Raymund P. Skowronski and Laszlo A. Heredy
Rockwell International, Rocketdyne Division, 6633 Canoga Avenue, Canoga Park, CA 91303, USA
Abstract
Coal hydrogenation was investigated in the temperature range 275 to 325 °C in order to minimize the number of thermal side reactions that take place. Gas-phase hydrogen was used in batch experiments without an added donor solvent, to avoid the additional analytical complexities introduced by such a solvent. It was found that significant oil yields (up to 72% of the daf coal) can be obtained from the hydrogenation of bituminous coal at 325 °C. Furthermore, at this temperature, the data indicate that cleavage of certain C---O bonds may have an important role in oil formation. The metal surfaces of the liner and impeller of the autoclave had a strong catalytic effect on the liquefaction reactions under these conditions. The oil yield was 48% when the metallic surfaces were exposed and only 19% when these components were coated with glass. Catalysis by nickel, applied as nickel acetate impregnated into the coal, gave higher overall conversion, lower oil yield, and a more saturated oil product than catalysis by the autoclave surfaces."
Confirming reports by other researchers, roughly three-fourths, "72%", of the coal was converted into liquid hydrocarbons, although some other, perhaps more recent, research we've cited for you, which, unlike this Rockwell effort, did employ a hydrogen donor solvent, indicates that 90%, or more, of the carbon in coal can be converted.
Interesting, sadly, that, "to avoid ... analytical complexities", these researchers spared themselves from making the extra effort to see just how effectively coal could be converted into liquids by performing their "experiments without an added donor solvent".
They, for some reason, did not, apparently, want the process of converting coal into liquid hydrocarbons to be as good as it could be.
Strange attitude for a defense contractor. But, they just might have corrected that oversight. More, and much more current, news on Rockwell and Rocketdyne, and their coal conversion technology, will follow.