Exxon Methane from Coal and Carbon Dioxide

Herein, we present just more evidence of two facts, which can be summarized in one statement, which we have already many times documented to be true:
Both Coal and Carbon Dioxide can be efficiently converted into Methane.
The evidence herein comes again from one of the components of that lovable titan of the international petroleum industry, ExxonMobil, New Jersey's Exxon Research and Engineering Company. And, it will seem almost dreadfully repetitive to anyone who has somehow been motivated enough to follow our reports over the past four, and then some, years.
The entire Disclosure of the United States Patent we enclose is given over to exposition of how Methane can be efficiently synthesized from the products of Coal gasification; and, considerable space is given over to discussion of the Coal gasification process itself.
The true import of the entire Disclosure, however, is revealed and summarized in this United States Patent's final, concluding statement, as follows:
"Although the process has been described in connecton with a particular gasification process and in terms of a particular type of methanation reactor, it will be understood that mixtures of hydrogen and carbon oxides from a variety of different sources can be methanated using the improved catalysts and that the process is not restricted to the particular flow plan shown".
The "carbon oxides", as they are careful to emphasize throughout the Disclosure, do include Carbon Dioxide, and, again, we submit for emphasis, as can be obtained "from a variety of different sources".
Comment follows and is inserted within excerpts we'll try to keep merciful from the link to:
"United States Patent 3,958,957 - Methane Production
Date: May, 1976
Inventor: Kwang Koh, et. al., Texas
Assignee: Exxon Research and Engineering Company, NJ
Abstract: Methane is produced by contacting a mixture of carbon monoxide or carbon dioxide and hydrogen with a carbon-alkali metal catalyst at a temperature in the range between about 800 F and about 1500 F and at a pressure between about atmospheric and about 2000 psig. The catalyst employed may be prepared by heating an intimate mixture of coal, coal char, coke or other carbonaceous solids and an alkali metal salt, hydroxide or similar constituent. Such a catalyst promotes the methanation of carbon monoxide and carbon dioxide and the formation of higher hydrocarbons by the Fischer-Tropsch reaction and at the same time is resistant to high temperature sintering and poisoning by sulfur compounds present in the feed gas. The catalyst can be regenerated if necessary by air oxidation.
(The key to this US Patent is actually emphasized in the Abstract. This is really all just about an improved catalyst for converting a blend of Carbon Oxides and Hydrogen into either, preferably, Methane, and/or, via a reactor set up to operate the Fischer-Tropsch process, "higher hydrocarbons".)
Claims: A method for the production of a methane-rich gas which comprises introducing a gaseous mixture of hydrogen and at least one carbon oxide into a reaction zone containing a carbon-alkali metal catalyst at a temperature between about 800 F and about 1500 F and at a pressure between about atmospheric and about 2000 psig, said catalyst being prepared by heating an intimate mixture consisting essentially of a carbonaceous solid and an alkali metal constituent to an elevated temperature sufficient to produce a reaction between the carbon and alkali metal in said mixture and form a carbon-alkali metal reaction product, and recovering a methane-rich gas from said reaction zone.

A method ... wherein said gaseous mixture is a raw synthesis gas produced by the steam gasification of a carbonaceous feed material (and) wherein said carbonaceous solid is coal (and/or) coal char.

A method ... wherein said alkali metal constituent is a potassium compound (or) a cesium compound.

A method ... wherein said carbon oxide is carbon monoxide.
(Note that "carbon monoxide" is preferred over Carbon Dioxide. Both can be reacted with Hydrogen to form Methane in this process; but, CO2 will consume more of the Hydrogen, which is lost to the formation of Water, H2O, the co-product of the reaction that consumes the Oxygen taken from the CO2.)
A method wherein said intimate mixture of said carbonaceous solid and said alkali metal constituent is prepared by impregnating said solid with a liquid containing an alkali metal compound soluble in said liquid.

A process for the production of a methane-rich gas which comprises reacting steam with a carbonaceous feed material to produce a synthesis gas containing hydrogen and carbon monoxide; contacting said hydrogen and carbon monoxide with a carbon-alkali metal catalyst prepared by impregnating finely-divided carbonaceous solids with a solution consisting essentially of an alkali metal compound and an aqueous carrier and heating the impregnated solids at an elevated temperature sufficient to produce a carbon-alkali metal reaction product in the impregnated solids, said gas being contacted with said catalyst at a temperature in the range between about 800 F and about 1500 F and at a pressure between about atmospheric and about 2000 psig; and recovering a gas of enhanced methane content.
(There are a number of processes for "reacting steam with a carbonaceous feed material"; and, ExxonMobil owns the rights to few of them, as seen for one instance in:
West Virginia Coal Association | Exxon Coal to Methanol | Research & Development; concerning: "United States Patent 4,348,487 - Production of Methanol via Catalytic Coal Gasification; 1982; Assignee: Exxon Research and Engineering Company; Abstract: Methanol is produced by gasifying a carbonaceous feed material with steam ... to produce a raw product gas comprising methane, steam, carbon dioxide, carbon monoxide, hydrogen and hydrogen sulfide; withdrawing the raw product gas from the gasifier and treating ... it ... to produce a treated gas containing primarily carbon monoxide, hydrogen and methane; separating the treated gas into a methane-rich gas stream and a gas stream containing primarily carbon monoxide and hydrogen; passing the gas stream containing primarily carbon monoxide and hydrogen to a methanol synthesis reactor where the carbon monoxide is reacted with the hydrogen in the presence of a methanol synthesis catalyst to form methanol; recovering methanol product from the effluent exiting the methanol synthesis reactor thereby leaving a gas comprised of carbon monoxide, hydrogen, methane and carbon dioxide; and passing a portion of this gas to a steam reforming furnace wherein at least a portion of the methane is reacted with steam to produce hydrogen and carbon monoxide which is then passed from the steam reforming furnace into the gasifier. Preferably, at least a portion of the methane-rich gas produced in the separation step is used as fuel for the steam reforming furnace. This invention provides a process for producing methanol by the substantially thermoneutral reaction of steam with coal";
where the valuable Methanol is the desired product, and any co-produced Methane is cycled back into the gasification process to make, with the Steam and the Coal, more "hydrogen and carbon monoxide" Methanol synthesis gas.)

A process ... wherein said carbonaceous feed material is coal.

A process ... wherein said alkali metal compound is a potassium salt of an acid (as specified) and wherein said alkali metal compound is a hydroxide (or) a carbonate (or) a sulfate.

A process ... wherein said steam is reacted with said carbonaceous feed material in the presence of an alkali metal compound.

A process ... wherein said hydrogen and carbon monoxide are contacted with said catalyst in staged reactors and the gas is cooled between stages.

Background and Field: This invention relates to the manufacture of synthetic fuels and is particularly concerned with a method for the production of methane from synthesis gas and similar mixtures of carbon monoxide or carbon dioxide and hydrogen.

Summary: This invention relates to the manufacture of synthetic fuels and is particularly concerned with a method for the production of methane from synthesis gas and similar mixtures of carbon monoxide or carbon dioxide and hydrogen.

The present invention provides an improved process for the production of methane from mixtures of carbon oxides and hydrogen which at least in part avoids (difficulties in prior art as discussed).

In accordance with the invention, it has now been found that high yields of methane can be obtained by contacting a mixture of carbon monoxide or carbon dioxide and hydrogen with a carbonalkali metal catalyst at a temperature in the range between about 800 F and about 1500 F and at a pressure between about atmospheric and about 2000 psig. Experimental work has shown that these catalysts, produced by heating an intimate mixture of coal, coke or similar carbonaceous solids with an alkali metal constituent to an elevated temperature, are surprisingly effective for the methanation of carbon monoxide and carbon dioxide; that they resist poisoning by sulfur compounds in the feed gas stream and therefore require less pretreatment of the gas than conventional iron, nickel and cobalt type catalysts; that, unlike the conventional catalysts, they are resistant to high temperature sintering and catalyst degradation; that they can be readily regenerated by oxidation in air to eliminate any carbon laydown which may occur; and that they are considerably less expensive than the conventional catalysts used and proposed for use in the past. As a result of these and other advantages, methanation processes using these catalysts have many potential applications.

The process of the invention can be used for the methanation of synthesis gas produced by the gasification of coal ... and similar carbonaceous feedstocks or other mixtures of hydrogen and carbon oxides and may be carried out in a fixed bed, moving bed or fluidized bed system.

The resulting gas can then be treated for the removal of carbon dioxide, sulfur compounds and other impurities and employed as a fuel of intermediate B.t.u. content or further methanated to produce a high B.t.u. synthetic natural gas.

(As illustrated by) Example 4; Fig. 6: CO2 + 4H2 = CH4 + 2H2O. "

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We regret the lengthy excerpts, since we know it seems simply to repeat one of our refrains:

Coal can be efficiently converted, through gasification and subsequent catalysis, into Methane.

But, through reaction with Hydrogen, so can Carbon Dioxide.

And, once we have the Methane, as explained by ExxonMobil themselves in:

West Virginia Coal Association | Exxon 2010 CO2 + Methane = Liquid Hydrocarbons | Research & Development; concerning: "United States Patent 7,772,447 - Production of Liquid Hydrocarbons from Methane; 2010; Assignee: ExxonMobil; Abstract: (A) process for converting methane to liquid hydrocarbons ... and ... hydrogen ... . A process for converting methane to higher hydrocarbons, the process comprising: (a) contacting a feed containing methane and ... H2O (and) CO2 with a (specified) catalyst under conditions effective to convert said methane to aromatic hydrocarbons, including benzene and naphthalene, and produce a first effluent stream comprising aromatic hydrocarbons and hydrogen";

we can react that Methane with more Carbon Dioxide, and Water, H2O, to make both liquid hydrocarbons and by-product Hydrogen, which could be cycled back into the process of our subject, "United States Patent 3,958,957 - Methane Production", to be reacted with more Carbon Dioxide to make more Methane.

We submit that "United States Patent 3,958,957 - Methane Production" is mostly about improved catalysis, reaction sequences and exothermic heat management in the synthesis of Methane from Hydrogen, Carbon Monoxide and/or Carbon Dioxide - no matter where we get them, although the Disclosure uses Coal gasification as the exemplary source.

But, we remind you that, as Exxon themselves specify, the process is applicable to, basically, any "mixtures of hydrogen and carbon oxides", and, thus, if we can make, as in:

West Virginia Coal Association | Japan Maximizes Hydrogen Production from Wind Power | Research & Development; concerning: "United States Patent 7,667,343 - Hydrogen Production System Using Wind Turbine Generator; 2010; Assignee: Hitachi, Ltd.; Abstract: A wind turbine-driven hydrogen production system controlling a power converter system such that the wind turbine stays in its operable range for a longer time and thus the hydrogen production system produces hydrogen for a longer time";

Hydrogen in some windy place in US Coal Country; and, as in:

West Virginia Coal Association | Columbia University August 2012 Practical CO2 Air Capture | Research & Development; "United States Patent 8,246,731 - Systems and Methods for Extraction of Carbon Dioxide from Air; 2012; Assignee: The Trustees of Columbia University; Abstract: The present invention describes methods and systems for extracting, capturing (etc.,) carbon dioxide (CO2), particularly from the air. The CO2 extraction methods and systems involve the use of chemical processes. Methods are also described for extracting and/or capturing CO2 via exposing air containing carbon dioxide to - - a basic solution which absorbs carbon dioxide and produces a carbonate solution. The solution is causticized and the temperature is increased to release carbon dioxide, followed by hydration of solid components to regenerate the base";

capture CO2 from the same wind that's making the Hydrogen for us, then we could, according to the catalytic process specified by our subject herein, "US Patent 3,958,957 - Methane Production", and according to the efficient, and perhaps even exothermic, reaction they specify: "CO2 + 4H2 = CH4 + 2H2O", begin converting, with little or no need for fossil energy input, atmospheric CO2 into Methane, and, for yet another example, as in:

West Virginia Coal Association | Standard Oil 1954 CO2 + CH4 + H2O = Syngas | Research & Development; concerning: "United States Patent 2,676,156 - Preparation of Synthesis Gas; 1954; Assignee: Standard Oil Development Company; Abstract: The present invention relates to the preparation of a gas comprising carbon monoxide and hydrogen. In accordance with the present invention, carbon dioxide, steam and a light hydrocarbon gas such as methane (are reacted) to produce carbon monoxide and hydrogen in proportions suitable for employment in the hydrocarbon synthesis process. By manipulation of the quantities of CH4, H2O and CO2 to be reacted, desired ratios of H2 to CO in the product may be obtained";

then start reacting that CO2-derived Methane with even more Carbon Dioxide, "to produce carbon monoxide and hydrogen in proportions suitable for employment in the hydrocarbon synthesis process"; and, ultimately, just about any liquid hydrocarbon we might want.

The raw materials: H2O, CO2 and, for one example of applicable environmental energy, Wind, are already freely available; and, as in the process of our subject, "United States Patent 3,958,957 - Methane Production", in combination with the processes represented by some of our other references, so are the intellectual tools needed to use those raw materials, and to thereby both free our nation from economic enslavement to OPEC and build a road to a better future for all of us.

All we're lacking, it seems, are some ready hands and, maybe most importantly, maybe more rare, minds that remain open to the rather vast Coal Country potentials lying in the ground beneath our feet, flowing past us in our streams, and blowing by us in the breeze.