From the old Texaco Corporation, now a component of Chevron, we have herein more evidence of the extensive body of Coal conversion technology Texaco had, over the course of decades, developed; and, even more confirmation of the fact that any Hydrogen, which might be needed for the complete hydrogenation of Coal and the conversion of the Carbon in Coal, in order to synthesize versatile and valuable hydrocarbons, can be generated as one integral function within a total Coal conversion process.
And, in confirmation of other, earlier reports we've made, the Hydrogen can be generated as a co-product in the further processing of still-carbonaceous residues left by an initial conversion of raw Coal.
Comment follows excerpts from the plainly-titled:
"United States Patent 4,523,986 - Liquefaction of Coal
Date: June, 1985
Inventor: Frederick Suefert, NY
Assignee: Texaco Development Corporation, NY
Abstract: Coal or similar solid carbonaceous fuels are liquefied by catalytic hydrogenation of coal-liquid hydrocarbon oil slurries with a hydrogen-rich gas. Both the liquid hydrocarbon slurrying oil and the hydrogen-rich gas are derived in the process. Noxious hydrogen-containing purge and vent gases and optionally high ash-containing bottoms from a vacuum fractionator are used as feed to a partial oxidation gas generator to produce synthesis gas from which the hydrogen-rich gas is derived.
Claims: A process for the liquefaction of ground coal or similar liquefiable carbonaceous solids which comprises: reacting a preheated slurry mixture comprising dried ground coal or similar liquefiable carbonaceous solids and liquid hydrocarbon slurry oil (derived, as described, from the process) and at least a portion of the hydrogen-rich gas (derived, as described, from the process) while in contact with a hydrogenation catalyst in a liquefaction zone.
(And) separating the effluent stream from the liquefaction zone ... into at least the following separate streams
by the steps of: introducing the effluent stream from the liquefaction zone ... into a separation zone and separating said effluent stream into the stream of hydrogen-containing gas mixture and a stream of liquid hydrocarbon.
(And) separating a portion of hydrogen-rich gas from said hydrogen-containing gas mixture ... to produce a recycle stream of hydrogen-rich gas, and introducing the remainder of the hydrogen-containing gas mixture into the partial oxidation gas generating zone ... as a portion of the feed;
(And) reducing the pressure on the stream of liquid hydrocarbon ... and separating said stream into hydrocarbon vapors and liquid hydrocarbon oil.
The process ... with the step of mixing a hydrogenation catalyst with said mixture of dried ground coal or similar liquefiable carbonaceous solids, liquid hydrocarbon slurry oil, and hydrogen-rich gas.
Description and Background: This invention relates to a process for liquefying coal or similar solid carbonaceous fuels. More particularly, this invention relates to a coal liquefaction process employing process derived hydrogen-rich gas made by the partial oxidation of purge and vent hydrogen-containing gases, optionally in admixture with a vacuum bottom stream containing ash.
(Again, note: All needed Hydrogen can be "process-derived".)
Coal will emerge as an increasingly important energy source by the end of the decade.
Liquefaction of coal to produce liquid fuels and chemical by-products will become increasingly important, especially when petroleum supplies become uncertain.
(It) would be uneconomical to burn up substantial amounts of the feed coal or the valuable liquid hydrocarbon products to make hydrogen. Also, there would still remain the problem and cost of disposing of the noxious vent and purge gases produced in the liquefaction step.
In the subject process, preferably no supplemental water or steam is required; and the noxious vent and purge gases are readily disposed of in the gas generator in an environmentally acceptable manner.
Advantageously, by the subject process catalytic steam reforming requiring costly gas purification steps is eliminated. Noxious vent and purge gas streams and optionally high ash-containing vacuum bottom streams may now be advantageously used as feedstock to obtain hydrogen for use in the subject solvent coal liquefaction process.
(And) synthesis or hydrogen-rich gas may be produced as a valuable by-product in the subject process.
(All) of the start-up hydrogen-rich gas ... that is used in (the) catalytic hydrogenation reactor ... may be made on the site ... .
(Again: All of the needed Hydrogen "may be made on ... site".)
In addition, a portion of the synthesis gas may be produced for export ... or for use as fuel for the fired heaters ... in the process.
Further, low cost waste products are used as a source of low cost feedstock to the hydrogen-containing gas producing zone. These feedstocks include all of the noxious purge and vent gases, ... optionally at least a portion of the high ash-containing liquid hydrocarbonaceous vacuum still bottoms stream ... and optionally a slurry stream ... comprising at least a portion of the soot, ash and unreacted solid carbonaceous fuel."
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We note, in closing, that the "purge and vent gases", depending upon the type and grade of Coal used, could include Hydrogen Sulfide, which, as we have documented, and as we will further document, has been made to serve as a Hydrogen donor in other Coal conversion processes.
In any case, note as well that the economy of utilizing this Texaco technology, to generate all of the Hydrogen needed "for use in the subject solvent coal liquefaction process", from, essentially "coal liquefaction" wastes and residues, is so productive that the extra Hydrogen it produces can be treated "as a valuable by-product" and could even allow "for export" of such surplus Hydrogen - to an oil refinery, perhaps, where it is needed and used for the "hydro-treatng" and the desulfurization of heavy, high-sulfur crude natural petroleum; and, where it will be needed in almost vast quantities for upgrading other, very crude, carbon resources, such as the bitumen recovered from the highly-touted Canadian tar sands.