Production of hydrocarbon synthesis gas
We've lately been reporting on the use of "Oxygen donor" substances, the oxide compounds of specific metals, in Coal gasification processes, as, for one especially intriguing example, in our report of:
Oklahoma Oxygen Donor Coal Gasification | Research & Development; concerning: "United States Patent 4,496,370 - Zinc Oxide-Char Gasification Process; 1985; Phillips Petroleum Company; Abstract: In the gasification of char with zinc oxide, the improvement which comprises reacting the off-gas stream of gaseous zinc and carbon monoxide with steam at elevated temperatures in a second reactor means thereby oxidizing the zinc to zinc oxide and yielding a second gaseous stream containing carbon monoxide and hydrogen';
wherein the use of Zinc Oxide facilitates not only the efficient conversion of Coal into Carbon Monoxide, but, then enables the production of Hydrogen, from Water, in the regeneration of the Zinc Oxide.
Taken together, of course, the Carbon Monoxide and Hydrogen represent a synthesis gas, or syngas, which, as has long been known, and as we have documented in reports such as:
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 (a process) comprising contacting the light hydrocarbons with carbon dioxide ... (and) wherein the light hydrocarbon is methane. (Gas) mixtures containing carbon monoxide (and) hydrogen ... are particularly useful as feed gases in processes for producing higher hydrocarbons and (in) alcohol synthesis processes";
can be chemically condensed through a variety of well-established catalytic processes into a full range of liquid hydrocarbon fuels.
The above-cited report concerning "United States Patent 4,690,777", it should be obvious, describes another especially intriguing way in which hydrocarbon synthesis gas can be formed: i.e., through reactions between Methane gas and Carbon Dioxide; with such methods made even more intriguing in light of the fact, as documented for just one instance, and as just one variation of the related technologies, in:
Penn State Solar CO2 + H2O = Methane | Research & Development; concerning: "High-Rate Solar Photocatalytic Conversion of CO2 and Water Vapor to Hydrocarbon Fuels; The Pennsylvania State University; 2009; Efficient solar conversion of carbon dioxide and water vapor to methane";
that the Methane needed to react with Carbon Dioxide, as in the process of "United States Patent 4,690,777", can efficiently be synthesized, in a process powered by environmental energy, from Carbon Dioxide itself.
A more formal, and complete, description of that technology can be found in our report of:
Penn State Seeks CO2 Recycling Patent | Research & Development; concerning: "United States Patent Application 20100213046 - Nanotube ... Photocatalytic Conversion of Carbon Dioxide; 2010; The Penn State Research Foundation; Abstract: Nitrogen-doped titania nanotubes exhibiting catalytic activity on exposure to any one or more of ultraviolet, visible, and/or infrared radiation, or combinations thereof are disclosed. The nanotube arrays may be (used for the) catalytic conversion of carbon dioxide alone or in admixture with hydrogen-containing gases such as water vapor ... into products such as hydrocarbons".
Further, in addition to what might be called "bi-reforming" technologies for the recycling of Carbon Dioxide, as exemplified by the process of Standard Oil's "United States Patent 4,690,777", there also exist variations known as "tri-reforming", wherein Water, H2O, is added to the reactant mix of Carbon Dioxide and Methane, to influence in specific ways the ratios of Carbon Monoxide and Hydrogen in the resultant hydrocarbon synthesis gas ultimately produced.
A recent description of such technology, with innovative modernistic adaptations, can be found in our report:
Exxon CO2 and Methane to Syngas via Microwave Radiation | Research & Development; which concerns: "United States Patent 5,266,175 - Conversion of Methane, CO2 and H2O Using Microwave Radiation; 1993; Exxon Research and Engineering Company; Abstract: A mixture of methane, water and carbon dioxide can be effectively converted to carbon monoxide and hydrogen by subjecting the mixture to microwave radiation in the presence of at least one plasma initiator that is capable of initiating an electric discharge in an electromagnetic field".
However, despite the space-age implications of the above-noted "United States Patent 5,266,175", such reactions have been known for a long time, and, their use in the synthesis of hydrocarbons first started being proposed more than half a century ago, as seen, for just one instance, in our report of:
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; The present invention relates to the preparation of a gas comprising carbon monoxide and hydrogen ... in proportions suitable for employment in the hydrocarbon synthesis process (wherein various) quantities of CH4, H2O and CO2 (are) reacted (and, thus) desired ratios of H2 to CO in the product may be obtained".
Such reforming reactions do require the input of energy, however, as with the process of Exxon's "United States Patent 5,266,175", and, before such innovative sources of energy, such as microwaves, became available to provide that energy, straightforward chemical reactions of oxidation were employed to generate heat, which reactions, also, unfortunately, tended to generate Carbon Dioxide, which thus reduced the net Carbon Dioxide consumption effects of those reactions.
That gets us back to technologies such as that disclosed by Phillips Petroleum, in our introductory citation above of "United States Patent 4,496,370 - Zinc Oxide-Char Gasification Process", wherein, through the oxide compounds of specific metals, Oxygen can be supplied to such needed oxidation reactions in a limited, even "metered", way, so that, in addition to needed heat energy, more of the useful and desired Carbon Monoxide is generated, and less of the unwanted Carbon Dioxide.
And, almost by now unsurprisingly, the petroleum industry was well-aware of the potentials for utilizing Oxygen donor substances in Carbon Dioxide recycling processes similar to that disclosed by the above-noted "United States Patent 2,676,156 - Preparation of Synthesis Gas", as we recently documented via:
Standard Oil 1954 Oxygen Donor CO2 + CH4 + H2O = Syngas | Research & Development; concerning: "United States Patent 2,671,719 - Production of Mixtures of Hydrogen and Carbon Monoxide; 1954; Standard Oil Development Company; The present invention is directed to a method for producing industrial mixtures of carbon monoxide and hydrogen ... suitable ... to produce ... liquid hydrocarbons (in which) a metal oxide capable of ... catalyzing the reaction between a hydrocarbon and steam and carbon dioxide (and) in which improved yields of CO and H2 are obtained by adding additional amounts of ... hydrocarbon, water vapor and carbon dioxide."
Herein, we learn that the process disclosed by "United States Patent 2,671,719" wasn't just an isolated excursion into CO2-recycling fancy by Standard Oil scientists. It was a component of an, obviously, organized and focused effort to develop such Methane and CO2-based technology, as witnessed by, with comment appended, our excerpts from the initial link in this dispatch to the immediately subsequent:
"United States Patent 2,671,720 - Production of Hydrocarbon Synthesis Gas
Date: March, 1954
Inventors: Warren Lewis and Edwin Gilliland, MA
Assignee: Standard Oil Development Company, DE
Abstract: The present invention relates to a hydrocarbon synthesis process. It is more particularly concerned with an improved process for the preparation of the feed synthesis gases.
In accordance with the present invention substantial improvements are secured by controlling the character of the catalyst employed with respect to the feed gases.
Furthermore, in accordance with this invention substantial economies are secured by utilizing a novel operating technique wherein the heat evolved in one reaction zone is economically utilized in the other.
(Note: As seen, for just one example, in our report of:
ExxonMobil Self-Powered Coal Conversion | Research & Development; concerning: "United States Patent 3,254,023 - Heat Balancing in Organic Reactions; 1966; Socony Mobil Oil Company; Abstract: This invention relates to a method of carrying out an exothermic chemical reaction and an endothermic reaction in a single reaction zone wherein the heat evolved in the exothermic reaction is utilized to effect the endothermic reaction";
some chemical reactions that take place in a sequence of reactions leading to the conversion of one form of Carbon resource into another, are exothermic, which means they give off heat energy; and, as in the above process of "United States Patent 3,254,023", and, in the process of our subject, "United States Patent 2,671,720", such exothermic heat of reaction can in some cases be recovered and utilized to drive other needed, although endothermic, reactions that are a part of the total Carbon conversion process. In some cases, the net effect is to reduce the need for externally-supplied energy to zero, with potential attendant benefits, in addition to the obvious economies, that include avoiding extraneous CO2 emissions.)
These novel operating techniques, coordinated with the control of the catalysts, result in substantial improvements in a process for the production of feed gases suitable for a hydrocarbon synthesis reaction.
Our invention is particularly concerned with the production of a mixture of hydrogen and carbon monoxide from hydrocarbons, particularly methane ..., and consists in oxidizing the hydrocarbons with a metal oxide.
To eliminate the CO2 and water vapor, we react them with ... methane. These reactions are illustrated as follows:
CH4 + FeO = CO + 2H2 + Fe
CH4 + 2FeO = CO2 + 2H2 + 2Fe
CO2 + H2 = CO + H2O
CH4 + H2O = CO + 3H2
CH4 + CO2 = 2CO + 2H2
(Note, that, in the above set of reactions, a significant amount of Carbon Dioxide is being consumed, and, plenty of Hydrogen is being generated for combination with the Carbon Monoxide in ensuing hydrocarbon synthesis reactions.
Further, although the fact won't be reflected in our excerpts, Standard Oil specifies that, in addition to the Iron Oxide, FeO, Oxygen donor, a relatively large amount of metallic Iron or Nickel also be included in the mix, to help catalyze the various reactions.
Since the metal catalysts are readily available, and aren't actually consumed to any appreciable extent, we don't see how that could be an impediment.)
Claims: (An improved) process for the production of carbon monoxide and hydrogen from hydrocarbon gases which comprises contacting the hydrocarbon feed with a fluidized iron group metal catalyst.
(And) reforming the carbon dioxide and water vapor ... with the remaining portion of the said total hydrocarbon feed to produce a product gas consisting essentially of carbon monoxide and hydrogen.
An improved process for the manufacture of gases comprising carbon monoxide and hydrogen from feed gases comprising methane."
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We're compelled to close our excerpts there so that we can emphasize and explain a few things.
First, Standard Oil is not starting with Carbon Dioxide and Water vapor.
They are first deliberately making Carbon Dioxide, almost perversely, from a portion of the Methane, then reacting that Carbon Dioxide, and H2O, with more Methane.
Again: They are intentionally converting some if the Methane into Carbon Dioxide, so that they can have Carbon Dioxide to react with more of the Methane.
But: The reactions remain valid, no matter what the sources of the individual gases.
First, we presume that we'll be able to scrape together in a little H2O in the Ohio River Valley, and, perhaps, especially in the vicinities of Wheeling, WV, and Pittsburgh, PA, a little Iron.
Aside from that, we should be able to collect a little Carbon Dioxide from the fermentation vats of an Iron City(r) brewery, or, soon, from a Marcellus Shale Gas cleaning and pumping facility.
Then, we can make some Methane, as seen in:
GE Converts Coal to Methane and Recycles Carbon for USDOE | Research & Development; concerning: "United States Patent 4,558,027 - Catalysts for Carbon and Coal Gasification; 1985; Assignee: The United States of America; The invention relates to improved catalysts for carbon and coal gasification and improved processes for catalytic, coal gasification. The United States Government has rights in this invention pursuant to Contract No. DE-AC21-80MC14591 between the U.S. Department of Energy and General Electric Co.; Abstract: Catalyst for the production of methane from carbon and/or coal by means of catalytic gasification;
from both a little of our abundant Coal and some naturally CO2-recycling botanically-derived organic Carbon, or, as seen for just one example in:
NASA Recycles CO2 to Methane at Room Temp | Research & Development | News; concerning the: "Electrocatalytic Reduction of Carbon Dioxide to Methane; Lyndon B. Johnson Space Center; 2008; (A)
room-temperature electrocatalytic process that effects the overall chemical reaction CO2 + 2H2O → CH4 + 2O2 has been investigated";
from Carbon Dioxide itself; and, react that Methane with the Iron City(r) and Marcellus Shale Carbon Dioxide, according to the reactions, and in the presence of the Iron or Nickel metal catalysts, all as specified and fully disclosed herein by Standard Oil, in the process of our subject, "United States Patent 2,671,720 - Production of Hydrocarbon Synthesis Gas", and make for ourselves, again as specified by Standard Oil, and as certified herein by our own US Government to be feasible and practical, "a product gas consisting essentially of carbon monoxide and hydrogen" which would be quite "suitable for a hydrocarbon synthesis reaction".