The better part of a year ago, we sent you a report, now accessible via:
Exxon 1982 Hydrogenated Syngas from Carbon & Steam | Research & Development | News;
wherein was disclosed details of: "United States Patent: 4331529 - - Fluid Coking and Gasification Process; 1982; Assignee: Exxon"; a technology that, starting with a "charge stock" which "comprises coal", used two sequential gasification zones, to, "in the presence of steam" convert, first, the raw Coal, and, then, the carbonaceous residues left by the initial Coal gasification into "a gas comprising hydrogen and carbon monoxide, which is suitable, after conventional shift and clean up, for use as synthesis gas".
That technology, which utilizes Steam to sequentially gasify and hydrogenate both raw Coal and the carbon residues left by the initial Coal gasification, was, it seems, based on, or at least related to, an earlier Exxon technology, developed by another Exxon Coal scientist we have previously cited; a technology which was focused primarily on the use of Steam gasification to extract hydrocarbon values only from the carbonaceous residues generated by a different sort of, more direct, Coal liquefaction process.
Comment follows excerpts from the precedent:
"United States Patent 4,060,478 - Coal Liquefaction Bottoms Conversion by Gasification
Date: November, 1977
Inventor: Robert Lang, TX
Assignee: Exxon Research and Engineering Company, NJ
Abstract: Heavy bottoms produced by the liquefaction of coal ... are converted into more valuable products by ... (after initially producing) gases, hydrocarbon liquids and ...char, thereafter gasifying the char with steam.
Claims: A process for upgrading heavy bottoms produced by the liquefaction of coal ... which comprises pyrolyzing said bottoms in the presence of ... steam.
(And) wherein said ... bottoms product (is) produced by the hydrogen donor solvent liquefaction of coal.
An improved coal liquefaction process which comprises ... pyrolyzing said bottoms fraction and recovering coke; and thereafter gasifying said coke in the presence of steam.
Summary: The present invention provides an improved process for the production of liquid and gaseous hydrocarbons from coal ... .
This improved process involves the addition of calcium hydroxide ... or a similar alkaline earth metal compound to heavy bottoms produced by the liquefaction of bituminous coal ..., ... pyrolysis of the bottoms product to produce gases, liquids and coke containing the added alkaline earth metal compound, and subsequent gasification of the coke thus produced.
The invention is based in part on the discovery that calcium and other alkaline earth metal compounds, although relatively ineffective when used conventionally as catalysts for the gasification of coal ..., are highly effective when employed to catalyze the gasification of coke produced from heavy liquefaction bottoms as described above. Studies have shown that such ... higher (gasification) rates, coupled with the lower cost of the calcium compounds, provide significant economic incentives... .
The process of the invention is preferably employed in an integrated operation where coal or similar feed material is first liquefied ... with a hydrocarbon solvent ... to produce coal liquids and heavy bottoms.
(The) bottoms are pyrolyzed with calcium hydroxide or a similar alkaline earth metal compound to form gases, additional hydrocarbon liquids and coke containing added alkaline earth metal constituents ... .
(This) coke is then gasified with steam to form a synthesis gas composed primarily of hydrogen and carbon monoxide, and at least part of the hydrogen generated may be recylced for use in the liquefaction stage of the operation. This sequence of operation has significant advantages over processes suggested in the past and makes possible the production of liquid hydrocarbon products from coal and related materials at lower cost than has generally been possible heretofore."
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So, a close read reveals this to actually be a three-stage Coal conversion process, that, finally, in the third stage, by gasifying carbonaceous process residues with Steam, generates enough excess Hydrogen which can be used in the initial "liquefaction stage of the operation"; and, that "makes possible the production of liquid hydrocarbon products from coal ... at lower cost than has generally been possible heretofore".
All of which - aside from the fact that all of this Coal conversion technology was clearly known both to the petroleum industry and to our own US Government more than three decades ago - begs the question: