Electrochemical synthesis of methane - Patent 4609440
We've submitted an almost copious amount of evidence attesting to the fact that Carbon Dioxide can be productively recycled, most especially and directly into the basic hydrocarbon, Methane, from which, as we've also copiously documented, liquid fuels such as Methanol and Gasoline can be synthesized; with some of those syntheses proceeding through reaction sequences that actually consume, or recycle, more Carbon Dioxide.
Herein we present yet another US Patent, almost a quarter-century old, as even more verification of those claims.
Our highly-condensed, due to technical detail, excerpt; with comment appended:
"Electrochemical synthesis of methane; US Patent Number 4609440
Date: September, 1986
Inventor(s): Karl W. Frese, Steven C. Leach, David P. Summers
Assignee: Gas Research Institute (Chicago, IL)
Claims:
1. A method for electrochemically reducing carbon dioxide to form methane, comprising: electrolyzing an aqueous solution containing carbon dioxide utilizing a cathode which comprises ruthenium to produce methane.
2. A method as set forth ... wherein the pH of the solution falls within a range from about 1 to about 7.
3. A method as set forth in claim 1, wherein the solution is at a temperature which falls within a range from about 20° C. to about 100° C.
4. A method as set forth in claim 1, wherein the electrolyzing is carried out at a potential which falls in a range from about -0.3 V to about -0.7 V versus SCE.
Disclosure of Invention:
In accordance with the present invention, a method is set forth for electrochemically reducing carbon dioxide to form methane. The method comprises electrolyzing an aqueous solution containing carbon dioxide and utilizing a cathode which comprises ruthenium to produce the methane.
Utilizing a ruthenium cathode in accordance with the present invention allows the production of methane by the aqueous electrolysis of a carbon dioxide solution at reasonably high faradaic efficiency. In this manner, electrical energy can be converted into chemical energy, effectively storing the chemical energy in the methane fuel. Methane fuel can later be burned to recapture the energy. The energy for the electrochemical reaction can be provided by solar cells or the like."
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Note, that, even in 1986, Carbon Dioxide recycling into Methane was presented as an almost "green" technology, wherein, as in similar proposals from Sandia National Laboratory for CO2 recycling, "solar cells or" similar could harness environmental energy to recycle what many believe to be an environmental pollutant.
The energy requirements for the Gas Institute's CO2-recycling process, as they state them, certainly seem low enough to be easily met by the most common environmental energy conversion technologies - wind, solar, hydro - we now already have available to us.
Use of such "renewable" energy for Carbon Dioxide recycling should make it even more attractive, relative to Carbon Dioxide geologic disposal, in terms of providing at least some return on investment, and adding some element of sustainability.
And, we are compelled to continue repeating that, once Methane is obtained, it can be either catalytically condensed into liquid fuels, or, better, employed in "Tri-reforming" processes to recycle even more Carbon Dioxide into liquid fuels.
Moreover, we are beginning to learn that Methane can be added as a valuable supplemental feed to syngas derived from Coal, prior to it's catalysis into liquid fuels.
Methane is versatile, valuable stuff. And, we can make it from that old devil, Carbon Dioxide.