Oregon Converts CO2 to Methane and Regenerates CO2 Absorbents

United States Patent: 4571384

 

We've already documented from multiple sources that certain types of microorganisms can be harnessed and employed to convert Carbon Dioxide, recovered from whatever source, into Methane.

 

An example would include:

 

Minnesota Bacteria Convert Exhaust Gas CO2 to Methane | Research & Development; which reports:

"US Patent Application 20070298478 - Bio-Recycling of Carbon Dioxide Emitted from Power Plants; 2007; 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."

That Minnesota invention, as do other published concepts similar in theme, suggests that the Carbon Dioxide can be collected at it's place of emission, and then be converted into Methane, and/or other products of value, by utilizing microorganisms, bacteria or algae.

Direct industrial chemical technologies, leading to similar products, supported or driven, perhaps, in part, by waste heat energy recovered from the process that generated the by-product Carbon Dioxide, have also been proposed.

Other, conceptually-related, Carbon Dioxide recycling technologies, as seen in:

USDOE Bugs Eat C02, Excrete Liquid Fuel | Research & Development; which concerns the report:

 

"Engineering Bacteria to Turn Carbon Dioxide into Liquid Fuel; 2009", a synopsis of work performed by the University of California, Los Angeles, for the USDOE; posits that "genetically modified" microorganisms can "consume carbon dioxide and produce (a) liquid fuel ... gasoline alternative" in a process that's "powered directly by energy from sunlight";

 

document that environmental energy can be employed to drive such CO2-recycling conversion reactions.

 

Furthermore, just as environmental energy can power the chemical transformation of Carbon Dioxide, it can also power the processes which, in the first place, collect the CO2 for further processing; and, as in:

 

CO2 Air Capture Practical - U of Colorado | Research & Development; concerning: "An idealized assessment of the economics of air capture of carbon dioxide in mitigation policy; 2009; University of Colorado; Abstract:

(A discussion of) the technology of direct capture of carbon dioxide from the atmosphere called air capture. The simple assessment finds that ... the costs of air capture are directly comparable to the costs of stabilization using other means":

 

such "air capture" can be seen as "directly comparable" to other means of collecting Carbon Dioxide, so that any CO2 collection facilities can be sited so as to take advantage of environmental energy, such as Solar, Wind or Hydro, that might be more abundantly available in certain locations.

 

To that end, as an aside, we remind you of a recent report, accessible via:

 

Kentucky Converts Coal and CO2 to Hydrocarbon Syngas | Research & Development; wherein we included an additional link,West Virginia Geothermal Maps: Another Energy Bonanza for WV?; to information concerning: "West Virginia Geothermal; 2010; Southern Methodist University; (The) temperature of the Earth beneath the state of West Virginia is significantly higher than previously estimated and capable of supporting commercial baseload geothermal energy production."

 

And, so, in addition to her Hydro and Wind resources, West Virginia, and nearby parts of US Coal Country, might well have available yet another Carbon-free environmental energy resource that could be harnessed to the task of effecting the "air capture" of atmospheric Carbon Dioxide, in economically and environmentally  suitable and convenient locations, and, then, transforming that CO2 into hydrocarbon products.

 

We don't have to saddle our individual Coal-based electricity generating facilities with hugely-expensive and energy-squandering Carbon Dioxide collection devices.

 

All of that said, following, as accessible via the initial link in this dispatch, is disclosure, from Oregon State University, of how all those considerations can be brought together, in what could, depending on the sources of environmental energy which were utilized, be a continuous process for, first, harvesting Carbon Dioxide from the atmosphere, and, then, converting that Carbon Dioxide into Methane.

 

Comment follows, and is inserted within, excerpts from:

 

"United States Patent 4,571,384 - Methane Production

 

Date: February, 1986

 

Inventors: Richard Morita and Ronald Jones, OR

 

Assignee: State of Oregon

 

(Note: Although not clearly identified, both named inventors were, at the time of issue, with the Oregon State University. Morita is a distinguished scholar with a long background; and, was, or is, a Professor Emeritus,  specializing in marine microbiology. Jones, according to available sources, was a graduate student in OSU's Department of Chemistry

 

Abstract: Methane is produced by dissolving mineral carbonate in water to produce dissolved carbon dioxide which is converted to methane by anaerobic methanogenic bacteria in the presence of hydrogen gas supplied to the water. Preferably, the mineral carbonate is in the form of a bed of particulate mineral carbonate with the bacteria attached thereto. The bed is submersed in the water in a closed vessel and a flow of hydrogen gas is passed through the vessel.

 

(Note that "mineral carbonate" most likely would mean "Calcium Carbonate", which is formed when Calcium Oxide, as is commonly proposed, is utilized as an absorbent for Carbon Dioxide. The Calcium Oxide is regenerated, for recycling and reuse, when the CO2 is driven out of it, typically by heating.)

 

Claims: A method of producing methane gas comprising: providing in a closed vessel ... a bed of particulate mineral carbonate ...; a volume of water submersing the bed of mineral carbonate, and ... a population of anaerobic methanogenic bacteria specifically adapted for the conversion of carbon dioxide to methane attached to the particulate mineral carbonate in said bed,

(And) circulating water through the vessel and passing a flow of hydrogen gas through the vessel, the mineral carbonate in said bed through dissolution introducing dissolved carbon dioxide and mineral ions to the water within the vessel, the methanogenic bacteria utilizing the ... hydrogen gas to convert the dissolved carbon dioxide to methane gas, the water circulated through the vessel removing mineral ions introduced by dissolution of the mineral carbonate,

 

(And) withdrawing from the vessel the methane gas so produced.

 

(Note that this process, somewhat unfortunately, entails the use of free, molecular Hydrogen. However, as we have documented, for example, in: NASA Hydrogen from Water and Sunlight | Research & Development; concerning: "USP 4,045,315 - Solar Photolysis of Water; 1977; NASA; Hydrogen is produced by the solar photolysis of water"; and, in: Morgantown, WV, USDOE Hydrogen from Coal | Research & Development; which discloses: "USP 4,976,940 - Method for Producing H2; 1990; USDOE; A method of producing hydrogen by an endothermic steam-carbon reaction"; we do have a number of sound, economically viable options available to us that would enable the efficient production of that elemental Hydrogen; options that are by far more economically viable than Cap & Trade taxation and mandated Geologic Sequestration.)

 

Background and Summary: This invention relates to a method and apparatus for producing methane, and more particularly to such a means and apparatus which relies upon methanogenic bacteria to convert a carbon source to methane.

With the world facing a dwindling supply of sources of so-called fossil fuels, many have come to believe that energy in the future will be provided through the generation and use of hydrogen. There are many problems, however, associated with this approach. For one thing, each molecule of methane possesses much more energy when combusted than a molecule of hydrogen. Natural gas is essentially methane, and all our natural gas lines are geared to the transport of methane rather than hydrogen. Hydrogen is a far more explosive material than methane.

 

(Remember the Hindenberg.)

 

While methane technology has been fairly well developed, fairly little has been perfected in connection with hydrogen technology. Hydrogen, therefore, should be converted to methane. The need, therefore, exists for a methane generation process which is practical, nonlabor intensive, sanitary, efficient, and, in essence, provides a renewable source of methane.

The production of methane using methanogenic bacteria is not new.

 

Generally, an object of this invention is to provide a unique process for producing methane utilizing methanogenic bacteria which obviates or minimizes many of the problems associated with processes such as those described (in the accompanying history of such technologies).

More particularly, the invention includes amongst its objects producing methane through bacteria reactions utilizing as a carbon source a water-dissolved mineral carbonate. The carbonate equilibrates in water producing dissolved carbon dioxide ... .

More particularly, the invention contemplates the utilization of mineral carbonates as the source of carbon dioxide which have limited solubility ... . A bed of such material when submerged in a volume of water functions continuously to supply to the water dissolved carbon dioxide available for conversion to methane.

 

As carbon dioxide is used up by converting to methane, additional carbonate is dissolved.

 

Further contemplated in the invention is the continuous introduction of water to the vessel containing the methanogenic bacteria, and withdrawal of water from such vessel of water which is displaced by the introduced water. In this manner, the mineral ion content of the water is held relatively constant. The water displaced and containing mineral ions produced by the dissolving of the mineral carbonate reacts with carbon dioxide present in the air to reproduce the mineral carbonate which may then be reused in the production of methane.

 

(Note: The process of the invention regenerates the Carbon Dioxide absorbent. After CO2 is extracted, for conversion into Methane, the absorbent is recycled to the device which extracts CO2 from the air.)

 

If the water within the tank is acidified ... usually with any inorganic acid such as ... H2SO4 ... the equilibrium is adjusted tending to produce an increase in the carbon dioxide produced. As the carbon dioxide is used up, more carbonate dissolves, with the production of more bicarbonate and carbon dioxide.

 

(Which leads to "more" Methane production, from the "produced" Carbon Dioxide. And, such proposed employment of "H2SO4", sulfuric acid, leads to speculation about how yet another much-decried by-product of our essential Coal use, Sulfur and it's compounds, might be productively utilized. However, we do note that the Sulfur doesn't seem to be passed through in some sort of product, and we don't have any concept as to what, if any, continuous and ongoing supply of it might be needed.)

 

While continuously providing carbon dioxide, as such is depleted by the action of the methanogens, as already briefly indicated, the crushed relatively insoluble carbonate also serves as sites for the attachment of the methanogens producing the methane.


In accordance with the present invention, methane is produced through the reduction of carbon dioxide dissolved in water by methanogenic bacteria. The dissolved carbon dioxide is produced by dissolving a mineral carbonate in water.

 

Since the carbon source is essentially carbon dioxide produced by the dissolving of the mineral carbonate, eliminated from the methanogenic reaction mixture are complex organic compounds containing carbon introducing competing non-methanogenic reactions.

 

The mineral carbonate which is employed is ... reclaimable, in the sense that an aqueous solution containing a high concentration of calcium ion (which results by reason of the production of methane) is quickly converted to calcium carbonate on exposure to carbon dioxide in the air.

 

Illustrative of mineral carbonates that are advantageously used in practicing the instant invention are those materials which are principally calcium carbonate such as ... limestone ... .

 

The process above-described has several advantages. For one thing, it should be noted that the source of carbon in the process, i.e., the mineral carbonate, is an extremely inexpensive source of material. ... The equipment required and the method of the invention is relatively simple. Once operating conditions have been established ... methane production will continue uninterruptedly, with minimal supervision required.

 

A colony of methanogenic bacteria once established in a fermentation tank becomes selective to the operating conditions present, then the colony will continue to operate effectively with such conditions are maintained.

The process contemplated is far less complicated and time consuming then marine biomass systems which have been proposed to date. By utilizing a mineral carbonate as the source of carbon, competing complex methanogenic reactions such as occur with the usual biomass systems are substantially eliminated."

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First, as we have indicated in previous reports of similar technology, such as the above-noted "US Patent Application 20070298478 - Bio-Recycling of Carbon Dioxide Emitted from Power Plants; 2007; Assignee: Novus Energy, LLC, MN", "methanogenic" bacteria are well-known to biological science, and particularly useful strains of those microorganisms are always specified by the patents concerning them. Furthermore, again as indicated in USP Application 20070298478, and, to a certain extent in our subject, USP 4,571,384, bacteria can be modified, genetically engineered, to enhance both their Methane production and their viability in the industrial, Methane-producing environments.

 

But, we most often don't reproduce the names of those bacteria in our reports concerning them, since their names would appear only as strings of Latinate gibberish to us mere mortals.

 

Finally, though we know this dispatch has been overly-long, we are compelled to remind you, that, as seen, for just one out of now many, many possible examples, in:

 

More Standard Oil 1944 CO2 + CH4 = Hydrocarbons | Research & Development; concerning: "United States Patent 2.347.682 - Hydrocarbon Synthesis; 1944; Assignee: Standard Oil Company of Indiana; Abstract: This invention relates to an improved method and means for effecting the synthesis of hydrocarbons from carbon monoxide and hydrogen (obtained from) methane (which is) mixed with such proportion of carbon dioxide and steam as to give a gas mixture ... consisting chiefly of hydrogen and carbon monoxide ... hereinafter referred to as ... 'synthesis' gas' (which may be converted into and through)  C3 and C4 hydrocarbons ... into high quality motor fuels or heavier oils";

 

we can, once we have the Methane, generated as herein, via our subject process of US Patent 4,571,384, from Carbon Dioxide, react that Methane with even more Carbon Dioxide, recovered from whatever convenient source, perhaps, again, just the atmosphere, and produce, via reaction between CO2-derived Methane and even more Carbon Dioxide, "high quality motor fuels".