A small suite of well-characterized Australian and N. American coals ranging in rank from brown to high-volatile bituminous and in H/C atomic ratio from 0.73 to 1 was reacted at 365 and 400°O0C with CO, H2 and CO-H2 mixtures in water. The effect of acid-washing was negligible, except for one coal of high Mg and Ca content. Impregnation of the coals with sodium aluminate (NaAlO2) and Fe, Co, Ni, Cu and Ni-Mo led to modest increases in conversion compared with coals impregnated with NaAlO2 alone for reaction at 365°C. Impregnation with Sn gave no increase in conversion. Greater effects were observed on addition of transition metals for reaction at 400°C. Nickel and nickel-molybdenum were the most effective additives. There were no consistent effects of coal rank or H/C atomic ratio. Reactions in which the alkali and transition metals were added as the carbonylates NaHFe(CO)4 and NaCo(CO)4 gave similar results to those obtained by the impregnation method of catalyst addition. Reactions with two-stage heating (first stage 365°C; second stage 400°C) using CO or CO-H2 gave little benefit for brown (Loy Yang) and subbituminous (Taiheiyo) coals but modest increases in conversion and asphaltene yields for high-volatile bituminous (Surat Basin) coal. However, two-stage reactions of Loy Yang brown coal with CO-H2O-NaAlO2 in which CO was recharged before the second stage (first stage 330, 365 or 400°C; second stage 400°C) gave large increases in both total conversion and oil yield compared with reactions for the same duration at 400°C with only a single charge of CO.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Fuel Technology
- Energy Engineering and Power Technology
- Organic Chemistry