W. Steedman et al., ONE-STAGE AND 2-STAGE COPROCESSING OF COAL AND PETROLEUM RESIDUES, International journal of energy research, 18(2), 1994, pp. 299-307
The potential of two atmospheric and three vacuum petroleum residues a
s feedstocks for coprocessing with a UK bituminous coal has been asses
sed. In a simulation of the British Coal Corporation's two-stage liqui
d solvent extraction process, the residues were first examined as pros
pective solvents in the extraction stage. Coal conversions varied from
about 6-37%, the best yields being obtained from residues with a high
asphaltene content or a high (aromatic and polar) content in the malt
ene fraction. These yields compare poorly with those obtainable with c
oal-derived solvents. In two cases, catalytic prehydrogenation of the
petroleum residue improved conversions to about 65%, but these results
were not reproducible. One-stage coprocessing at 450-degrees-C and 12
MPa hydrogen pressure was much more successful. Coal conversions of a
bout 75% were obtained at optimum conditions. Conversions under one-st
age coprocessing were insensitive to the nature of the residue.