FUEL 210 |
| The Bergius coal liquefaction process and all further developments can be used to liquefy only lignites (brown coals), subbituminous coals and low-rank bituminous coals, whereas high-rank bituminous coals (rank from medium-volatile bituminous coals or coking coals to low-volatile bituminous coals), semi-anthracite and anthracite are not reactive enough for such hydrocracking processes. On the other hand, just these high-rank bituminous coals including anthracite are the most appropriate coals for our hydrogenation process with homogeneous borane and iodine catalysts. The solid products obtained by this hydrogenation were, for the most part, highly soluble in pyridine (up to 90%). Their 13C CP/MAS solid state spectra showed a strong increase of the aliphatic carbon atoms on the expense of the aromatic carbon atoms originally present in the coals. For instance, the ratio Caliph/Carom increased from 11:89 in an original low-volatile bituminous coal and from 5:95 in an original anthracite up to 60:40 in both coal products. A two-stage liquefaction process of high-rank coals becomes possible by combining the borane-catalyzed hydrogenation with a subsequent conventional Bergius hydrocracking process. This was demonstrated on the example of a German Magerkohle (low-volatile bituminous coal): whereas the one-stage liquefaction in tetralin, which was used to simulate the role of the hydroaromatic recycling oil in the Bergius hydrocracking process, gave oil in only 20% yield, the two-stage process produced gas and oil in 66% yield (17% gas: volatile compounds which distilled with tetralin; 49% oil: compounds soluble in pentane). |
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Advances in Solid and Liquid Fuel Chemistry
1:30 PM-5:00 PM, Wednesday, 13 September 2006 Palace -- Mendocino Room, Oral
Division of Fuel Chemistry |