We have previously cited the Coal conversion achievements of Pittsburgh, PA's former Gulf Oil Company, since assimilated into Chevron, multiple times.
We have also previously cited the Gulf Oil Coal scientist named as lead inventor herein, where is described a somewhat different way in which Coal can be converted into more versatile hydrocarbons.
First, note must be made that the reaction conditions specified in this US-Patented Coal conversion process are, or can be, "severe", to employ a phrase commonly utilized by the petroleum refining industry.
High pressures and high temperatures, and thus some additional expense, could be required.
However, there are advantages inherent in Gulf's process, since solid, though pulverized, Coal can be transformed directly into hydrocarbons by this technology, without first being converted into synthesis gas.
And, the liquid carrier and solvent for the coal particles is specified by Gulf, in one example they provide, to be the primary Coal oil, Anthracene; so, solvent expense would be, relatively speaking, minimal.
Comment concerning those potential advantages follows excerpts from:
"United States Patent 4,116,808 - Hydrogenating a Solid Carbonaceous Material
Date: September, 1978
Inventors: Donald Cronauer, et al., PA
Assignee: Gulf Research and Development Company, Pittsburgh
Abstract: A process for hydrogenating a carbonaceous material using a novel hydrogenation catalyst comprising a hydrogenation metal mounted on a magnesium-deficient magnesium aluminate spinel.
Claims: A process for hydrogenating a carbonaceous material which comprises subjecting said carbonaceous material, together with hydrogen, under hydrogenation conditions in the presence of a catalyst comprising a magnesium-deficient magnesium aluminate spinel .... .
(And) wherein said carbonaceous material is coal.
Background: This invention relates to a process for using a hydrogenation catalyst wherein the support thereof is a specific magnesium-deficient magnesium aluminate spinel for the hydrogenation of a carbonaceous material, such as coal.
Since the hydrogenation of coal is generally accompanied by the formation of by-product carbon, which tends to coat the catalyst and thereby deactivate the same, it is the desire of those who operate in such art to reduce the carbon deposition on the hydrogenation catalyst in order to maintain its hydrogenation activity over extended periods of time.
Summary: We have found that in the hydrogenation of a solid carbonaceous material, such as coal, in the presence of a hydrogenation catalyst mounted on a magnesium aluminate spinel, the amount of carbon deposited on the support is appreciably reduced if the hydrogenation is conducted in the presence of the novel catalyst ... , namely, a hydrogenation catalyst mounted on a specific magnesium-deficient magnesium aluminate spinel of the ... formula (specified herein).
Any hydrogenation catalyst well-known to those having ordinary skill in the art can be employed herein, but preferably the catalyst comprises at least one hydrogenating component selected from the group consisting of the metals, metal sulfides and/or metal oxides of ... molybdenum and at least two iron group metals .. tungsten. ... Those preferred among the hydrogenating metals are nickel, cobalt, titanium, molybdenum and tungsten.
The process comprises blending the carbonaceous material, finely ground, with a solvent to form a slurry. The slurry is then introduced, together with hydrogen, into a reaction vessel containing the hydrogenation catalyst defined above. After hydrogenation, solids that are present can be removed from the product stream. The product stream is then stripped of solvent, the amount of solvent so stripped being sufficient for recycle purposes for blending with additional amounts of carbonaceous material to form a slurry. The balance of the product stream, not recycled, can thereafter be subjected to distillation to obtain products of various boiling ranges. Some of the products are useful per se as fuels. The remainder can further be treated by conventional petroleum processes, including cracking, hydrocracking, hydrotreating, etc."
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Gulf actually goes to some length in specifying how the "magnesium aluminate spinel" catalyst support for the "molybdenum, .. tungsten ... nickel (and/or) cobalt" is to be prepared.
That preparation process for the spinel catalyst support is somewhat involved, but shouldn't be that costly; and, the catalytic metals, as again specified immediately above, are non-exotic and not themselves overly expensive.
Although free Hydrogen is required, some conventional petroleum refineries already make that on a commercial basis for their current "conventional petroleum processes, including cracking, hydrocracking, hydrotreating, etc."; especially when and where heavy crude and tars are being processed, and, thus, getting some extra to react with Coal particles suspended in a Coal oil, in order to directly synthesize some liquids immediately "useful per se as fuels", and others which can be further processed, as Gulf indicates, via those "conventional petroleum processes", shouldn't be an inhibiting technical or economic limitation.