Since we've continued to document the now-plain fact that Carbon Dioxide - - which, like the unrecognized answer to a prayer, is co-produced by our economically essential use of Coal in the generation of abundant and truly affordable, over the long term, electric power - - is a valuable raw material resource, which can, as seen in our recent report of:
West Virginia Coal Association | New York City CO2 to Methane via Artificial Photosynthesis | Research & Development; concerning: "US Patent Application 20120208903 - Conversion of Carbon Dioxide to Methane Using Visible Light; 2012; City University of New York, NYC; A method for converting carbon dioxide to methane, ... comprising exposing carbon dioxide ... to light in the presence of a source ... of hydrogen
Solar energy, e.g., sunlight, is preferred (and a) preferred source of hydrogen is water";
be converted into the substitute natural gas, Methane, with the only other consumables required being sunlight and Water; we wanted herein to confirm, that, as in, for only one example, our report of:
West Virginia Coal Association | Pittsburgh 1941 CO2 + Methane = Hydrocarbon Syngas | Research & Development; concerning: "United States Patent 2,266,989 - Manufacture of a Gas from CO2 and Methane; 1941; Koppers Company, Pittsburgh, PA; The present invention relates to the manufacture of gases suitable for the synthesis of higher hydrocarbons or the like, said gases containing definite volumes of carbon monoxide and hydrogen in a certain proportion, by reacting on methane ... with carbon dioxide or a mixture of carbon dioxide and steam";
such CO2-derived Methane can then be reacted with even more Carbon Dioxide, and made thereby to form a synthesis gas, or "syngas", blend of Carbon Monoxide and Hydrogen suitable for catalytic condensation into "higher hydrocarbons".
In this case, as testament to how widely known such facts are, we bring you description of such productive Carbon Dioxide recycling, "reforming", processes from a noted Carbon chemistry scholar in India, one whom we have cited for you previously, as seen in:
West Virginia Coal Association | India Methanol & Methane to Gasoline | Research & Development; concerning: "United States Patent 7,022,888 - Conversion of Methane and Organic Oxygenate to Hydrocarbons; 2006; Inventor: Vasant Choudhary, et. al., India; Assignee: Council of Industrial and Scientific Research, New Delhi; Abstract: A process for the non-oxidative conversion of methane simultaneously with the conversion of an organic oxygenate ... to gasoline range hydrocarbons";
wherein it's actually described how Methane, as can be, as noted above, synthesized from Carbon Dioxide, can be made to react with Methanol, one of the "organic oxygenate"s specified in the full Disclosure of "United States Patent 7,022,888", and which Methanol, as seen in:
West Virginia Coal Association | US Navy Coal + H2O = Low Cost Methanol | Research & Development; concerning: "United States :Patent 4,476,249 - Low Cost Method for Producing Methanol; 1984; The Johns Hopkins University; The Government has rights in this invention pursuant to Contract N00024-78-C5384 awarded by the Department of the Navy. Method of producing low cost methanol from coal"; and:
concerning: "United States Patent 8,212,088 - Efficient and Selective Chemical Recycling of Carbon Dioxide to Methanol, Dimethyl Ether and Derived Products; July 3, 2012; University of Southern California; An efficient and environmentally beneficial method of recycling and producing methanol from varied sources of carbon dioxide including flue gases of fossil fuel burning powerplants, industrial exhaust gases or the atmosphere itself. Converting carbon dioxide by chemical or electrochemical reduction seconardy treatment to produce essentially methanol";
can itself be made, in the first place, either from Coal, or, from CO2, with the end product being Gasoline.
And, herein, Vasant Choudhary, in a scholarly dissertation, describes how, instead of Methanol, the Methane, synthesized, we suggest, via the process described in our above-cited report concerning "US Patent Application 20120208903 - Conversion of Carbon Dioxide to Methane", from Carbon Dioxide, can be made to react with even more Carbon Dioxide, and be made thereby form a synthesis gas blend of Carbon Monoxide and Hydrogen likely well-suited compositionally for catalyzed chemical combination, such as via the Fischer-Tropsch process, into hydrocarbon fuels.
As seen in excerpts from the initial link in this dispatch to:
"Energy Efficient Methane-to-Syngas Conversion with Low H2 / CO Ratio by Simultaneous Catalytic Reactions of Methane with Carbon Dioxide and Oxygen
Catalysis Letters; March, 1995
V.R. Choudhary; et. al.; National Chemical Laboratory, India
By simultaneous reactions of methane with CO2 and O2 over Nickel Oxide-Calcium Oxide catalyst under certain reaction conditions, it is possible to convert methane into syngas with low HE/CO ratio ... at above 95% conversion, with 100% CO selectivity and above 90% H2 selectivity and also with very high CO productivity without catalyst deactivation due to coking for a long period, in a most energy efficient and safe manner, requiring little or no external energy.
(Conversion rates in excess of 90% in any industrial chemical process are pretty darned good. You would like to say "100% conversion", but that rarely happens in any industrial chemical processing. Follow on separation and concentration of one sort or another is almost always required. But, note that "no external energy" needs to be added. The partial oxidation made possible by the inclusion of some elemental Oxygen provides enough exothermic energy to drive the CO2-Methane reforming reaction, much as, as seen in:
West Virginia Coal Association | Standard Oil 1954 Oxygen Donor CO2 + CH4 + H2O = Syngas | Research & Development; concerning: "United States Patent 2,671,719 - Production of Mixtures of Hydrogen and Carbon Monoxide; 1954; Standard Oil Development Company; Abstract: The present invention is directed to a method for producing industrial mixtures of carbon monoxide and hydrogen (for) methanol synthesis (and) the Fischer-Tropsch synthesis, in which carbon monoxide and hydrogen, in suitable proportions, are reacted in the presence of a suitable catalyst and under selected conditions to produce an product primarily composed of liquid hydrocarbons. (One) way to obtain a mixture of carbon monoxide and hydrogen is to subject ... methane, and air to controlled combustion. One procedure which has been suggested is to use a metal as an oxygen carrier, said metal being first reacted with air to produce an oxide, which then is reacted with the hydrocarbon to produce a mixture of carbon monoxide and hydrogen. It has already been proposed to improve the process ... by mixing the gas resulting from the reaction of the hydrocarbon with the metal oxide with additional hydrocarbon ... and to (then) contact the resulting mixture with a reforming catalyst at a temperature suitable for the reaction of the hydrocarbon (i.e., Methane) with steam and carbon dioxide. This reaction is endothermic and requires a considerable heat supply. (But, since) the oxidation stage of the overall process is highly exothermic, it is desirable to provide a method of this character in which the exothermic heat of reaction may be utilized to supply heat for the endothermic reforming step. The present invention contemplates a process in which the exothermic heat of reaction in the oxidation stage is carried directly into the reduction and reforming stages";
a metal oxide can be used to convey Oxygen into a partial oxidation reaction with Methane, which reaction provides the heat energy needed to drive the associated reactions between CO2 and Water, and more Methane, to generate a synthesis gas which can be used for either the "methanol" or "Fischer-Tropsch" synthesis.)
Introduction: Since last few years, research activities on the activation of carbon dioxide by its reaction with methane, commonly known as CO2 reforming of methane to syngas (CO and H2), using different catalysts have got a lot of momentum because of a need for effective utilization of methane and CO2 ... . However, CO2 reforming is highly endotherrnic ... and (is) a highly energy intensive process. Further, it yields syngas with H2/CO ratio of (less than) 1 (which is not suitable for Fischer-Tropsch synthesis processes and also involves rapid coke deposition, particularly on nickel catalyst. Recently, efforts have been made also for the direct oxidative conversion of methane to syngas (with H2/CO = 2.0), which is an exothermic process and hence not at all energy intensive, using different catalysts. However, the exothermic heat produced in this process is very strongly dependent upon the selectivity, which makes the process very difficult to control and thus highly hazardous or unsafe. In this communication, we show that, by carrying out the exothermic oxidative methane-to-syngas conversion simultaneously with the endothermic CO2 reforming over NiO-CaO catalyst and manipulating the reaction conditions (viz. temperature and relative concentration of CH4, CO2 and O2 in the feed), all the limitations of the CO2 reforming process could be overcome.
(Results of described and illustrated experiments) reveal that by coupling the endothermic CO2 reforming with the exothermic oxidative methane conversion, the following advantages of great practical importance could be obtained:
1. The coupled process can be made mildly endothermic, thermoneutral or mildly exothermic by manipulating the process conditions (particularly the reaction temperature and the CH4/O2 and CH4/CO2 ratios in the feed) and, therefore, can be operated with requiring little or no external energy.
2. The heat produced in the exothermic reactions of methane with O2 ... is used instantly in the endothermic CO2 reforming ... , thus making the process most energy efficient, and also avoiding hot spot formation and consequently avoiding reaction runaway conditions and thereby making the process very safe to operate.
3. Further, in this coupled process, methane can be converted to syngas with a low H2/CO ratio (between 1 and 2, which is required for Fischer-Tropsch synthesis) with very high conversion (even above 95%), CO selectivity (100%) and H2 selectivity (above 90%) at very high (rate and) productivity.
The ... H2/CO ratio can be increased by increasing and by manipulating the CH4/O2 and CH4/CO2 ratios in the feed. Coke formation on the catalyst is a serious problem in CO2 reforming alone but not in the coupled process.
By coupling the endothermic and exothermic reactions of methane with CO2 and O2, respectively, ... and manipulating the process conditions, methane can be converted to syngas with low H2/CO
ratio required for
Fischer-Tropsch synthesis, with very high conversion, selectivity and productivity without catalyst deactivation due to coking for a long period and also with requirement of little or no external energy, in a most energy efficient and safe manner."
-----------------------
Though not dealt with by Choudary, it also seems likely that, as in our above citation of "United States Patent 2,671,719 - Production of Mixtures of Hydrogen and Carbon Monoxide", since heat balancing between the "endothermic and exothermic reactions" can be achieved by "manipulating the CH4/O2 and CH4/CO2 ratios in the feed", some H2O, Steam, could be calculated into the equation, as well, so that a "syngas with" a somewhat higher "H2/CO ratio" could also be evolved, one perhaps better suited for an alcohol synthesis, if that were preferred.
But, in any case, it is clear that Methane, as can be synthesized, as seen for yet another example in:
West Virginia Coal Association | US Gov Hires Penn State Bugs to Convert CO2 to Methane | Research & Development; concerning: "US Patent Application 20090317882 - Electromethanogenic Reactor and Process for Methane Production; 2009; The Penn State Research Foundation; Abstract: Biological processes for producing methane gas and capturing carbon from carbon dioxide are provided according to embodiments of the present invention (wherein) methanogenic microorganisms reduce the carbon dioxide to produce methane gas, even in the absence of hydrogen and/or organic carbon sources. Government Interests: This invention was made with government support under Contract Nos. BES-0401885 and CBET-0730359 awarded by the National Science Foundation. The government has certain rights in the invention";
from Carbon Dioxide, can be reacted with even more Carbon Dioxide, in the presence of some added Oxygen, and, in an efficient reaction that proceeds with "little or no external energy" being supplied to it, be thereby "converted to syngas ... for Fischer-Tropsch synthesis" of hydrocarbons.