Carbon Dioxide, as it is co-produced in only a small way - - relative to some all-natural and un-taxable sources of it's emission, such as the Earth's inexorable processes of planetary volcanism - - by our economically essential use of Coal in the generation of abundant, reliable and affordable electric power, is a valuable raw material resource.
Carbon Dioxide can be reclaimed, either from the environment or from various industrial exhaust gas streams, such as those produced by some plants that process that "clean energy alternative", natural gas, which is often contaminated with a large percentage of CO2 just it exits it's natural reservoirs, to make the long-distance shipment and subsequent combustion of that natural gas more efficient. Such extracted Carbon Dioxide from natural gas, as far as we know, is now most often just simply vented to the atmosphere, and is in addition to that generated by natural gas when it is combusted.
An industry has come into existence, by the way and in fact, to handle such natural gas CO2 issues. See, for example:
CO2 in Natural Gas - SpectraSensors; "CO2 measurements are required at natural gas custody transfer points to ensure the levels are low enough to meet quality specifications for pipeline transportation. CO2 is a naturally occurring diluent in oil and gas reservoirs and it can react with H2S and H2O to make corrosive compounds that threaten steel pipelines. Removal of CO2 from natural gas utilizes membrane technologies or larger amine plants. Rapid online analysis is sometimes critical to prevent volumes of contaminated gas from accidentally traveling downstream where it can affect combustion".
In any case, we've many times reported on the one century-old, Nobel Prize-winning Sabatier process, wherein Carbon Dioxide, no matter what it's source, is converted into substitute natural gas Methane.
See, for example:
CO2 Solution Wins Nobel Prize - in 1912 | Research & Development; wherein we're told of the Sabatier reaction, that: "Carbon monoxide and carbon dioxide are both changed immediately into methane, which can therefore be synthesized with the greatest ease".
In the Sabatier reaction, CO2 reacts with elemental, molecular Hydrogen over a catalyst to form Methane and water. The reaction vessel must be first heated to initiate the reaction, which, if properly catalyzed, proceeds with such vigor that it generates an appreciable amount of extra heat, which excess heat must then be controlled from building up, and, which also enables, as seen in:
NASA 2014 CO2 to Methane | Research & Development | News; concerning: "United States Patent 8,710,106 - Sabatier Process and Apparatus for Controlling Exothermic Reaction; 2014; Inventors: Christian Junaedi, et. al., CT; Assignee: Precision Combustion, Inc., CT; Abstract: A Sabatier process involving contacting carbon dioxide and hydrogen in a first reaction zone with a first catalyst bed at a temperature greater than a first designated temperature; feeding the effluent from the first reaction zone into a second reaction zone, and contacting the effluent with a second catalyst bed at a temperature equal to or less than a second designated temperature, so as to produce a product stream comprising water and methane. The first and second catalyst beds each individually comprise an ultra-short-channel-length metal substrate. An apparatus for controlling temperature in an exothermic reaction, such as the Sabatier reaction, is disclosed. Government Support: This invention was made with support from the U.S. government under U.S. Contract No. NNX10CF25P sponsored by the National Aeronautics and Space Administration. The U.S. Government holds certain rights in this invention";
the extraction of that exothermic heat as a potentially useable energy source, which could perhaps be used to help to drive other needed steps within the process, maybe, as perhaps suggested by:
US Navy Captures CO2 and Hydrogen for Hydrocarbon Synthesis | Research & Development | News; concerning: "United States Patent Application 20140238869 - Electrochemical Module Configuration for the Continuous Acidification of Alkaline Water Sources and Recovery of CO2 with Continuous Hydrogen Gas Production; 2014; Inventors: Felice DiMascio, Heather Willauer, Dennis Hardy, Frederick Williams, Kathleen Lewis; CT, VA, MD & PA; (Presumed eventual Assignee of Rights: the United States of America as represented by the Secretary of the Navy); Abstract: An electrochemical cell for the continuous acidification of alkaline water sources and recovery of carbon dioxide with simultaneous continuous hydrogen gas production having a center compartment, an electrolyte-free anode compartment having a mesh anode in direct contact with an ion permeable membrane, an endblock in direct contact with the anode where the endblock provides a gas escape route behind the anode, an electrolyte-free cathode compartment having a mesh cathode in direct contact with an ion permeable membrane, and an endblock in direct contact with the cathode where the endblock provides a gas escape route behind the cathode. Current applied to the electrochemical cell for generating hydrogen gas also lowers the pH of the alkaline water to produce carbon dioxide with no additional current or power";
the extraction of both CO2 and Hydrogen from "alkaline water" that has been used to absorb or capture Carbon Dioxide in the first place.
And, when we have the Carbon Dioxide and the Hydrogen, as confirmed less than a year ago by technical experts in the employ of our United States Government, a once well-known purveyor of gasoline and oil has developed a perhaps more efficient reaction, similar to that of NASA's above-cited "United States Patent 8,710,106 - Sabatier Process and Apparatus for Controlling Exothermic Reaction", to convert them into substitute natural gas Methane.
As seen in excerpts from the initial link in this dispatch to:
"US Patent 8,754,137 - Methanation Reaction Methods Utilizing Enhanced Catalyst Formulations
Date: June 17, 2014
Inventors: Scott Scholten, et. al., TX and OK
Assignee: Phillips 66 Company, Houston
(Many will remember the "Phillips 66"-branded service stations that were once common along our southeastern highways. Though you don't see a lot of that trade name anymore, as can be learned via:
Phillips 66 - Wikipedia, the free encyclopedia; Phillips 66 is an American multinational energy company headquartered in Westchase, Houston, Texas. It debuted as an independent energy company when ConocoPhillips spun off its downstream assets and midstream. Phillips 66 began trading on the New York Stock Exchange on May 1, 2012, under the ticker PSX. The company is engaged in producing natural gas liquids (NGL) and petrochemicals. The company has approximately 13,500 employees worldwide and active in more than 45 countries. Phillips 66 is ranked No. 6 on the Fortune 500 list";
they are still a very significant corporation, and operate on a global scale.)
Abstract: Enhanced mixed metal catalysts are provided which allow high conversions of carbon dioxide to methane, in some cases up to about 100% conversion. Methods of preparing enhanced mixed metal catalysts comprise a series of steps involving combining nickel and chromium salts with a nucleation promoter in a base environment to form a gel, allowing the gel to digest to form a solid and a mother liquor, isolating the solid, washing the solid, drying the solid, and thermally treating the solid to form a nickel-chromium catalyst. Methanation processes using the catalysts are also provided. The enhanced mixed metal catalysts provide more efficient conversion and lower operating temperatures for carbon dioxide methanation when compared to conventional methanation catalysts. Additionally, these enhanced catalyst formulations allow realization of higher value product from captured carbon dioxide.
(The highlighted final statement is the essence of the thing. The Sabatier CO2-to-Methane reaction proceeds so vigorously, and generates so much heat energy, that the heat can ruin the catalyst and stop the production of synthetic natural gas Methane by causing deposition of elemental carbon on the catalyst surfaces. The NASA CO2-to-Methane process of the above-cited "US Patent 8,710,106 - Sabatier Process and Apparatus for Controlling Exothermic Reaction" deals with that issue by extracting excess heat from the reaction, perhaps making it available for utilization. The Phillips 66 Company's CO2-to-Methane process of our subject herein, "US Patent 8,754,137 - Methanation Reaction Methods", on the other hand, provides a less-complicated, and thus perhaps less-expensive, means of controlling the CO2-to-Methane exothermic energy, by providing catalysts and a catalyst layout, and prescribing process conditions, for the reaction which, in the first place, while still allowing 100% conversion of the CO2 to substitute natural gas, prevent large amounts of reaction heat from being generated or accumulating.)
Claims: A methanation reaction process comprising the steps of: preparing a nickel-chromium catalyst, wherein the step of preparing comprises the steps of:
(a) combining a nickel(II) salt and a chromium(III) salt with a nucleation promoter and ammonium hydroxide to form a gel, the gel comprising a solid and a liquid;
(b) allowing the gel to digest to form a mother liquor and an isolatable solid;
(c) isolating the solid from the mother liquor;
(d) washing the solid;
(e) drying the solid;
(f) thermally treating the solid to form the nickel-chromium catalyst; wherein steps (a)-(f) result in a nickel/chromium ratio of about 98:2 to about 50:50 in the nickel-chromium catalyst (and:)
providing a single reactor vessel; continuously introducing carbon dioxide and hydrogen gas into the single reactor vessel over a fixed bed, the fixed bed comprising the nickel-chromium catalyst;
allowing the carbon dioxide and hydrogen gas to react in the single reactor vessel at a conversion rate in the presence of the nickel-chromium catalyst at a reaction temperature; maintaining the reaction temperature in the single reactor vessel at about 205 C to about 220 C by controlling a flow rate of one of the carbon dioxide and the hydrogen gas fed to the single reactor vessel; and wherein the conversion rate to methane is about 25 percent to about 100 percent.
The process ... wherein the nickel(II) salt comprises nickel(II) nitrate hexahydrate and wherein the chromium(III) salt comprises chromium(III) nitrate hexahydrate (and) wherein the conversion rate is about 97 to about 100 percent.
The process ... wherein the nucleation promoter is colloidal silica.
The process ... wherein the combining of step (a) further comprises the steps of: (i) combining the nickel(II) salt, the chromium(III) salt, and the colloidal silica in an aqueous solution; (ii) adding the ammonium hydroxide and the aqueous solution to a quantity of water to form a resulting solution and modulating the addition of the ammonium hydroxide at a flow rate sufficient to maintain a target pH of the resulting solution of about 7.5 to about 10; and wherein step (ii) occurs after step (i) (and) wherein the target pH is about 9 (and, as further described and specified).
The process ... wherein the nickel(II) salt comprises nickel(II) nitrate hexahydrate and wherein the chromium(III) salt comprises chromium(III) nitrate hexahydrate and (further comprising) the step of thermally treating the solid to form the nickel-chromium catalyst by heating in a furnace with continuously flowing air and raising the temperature to between about 300 C to about 450 C at a rate of about 2 C./min to about 5 C./min and maintaining the temperature for a sufficient period of time to decompose any hydroxide and nitrate salts.
The process ... wherein the nickel/chromium ratio in nickel-chromium catalyst is about 80:20.
The process ... wherein the conversion rate to methane is about 100 percent.
A methanation reaction method comprising the steps of:
(a) providing a nickel-chromium catalyst, the nickel-chromium catalyst having a nickel/chromium ratio of about 98:2 to about 50:50;
(b) providing a single reactor vessel;
(c) introducing carbon dioxide and hydrogen gas into the single reactor vessel;
(d) allowing the carbon dioxide and hydrogen gas to react at a conversion rate in the presence of the nickel-chromium catalyst in the single reactor vessel at a reaction temperature;
(e) maintaining the reaction temperature in the single reactor vessel at about 205 C to about 220 C; and:
(f) wherein the conversion rate to methane is about 100 percent.
Background: Reducing carbon dioxide emissions has traditionally focused on either reducing fossil fuel combustion or sequestration of carbon dioxide. Sequestration of carbon dioxide is the process of removing carbon from the atmosphere and depositing it in a reservoir. It is a geoengineering technique for long-term storage of carbon dioxide or other forms of carbon to either mitigate or defer global warming. By capturing carbon dioxide as a by-product in processes related to petroleum refining or from flue gases from power generation, the carbon dioxide may be sequestered in this way for long term storage in permanent artificial reservoirs such as subsurface saline aquifers, reservoirs, ocean water, aging oil fields, or other carbon sinks.
Another way of taking advantage of carbon dioxide production is by converting the carbon dioxide to a higher value product.
Methanation reactions are one example of a reaction process for converting carbon dioxide to a more desirable product, in this case, methane.
(Conventional) carbon dioxide methanation processes are plagued with low efficiencies and high costs.
The chemical reaction of carbon dioxide to methane is depicted as follows:
CO2 + 4H2 = CH4 + 2H2O
Achieving desirable reaction in methanation reactions typically requires temperatures exceeding approximately 230 C using conventional catalysts. This high temperature means that reaction vessels for these reactions must be fabricated out of metallurgies able to withstand the high temperatures or alternatively, one must stage the reaction over multiple reactors in series. In other words, the high temperatures required to achieve economically satisfactory completion of the methanation reactions essentially require either higher capital costs or higher operating costs. The high capital costs are due to having to use reactor metallurgies capable of withstanding the higher temperatures involved or having to stage multiple reactors in series. Where such higher temperatures are avoided by additional cooling equipment, higher operating costs are necessarily incurred.
(Again, as indicated above, a minimum temperature must be achieved to start the reaction, but the exothermic heat of the reaction is more than enough to keep the reaction going. It, in fact, can interfere with and cripple the reaction, perhaps via, as noted above and as explained in following passages, carbon, or "coke" deposition if allowed to accumulate.)
Another disadvantage of conventional catalysts is the higher coke formation inherent in the use of these conventional catalysts. Catalyst deactivation via coke deposition occurs with any carbon-containing source when oxygen is not present in the stream. The rate of coke deposition is strongly dependent on reaction temperature with higher deposition rates at higher temperatures. Operation at lower temperatures favors slower deposition rates, hence, less deactivation.
Thus, conventional catalysts are deficient in that they lack the ability to satisfactorily complete methanation reactions at sufficiently low temperatures. Consequently, conventional catalysts currently available for methanation reactions fail to realize satisfactory economic results.
Description and Summary: The methods disclosed herein provide an enhanced mixed metal catalyst which may lead to energy savings by lowering the operating temperature of carbon dioxide methanation.
In particular, the addition of chromium may promote the reverse water gas shift reaction which is described by the following chemical reaction: CO2 + H2 = CO + H2O
(The above "reverse water gas shift", or RWGS, conversion of CO2 to Carbon Monoxide is discussed in our report of:
France Efficient CO2 to Carbon Monoxide Conversion | Research & Development | News; concerning: "United States Patent Application 20030113244 - Method for Producing Carbon Monoxide by Reverse Conversion with an Adapted Catalyst; 2003; Inventor: Rene Dupont, et. al., France; Assignee: Air Liquide; Abstract: The invention concerns a method for producing carbon monoxide by reverse conversion, in gas phase, of carbonic acid gas and gaseous hydrogen while minimising the production of methane. The invention is characterised in that the reaction is carried out at a temperature between 300 and 520 C and under pressure between 10 to 40 bars in the presence of an iron-free catalyst based on zinc oxide and chromium oxide. Said method is preferably carried out continuously and comprises preferably the following steps which consist in: a) preparing a gas mixture rich in carbon dioxide and in hydrogen (and)reacting said gas mixture, forming carbon monoxide and water vapour, by passing said mixture through a catalytic bed".
And, our take on this Phillips 66 process is, that, by promoting an initial RWGS, they improve the Methane synthesis since Carbon Monoxide resulting from the RWGS conversion of Carbon Dioxide then reacts more efficiently with additional Hydrogen to form substitute natural gas Methane.)
In certain embodiments, the enhanced mixed metal methanation catalyst disclosed herein demonstrates methanation of carbon dioxide with 100% conversion at approximately 210 C, which represents a 20 C improvement over other conventional commercial catalysts tested.
At lower reaction conversions, the enhanced mixed metal methanation catalyst provides even lower reaction temperatures, resulting in further economic savings. These lower reaction temperatures translate into reduced operating costs and/or lower equipment capital costs depending on reactor design.
Methanation Reactions and Methods of Use: The enhanced mixed metal catalysts prepared according to the methods disclosed herein allow for a more efficient methanation of carbon dioxide, allowing high conversion of carbon dioxide at temperatures significantly lower than those of conventional catalysts.
One example of a method for methanation of carbon dioxide comprises the steps of preparing an enhanced mixed metal nickel-chromium catalyst according to the methods disclosed herein, providing the catalyst in a single reactor vessel, supplying carbon dioxide and hydrogen feed to the reactor, allowing the carbon dioxide and hydrogen gas to react in the presence of the catalyst, and maintaining a reaction temperature of about 205 C to about 220 C. As demonstrated by the examples below, conversions around 100% are achievable when using the enhanced mixed metal catalysts of the present invention for methanation of carbon dioxide.
In certain embodiments, the ratio of hydrogen to carbon dioxide is 4:1. Higher H2:CO2 ratios will have no impact on the catalyst but will result in unnecessary capital expense from the required recycling of the excess hydrogen. Lower ratios promote formation of byproduct carbon monoxide".
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We'll leave it at that.
We can, in sum - - as proposed by a very major petroleum company and as confirmed by our United States Government - - using Carbon Dioxide recovered perhaps via a process like that seen in our report of:
Renewable Energy Reclaims Coal Power Plant Carbon Dioxide | Research & Development | News; concerning: "United States Patent Application 20130152596 - Fossil Fuel-Fired Power Station Having a Removal Apparatus for Carbon Dioxide and Process for Separating Carbon Dioxide from an Offgas from a Fossil Fuel-Fired Power Station; 2013; Inventors: Hermann Kremer and Nicolas Vortmeyer, Germany; Assignee: Siemens Aktiengesellschaft (AG), Munich; Abstract: A fossil fuel-fired power station having a removal apparatus for carbon dioxide which is located downstream of a combustion facility and through which an offgas containing carbon dioxide may flow is provided. The removal apparatus comprises an absorption unit and a desorption unit. The desorption unit is connected to a renewable energy source.
The fossil-fired power plant ... wherein the renewable energy source is a solar thermal plant and comprises a solar array (or) wherein the renewable energy source is a geothermal plant";
in combination with Hydrogen generated via a process perhaps like that seen in our report of:
North Carolina Sunshine Extracts Hydrogen from H2O for USDOE | Research & Development | News; concerning: "US Patent 8,524,903 - Ruthenium or Osmium Complexes and Their Uses as Catalysts for Water Oxidation; 2013; Inventors: Javier Jesus Concepcion Corbea, et. al., North Carolina; Assignee: The University of North Carolina at Chapel Hill; Abstract: The present invention provides ruthenium or osmium complexes and their uses as a catalyst for catalytic water oxidation. Another aspect of the invention provides an electrode and photo-electrochemical cells for electrolysis of water molecules. Government Interests: This invention was made, in-part, with United States government support under grants numbered DE-FG02-06ER15788 and DE-SC0001011 from the Department of Energy. The U.S. Government has certain rights to this invention. Hydrogen is one of the most promising alternative energy sources. It can be obtained by electrolysis of water, which is environmentally friendly and efficient. However, the electrolysis of water is an energy intensive process, which is very expensive. On the other hand, photolysis, the splitting of water by light, presents an attractive alternative method of obtaining hydrogen";
wherein nothing but renewable, environmental energies are utilized or consumed, efficiently generate all of the fracking-free, environmentally-benign substitute natural gas Methane we might ever want or need.
And, in conclusion, we remind you that an industry founded on such technology might not only provide some initial basis for the supporters of Coal use and the environmentally-concerned among our citizenry to come together on, in addition to supplying a nearly-infinite and constantly renewing supply of substitute natural gas Methane, it would also lead to, in United States Coal Country, the creation of new industries and a lot of new and badly-needed permanent jobs - - jobs that would be filled by Coal Country's native citizens, as opposed to migrants employed by industries of perhaps only transient significance and temporary value.