Without attempting linkage to any of our prior reports concerning the fact, we see herein that Phillips Petroleum again confirms that several known and established processes can be combined to synthesize a hydrocarbon fuel, in this case, and perhaps importantly, Methane, by recycling and reacting Carbon Dioxide, from whatever source, with hot Coal, to form Carbon Monoxide; and, then, reacting that Carbon Monoxide with Steam to form a hydrocarbon gas consisting primarily of Methane.
Such rather direct synthesis of Methane, in a process that, as a first step, recycles Carbon Dioxide through reactions with Coal, offers additional Carbon Dioxide recycling potentials, as well, as we emphasize, following excerpts from the link to:
"US Patent 4,011,058 - Production of Substitute Natural Gas from Gasification of Coal Char
Date: March, 1977
Inventors: Marvin Johnson, et. al., OK
Assignee: Phillips Petroleum Company, OK
Abstract: A carbonaceous material is converted to a fuel gas which is fungible with natural gas by a combination of steps comprising gasifying the carbonaceous material in the presence of air and carbon dioxide, purifying the effluent stream and separating carbon monoxide therefore, catalytically reacting steam with the separated carbon monoxide and recovering a methane-rich product gas.
Claims: A process for the production of a gas comprising methane which comprises, in combination, the steps of:
a. gasifying a solid carbonaceous material at an elevated temperature in the presence of air and carbon dioxide to produce a raw process stream comprising carbon monoxide, carbon dioxide and nitrogen;
b. cooling, cleaning and purifying said raw process stream to obtain a stream consisting essentially of carbon monoxide and nitrogen;
c. separating carbon monoxide from ... nitrogen by (a specified process)
d. combining stream (Note: The foregoing is, without doubt, a misprint. And, it is one exactly the same as others we have seen in other US Patents disclosing related technologies, and which we have pointed out to you and corrected. It should, again without doubt, read: "combining steam") with said separated carbon monoxide and reacting the resulting CO/steam mixture in a catalytic methanation zone to produce an effluent gas stream consisting essentially of carbon dioxide, methane and hydrogen; and
e. cooling said effluent gas stream and separating impurities therefore to produce a product stream comprising methane.
Description: This invention relates to the production of fuel gas from a carbonaceous material which is interchangeable with natural gas.
The synthetic production of fuel gas is desirable to meet the supply for utility pipeline gas in those areas where the demand exceeds the supply, particularly during periods of peak load. Such pipeline gas should preferably be made from a cheap fuel. Additionally, the process by which the gas is made must be competitive with other energy sources.
It has been proposed in the past to gasify carbonaceous solids such as coal, lignite and the like in the presence of other gases to obtain more useful gases for further synthesis or as a source of high B.t.u. gas. It is well known that carbonaceous fuels react with hydrogen under pressure to produce methane gas. However, the cost of hydrogen required for the process can make the process prohibitively expensive. It is also known that carbonaceous fuels react with oxygen under proper conditions to produce carbon monoxide which can, by means of a methanation process, be converted catalytically to methane. The cost of pure oxygen required for the process can make the process prohibitively expensive. Air is generally not used as the source of oxygen due to the diluting effect of the nitrogen in the air and the problems generally encountered in separating the nitrogen from the various process streams.
Accordingly, it is an object of this invention to provide a process for the production of a fuel gas from a carbonaceous solid.
Other objects, aspects and advantages of the present invention will be readily apparent to those skilled in the art from a study of this disclosure, appended claims and the attached drawing which is a detailed schematic diagram of the process of the present invention.
In accordance with the present invention there is provided a process for the production of a product gas comprising methane, which comprises (and with capitalized emphases as directly reproduced from the official US Patent record):
A. GASIFYING A CARBONACEOUS MATERIAL AT AN ELEVATED TEMPERATURE IN THE PRESENCE OF AIR AND CARBON DIOXIDE TO PRODUCE A RAW PROCESS STREAM COMPRISING CARBON MONOXIDE, CARBON DIOXIDE AND NITROGEN,
B. SEPARATING CARBON MONOXIDE FROM THE RAW PROCESS STREAM, AND
C. REACTING THE SEPARATED CARBON MONOXIDE IN A CATALYTIC METHANATION ZONE TO PRODUCE AN EFFLUENT GAS STREAM COMPRISING METHANE.
More particularly, in accordance with the present invention, there is provided a process for the production of a product gas comprising methane, which comprises, in combination, the steps of
A. GASIFYING A CARBONACEOUS MATERIAL AT AN ELEVATED TEMPERATURE IN THE PRESENCE OF AIR AND CARBON DIOXIDE TO PRODUCE A RAW PROCESS STREAM COMPRISING CARBON MONOXIDE, CARBON DIOXIDE AND NITROGEN;
B. COOLING, CLEANING AND PURIFYING THE RAW PROCESS STREAM TO OBTAIN A STREAM CONSISTING ESSENTIALLY OF CARBON MONOXIDE AND NITROGEN;
C. SEPARATING CARBON MONOXIDE FROM THE STREAM CONSISTING ESSENTIALLY OF CARBON MONOXIDE AND NITROGEN;
D. COMBINING STEAM WITH THE SEPARATED CARBON MONOXIDE AND REACTING THE RESULTING CO/steam mixture in a catalytic methanation zone to produce an effluent gas stream consisting essentially of carbon dioxide, methane and hydrogen; and
e. cooling the effluent gas stream consisting essentially of carbon dioxide, methane and hydrogen and separating impurities therefrom to produce a product stream comprising methane.
While any carbonaceous material can be employed in the practice of this invention, the invention is particularly suitable for the conversion of materials such as low grade bituminous coal."
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And, that, basically, is it: By gasifying a "solid carbonaceous material" specified to be "low grade bituminous coal", and doing so "in the presence of ... carbon dioxide", we can produce "carbon monoxide" that "can, by means of a methanation process" whereby a mixture of "steam with ... carbon monoxide" is reacted, and, as they put it, "converted catalytically", we can manufacture "methane".
And, as in just one example: WVU CO2 + CH4 = Hydrocarbon Syngas | Research & Development | News; concerning: "New Catalysts for Syngas Production from Carbon Dioxide and Methane; Mahesh V. Iyer; West Virginia University"; we can then manufacture a synthesis gas suitable for catalytic condensation into liquid hydrocarbon fuels, by reacting the Methane so produced, via the process herein of US Patent 4,011,058, from, basically, Water and Coal, with, as reclaimed from any convenient source, Carbon Dioxide.