The activities of several iron-based catalyst precursors towards the liquefaction of various kinds of coals, ranging from brown to bituminous, were examined in alcohol-carbon monoxide systems. Pentacarbonyliron (Fe(CO)5) with or without sulfur, or synthetic pyrite were found to be excellent catalyst precursors. Primary alcohols (ethanol and 1-propanol)-CO acted as an effective hydrogen source, whereas branched alcohols were less effective. In the Fe(CO)5/sulfur catalyzed liquefaction of Yallourn coal at 375°C for 120 min, a high conversion (99.5%) was achieved in the presence of ethanol and CO (7.0 MPa/cold). The two-staged reaction (375°C, 60 min + 425°C, 60 min) further improved the oil yield to 59.1% with a slight decrease in the coal conversion. The uptake of alcohol into asphaltene and preasphaltene fractions was distinctly observed, especially for Illinois No. 6 coal. The infrared analyses of the asphaltene fractions from each coal showed absorption at around 1705 cm-1, characteristic for those obtained in the linear alcohol-CO systems. According to the characterization of the products by NMR and the preliminary study using a model compound, alkylation as well as the hydrogenolysis seem to contribute to the dissolution of coals.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Fuel Technology
- Energy Engineering and Power Technology