As we continue to document for you the chronological development of Coal liquefaction technologies by the companies that became ExxonMobil, we herein submit one, which we might have missed along our way, from 1970.
It is similar to other Coal liquefaction technologies we've reported, in that it bills itself as a multi-stage process. And, it seems to represent something of another reversal, similar to others we've already reported, of the Coal conversion and extraction sequence practiced by the FMC Corporation for the US Government, as we earlier detailed in a series of reports, at the Princeton, NJ, "COED" facility.
There, Coal was subjected to an initial gasification, with the carbonaceous residues then being sent all the way to Spain for further extraction, and direct liquefaction, with the hydrogen-donor solvent, Tetralin.
Herein, it is seen that Esso first treats the Coal with, as identified in the full Disclosure but not represented in our excerpts, Tetralin; which is itself, we believe, an hydrogenated version of the primary Coal oil, Naphthalene; and then further processes both the dissolved, liquefied Coal and the carbonaceous residue remaining from the initial extraction.
Comment follows brief excerpts from:
"United States Patent 3,488,279 - Two-stage Conversion of Coal to Liquid Hydrocarbons
Date: January, 1970
Inventor: Bernard L. Schulman, NJ
Assignee: Esso Research and Engineering Company
Abstract: Coal is hydrogenated to produce liquid products in two stages. The first stage is an initial mild conversion by hydrogen-donor extraction followed by a second stage of catalytic hydrogenation using a cobalt molybdate catalyst and added molecular hydrogen.
The present invention is directed to the conversion of a solid carbonaceous material such as coal into liquid products (which can be further ) converted into gasoline.
It is thus submitted that the present invention provides a superior process for reducing the solid material in coal to liquid products suitable for commercial use.
Summary: An improved method of converting coal to liquid hydrocarbons comprises subjecting the coal to mild conversion by hydrogen-donor extraction followed by a second-stage catalytic hydrogenation. By this process, a higher overall conversion of coal is attained."
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Molecular Hydrogen is required in this Esso "two-stage" process. However, as we have documented, the art of producing such free Hydrogen, for the refining, the "hyrocracking", of "heavy" crude petroleum, and of petroleum refining "resids", is well-established in the petroleum industry. In fact, schematics which accompany this patent clearly show some by-products of the Coal processing stages being diverted to a generically-labeled "Hydrogen Generator".
