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 coal and untreated resid, as well as resids hydrogenated at temperatures where cracking was low, was greater than that predicted from runs made when the resids and coal were processed separately for coal-feed concentrations up to about 33 wt %. Coal conversion during thermal coprocessing with petroleum vacuum resid can be significantly increased if the resid is first hydrogenated at conditions where cracking is suppressed. However, pretreatment of the resids, by methods used in this study, resulted in only minor improvements in PSO yields.

Acetylene has been added to the Fischer-Tropsch (F-T) synthesis on cobalt and iron catalysts. The added acetylene initiates the F-T chain growth and is incorporated into the product only once. Acetylene incorporation is three times greater than that of 1-hexyne. With the addition of acetylene, the F-T product distribution follows Anderson-Schulz-Flory (ASF) distribution while the chain growth factor (alpha value) slightly decreases. Only C3 oxygenates are formed via hydroformylation on adding acetylene to cobalt. With iron, C3+ oxygenate production is enhanced and follows the ASF distribution. It is likely that both acetylene and ethylene addition to the synthesis involve the same intermediates but acetylene is more strongly adsorbed on the F-T catalyst, making it a more effective chain initiator at low temperatures.