"Low emission liquefaction processes are particularly important in a scenario in which greenhouse gas mitigation is essential. Likely such scenarios will emphasize the use of technologies such as wind and nuclear power for central station power, while hydrocarbons will be increasingly reserved for liquid transportation fuel applications."
(In other words, we'll want more innovative "renewable" energy installations for power supply, like New Martinsville's hydroelectric retrofit of the Hannibal Locks.)
"Lower rank coals such as sub-bituminous coal and lignite are desirable feedstocks for this process due to their low cost, high hydrogen to carbon ratio and high aliphaticity compared to bituminous coals, which can result in superior transportation fuels. However, these advantages are partially offset by the high moisture content and high ash content which typically accompany lignite and sub-bituminous coals. In particular, ash content of approximately 20% is problematic because centrifugation might not succeed in increasing the ash content of the tails. Hence, much of the liquid product would be contained in the nominal tails rather than in the separated liquid centrate, if conventional centrifugation techniques were utilized."
(We've no idea what "higher aliphaticity" means, but, when it comes to lignite versus WV-type bituminous as feed stock for liquid fuel production, it sounds like the plusses and minuses might balance out. That bodes well not only for WV's bountiful stores of bituminous coal, but for some of her mine waste accumulations, as well, many of which are composed in part of highly carbonaceous material that wasn't, when it was mined, considered to be of high-enough quality for the market.)
"In order to overcome this inherent difficulty, a more complete liquid separation can be accomplished by vacuum distillation. Mineral matter is further heat treated to produce a value-added slag product. Solids separation can be over 90% effective using this technique depending upon the degree to which coal molecules are broken down during the solvent extraction process. The result is correspondingly higher yield of lighter products such as transportation fuels, with lower yield of heavy hydrocarbon products such as pitches and coke precursors."
So, they can get a higher yield of "transportation fuels", and another, "value-added", by-product with this advance in coal-to-liquid conversion technology.
As with some of the other reports we've submitted, this work from WVU makes it seem as if coal-to-liquid conversion technology is not only well-known and thoroughly understood, but is undergoing continuous refinement, which should make of it an even better commercial replacement for petroleum-based fuels than our South African friends, Sasol, discovered it to be some decades ago. The "solvent extraction" technique implies that the "West Virginia Process" might be quite different from the pyrolytic methods of coal reduction that have been traditionally employed to obtain syngas from coal for Fischer-Tropsch conversion into liquids.