We preface this dispatch, concerning the efficient capture and separation of Carbon Dioxide from the flue gas of industrial processes that combust hydrocarbon fuel, especially Coal, by attempting to address the question of:
When technologies such as disclosed, for example, in our reports of:
Efficient Capture of Atmospheric CO2 | Research & Development; concerning: "United States Patent 7,993,432 - Air Collector ... for Capturing Ambient CO2; 2011; Kilimanjaro Energy, Inc.; Abstract: An apparatus for capture of CO2 from the atmosphere";
with more reports of similar technology for extracting very clean and concentrated Carbon Dioxide from the atmosphere to follow, wherein freely-available environmental energy sources, such as wind and solar, are available to drive the reclamation;
and:
Pittsburgh USDOE Converts CO2 to Methane & Methanol | Research & Development; concerning: "Visible Light Photoreduction of CO2; 2009; National Energy Technology Laboratory, USDOE, Pittsburgh, PA; Abstract: A series of ... Titanium Dioxide (catalysts) have been synthesized, characterized, and tested for the photocatalytic reduction of CO2 in the presence of H2O (wherein) the primary reaction product is CH4, with CH3OH, H2, and CO observed as secondary products";
and:
USDOE 1990 Solar CO2-Methane Recycling-Reforming | Research & Development; concerning: "Solar Reforming of Methane in a Direct Absorption Catalytic Reactor on a Parabolic Dish; 1990; Sandia National Labs; Solar reforming of methane (CH4) with carbon dioxide (CO2) was achieved";
wherein environmental energy can again be harnessed, to, after the Carbon Dioxide has been captured, first convert that CO2 into Methane, CH4, and, then, to drive the reaction of that CH4 with even more Carbon Dioxide to form a synthesis gas suitable for catalytic chemical condensation into liquid hydrocarbons, exist,
then:
Why, in the world, would we want, in the first place, to attempt extracting Carbon Dioxide from the flue gases of Coal-fired power plants, where a large percentage of the Coal-based energy would be needed to collect the gases, and, wherein the CO2 would be just one of a number of product gases in that Coal plant exhaust?
Well, it just might make economic sense to do so.
As demonstrated by the quite recent United States Patent we enclose via the initial link in this dispatch, we see that a long-time member of the United States chemical industry has devised a means to extract and separate the individual components of Coal power plant exhaust, a process which employs, primarily, chemical reactions between those exhaust gas components to effect the separation.
The net result is a collection of products with established industrial uses and current commercial demand, which, even aside from the above-noted potentials for recycling Carbon Dioxide into hydrocarbons, might make the process a profitable one to install and employ at Coal-fired power plants.
We caution that the full disclosure seems enormously complex to us.
And, since the high-school chemistry instructor who had, from time to time, been advising us, is now back to teaching and grading on a full-time basis, with little time to spare for what seem increasingly-quixotic enterprises such as our now-vast exploration of Coal conversion and Carbon Dioxide recycling technologies, the attempts we make at translation and summation might leave this exposition in need of further explanation by someone genuinely qualified.
But, the key points, we think, will be clear, in our excerpts from the initial link in this dispatch to:
"United States Patent 7,927, 572 - Purifying Carbon Dioxide and Producing Acid
Date: April, 2011
Inventors: Nick Degenstein and Mahendra Shaw, NY
Assignee: Praxair Technology, Inc, CT
(Note: Many of our readers might be unfamiliar with the company, "Praxair", even though they are major suppliers of industrial gases to the chemical industry, including many of the chemical plants operating along the Ohio River and its tributaries. As seen in:
Praxair, Inc. - Manufacturer of industrial, process and specialty gases; they have: "26,000 employees and operations in more than 30 countries", and, are "focused on helping" their "customers become more profitable, efficient and environmentally friendly" by supplying "atmospheric, process and specialty gases (including) oxygen, nitrogen, carbon dioxide, helium and hydrogen";
they are a quite substantial corporation with specialized expertise in the supply of CO2 for industrial purposes. And, perhaps intriguingly, as can be learned in:
Praxair, Inc. -- Company History; they were founded all the way back in 1907 as "Linde Air Products Company", but, in 1917, became a part of Union Carbide Corporation, from whom, in 1992, they were "spun off'" as Praxair, "an independent company".
Which means, of course, that they were likely involved in any number of Union Carbide operations, including, as seen in:
West Virginia Hydrocracks Coal Liquids with Brute Force | Research & Development; concerning: "United States Patent 2,913,397 - Hydrogenolysis of Coal Hydrogenation Products; 1959; Inventors: James Murray, et. al., South Charleston and Nitro, WV; Assignee: Union Carbide Corporation; Abstract: This application relates to chemical processes. More particularly it relates to an improvement in processes for obtaining chemicals from coal"; and:
Charleston, WV, Coal + Steam = Hydrocarbon Syngas | Research & Development; concerning: "United States Patent 3,988,237 - Integrated Coal Hydrocarbonization and Gasification of Char; 1976; Inventors: Hubert Davis, Charles Albright, et. al.; all of West Virginia; Assignee: Union Carbide Corporation, NY;
Abstract: An integrated continuous process for the production of liquid and gaseous fuels (from) coal";
their exemplary, decades-long development of Coal gasification and liquefaction technologies in and around the state capitol of West Virginia.)
Abstract: Carbon dioxide is purified by processes employing NOx-rich sulfuric acid that can be formed by removal of SO2 from the carbon dioxide.
Claims: A process for treating gaseous carbon dioxide, comprising:
(A) providing a gaseous feed stream of carbon dioxide that also comprises NOx (i.e., various Nitrogen Oxides, as might be co-produced when plain Air is used for the gasification of Coal) and sulfur dioxide;
(B) contacting NOx-rich sulfuric acid with said gaseous feed stream and with NO2 desorbed in step:
(C) to strip NOx from said NOx-rich sulfuric acid and form NOx-reduced sulfuric acid and NOx-augmented gaseous carbon dioxide that (also contains) SO2 and NO2; (and) converting NO in said NOx-reduced sulfuric acid to NO2, and desorbing said NO2 from said NOx-reduced sulfuric acid to form NOx-lean sulfuric acid and desorbed NO2; and:
(D) controlling the amount of desorbed NO2 contacted with NOx-rich sulfuric acid in step (B) by converting desorbed NO2 to nitric acid and NO, and recovering said nitric acid.
A process ... further comprising recovering product sulfuric acid from said NOx-lean sulfuric acid.
(Not explained in our excerpts, though summarized in the above Abstract, is Praxair's specification that the "sulfuric acid" is to be made from the "SO2" in the exhaust stream. More of it, and of the Nitric Acid produced later, are made from the exhaust gas on a continuing basis. Again, the assistance of a professional chemist would be very helpful in clarifying all of this.)
A process ... wherein said gaseous feed stream of carbon dioxide is formed by combustion.
A process ... further comprising recovering product sulfuric acid.
Background and Field: The present invention relates to the treatment of gaseous streams such as flue gas containing carbon dioxide, to remove impurities from the gas and to produce valuable byproducts.
It is often desirable to treat carbon dioxide streams, whether naturally occurring or produced by man-made processes, to remove other components and thereby purify the carbon dioxide. For instance, combustion processes, such as coal-fired boilers, produce flue gases that contain carbon dioxide which it may be desirable to capture and sequester, for instance in saline aquifers or in oil or gas wells where the carbon dioxide is used for enhancing the production of oil or gas from the well. However, flue gas often contains impurities such as SO2 and NOx which must be removed down to very low levels before the carbon dioxide can be used for enhanced oil recovery or sequestered. The present invention is a process for achieving such removal, in a way that also produces sulfuric acid and nitric acid of strengths, and in amounts, that are commercially valuable.
(Note, that: Although there is expense involved in this process for extracting purified Carbon Dioxide from Coal power plant flue gas, we just might, if laws mandating that we "sequester" our effluent CO2 in "oil or gas wells", have to eat all of that expense, anyway, so that the operators of those "oil or gas wells" find our waste Carbon Dioxide acceptable for "enhancing" their profitable "production of oil or gas".)
The invention is useful in treatment of gaseous carbon dioxide streams which may be obtained in many ways. In particular, gaseous carbon dioxide streams with which the invention is useful include those produced by combustion, especially flue gas streams produced by combustion of hydrocarbonaceous fuels such as coal.
Operating costs associated with the process of the present invention will also be reduced over a comparable wet-limestone based desulfurization process because this process will yield separate streams of concentrated saleable sulfuric and nitric acid. If the SOx and NOx is captured as acid and sold, the costs associated with purchase, transportation and disposal of limestone will be eliminated while additional income will be realized.
Contaminants ... and moisture are removed and a cleaned-up stream containing carbon dioxide and atmospheric gases (O2, N2 and Ar) is formed which is fed to a sub-ambient-temperature processing stage which upgrades the purity of the carbon dioxide and produces a product stream having a desired high carbon dioxide level (95 to 99.9%)."
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So, while eliminating the expense of messing around with "limestone", we can produce "95 to 99.9%" pure Carbon Dioxide, from Coal power plant flue gas, in a process whose thus-reduced costs will be further offset by the co-production of "saleable sulfuric and nitric acid".
Additionally, even though we're not talking primarily about a CO2 extraction that could be independently sited, so as to take full advantage of environmental energy, we have documented, as in:
Green Energy to Recycle CO2 | Research & Development; concerning: "United States Patent Application No.: 20100146927 - Hybrid Power for Cracking Power Plant CO2; 2010; Abstract: Power from wind, solar, and other intermittent energy sources cracks carbon dioxide, NOx, SOx, and other emissions from fossil fuel power plants, which provide baseload power to the grid. By this hybrid power system, intermittent sources can be integrated in power generation without compromising the reliability of the grid. A hybrid power system, comprising: a power plant wherein energy from carbonaceous fuel is used to produce electric power, the power plant producing waste products including CO2; a source of energy selected from the group consisting of wind, photovoltaic solar, concentrating solar, and tidal" (and) means for simultaneous electrolysis of carbon dioxide and water to produce syngas (which) can be processed by the Fischer-Tropsch synthesis into liquid vehicle fuel (synfuel)";
that, a wide variety of environmental energies, in whatever amounts they might be obtained in whatever given environment, can be harnessed to at least supplement energy that might be derived from the power generation facility to reclaim and recycle Carbon Dioxide, thus reducing the operational costs even further, while conserving to some extent the basic power plant fuel and the energy it generates.
And, we submit, that, such "95 to 99.9%" pure Carbon Dioxide, as extracted from flue gas via our subject process herein, of "US Patent 7,927, 572", would be eminently suitable as the raw material for yet another technology, as reported in:
Texaco Recycles CO2 to Methanol & Methane | Research & Development; concerning: "United States Patent 4,523,981 - Means and Method for Reducing Carbon Dioxide to Provide a Product; 1985; Assignee: Texaco, Incorporated; Abstract: A process for reducing carbon dioxide to at least one useful product includes two redox couple electrolyte solutions separated by a first membrane having photosensitizers."
Wherein is explained another process that, using only Water and "solar" energy, is capable of transforming CO2, as recovered so cleanly and efficiently via our subject process, into a variety of products, including "formic acid", which is useful in fuel cells, among other things; (and/or) "formaldehyde", which can be used to formulate certain types of plastic; (and.or) "methanol", which is a useful liquid fuel in it's own right, but can as well, through, for instance, ExxonMobil's "MTG"(r) technology, be further converted into Gasoline;
(and/or) "methane".
And, which Methane, we remind you, through technologies like that disclosed in:
Standard Oil 1987 CO2 + CH4 = Syngas | Research & Development; concerning: "United States Patent 4,690,777 - Production of Synthesis Gas; 1987; The Standard Oil Company; Abstract: Gas mixtures containing at least hydrogen and carbon monoxide are prepared by reforming ... light hydrocarbons with carbon dioxide ... (and) wherein the light hydrocarbon is methane. (Such gas) mixtures containing carbon monoxide/hydrogen (in) ratios of 1/1 or 1/2 are particularly useful as feed gases in processes for producing higher hydrocarbons ... such as Fischer-Tropsch and alcohol synthesis processes";
can be reacted with even more Carbon Dioxide, also perhaps recovered, as via the process of our subject herein, "United States Patent 7,927, 572 - Purifying Carbon Dioxide and Producing Acid", economically from Coal power plant flue gas, and be made through such reactions to yield yet more blends of Carbon Monoxide and Hydrogen, which are so "useful as feed gases in processes for producing higher hydrocarbons".