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Without preamble, the excerpt:
"Improvement of coal direct liquefaction by steam pretreatment
Authors
IVANENKO O. ; GRAFF R. A. ; BALOGH-NAIR V. ; BRATHWAITE C. ;Authors Affiliations
Departments of Chemical Engineering and Chemistry, The City College of New York, New York, New York 10031, ETATS-UNISAbstract
Pretreatment of coal by reaction with subcritical steam enhances its performance in direct liquefaction. Illinois No. 6 coal, first reacted with 51 atm of steam for 15 min at 340 °C, was liquefied in a coal injection autoclave to provide rapid heating. Liquefactions were carried out with raw and pretreated coal at high-severity (400 °C, 30 min) and low-severity (385 °C, 15 min) conditions under 1500 psia of hydrogen with tetralin as the donor solvent. Substantial improvement in product liquid quality is realized provided the pretreated coal is protected from oxygen and heated rapidly to liquefaction temperature. Under low-severity conditions, the oil yield is more than doubled, going from 12.5 to 29 wt %. Since previous work pointed to the destruction of ether cross-links by water as the dominant depolymerization mechanism during pretreatment, tests were conducted with several aromatic ethers as model compounds. These were exposed to steam and inert gas at pretreatment conditions and in some cases to liquid water at 315 °C. α-Benzylnaphthyl ether and α-naphthylmethyl phenyl ether show little difference in conversion and product distribution when the thermolysis atmosphere is changed from inert gas to steam. Hence, these compounds are poor models for coal in steam pretreatment. The otherwise thermally stable 9-phenoxyphenanthrene, on the other hand, is completely converted in 1 h by liquid water at 315 °C. At pretreatment conditions, however, mostly rearranged starting material is obtained. Therefore, 9-phenoxyphenanthrene, though less reactive, is a model for ether linkages in coal.Journal
Energy & Fuels; 1997, vol. 11, pp. 206-212
Publisher
American Chemical Society, Washington, DC, ETATS-UNIS (1987) (Revue)"
So, a college, in New York City, is improving a process for the direct liquefaction of coal into liquid fuels. We're glad that it's a United States institution, at least. But, what about the institutions of higher learning in Coal Country? Well, you do recall our dispatch of yesterday regarding the conversion of BS and dead horses' patoots, don't you?
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We've never heard of C. John Mann, and doubt many in our local corner of Coal Country have either.
But, we should all be talking, and writing, like him.
There's not much new in here, except that Mann is neither a politician nor a journalist. He is, though, as some research reveals, an accomplished scientist; a Mann of learning, so to speak. He knows what he's talking about, and we all should be listening.
And, again, writing.
The excerpt:
C. John Mann: Nation must use oil from unconventional sources
THE STATE JOURNAL-REGISTER
Posted Oct 27, 2009 @ 01:02 AM
All but ardent environmentalists who have a perverse antipathy toward science seem to recognize that continued use of fossil fuels is inevitable. What is not inevitable is a costly energy crisis that results from an over-emphasis on unreliable energy sources and neglect of oil, natural gas and coal.
Though they’re helpful in meeting energy demand in some parts of the country, solar and wind energy are too undependable to run factories and keep the lights on in cities. Solar and wind can’t move the nation’s transportation system. Nor can biofuels. For America’s motor vehicles, we’re still going to rely on gasoline and diesel. But our foreign-oil dependence is about to get much worse unless something is done about it.
If the Obama administration is really interested in reducing U.S. reliance on foreign energy supplies, then it should recognize the value and validity of unconventional oil made from liquefied coal, Canadian oil sands and Western oil shale.
Using these vast resources to meet America’s energy needs would be a boon for U.S. consumers and this country’s energy security. And everyone would benefit from well-paying jobs and revenue that come from producing, processing and refining liquefied coal and oil sands.
A recent decision by the U.S. State Department to support oil-sands production offers at least a glimmer of foresight and flexibility.
Canada’s oil sands formations hold an estimated 173 billion barrels of recoverable oil, making Canada second only to Saudi Arabia in the size of its reserves. The International Energy Agency has said that with future advances in technology as much as 1.7 trillion barrels of Canadian oil sands could be extracted.
Despite protests from environmental groups, the State Department approved a permit for a 1,000-mile-long pipeline that would carry oil from Canada’s oil sands formations in northern Alberta to refineries on Lake Superior in Wisconsin. The Alberta Clipper pipeline will be capable of carrying 800,000 barrels per day of crude oil, shoring up Canada’s position as America’s No. 1 source of foreign oil.
Environmentalists, however, are waging an all-out battle against the use of oil sands, largely on grounds that it is more carbon-intensive than conventional crude oil, as if the crucial role of unconventional oil in meeting America’s energy needs doesn’t matter.
Environmental groups have filed lawsuits to block expansion of the vast infrastructure (production facilities, pipelines, and refineries) that are needed to accommodate the growth in oil sands production.
Earlier, they succeeded in getting Congress to include a provision in 2005 energy legislation that prohibits U.S. government agencies from using petroleum products made from oil sands, shale oil and liquefied coal. The Air Force has objected strongly to this ban, pointing out that it prevents military aircraft from using jet fuel made from oil sands.
California and Oregon have banned use of oil sands, oil shale and liquefied coal, and several northeastern states reportedly plan to follow suit. At the same time, the U.S. House of Representatives is considering legislation that would impose a national ban in the guise of a low-carbon fuel standard. House members who are pushing for its passage seem heedless of economic consequences.
Quite simply, lawmakers should steer clear of regulations that discriminate between conventional and unconventional fuel sources, as they would exacerbate energy security problems without delivering compensating climate benefits. Imposing greater costs on oil sands producers and the liquefied coal sector will only benefit OPEC and would have little impact on reducing greenhouse-gas emissions. Given this country’s increasing rate of unemployment, we can ill-afford to turn our back on unconventional fuels.
Take liquefied coal. Helped by rising energy prices and new research, coal is moving to the forefront as a cleaner-burning fuel and a source for liquid fuel. The technology for converting coal into diesel and jet fuel is well established, having been used for nearly 100 years in Germany and for several decades in South Africa.
Plans for two-dozen major coal-to-liquid projects in the United States are under way. Some of the projects are awaiting federal loan guarantees so that construction can begin. Importantly, research has shown how to capture carbon dioxide at coal facilities and store the gas in the earth's subsurface.
As for Western oil shale, the technology for tapping it is still being developed. But policymakers are counting on oil shale to help meet the nation’s energy needs in future years. In fact, Western shale is far and away Americas most abundant source of oil. Shale in Colorado, Utah and Wyoming holds an estimated 800 billion barrels of recoverable oil. And there is no doubt its development could obviate the need for imported oil.
As the administration works with Congress to develop energy policies, those who shape legislation need to wake up and realize that our country cannot afford to forego the use of unconventional oil. A misguided push to prevent its use can only succeed in undermining our economy.
C. John Mann is a professor emeritus of geology at the University of Illinois at Urbana-Champaign.
----------------
We all "need to wake up and realize that our country cannot afford to forego the use of unconventional oil".
And, it's way past time Coal Country journalists started pouring the coffee.
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It is, unfortunately, not Coal-to-Liquid technology that WVU has patented. China, as we some time ago reported to you, has Shanghaied WVU's "West Virginia Process" for direct coal liquefaction, and applied for their own US and/or International Patent(s) on the technology; again, as we much earlier documented.
That info is in the WV Coal Association R&D Blog archives.
However, as a sort of consolation prize, WVU has, apparently, been awarded a US patent for converting Corpses and Cow pies To Liquid fuel.
An excerpt from the link, edited somewhat for concision:
"Title: Method of converting animal waste into a multi-phase fuel
Patent Number: US2008271363 - November 06, 2008
Inventors: Stiller; Alfred Herman and Eddy; Laura Shannon
Assignee: West Virginia University
Abstract and Claims:
A method of creating a multi-phase fuel wherein said fuel comprises a gas, a solid, a liquid solvent phase and an aqueous phase from animal waste comprising the combination of the animal waste, a solvent, and a water/alcohol solution into a fluid mixture, placing the mixture into a closed reactor, heating said reactor between about 245.degree. C. and 385.degree. C. for between about 5 and 70 minutes and cooling said resulting multi-phase fuel. The animal waste may be manure, mortalities, municipal waste, or chicken litter. The preferred solvent is petroleum with the preferred petroleum being diesel fuel. The final multi-phase fuel can be separated into four separate fuels: a solid fuel, an emulsified solid in the liquid solvent phase by blending the solid, the solvent and a surfactant, an aqueous phase, and the recovered liquid solvent phase. Petroleum is the preferred solvent and the separation may be any conventional means. The mixture preferably consists of 1 part by weight animal waste, about 1.5 parts by weight diesel and between about 0.11 to about 1.86 parts by weight a water/alcohol solution. The water/alcohol solution is between about 5% to about 85% alcohol before heating. Additionally, an alkali base may be added to increase waste solubility.
1. A fuel reactant mixture comprising about 1 part by weight animal waste, about 1.5 parts by weight petroleum based solvent and between about 0.11 to about 1.86 parts by weight a water/alcohol solution, wherein said water/alcohol solution is between about 5% to about 85% alcohol. 3. The fuel reactant mixture of claim 1 wherein said animal waste is selected from one or more of the group consisting of manure, mortalities, municipal waste, and chicken litter. 4. The fuel reactant mixture of claim 1 wherein said petroleum based solvent is diesel. 5. The fuel reactant mixture of claim 1 further comprising adding an alkali base to said mixture. 6. The fuel reactant mixture of claim 5 wherein said alkali base is sodium hydroxide. 7. The fuel reactant mixture of claim 1 wherein said alcohol is normal propyl alcohol. 8. The fuel reactant mixture of claim 1 wherein said water/alcohol solution is about 25% alcohol. 9. The fuel reactant mixture of claim 1 wherein said water/alcohol solution is about 1 part per weight. 10. The fuel reactant mixture of claim 1 further comprising mixing said animal waste, said petroleum based solving, and said water/alcohol solution into a fluid solution. 11. The fuel reactant mixture of claim 10 further comprising heating said mixture for an effective time and effective heat to produce a multi-phase fuel. 12. The fuel reactant mixture of claim 11 wherein said multi-phase fuel is further comprised of an aqueous phase fuel, a liquid solvent phase fuel, a solid fuel, and a gas."
We congratulate, of course, WVU on this achievement. The conversion of any bio-based resource into liquid fuel represents a step forward in both domestic liquid fuel self-sufficiency and carbon recycling.
But: We are allowing China to patent the West Virginia Process for direct coal liquefaction, and we have herein only a consolation prize. We Mountaineers, while paying royalties to China, when we eventually get around to converting our vast reserves of coal into the liquid fuels we need, will be able to liquefy, free of foreign charges, all the animal corpses and manure we can scrape together. Does that mean we'll be converting ourselves into liquid fuel? One might think so, since, if we do allow the game play out the way it appears, then we are, and will remain, really, nothing more than horses' patoots, full of BS.
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Oregon State University, at least at one time, was engaged by NASA to research ways to optimize life support systems aboard the International Space Station, where, according to reports we've already brought to your attention, they utilize Noble Prize-winning Sabatier technology to recycle Carbon Dioxide into Oxygen, and the fuel gas, treated as waste aboard the ISS, Methane.
As part of OSU's efforts, they accumulated a body of reference works detailing research already accomplished on the subject of Carbon Dioxide recycling.
We reproduce, following below, a partial list of their collected references, and call your attention, especially, both to the mention of Sabatier, in research published in 1902, and to the citation: "Lunde, P.J. and Kester, F.L. Carbon Dioxide Methanation on a Ruthenium Catalyst, Ind. Eng. Chem., Process Des. Dev., 13(1):27-33, 1974."
More on Lunde will follow in a separate dispatch. But, here is the list of references demonstrating that we have a far greater understanding of how to profitably utilize the Carbon Dioxide by-product of our coal-use industries as the valuable raw material resource it truly is. We have an understanding of Carbon Dioxide's value that has, however, and for whatever reason, been occluded and subverted.
Joe the Miner
(Note, again: Mention of "Carbon Dioxide Reduction" means not just reduction in the amount of CO2, but the chemical reduction of it into it's elemental components, Carbon and Oxygen. - JtM)
Boyda, R.B., Lee, M.G., and Grigger, D.J., Sabatier Carbon Dioxide Reduction System for Space Station Freedom, SAE Technical Paper Series No. 921189, presented 22nd International Conference on Environmental Systems, Seattle, WA, July 13-16, 1992.
Forsythe, R.K., Verostko, C.E., Cusick, R.J., and Blakely, R.L., A Study of Sabatier Reactor Operation, in Zero "G", SAE Technical Paper Series No. 840936, presented 14th Intersociety Conference on Environmental Systems, 1984.
Kashiwai, T., Matsumoto, H., Kamishima, N., Hatano, S., Nitta, K., and Ashida, A., Study of Oxygen Recovery Stystem using Reduction of Carbon Dioxide, SAE Technical Paper Series No. 951558, presented at 25th International Conference on Environmental Systems, San Diego, CA, July 10-13, 1995.
Lunde, P.J. Modeling, Simulation, and Operation of a Sabatier Reactor, Ind. Eng. Chem., Process Des. Dev., 13(3), 226-232, 1974.
Lunde, P.J. and Kester, F.L. Carbon Dioxide Methanation on a Ruthenium Catalyst, Ind. Eng. Chem., Process Des. Dev., 13(1):27-33, 1974.
Noyes, G.P., Carbon Dioxide Reduction Processes for Spacecraft ECLSS: A Comprehensive Review, SAE Technical Paper Series No., 881042, presented at 18th Intersociety Conference on Environmental Systems, San Francisco, CA, July 1988.
Noyes, G.P., and Cusick, R.J., An Advanced Carbon Reactor Subsystem for Carbon Dioxide Reduction, SAE Technical Paper Series No. 860995, presented 16th Intersociety Conference on Environmental Systems, San Diego, CA, July 14-16, 1986.
Otsuji, K., Hanabusa, O., Sawada, T., Satoh, S., and Minemoto, M., An Experimental Study of the Bosch and the Sabatier CO2 Reduction Processes, SAE Technical Paper Series No. 871517, presented 17th Intersociety Conference on Environmental Systems, Seattle, WA, July 1987.
Sabatier, P., and Senderens, J.B., Comptes Rendus Acad. Sci., 134, 689, 1902.
Samsonov, N.M., Kurmazenko, E.A., Gavrilov, L.I., Farafonov, N.S., Dokunin, I.V., Markin, S.V., Pavlova, T.N., Naumov, V.A., and Jakimenko, A.O., Results of Engineering Development of the Carbon Dioxide Reduction Assembly for a Space Station Integrated Life Support System, SAE Technical Paper Series No. 951557, presented at 25th International Conference on Environmental Systems, San Diego, CA, July 10-13, 1995.
Samsonov, N.M. and et al, A Complex of Systems for Oxygen Recovery Aboard a Manned Space Station, SAE Technical Paper Series No. 932275, Society of Automotive Engineers, Warrendale, PA, 1993.
Secord, T.C. and Bonura, M.S., Operational Ninety-Day Manned Test of Regenerative Life Support Systems, SAE Technical Paper Series No. 901257, Society of Automotive Engineers, Warrendale, PA, 1990.
Son, C.H., and Barker, R.S., Comparative Test Data Assessment and Simplified Math Modelling for Sabatier CO2 Reduction Subsystem, SAE Technical Paper Series No. 921228, presented 22nd International Conference on Environmental Systems, Seattle, WA, July 13-16, 1992.
Strumpf, H.J., Chin, C.Y., Lester, G.R., and Homeyer, S.T., Sabatier Carbon Dioxide Reduction System for Long-Duration Manned Space Application, SAE Technical Paper Series No. 911541, presented 21st International Conference on Environmental Systems, San Francisco, CA, July 15-18, 1991.
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Scattered among the references, collected by Oregon State University, we sent you earlier to document the fact that Carbon Dioxide can be chemically reduced and converted into hydrocarbons and Oxygen, are mentions of Ruthenium, a Platinum Group metal, as a catalyst for Carbon Dioxide conversion reactions.
It is so efficient at splitting Carbon from CO2, and recombining it with Hydrogen to form the hydrocarbon fuel gas, and liquid fuel and chemical manufacturing raw material, Methane, that the reactions can be conducted in a low-heat, low-pressure environment, thus making the process of recycling Carbon Dioxide much more energy efficient.
The fact that it works, and works well, is confirmed herein by our own, US, patent examiners in their approval and issuance of Patent 4847231, parts of which we've reproduced below.
First, a brief excerpt from the text to emphasize the technology's efficiency:
"It is an object of this invention to provide a low pressure and low temperature process for the direct formation of methane from carbon dioxide and hydrogen by a heterogeneous catalytic gas phase reaction."
And, note, too, that this patent was issued in 1989. That's not as long ago as Paul Sabatier won the Nobel Prize for demonstrating that CO2 could be effectively recycled, but long ago enough that we should by now have stopped arguing about CO2 emissions from coal-use industries, and be well on our way to domestic liquid fuel self-sufficiency, through the conversion of our abundant coal and the recycling of coal's most abundant by-product.
Does anyone know why we are not?
PS: Ruthenium, though a somewhat uncommon Platinum Group metal, does have fairly wide-spread natural occurrence, and it can, according to web-based references, be synthesized in relative abundance in some nuclear reactors.
Excerpt (presented with overly-dense technical passages deleted. Interested readers are invited to explore through the link, but please do make note of the mention of Fischer-Tropsch coal-to-liquid conversion technology. It all ties in together. - JtM):
US Patent 4847231 - Mixed ruthenium catalyst
US Patent Issued on July 11, 1989
Inventors
- Gratzell, Michael
- Kiwi, John
- Thampi, Krishnan R.
Assignee
- Gas Research Institute
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
Heterogeneous catalytic gas phase methane production from hydrogen and carbon dioxide is achieved directly at temperatures as low as 25° C. and at atmospheric pressures by use of a catalyst having a mixture of Ru and RuOx, wherein x is greater than 0 and equal to or less than 2, supported by a suitable metal oxide support. Photo-methanation using such catalysts having photo excitable support materials significantly increases methane production, yielding almost stoichiometrically quantitative amounts of methane according to Sabatier reaction.
2. Description of the Prior Art
Use of ruthenium as a hydrogenation catalyst on a titania support for Fischer-Tropsch reactions of CO and H2 to produce hydrocarbons, principally liquid hydrocarbons at elevated pressure and methane at atmospheric pressure, is known from a number of patents including U.S. Pat. Nos. 4,042,614; 4,477,595; 4,558,030; 4,567,205; and 4,619,910. The 4,047,614 and 4,477,595 patents teach suppression of methane formation in the Fischer-Tropsch reaction when using titania as opposed to alumina or carbon support material.
Nickel is a known hydrogenation catalyst for reforming of methane by reaction of carbon monoxide and hydrogen. U.S. Pat. No. 4,132,672 teaches addition of a small amount of iridium for improved conversion of hydrogen and carbon monoxide to methane.
The electrochemical reduction of carbon dioxide to methane on Ru electrodes is taught by K. W. Frese, Jr. and S. Leach "Electrochemical Reduction of Carbon Dioxide to Methane, Methanol, and CO on Ru Electrodes", Journal of the Electrochemical Society, Vol. 132, No. 1, pgs. 259-260, January 1985. This electrochemical reduction works only at low current densities and is not a selective as desired for methane.
Photoreduction of CO2 to methane and higher hydrocarbon in aqueous solution using Ru or Os colloids as catalysts is taught by Itamar Willner, Ruben Maidan, Daphna Mandler, Heinz Durr, Gisela Dorr and Klaus Zengerle, "Photosensitized Reduction of CO2 to CH4 and H2 Evolution in the Presence of Ruthenium and Osmium Colloids: Strategies to Design Selectivity of Products Distribution", J. Am. Chem. Soc., Vol. 109, No. 20, pgs. 6080-6086, 1987. This photoreduction reaction utilizes Ru metal as an electron transfer catalyst and consumes triethanol amine making the process commercially unattractive.
The Sabatier reaction:
CO2 + 4H2 > CH4 + O2
is a known important catalytic process which despite its favorable thermodynamics, has been difficult to achieve due to high energy intermediates imposing large kinetic barriers and the formation of side products is common. Investigations during recent years aimed toward improving the activity and selectivity of methanation catalysts has been reported, including Lunde, P. J. and Kester, F. L., J. Catal. 30, 423-429 (1973); Phyng Quack, T. Q. and Rouleau, D., J. appl. Chem. Biotechnol. 26, 527-535 (1976); Tomsett, A. D., Hagiwara, T., Miyamoto, A. and Inui, T., Appl. Catal., 26, 391-394 (1986); Solymosi, F., Erdoheli, A. and Bansagi, T., J. Catal. 68, 371-382 (1981); Weatherbee, G. D. and Bartholomew, C. H., J. Catal, 87, 352-362 (1984); and Inui, T., Funabiki, F., Suehiro, M. and Sezume, T., JCS Faraday Trans. 1, 75, 787-802 (1979). Although progress has been made, elevated temperatures of greater than 300° C. and pressures of greater than 1 atmosphere are still required for methane generation to proceed at significant rates and yields according to the Sabatier reaction.
SUMMARY OF THE INVENTION
It is an object of this invention to provide a low pressure and low temperature process for the direct formation of methane from carbon dioxide and hydrogen by a heterogeneous catalytic gas phase reaction.
It is another object of this invention to provide catalytic gas phase methane production from hydrogen and carbon dioxide using a mixed Ru/RuOx catalyst wherein x is greater than 0 and less than or equal to 2.
It is yet another object of this invention to provide a process for the direct formation of methane from carbon dioxide and hydrogen providing a very selective yield of methane of greater than about 95 percent, and preferably greater than 99 percent.
It is still another object of this invention to provide a process for catalytic direct methanation of carbon dioxide and hydrogen using highly dispersed mixture of Ru/RuOx on a photoexcitable catalyst support material wherein the reaction rate is significantly enhanced through photoexcitation of the support material.
The catalyst used in the process of this invention is a mixed ruthenium catalyst of about 10 to about 90 percent Ru and about 10 to about 90 weight percent RuOx, wherein x is greater than 0 and less than and equal to 2. The mixed ruthenium catalyst is highly dispersed on a suitable metallic oxide support with Ru loading of about 1 to about 15 percent. Specifically, a mixed ruthenium catalyst of about 25 mole percent Ru and about 75 mole percent RuOx loaded onto a TiO2 support material, Ru loading of 3.8 percent, has been found to provide very selective, greater than 99 percent, yield of methane by direct reaction of CO2 and H2 at about ambient temperature and atmospheric pressure. Reaction rates may be enhanced in the order of four to five times by photoexcitation of the TiO2 support material under photoexcitation of the support material stoichiometry according to the Sabatier reaction continued to be greater than 99 percent at 1 atmosphere pressure and 46° C.
DESCRIPTION OF PREFERRED EMBODIMENTS
The process of this invention provides highly selective direct formation of methane from carbon dioxide and hydrogen according to the stoichiometry of the Sabatier reaction. High methane selectivity and yield is achieved at low temperatures and low pressures by use of a catalyst of a mixture of Ru and RuOx
The mixed ruthenium portion of the catalyst comprises about 10 to about 90 mole percent Ru and about 10 to about 90 mole percent RuOx wherein x is a number greater than 0 and less than and equal to 2. Preferred proportions of the mixed ruthenium catalyst are about 15 to about 35 mole percent Ru and about 65 to about 85 mole percent RuOx. Catalytic activity of the mixed ruthenium catalyst has been found to be superior to use of the fully reduced Ru or the unreduced RuO2 in the methanation reaction.
The support portion of the catalyst is a metal oxide which may be photoinsensitive for dark methanation or a semiconducting oxide for light activated methanation. highly dispersed on specific metal oxide support materials.
Loading of mixed Ru and RuOx on the support material in accordance with this invention should be about 1 to about 15 weight percent of the total mixed ruthenium/support material catalyst, preferably about 2.5 to about 7.5 weight percent. The powdered catalyst of this invention may be used in catalytically effective quantities and in any suitable manner known to the art for conduct of solid catalyst/gas phase reactions as known to the art. Hourly space velocities up to 100,000 h-1 have been employed and gave good conversions.
The direct reduction of carbon dioxide to methane by hydrogen according to the Sabatier reaction is highly selectively achieved by the process of this invention under low pressure and low temperature conditions. The process of this invention is carried out by passing gaseous carbon dioxide and hydrogen in contact with the mixed ruthenium/metallic oxide support catalyst of this invention. It is preferred that hydrogen be present in stoichiometric excess amounts, about 1 to about 5 times the stoichiometric amount required for the Sabatier reaction being suitable, about 2 to about 4 times stoichiometric hydrogen being preferred. The process for direct formation of methane from carbon dioxide and hydrogen according to this invention is carried out at low pressure, ambient up to about 10 atm, preferably ambient to about 3 atm. The process is suitably carried out at low temperatures below about 300° C. and preferably below 200° C., ambient to about 200° C. being suitable, about 50° to about 150° being preferred.
The process of this invention appears to proceed directly according to the Sabatier reaction. Analyses of gas mixtures during the process have found no evidence of formation of carbon monoxide and Fischer-Tropsch products, as further set forth specifically in Example II. This has been further confirmed by separate work showing that the hydrogenation of carbon monoxide using the catalyst of this invention requires much higher temperatures than the mild near ambient conditions suitable for the process of this invention. Still further, the direct conversion of carbon dioxide to methane according to the present process has been found to be very selective, the yield of methane being greater than 99 percent under many conditions. To the inventors' knowledge, the catalyst of this invention provides the first process for ambient room temperature conversion of carbon dioxide to methane.
Methane formation and carbon dioxide consumption strictly obeyed the 1:1 stoichiometry of the Sabatier reaction indicating that the catalyst operated in a very selective fashion. This was confirmed by gas chromotograph, mass spectrometry and high pressure liquid chromotography which failed to detect other byproducts. Particularly, the formation of carbon monoxide, methanol, formaldehyde, ethane and higher homologues can be excluded within the detection limit for these compounds which was at least 0.002 μmol per μmol of methane generated. There was no formation of formic acid or oxalic acid.
While in the foregoing specification this invention has been described in relation to certain preferred embodiments thereof, and many details have been set forth for purpose of illustration,
* * * * * it will be apparent to those skilled in the art that the invention is susceptible to additional embodiments and that certain of the details described herein can be varied considerably without departing from the basic principles of the invention.
Other References
- K W. Frese, Jr. and S. Leach "Electrochemical Reduction of Carbon Dioxide to Methane, Methanol, and CO on Ru Electrodes", Journal of the Electrochemical Society, vol. 132, No. 1, pp. 259-260
- Itamar Willner, R. Maidan, D. Mandler, Heinz Durr, G. Dorr and K. Zergerle, "Photosensitized Reduction of CO2 to CH4 and H2 Evolution in the Presence of Ruthenium and Osmium Colloids; Strategies to Design Selectivity of Products Distribution", J. Am. Chem. Soc., vol. 109, No. 20, pp. 6080-6086, 1987
- Lunde, P. J. and Kester, F. L., J. Catal. 30, 423-429 (1973)
- Phyng Quzck, T. Q. and Rouleau, D., J. Appl. Chem. Biotechnol. 26, 527-535 (1976)
- Tomsett, A. D., Hagiwara, T., Miyamoto, A. and Inui, T., Appl. Catal., 26, 391-394 (1986)
- Solymosi, F., Erdoheli, A. and Bansagi, T., J. Catal. 68, 372-381 (1981)
- Weatherbee, G. D. and Bartholomew, C. H., J. Catal., 87, 352-362 (1984)
- Inui, T., Funabiki, F., Suehiro, M. and Sezume, T., JCS Faraday Trans. 1, 75, 787-802 (1979)
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