrolysis and transferable hydrogen within the coal itself effectively contributed to the liquefaction of the coal in the N2-tetralin system. The so derived SCTSRC from the first stage was upgraded in a H2-tetralin system in the presence of MoCl3- and NiCl2LiClKCl salt catalysts. The yields of oil (hexane-solubles) including light distillates (C5-250 °C) were as high as in the range 69-79 wt % of SRC and gas yields were < 2.9 wt % of SRC with hydrogen consumptions of < 1.4 wt % of SRC. The use of the MoCl3 and the NiCl2 salt catalysts appeared to decrease the heteroatom content and improved the quality of the oil products. The results are discussed on the basis of a generalized reaction model for coal liquefaction.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Fuel Technology
- Energy Engineering and Power Technology
- Organic Chemistry