United States Patent: 3929431
We have documented, in various of our recent reports, that Methane, as can be synthesized, via the Sabatier process, from Carbon Dioxide, among it's many valuable uses, both as a co-reactant for additional Carbon Dioxide, in Tri-reforming processes; and, as a raw material for direct chemical condensation into liquid hydrocarbons via multiple patented technologies; can serve as well to improve some processes of indirect Coal liquefaction, and to thereby enhance the synthesis of liquid hydrocarbons from Coal.
As further evidence of that last assertion, we submit herein another US-patented, three decades-old technology developed by Exxon's Texas R&D facilities.
The wording, as we've come to expect of Big Oil's Coal conversion patents, is as difficult to translate as they could make it.
But, we'll attempt clarification of the juicy bits, following excerpts from the above link, as follows:
"United States Patent 3,929,431 - Catalytic Reforming Process
Date: December 30, 1975
Inventor: Kwang K. Koh, et. al.
Abstract: Methane and other hydrocarbons boiling up to about 450.degree. F. are converted into hydrogen and carbon oxides by reacting the hydrocarbon feed material with steam in the presence of a carbon-alkali metal catalyst at a temperature in the range between about 1200.degree. and about 1700.degree. F. and at a pressure between about atmospheric and about 5000 psig. The catalyst employed may be prepared by reacting coal, coal char, coke or other carbonaceous solids with an alkali metal or alkali metal compound at an elevated temperature. Such a catalyst is highly effective for the steam reforming of methane and similar hydrocarbon feed streams and at the same time is resistant to high temperature sintering and poisoning by sulfur compounds present in the feed.
Claims: 1. A process for the production of a hydrogen-containing gas which comprises reacting a hydrocarbon feed stream consisting essentially of constituents boiling below about 450.degree. F. with steam in a steam reforming zone and in the presence of a carbon-alkali metal catalyst at a temperature between about 1200.degree. and about 1700.degree. F. and at a pressure between about atmospheric and about 5000 psig, said catalyst being prepared by heating an intimate mixture of carbonaceous solids and an alkali metal constituent to a temperature in excess of about 800.degree. F., and recovering a hydrogen-containing gas from said steam reforming zone.
2. A method as defined by claim 1 wherein said hydrocarbon feed stream comprises methane.
3. A method as defined by claim 1 wherein said carbonaceous solids comprise coal.
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11. A process for the manufacture of a synthetic natural gas which comprises reacting hydrogen with carbonaceous solids in a hydrogasification zone maintained at a temperature and pressure sufficient to produce a methane-containing gas; circulating carbonaceous solids from said hydrogasification zone to a steam reforming zone and from said steam reforming zone to said hydrogasification zone; reacting a portion of said methane-containing gas with steam in said steam reforming zone in the presence of carbonaceous solids circulated from said hydrogasification zone and a carbon-alkali metal catalyst at a temperature below the temperature in said hydrogasification zone to produce sufficient hydrogen to replace substantially all of the hydrogen consumed in said hydrogasification zone, exothermic heat from said hydrogasification zone being transferred to said steam reforming zone by said circulating carbonaceous solids in sufficient quantities to supply substantially all of the exothermic heat required in said steam reforming zone; passing hydrogen produced in said steam reforming zone to said hydrogasification zone; and recovering a portion of said methane-containing gas from said hydrogasification zone.
21. A process for the manufacture of a synthetic natural gas which comprises contacting a hydrogen-rich gas with coal solids ... to produce a methane-containing gas; circulating coal solids from said hydrogasification zone to a steam reforming zone and from said steam reforming zone to said hydrogasification zone; contacting a portion of the methane-containing gas produced in said hydrogasification zone with steam in said reforming zone in the presence of a carbon-alkali ... to produce sufficient hydrogen to replace substantially all of the hydrogen consumed in said hydrogasification zone, the temperature in said steam reforming zone being ... lower than the temperature in said hydrogasification zone and exothermic heat being transferred from said hydrogasification zone to said steam reforming zone by said circulating coal solids in a quantity sufficient to supply substantially all of the exothermic heat required to produce said hydrogen in said steam reforming zone; recovering hydrogen produced in said hydrogasification zone and in said steam reforming zone; introducing the recovered hydrogen into said hydrogasification zone; and recovering methane from a portion of said methane-containing gas produced in said hydrogasification zone."
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Well, it's complicated. But, after some discussion among all of us, this is how we understand it:
Methane is being produced by this Coal conversion process, and a portion of the Methane so produced is recycled back into the process, where it's reacted with Steam to generate more free Hydrogen for further reaction with, and hydrogenation of, the raw Coal, so that even more Methane can be produced.
Not only that, but, as we have from other sources documented, concerning similar Coal conversion technologies, some reaction steps in the process are exothermic, and the generated heat can be recovered to help drive other stages of the reaction sequence, as in:
" ... exothermic heat from said hydrogasification zone being transferred to said steam reforming zone by said circulating carbonaceous solids in sufficient quantities to supply substantially all of the exothermic heat required in said steam reforming zone ... ".
And, such internal energy recycling might result in great, but as yet undefined, economies for the overall process by reducing or eliminating the need for external, purchased, energy inputs.
In any case, we have stated in previous dispatches that Methane, as can be synthesized via the Sabatier process from Carbon Dioxide, can improve the productivity of some indirect Coal conversion technologies.