Portal de Periódicos da CAPES

The potential of hydropyrolysis as a route for coal liquefaction

1994; Wiley; Volume: 18; Issue: 2 Linguagem: Inglês

10.1002/er.4440180221

1099-114X

Colin E. Snape, C.J. Lafferty, G. Eglinton, Nathaniel D. Robinson, R.J. Collier,

Coal and Its By-products

The use of sulphided molybdenum (Mo) as a dispersed catalyst enables tar yields of ∼ 60% daf coal to be achieved for bituminous coals (80–83% dmmf C) in fixed-bed hydropyrolysis using relatively low-severity conditions. Sulphur-containing Mo precursors, such as ammonium dioxydithiomolybdate are the most effective, Mo concentrations of 0.2% being required to achieve maximum tar yield. Ion-exchange preparation procedures offer the potential of improving catalyst dispersions, and concentrations as low as 0.02% are effective when Mo is ion-exchanged onto coals coated with hydrous titanium oxides. Iron sulphides are much less effective than in direct liquefaction because of the higher heating rates used in hydropyrolysis. Low-rank coals can yield up to 50% tar without catalyst, and improvements in yield on catalyst addition are considerably less than for bituminous coals. Exinite has a positive synergistic effect on vitrinite conversion in catalytic hydropyrolysis for one of the bituminous coals investigated.