United States Patent: 4111787
This past July, we presented information concerning: "United States Patent 4,094,765 - Coal Liquefaction Process" which was assigned, in June of 1978, to Exxon Research and Engineering Company.
In the process of that invention, according to the Patent Abstract, "coal liquefaction chargestock is first treated with a hydrogen sulfide-containing gas and thereafter subjected to coal liquefaction conditions" and, the Coal was blended with Coal oils, or Coal tars, as in "naphthenic hydrocarbons" and "phenolic materials" before being so treated with hydrogen sulfide.
Herein, we see that Exxon were so encouraged by the economic and technical implications of that invention that they, using the same team of scientists, continued development of the same technology, and were, just months later, awarded yet another US Patent for improvements they had made on it.
"United States Patent 4,111,787 - Staged Hydroconversion of an Oil-Coal Mixture
Date: September, 1978
Inventors: Clyde Aldridge and Roby Bearden, LA
Assignee: Exxon Research and Engineering Company, NJ
Abstract: A catalytic slurry hydroconversion process for producing normally liquid hydrocarbons from a heavy hydrocarbonaceous oil and from coal is performed in at least two stages in series. The heavy oil is introduced into the first hydroconversion stage and the coal is introduced into any of the hydroconversion stages other than the first stage.
Claims: A staged process for hydroconverting a non-hydrogen donor heavy hydrocarbon oil and coal, which comprises: ... reacting the oil ....with hydrogen under oil hydroconversion conditions in a first ... zone;
passing at least a portion of said first hydroconversion zone effluent to at least one additional ... zone maintained at coal hydroconversion conditions (and) introducing coal into (that) hydroconversion zone; and,
Recovering a hydroconverted normally liquid hydrocarbon product.
The process ... wherein said oil soluble metal compound is converted to said catalyst by (treating) in the presence of ... hydrogen-containing gas (and) wherein said hydrogen-containing gas ... (is comprised of up) to about 90 ... percent hydrogen sulfide.
(And) wherein said oil soluble metal compound (used as the catalyst) is molybdenum naphthenate (in other words, a Coal oil, i.e., Naphthalene, salt of molybdenum) or (other metal compounds) wherein said oil soluble metal compound is a salt of naphthenic acid.
Summary: In accordance with the invention, there is provided a staged process for hydroconverting a non-hydrogen donor heavy hydrocarbon oil and coal ... and recovering a hydroconverted normally liquid hydrocarbon product."
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Now, truth to tell, Exxon doesn't much like to reveal the fact that we can get the needed "heavy hydrocarbon oil" from Coal; much preferring the use, through specification, of petroleum refining resids and tar sand bitumen. But: their specification of "naphthenate"s and "naphthenic"s is a dead giveaway.
We can recover both Naphthalene and the Hydrogen Sulfide as by-products of Coke production, by simple processing of Coke oven off gasses - something that we've known, as we have many times documented, how to do for more than a century.
And, it's interesting, isn't it?
Exxon doesn't talk about the economics of Coal conversion all that much.
But, they obviously had teams of, presumably well-paid, scientists working on the refinement of Coal conversion processes at more than one of their development laboratories for many years.
They developed, consecutively, at least three Coal liquefaction processes, including the Esso/Exxon Donor Solvent technology and the Coal-to-Methanol-to-Gasoline technology, all as we have earlier documented, in addition to the one disclosed herein and in USP 4,094,765, as referred to above in our introductory notes.
Why, do you suppose, they did all of that, if they, as astute in matters of hydrocarbon chemistry and oil supply economics as they are, didn't see a buck to be made in it?