Upgrading the solvent used for the thermal extraction of sub-bituminous coal
- National Institute of Advanced Industrial Science and Technology, Tsukuba (Japan). Energy Technology Research Institute
HyperCoal is an ash-free coal produced by extraction with an industrial solvent at temperatures around 360{sup o}C, which can be fed directly to gas turbines. We searched for more powerful solvents to extract low-rank coals, such as sub-bituminous coal. Polar materials were successfully concentrated from a polar industrial solvent, crude methylnaphthalene oil (CMNO), by extraction with a mixture of methanol and water or aqueous HCl. The soluble fraction obtained using the former (MW-S) extracted 73 wt % (daf) of Wyodak Anderson sub-bituminous coal at 360{sup o}C, while that obtained using the latter (AC-S) extracted 63 wt %. These extraction yields were much higher than those with CMNO (43 wt %), indicating that fractionation concentrated the materials that dissolve the constituents of coal. MW-S contained more indole than AC-S. The results of addition tests suggested that indole had a greater ability to extract coal constituents than quinoline. In addition, the addition of 5 wt % methanol to a mixture of 1-methylnaphthalene, indole, and quinoline (30/20/50 wt %) increased the extraction yield from 58 to 69%, which was close to the yield of MW-S (73%). Therefore, the high extraction yield of MW-S can be explained by not only the composition of the nitrogen-containing polar materials in MW-S but also the presence of methanol. 20 refs., 6 figs.
- OSTI ID:
- 20813160
- Journal Information:
- Energy and Fuels, Journal Name: Energy and Fuels Journal Issue: 5 Vol. 20; ISSN ENFUEM; ISSN 0887-0624
- Country of Publication:
- United States
- Language:
- English
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