In a report last year: USDOE Hydrogenates Coal with Methane | Research & Development | News; we recorded the USDOE-developed technology: United States Patent: 4687570 - "Direct Use of Methane in Coal Liquefaction; 1987; Inventors: Muthu Sundaram and Meyer Steinberg, NY; Assignee: The USA; Abstract: This invention relates to a process for converting solid carbonaceous material, such as coal, to liquid and gaseous hydrocarbons utilizing methane.".
Herein, we learn that such USDOE- patented Coal conversion technology, utilizing Methane, was actually predated by one similar, developed in the same National Laboratory by one of USP 4,687,570's co-inventors.
In it, Methane again serves as the primary contributor of Hydrogen in the hydrogenation of Coal; but, the hydrocarbons synthesized are somewhat different than those evolved in the process of USP 4,687,570.
The primary product of our subject Coal conversion technology is "Ethylene"; and, with the help our omniscient friend, as in: Ethylene - Wikipedia, the free encyclopedia; we learn that: "Polyethylenes of various types consume more than half of world ethylene supply". And, that: "Polyethylene ... is the world's most widely-used plastic.".
And, we think it very important to note, that: Most, but not all, of the Methane required in our subject invention is actually generated as a co-product within the process of the invention itself; where it is recovered and recycled back, to react with more raw Coal.
All of that said, additional links and comments, concerning especially some sources of any, perhaps needed, supplemental Methane, follow excerpts from the initial link in this dispatch, to:
"US Patent 4,563,197 - Process for the Production of Ethylene ... from Coal
Date: January, 1986
Inventors: Meyer Steinberg and Peter Fallon, NY
Assignee: The United States of America
Abstract: A process for the production of economically significant amounts of ethyl and other hydrocarbon compounds, such as benzene, from coal is disclosed wherein coal is reacted with methane at a temperature in the approximate range of 500C to 1100C at a partial pressure less than about 200 psi for a period of less than 10 seconds. Ethylene and other hydrocarbon compounds may be separated from the product stream so produced, and the methane recycled for further production of ethylene. In another embodiment, other compounds produced, such as by-product tars, may be burned to heat the recycled methane.
(We wonder if those semi-hydrogenated, coal-based "by-product tars" couldn't, instead, be shipped off to an oil refinery for further, very standard, petroleum-type hydrogenation, and subsequent conversion into more familiar types of conventional liquid hydrocarbons. Some form of environmental energy could be harnessed to the simple task of heating "the recycled methane".)
Claims: A process for the production of ethylene from coal in commercially significant yields greater than 10% (% carbon converted to product).
(Yes, we know: The "10%" of "carbon converted to product" ethylene sounds pretty dismal. But, remember, the rest of the Carbon, in the raw Coal, is converted into Methane, and, into those "by-product tars", which, even if we don't ship them off to a refinery for conversion into something value-added, may still be "burned", i.e., used as fuel.)
(And) wherein a portion of said other reaction products comprising tars, hydrogen sulfide, benzene, and light oils, are recovered from said methane (and) wherein after said recovery a first portion of said methane is recycled for further reaction with said coal particulates.
(Note, in addition to the "tars", which are, as herein, already useful as fuels, and likely amenable to refining, the process also generates "benzene", a component of the basic Gasoline blending stock labeled most often as "BTX", that is: Benzene, Toluene and Xylene: and, "light oils"; and, some "hydrogen sulfide", which, if we want, we can, as in: Exxon Liquefies More Coal with Hydrogen Sulfide | Research & Development | News; wherein is disclosed: "USP 4,149,959 - Coal Liquefaction Process; 1979; Assignee: Exxon Research and Engineering Company, NJ; Abstract: A coal liquefaction chargestock is first treated with a gaseous mixture comprising ... hydrogen sulfide"; utilize in a separate process to hydrogenate and liquefy more Coal.)
Background: With the advent of the "energy crisis" and the concomitant realization of the generally limited nature of oil and natural gas supplies, numerous efforts were begun to develop methods whereby the abundant United States deposits of coal could be used in the production of gaseous and liquid fuels (and, subsequently) numerous other patents ... teach various methods for the production of liquid and gaseous fuels from coal.
Despite the large research effort in the field of producing gaseous and liquid fuels from coal, little attention has been given to the production of chemical feedstocks, most importantly ethylene and benzene, using coal as the raw material.
According to (a) recent report in Chemical and Engineering News ... approximately 31 billion pounds of ethylene were produced in the United States in the previous year. Ethylene is an important raw material in the plastic and polymer industries and it is anticipated that the demand for ethylene will continue to increase in the future.
At present, no coal conversion process is known which produces economically significant amounts of the chemical feedstocks ethylene and benzene. Applicants have found that the flash methanolysis of coal, that is the pyrolysis of coal under pressure in an atmosphere of methane, when conducted at appropriate temperatures and gas pressures, using appropriate solids residence time and gas/solids ratios, results in economically significant yields of ethylene.
Thus, it is an object of the subject invention to provide a method for the production of substantial amounts of ethylene from coal.
It is another object of the subject invention to provide such a method which also produces substantial quantities of benzene and light oils.
It is still another object of the subject invention to provide a method for the production of ethylene from coal where substantially the only required raw material is coal."
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We close our excerpts there, since the USDOE notes that the only really "required raw material is coal".
However, we wonder if the overall productivity of the process could not be improved, if, in addition to the Methane generated in the process of USP 4,563,197, itself, additional Methane, perhaps as synthesized, as, for example, in: NASA Recycles CO2 to Methane at Room Temp | Research & Development | News; wherein is reported: "Electrocatalytic Reduction of Carbon Dioxide to Methane; 2008"; from Carbon Dioxide; or, as in: More Texaco Carbon-Recycling Methane from Coal | Research & Development | News, concerning: "United States Patent 3,888,043 - Production of Methane; 1975; Assignee: Texaco Incorporated, NY; Abstract: Continuous process for the production of a gaseous stream comprising at least 90 mole % of methane (dry basis) from a sulfur containing hydrocarbonaceous fuel (which can include) coal oil, coal tar, coke-oven gas, ... coal (and) concentrated sewer sludge ...", primarily from Coal, were used in the process of our subject US Patent 4,563,197, to react with Coal, and to thereby yield an increased product slate consisting of "substantial amounts of ethylene" and "substantial quantities of benzene and light oils".