Petrography of Liquefaction Residues: High-Vitrinite, High-Sulfur Davis (Western Kentucky No. 6) Coal

A sample of the high-vitrinite, high-sulfur, high volatile A bituminous Western Kentucky No. 6 coal from Union County, Kentucky, was subjected to liquefaction conditions at four reaction temperatures, a minimum of four reaction times, a 1.5 Tetralin to coal ratio, and 5.5 MPa of H₂ atmosphere. At reaction temperatures of 658 K and higher vitrinite is virtually absent, being replaced by vitroplast. Vitroplast appears to convert to a granular residue at longer reaction times. The peak of asphaltene + preasphaltene production coincides at three reaction conditions: 658 K/60 and 90 min and 700 K/15 min. The petrography of the residues obtained using these conditions is also similar, while the residues from a reaction condition with a lower severity index, albeit a similar product suite, have a vitroplast/granular residue ratio also suggestive of a lower severity.