Herein is yet another Coal liquefaction process developed by Exxon, prior to their merger with Mobil.
And, somewhat surprisingly, that is exactly what they call it.
Based on our experience in researching these technologies, it is unusual for the originators of such processes, and/or our US Patent examiners, to so plainly label inventions which describe the ways in which Coal can be transformed into petroleum replacements.
Of course, by the time this patent was applied for, there might already have been so many Coal conversion techniques available that they just ran out of unrevealing, anonymous and inoffensive synonyms.
In any case, this is an example of Coal hydrogenation technology wherein two "truths" concerning the transformation of Coal into versatile hydrocarbons are again confirmed.
First, products easily derived from Coal, the primary Coal oils, can be treated to serve as Hydrogen donors for the hydrogenation of more raw Coal.
In that respect, this Exxon technology relates directly to what we understand of WVU's "West Virginia Process" for the direct liquefaction of Coal.
Second, the needed Hydrogen, for hydrogenating both the Coal and the Coal-derived donor solvent, can be efficiently generated by reactions between still-carbonaceous Coal processing residues and Steam.
As revealed in, and as we further explain following, excerpts from:
"United States Patent 4,250,014 - Coal Liquefaction Process
Date: February, 1981
Inventor: Robert Long, et. al., NJ and TX
Assignee: Exxon Research and Engineering Company, NJ
Abstract: Particulate coal is contacted with a vapor phase hydrogen donor solvent to swell the coal particles and, thereafter, the swollen coal particles are subjected to coal liquefaction conditions in the presence of a liquid phase solvent.
Claims: In a coal liquefaction process wherein the particulate coal is converted to a hydrocarbonaceous oil in the presence of a liquid phase solvent, in a coal liquefaction zone, at coal liquefaction conditions, the improvement which comprises: contacting said particulate coal with a vapor phase hydrogen donor solvent (and) ... subsequently subjecting the resulting swollen coal to said coal liquefaction conditions (and) wherein said coal liquefaction is conducted in the presence of added molecular hydrogen.
The term "coal" is used herein to designate a normally solid carbonaceous material including all ranks of coal, such as anthracite coal, bituminous coal, semibituminous coal, sub-bituminous coal, lignite, peat and mixtures thereof.
In the process ... the improvement which comprises the additional steps of separating the effluent of said coal liquefaction zone into a vapor phase product and a solid residue, and contacting said solid residue with steam and an oxygen-containing gas to produce a hydrogen-containing gas.
Field: The present invention relates to an improved coal liquefaction process. More particularly, the invention relates to a process comprising pretreatment of solid coal particles with a vapor phase hydrogen donor solvent followed by coal liquefaction in the presence of a liquid phase solvent ... such as, for example, an intermediate hydrocarbonaceous stream recovered from the process."
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So, the "liquid phase solvent", which is "an intermediate hydrocarbonaceous stream recovered from the process", and the needed, additional "molecular hydrogen", which is generated as a "hydrogen-containing gas" by contacting "coal liquefaction ... solid residue with steam", are both produced through processes that are integral components of the overall system.
Though not reflected in our excerpts, Exxon does, in the full Disclosure, name one hydrogen donor "liquid phase solvent" as "tetralin", which we believe to be the same solvent specified by WVU in their own "West Virginia Process" for direct Coal liquefaction; and, which we believe to be an hydrogenated primary Coal oil.
And, thus, though not stated outright, note that, aside from some catalysts, the only raw materials required to convert Coal into "hydrocarbonaceous oil", since most, if not all, of the energy needed to drive the process can be derived from Coal, are Coal and plain old Water.
