Last April, the better part of a year ago, we alerted you that scientists in Minnesota had identified certain strains of bacteria, from a group of bacteria called "methanogens", and methods of utilizing them, that would enable the natural process of fermenting organic materials into Methane to be supplemented and increased by adding gaseous Carbon Dioxide to a "bioreactor", a vessel designed to both promote the growth of the bacteria, and, to facilitate collection of the product Methane.
That report is now accessible on the West Virginia Coal Association's web site via the link:
Minnesota Bacteria Convert Exhaust Gas CO2 to Methane | Research & Development; and concerns:
"United States Patent Application 20070298478 - Bio-Recycling of Carbon Dioxide Emitted from Power Plants; 2007; Inventor: John D. Offerman, et. al., MN; Assignee: Novus Energy, LLC, MN; Abstract: The invention provides a method to decrease emission of carbon dioxide from combustion of fossil fuels or other hydrocarbons and to enhance the efficiency of methane production from anaerobic biodigesters. The invention involves feeding carbon dioxide from the exhaust gas of hydrocarbon fuel combustion to an anaerobic biodigester where biomass is anaerobically fermented to produce methane."
The process, we point out, represents a two-fold CO2 recycling pathway, since botanical Biomass, formed by natural photosynthesis from, in part, atmospheric Carbon Dioxide, is being combined in the fermentation vessel with, as they specify, "carbon dioxide from the exhaust gas of hydrocarbon fuel combustion".
Such "biodigesters", that produce Methane, are not unknown, as we've documented previously, for one instance, in our report of:
USDOE Algae Recycle CO2 into Liquid Fuels | Research & Development; concerning : "Liquid Fuels from Microalgae; 1987; USDOE Contract Number: AC36-99-GO10337; National Renewable Energy Laboratory (NREL), Golden, CO; USDOE; Abstract: The goal of the DOE/SERI Aquatic Species Program is to develop the technology to produce gasoline and diesel fuels from microalgae (and, this report) demonstrates that liquid fuels can be produced from mass-cultured microalgae at prices that will be competitive with those of conventional fuels by the year 2010. The emphasis of the DOE-SERI Aquatic Species Program is to develop the technology base for large-scale production of lipid-yielding microalgae and conversion of the lipids into liquid fuels. The algae can be grown ...using the resources of sunlight, saline water, nitrogen, phosphorus, and carbon dioxide. The algae can convert these raw materials into proteins, carbohydrates, and lipids (and) harvested cells then are subjected to an extraction process to remove the lipids (which can be further processed) to produce fuels similar to diesel fuels and ... gasoline. Although microalgae lipids represent the premium energy product, the energy trapped in the other biomass constituents can also be used; e.g., the cell residue after lipid extraction can be anaerobically digested for the production of methane and carbon dioxide."
And, in the above USDOE "Liquid Fuels from Microalgae", the Carbon Dioxide that is co-produced, with the Methane, from the Algal cellular debris in the bio-"digester", is only a small fraction of the CO2 that was, in the first place, fed to the Algae for the biosynthesis of "lipids (which can be further processed) to produce fuels similar to diesel fuels and ... gasoline".
The innovation herein is that the Minnesota scientists have taken the USDOE's bacterial "digester" one step further, and, not only can the bacteria be fed with CO2-derived "biomass", but, they can also be fed with more Carbon Dioxide gas; and, any CO2 ultimately co-produced, with the Methane, by the methanogenic bacteria, would be a very small fraction of the CO2 the bacteria had, both directly and indirectly, consumed.
In fact, feeding the methanogenic bacteria additional Carbon Dioxide actually improves their digestion of the CO2-derived organic wastes, and the subsequent production of Methane, as borne out by one of the inventors' concluding statements in this advance excerpt, wherein we're told, that:
"providing supplemental carbon dioxide by the methods of the present invention promotes methanogenesis and more efficient and complete fermentation of organic substrates".
All of which is confirmed by our own US Government experts, in their issuance, as a result of "United States Patent Application 20070298478", as excerpted, with additional comments and links inserted and appended, from the initial link in this dispatch, of:
"United States Patent 7,919,290 - Bio-recycling of Carbon Dioxide Emitted from Power Plants
Date: April 5, 2011
Inventors: John Offerman and Hugh McTavish, MN
(Note: Some extended comment seems necessary here. In the original US Patent Application, as we reported, the Assignee of rights to this US Patent was intended to be "Novus Energy, LLC".
However, as can be learned via: http://www.becamericas.org/
co-inventor John Offerman, an accomplished scholar and scientist, who did serve "for six years as chief executive officer and chief technology officer of Novus Energy, LLC, a developer of various renewable energy technology platforms he co-founded in 2004"; no longer seems to be with the company.
Novus, is, though, still very much alive and kicking, with inventor Hugh McTavish still on board, as seen in:
Novus Energy | Alternative Energy, Biogas, Ethanol Fuel Producer; wherein we can learn that:
"Novus Energy’s three groundbreaking technologies offer production cost advantages over virtually every other biofuel methodology, including crop-based ethanol, bio diesel and petroleum-based gasoline and diesel"; and, that: "Hugh McTavish is a ... Ph.D biochemist and ... was on the staff of the National Renewable Energy Laboratory (NREL) in Golden, Colorado researching photosynthesis. His research background also includes solar hydrogen production and hydrogen production by enzyme engineering. He has patents and published scientific publications in green plant photosynthesis, solar energy, hydrogen production and enzymatic hydrogen production. Dr. McTavish has been instrumental in writing and developing Novus Energy’s patents and five pending patents".
And, our assumption for now is that, for whatever reason, Offerman left Novus Energy prior to issuance of our subject, "United States Patent 7,919,290", and, by some arrangement, the rights to the patent were then reassigned to, and divided between, him and McTavish, personally, since no mention of Novus is made in this official US Patent and Trademark Office record of their invention.
Abstract: The invention provides a method to decrease emission of carbon dioxide from combustion of fossil fuels ... and to enhance the efficiency of methane production from anaerobic biodigesters.
The invention involves feeding carbon dioxide from the exhaust gas of hydrocarbon fuel combustion to an anaerobic biodigester where biomass is anaerobically fermented to produce methane.
Carbon dioxide is an electron acceptor for anaerobic fermentation, and thus some of the carbon dioxide is reduced to methane, which can again be used for fuel. In this way, at least a portion of the exhaust gas CO2 is recycled to form fuel methane instead of being released into the atmosphere. Thus, the net CO2 emission from burning a given amount of fossil fuel is decreased. Adding carbon dioxide to an anaerobic fermentation also increases the efficiency and amount of methane production in the fermentation.
(Thus, again, although some Carbon Dioxide is co-produced, with the Methane, from the "anaerobic biodigesters"; adding "carbon dioxide from ... exhaust gas" to such "biodigesters", where Carbon-recycling "biomass is anaerobically fermented to produce methane", actually "increases the efficiency and amount of methane production" from that Carbon-recycling "biomass".
And, we further submit, this technology could serve, as noted above in our citation of "Liquid Fuels from Microalgae; 1987; USDOE", as the process wherein "the cell residue after lipid extraction can be anaerobically digested for the production of methane and carbon dioxide", after "biolipids" suitable for the production of both Diesel and Gasoline, had been extracted from Algae that had originally been "grown ...using the resources of sunlight, saline water, nitrogen, phosphorus, and carbon dioxide". - JtM)
Claims: A method of producing methane comprising: collecting combustion exhaust gas from a hydrocarbon fuel combustion process; separating O2 from CO2 in the exhaust gas to generate a CO2-rich anaerobic exhaust gas fraction; feeding the CO2-rich anaerobic exhaust gas fraction to a fermentation mixture containing methanogenic microorganisms; feeding a reduced substrate selected from the group consisting of H2 and organic material and a combination thereof, to the fermentation mixture; and producing a biogas comprising methane in the fermentation mixture by the anaerobic fermentation of methanogenic microorganisms; fractionating the biogas into a methane-rich fraction and a carbon dioxide-rich fraction; and processing the methane-rich fraction for energy; wherein feeding the CO2-rich anaerobic exhaust gas fraction to the fermentation mixture increases methane production in the fermentation mixture.
(Note that the process does seem to call, as well, for feeding some Hydrogen, in addition to the "organic material" and the Carbon Dioxide, to the anaerobic digester. As seen in our earlier report of:
USDOE Algae Make Hydrogen for Coal and CO2 Hydrogenation | Research & Development; concerning: "Photosynthetic Hydrogen and Oxygen Production by Green Algae; Oak Ridge National Laboratory; USDOE Contract Number: AC05-96OR22464; Abstract: Photosynthesis research at Oak Ridge National Laboratory is focused on hydrogen and oxygen production by green algae";
certain strains of Algae can be selected for use in the initial Algae-based Carbon Dioxide "scrubber", as in the above-cited "Liquid Fuels from Microalgae", which, in the cyclic course of their photosynthetic metabolism, will, while they are converting Carbon Dioxide, and a few other things, into "biolipids", also emit a certain amount of molecular Hydrogen. So, the CO2-recycling Algae cultivation, which will make both the biolipids, and, as well, the cellular residue for use in the process of our subject herein, "United States Patent 7,919,290", might be finagled into making the H2 required by "United States Patent 7,919,290", as well.
If not, then, as seen, for one example, in:
NASA Hydrogen from Water and Sunlight | Research & Development; concerning: "United States Patent 4,045,315 - Solar Photolysis of Water; 1977; NASA; Hydrogen is produced by the solar photolysis of water";
other economical options for obtaining any needed Hydrogen do exist.)
The method ... further comprising recirculating at least a portion of the carbon dioxide-rich fraction into the fermentation mixture.
(Thus, some, or all, of the Carbon Dioxide co-produced in, we would say "passed through", the Methane generator, can be collected and added to the Carbon Dioxide being fed to the Methane generator. There are, as will be seen immediately below, other productive options for the rest of it.)
A method of producing methane and alcohol/alcohols comprising: collecting combustion exhaust gas from a hydrocarbon fuel combustion process; separating O2 from CO2 in the exhaust gas to generate a CO2-rich anaerobic exhaust gas fraction; feeding the CO2-rich anaerobic exhaust gas fraction to a fermentation mixture containing methanogenic microorganisms; feeding a reduced substrate selected from the group consisting of H2 and organic material and a combination thereof, to the fermentation mixture; and producing a biogas comprising methane in the fermentation mixture by the anaerobic fermentation of methanogenic microorganisms; converting at least a portion of the biogas to synthesis gas comprising CO and H2; and contacting the synthesis gas with a catalyst to produce alcohol; wherein feeding the CO2-rich anaerobic exhaust gas fraction to the fermentation mixture increases methane production in the fermentation mixture.
(Thus, in one aspect, the gasses generated by the anaerobic digester, Methane and Carbon Dioxide, can instead be treated as the raw materials for a hydrocarbon synthesis gas generator, such as described, for just two out of now many examples, in our reports of:
Exxon 2010 CO2 + Methane = Liquid Hydrocarbons | Research & Development; concerning: "United States Patent 7,772,447 - Production of Liquid Hydrocarbons from Methane; 2010; ExxonMobil; Abstract: (A) process for converting methane to liquid hydrocarbons ... (by) contacting a feed containing methane and ... H2O (and) CO2 with a (specified) catalyst under conditions effective to convert said methane to aromatic hydrocarbons"; and:
Standard Oil 1954 CO2 + CH4 + H2O = Syngas | Research & Development; concerning: "United States Patent 2,676,156 - Preparation of Synthesis Gas; 1954; 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";
and be reacted, converted, together into a blend of Hydrogen and Carbon Monoxide "suitable for employment in the hydrocarbon synthesis process", which would convert the CO2 and the Methane, ultimately, into "liquid hydrocarbons".
But, further, and importantly, note that such anaerobic digestion, which produces the Methane from organic wastes and added Carbon Dioxide, also, concurrently, produces some "alcohol".)
Summary: The invention provides a method to decrease emission of carbon dioxide from combustion of fossil fuels or other hydrocarbons and to enhance the efficiency of methane production from anaerobic biodigesters. The invention involves feeding carbon dioxide from the exhaust gas of hydrocarbon fuel combustion to an anaerobic biodigester where biomass is anaerobically fermented to produce methane.
Carbon dioxide is an electron acceptor for anaerobic fermentation, and thus some of the carbon dioxide is reduced to methane, which can again be used for fuel. In this way, at least a portion of the exhaust gas CO2 is recycled to form fuel methane instead of being released into the atmosphere. Thus, the net CO2 emission from burning a given amount of fossil fuel is decreased.
Furthermore, feeding exhaust gas CO2 to the anaerobic biodigester increases the efficiency of the biodigester and the yield of methane ... .
In anaerobic biodigesters, anaerobic microorganisms ferment reduced carbon substrates to other products. For instance, some organisms transform hexose sugars to ethanol and CO2. Other common fermentation products include ... methane.
Organisms that produce methane are called methanogens. The hydrogen for methanogenesis from carbon dioxide in nature comes from fermentation of reduced carbon substrates. But hydrogen gas can also be supplied directly to a fermenter for methane production.
Thus, in addition to being a fermentation product, CO2 is ... crucial ... for methane production.
Anaerobic fermentation generally and methane production specifically are slowed when the carbon dioxide concentration is too low. Carbon dioxide is often a limiting factor in anaerobic methanogenesis.
The invention involves feeding a combustion exhaust gas that is rich in CO2 into an anaerobic digester to enhance methane production in the digester. The CO2 increases methane production from the digester, which means that a portion of the CO2 is reduced to methane, and carbon dioxide emissions from fossil fuel burning are reduced. By increasing methane production from anaerobic digestion of biomass, the method also increases the yield of a renewable form of energy.
If hydrogen gas is the reduced substrate for the anaerobic digester, all the fed CO2 can be converted to methane. The hydrogen gas can be produced renewably, such as by using wind energy to produce electricity for electrolysis of water.
(Concerning the above, see, for instance:
Hydrogen from Wind Power | Research & Development; concerning: "US Patent 7,329,099 - Wind Turbine and Energy Distribution System; 2008; A new design of vertical axis wind turbine is disclosed (and, a) new energy distribution system is proposed (wherein) wind energy (generates electricity to power an) electrolysis cell connected to an output stream of hydrogen gas and further connected to an input stream of water"; and:
Mountaineer Wind Energy Center - Wikipedia, the free encyclopedia; wherein we're told of the "Mountaineer Wind Energy Center ... a wind farm in Preston and Tucker counties in ... West Virginia".)
The biogas methane can be burned for energy to produce heat or electricity. Alternatively, it may be converted to a liquid fuel by first converting it to a syngas containing CO and H2, and then contacting the CO and H2 with a catalyst under high pressure and heat to form alcohol. This is known as a Fischer-Tropsch type process. Thus, one motivation for using hydrogen to reduce combustion exhaust CO.sub.2 to methane by the present process would be to further convert the methane to alcohol and thereby convert hydrogen gas to a liquid fuel that is more easily transportable and that, unlike hydrogen, has a present market as an automotive fuel.
(Concerning the above-noted " Fischer-Tropsch type process", see, from our own USDOE National Energy Technology Laboratories, including those in Morgantown, WV, and Pittsburgh, PA:
http://www.netl.doe.gov/
It should be noted that methanogenic microorganisms are very sensitive to oxygen. Therefore, it is important to eliminate oxygen from the exhaust gas CO2 before feeding the exhaust gas CO2 to an anaerobic fermenter.
Thus, one embodiment of the invention provides a method of producing methane comprising: (a) collecting combustion exhaust gas from a hydrocarbon fuel combustion process; (b) separating O2 from CO2 in the exhaust gas to generate a CO2-rich anaerobic exhaust gas fraction; (c) feeding the CO2-rich anaerobic exhaust gas fraction to a fermentation mixture containing methanogenic microorganisms; (d) feeding a reduced substrate selected from the group consisting of H2 and organic material and a combination thereof, to the fermentation mixture; and (e) producing a biogas comprising methane in the fermentation mixture by the action of methanogenic microorganisms; wherein feeding the CO2-rich anaerobic exhaust gas fraction to the fermentation mixture increases methane production in the fermentation mixture."
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And, thus, "combustion exhaust gas ... CO2" can be fed to a special "fermentation mixture containing methanogenic microorganisms", which "microorganisms" are at work digesting CO2-recycling "organic material", a practice which "increases methane production" by that "fermentation mixture".
And, again, the "organic material" can be the residue of a process such as that seen in:
Illinois Algae Convert Flue Gas CO2 into $60 Oil for USDOE | Research & Development; concerning: "Removal of Carbon Dioxide from Flue Gases by Algae; 1993: Institute of Gas Technology, Chicago (and) Illinois Dept. of Energy and Natural Resources, Springfield, IL (and) USDOE; The objective of this research program is to determine the feasibility of the alga Botryococcus braunii as a biocatalyst for the photosynthetic conversion of flue gas CO2 to hydrocarbons";
after "hydrocarbons", made by Algae from "flue gas CO2", have been extracted, to make oil in the "range between $45 and $75 per barrel", and leaving behind a semi-solid biomass comprised of the Algae's cellular remains.
Then, once more and finally, after we have that Methane, as made by microorganisms from CO2-recycling biomass and additional "combustion exhaust gas ... CO2", we can, as seen additionally in:
1939 CO2 + CH4 = Hydrocarbons | Research & Development; concerning: "US Patent 2,180,672 - Process for Converting Gaseous Hydrocarbons; 1939; Phillips Petroleum, Oklahoma; This invention relates to processes for the conversion of normally gaseous hydrocarbons into organic products of higher molecular weight and more specifically to the conversion of methane ... together with oxides of carbon into such organic products with aid of solid catalytic agents. Combustion products, ... carbon dioxide, ... may be mixed directly with the ... methane";
mix that Methane "directly" with more "carbon dioxide", recovered from whatever source, and convert them both into valuable and needed "organic products of higher molecular weight"