Effect of catalytic hydropretreatment of petroleum vacuum resid on coprocessing with coal

The coprocessing of coal with petroleum vacuum resids can be used to produce distillable oils. Improved coprocessing performance by using hydrotreated resids as host oils in coprocessing with coal was studied. Four host oils were prepared from petroleum vacuum resids (538 °C+/1000 °F+) by catalytic hydrogenation and hydrocracking. The untreated and pretreated resids were then thermally coprocessed with an Illinois No. 6 and with a Wyodak coal. Using solubility in tetrahydrofuran (THF) and pentane, products were separated into asphaltenes, pentane-soluble oils (PSO), coke, and gas. Phenolic compounds, derived mainly from coal, were present in the PSO products and their concentration, measured by IR spectroscopy, was used to estimate the fraction of coal liquids in the PSO products. The yield of PSO was strongly affected by the concentration of coal in the feed; depending on the pretreatment used, the yields of PSO from a 33% coal/resid mixture varied from 48 to 78 wt %. The yield of PSO from Illinois No. 6...