United States Patent Application: 0110240926
We first remind you that, as seen for just one example in:
West Virginia Coal Association | Chicago Recycles CO2 to Methane | Research & Development; concerning: "United States Patent 4,609,440 - Electrochemical Synthesis of Methane; 1986; Assignee: Gas Research Institute, Chicago; Abstract: A method is described for electrochemically reducing carbon dioxide to form methane by electrolyzing an aqueous solution containing carbon dioxide utilizing a cathode which comprises ruthenium. If desired, solar energy can be utilized to provide the potential for the electrolyzing";
it is feasible to synthesize Methane, CH4, by starting out with only Carbon Dioxide, CO2, and Water, H2O, as the raw materials. And, although electricity is specified by "United States Patent 4,609,440", other, related, technologies stipulate that other forms of energy can be employed to achieve the same end; and, that proper catalysis can lower the amount of energy required.
Second, as seen for only one example in:
West Virginia Coal Association | Pittsburgh 1941 CO2 + Methane = Hydrocarbon Syngas | Research & Development; concerning: "United States Patent 2,266,989 - Manufacture of a Gas from CO2 and Methane; 1941; Assignee: Koppers Company, Pittsburgh, PA; Abstract: The present invention relates to the manufacture of gases suitable for the synthesis of higher hydrocarbons or the like, said gases containing definite volumes of carbon monoxide and hydrogen in a certain proportion, by reacting on methane ... with carbon dioxide or a mixture of carbon dioxide and steam, so that the methane ... is decomposed into hydrogen and carbon monoxide";
Methane, CH4, perhaps as synthesized from CO2 and Water via a process like that of the above-cited "United States Patent 4,609,440", can be reacted with even more CO2, as reclaimed from whatever handy source, and perhaps more H2O, and be made to form through such "reforming" reactions a blend of Carbon Monoxide and Hydrogen, CO and H2, a "synthesis gas", or "syngas", suitable for catalyzed chemical recombination into various gaseous and liquid hydrocarbons.
Such reactions seem to be, typically, labeled "bi-reforming" when only CH4 and CO2 are involved; and, are labeled "tri-reforming" when H2O is added to the mix, as is indicated to be an option in the above-cited "United States Patent 2,266,989 - Manufacture of a Gas from CO2 and Methane".
Whether or not, and how much, H2O is added to the CH4 and CO2 influences the ratio of Hydrogen to Carbon Monoxide in the resultant hydrocarbon synthesis gas, and how much excess Oxygen must be somehow dealt with.
Further, reactions between relatively stable molecules like CH4, CO2 and H2O are what are known as "endothermic" reactions, that is, they need, even though catalyzed, at least some energy supplied to them to be driven forward; and, a number of options to accomplish that supply of energy have been proposed and reduced to practice, as, for example, seen in:
West Virginia Coal Association | 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; Abstract: The concept of solar driven chemical reactions in a commercial-scale volumetric receiver/reactor on a parabolic concentrator was successfully demonstrated in the CAtalytically Enhanced Solar Absorption Receiver (CAESAR) test. Solar reforming of methane (CH4) with carbon dioxide (CO2) was achieved".
There is, however, another way to obtain at least a part of the needed energy.
There exists another Methane reforming reaction, called the "partial oxidation of methane", often abbreviated in the literature as "POM". It is not a complete "burning" of Methane, which would result in the formation of Carbon Dioxide; but, instead, the supply of Oxygen is limited, and the reaction catalyzed, so that Carbon Monoxide, along with H2O, is preferentially formed.
It's difficult to summarize the nature of the reaction, and how it's undertaken, in a concise way that's easily understood, especially since we here aren't really educated or qualified to compose such a summary. However, it is in certain circles well known, and thorough descriptions and discussions of it's variations and applications are available.
A general review of partial oxidation, which is also sometimes called "oxidative coupling", can be found in:
Partial oxidation - Wikipedia, the free encyclopedia; while an explanation of how it can be applied to Methane is provided by:
http://web.anl.gov/PCS/acsfuel/preprint%20archive/Files/49_1_Anaheim_03-04_0922.pdf; "Partial Oxidation Of Methane To Syngas; Cuili Guo, et. al.; Tianjin University, China; Catalytic partial oxidation of methane to syngas is a slightly exothermic, highly selective, and energy efficient process".
The "slightly exothermic" part, as above, is one thing that's of interest to us herein.
The exothermic heat can be used to drive, at least in part, the endothermic reaction between Methane and Carbon Dioxide, as described in our above-referenced report of "US Patent 2,266,989 - Manufacture of a Gas from CO2 and Methane", which results in the formation of, as "US Patent 2,266,989" specifies, a blend of Carbon Monoxide and Hydrogen "suitable for the synthesis of higher hydrocarbons".
The products of the partial oxidation of Methane and the reforming of Methane with CO2 can then be combined to form a hydrocarbon synthesis gas that will, however, have too much Carbon Monoxide, relative to Hydrogen, for many liquid hydrocarbon synthesis processes, such as the venerable Fischer-Tropsch process.
However, again as noted by "United States Patent 2,266,989 - Manufacture of a Gas from CO2 and Methane", it is possible to form "gases containing definite volumes of carbon monoxide and hydrogen in a certain proportion, by reacting on methane ... with carbon dioxide or a mixture of carbon dioxide and steam"; with needed additional Hydrogen being provided by the H2O "steam".
And, again, an exothermic, partial oxidation of Methane can be entrained in the overall reaction sequence to help provide some of the heat needed to drive those additional reforming reactions.
That fact, and the fact that some restricted amount of Oxygen would need to be included in the mix of reactants, to support the partial oxidation of the Methane, is embodied, for one example, in:
West Virginia Coal Association | Canada Improves CO2 + Methane = Syngas Catalysis | Research & Development; concerning: "United States Patent 7,985,710 - Catalyst for Production of Synthesis Gas; 2011; Assignee: University of Saskatchewan; Abstract: The present invention relates to a novel composite metal oxide catalyst ... used to produce synthesis gas by the carbon dioxide reforming reaction of methane. A process for producing synthesis gas using a catalyst (by) reforming a hydrocarbon ... with an oxidant (and) wherein the hydrocarbon is ... methane (and) wherein the oxidant is ... steam, carbon dioxide, oxygen and their mixtures".
And, all of the above has been brought more recently together by a major, multinational, corporate resident of part of US Coal Country: Bayer Corporation, aka Bayer AG.
We remind you that we have cited Bayer Corporation's Carbon conversion and CO2 recycling achievements in a number of previous reports, including, recently:
West Virginia Coal Association | Bayer Is Converting Coal Power Plant CO2 Into Plastics | Research & Development; concerning the article: "Bayer Material Science CO2-to-Plastics Pilot Plant, Germany;
In February 2011, Bayer Material Science started a new pilot plant (in the) North Rhine-Westphalia state of Germany for producing plastics from carbon dioxide (CO2). It will be used to develop polyurethanes from the waste gas released during power generation.Bayer aims to use CO2 as an alternative to production of polymer materials from fossil fuels"; and:
West Virginia Coal Association | Bayer Improves Coal + CO2 = Carbon Monoxide | Research & Development; concerning: "United States Patent 7,473,286 - Carbon Monoxide Generator; 2009; Assignee: Bayer Material Science, AG, Germany; The present invention relates to a novel generator for the reaction of carbon-containing raw materials and also to an improved process for the production of carbon monoxide gas (CO gas) having a high degree of purity using such a generator. Carbon monoxide gas is frequently produced in the art by means of a continuous process in which carbon-containing raw materials are reacted with oxygen and carbon dioxide ... . An object of the present invention was ,,, to provide a continuous process for the production of CO gas by the gasification of coal ... by injecting CO2 and O2 into the furnace together through the (described apparatus, so that) the two reactions that take place ..., C + O2 (and) CO2 + C ... are concentrated in a single controllable combustion zone ... . The CO gas so produced may (thus) be passed directly into a subsequent desulfurisation device. Suitable fuels which ... can be reacted successfully in terms of technology and economy to CO gas in the process described herein are, for example ... coal coke".
And, herein we see that Bayer has recently refined the art of producing hydrocarbon synthesis gas, and a hydrocarbon product, Ethylene, from Methane and Carbon Dioxide, by combining, in a way similar to that explained in our above-cited report of "United States Patent 7,985,710" by the University of Saskatchewan, in a single integrated process, the partial oxidation, or oxidative coupling, of Methane, with the Carbon Dioxide reforming of Methane.
Comment is inserted within and follows excerpts from the initial link in this dispatch to:
"US Patent Application 20110240926 - Method for Oxidative Coupling of Methane and Producing Syngas
METHOD FOR OXIDATIVE COUPLING OF METHANE AND PRODUCING SYNGAS - Patent application
METHOD FOR OXIDATIVE COUPLING OF METHANE AND PRODUCING SYNGAS - BAYER TECHNOLOGY SERVICES GMBH
Date: October, 2011
Inventor: Ralph Schellen, et. al., Germany and Texas
Assignee: Bayer Technology Services Gmbh, Germany
Abstract: Process for preparing hydrogen and carbon monoxide (synthesis gas) by endothermic, catalytic gas phase oxidation of hydrocarbons with steam and carbon dioxide, and for simultaneous preparation of ethylene by exothermic, heterogeneously catalyzed, oxidative coupling of methane, wherein the particular reactions are performed in at least three series-connected reaction zones under adiabatic conditions, and wherein the heat of reaction of the exothermic, heterogeneously catalyzed, oxidative coupling of methane is supplied to the endothermic, catalytic gas phase oxidation of hydrocarbons with steam and carbon dioxide.
(Note: The concurrent, exothermic synthesis of "ethylene", along with additional Carbon Monoxide and Hydrogen, via the exothermic "oxidative coupling of methane", is, it seems to us, an extra reaction, or feature, of subtle, but very great, value. Synthesis of ethylene, with the formula C2H4, as indicated in the abstract, is exothermic, and, as indicated and as will be explained more fully, the heat generated by it's synthesis is used to help supply the energy needed by other reactions integral to the entire CO2-consuming process.
Secondly, noting it's chemical formula, ethylene consumes twice as much Carbon, relative to available Hydrogen, in it's synthesis as does Methane; and, it thus serves to scavenge Carbon from the blend of materials and to thus help adjust the ratios of co-produced Carbon Monoxide and Hydrogen synthesis gas, so that the co-product syngas is compositionally better-suited for the subsequent catalytic synthesis of other hydrocarbons.
Third, ethylene, as can be learned via:
Ethylene - Wikipedia, the free encyclopedia; "Ethylene (or ethene) is ... a colorless flammable gas (that) is widely used in chemical industry, and its worldwide production ... exceeds that of any other organic compound. In the United States and Europe, approximately 90% of ethylene is used to produce three chemical compounds: ethylene oxide, ethylene dichloride, and ethylbenzene - and a variety of kinds of polyethylene. Polyethylene ... is the world's most widely-used plastic";
is itself a product of absolutely immense commercial value. Produced as it is herein, as a co-product, would serve to subsidize and reduce in a dramatic way the costs of any hydrocarbons ultimately synthesized from the blend of Carbon Monoxide and Hydrogen, which hydrocarbons, as via the Fischer-Tropsch synthesis and it's relatives, could include such things as Gasoline and Diesel fuel.
And, that, again, is in addition to the Ethylene synthesis providing exothermic heat to help drive the reaction between Methane and Carbon Dioxide and scavenging, providing an outlet for, excess Carbon.)
Claims: Process for coproducing synthesis gas by endothermic, heterogeneously catalyzed gas phase reaction and ethylene by means of exothermic, heterogeneously catalyzed, oxidative coupling of methane, wherein the endothermic, heterogeneously catalyzed preparation of synthesis gas and the exothermic, heterogeneously catalyzed, oxidative coupling of methane are performed in at least three separate series-connected pairs of adiabatic reaction zones, a heat exchange zone being present between each pair of adiabatic reaction zones, in which the heat of reaction of the exothermic, heterogeneously catalyzed, oxidative coupling of methane from an upstream reaction zone is supplied at least partly through one wall to the process gases of the endothermic, heterogeneously catalyzed gas phase reaction to give synthesis gas which have been cooled in the upstream reaction zone.
(We'll keep our excerpts from the Claims section brief, since that section herein deals mostly with technical specification of temperatures and pressures in the several reaction zones. Note, however, use of the word "adiabatic" to describe the "pairs of reaction zones". "Adiabatic", as we've explained in one or two previous reports, and as defined by:
Adiabatic process - Wikipedia, the free encyclopedia; "An adiabatic process is any process occurring without input or output of heat within a system (i.e. during the process the system is thermodynamically isolated- there is no heat transfer with the surroundings)";
means that, aside from the energy expended to gather the reactants and to initiate the process, no energy needs to be added to keep the process going. The heat needed to drive necessary endothermic reactions is, for all practical purposes, supplied by concurrent exothermic reactions.
The term "autothermal" is one we have seen previously as applied to Carbon conversion processes, and it is, in one sense, closely related. They both indicate great efficiencies can be had in the processes, since we don't have to add energy to them, excepting the latent energy content of the reactants, to keep those processes going.)
Description: The present invention relates to a process for preparing hydrogen and carbon monoxide (synthesis gas) by endothermic, catalytic gas phase oxidation of hydrocarbons with steam and carbon dioxide, and for simultaneous preparation of ethylene by exothermic, heterogeneously catalysed, oxidative coupling of methane, wherein the particular reactions are performed in at least three series-connected reaction zones under adiabatic conditions, and wherein the heat of reaction of the exothermic, heterogeneously catalysed, oxidative coupling of methane is supplied to the endothermic, catalytic gas phase oxidation of hydrocarbons with steam and carbon dioxide.
(Don't lose sight of the fact that the "hydrocarbons" undergoing "catalytic gas phase oxidation ... with steam and carbon dioxide" would be, essentially, just more Methane, although some other hydrocarbons are named within the full Disclosure as being able to participate.)
The synthesis gas obtained from the reactions ... constitutes an essential starting material for further conversion, for example, to long-chain hydrocarbons by the Fischer-Tropsch process.
The controlled supply of heat in processes for obtaining synthesis gas is important since the ... yields and/or selectivities for hydrogen and/or carbon monoxide can be controlled as a result.
It is ... advantageous to control the temperature of the reaction zones in the course of the process for preparing synthesis gas at a level which enables rapid conversion with minimization of side reactions.
As ... described, synthesis gas constitutes a significant starting material for processes for preparing longer-chain hydrocarbons by means of a Fischer-Tropsch synthesis. In a first step, for instance, ethane and/or ethylene can thus be prepared from the synthesis gas.
Such ethane and/or ethylene can, however, also be obtained by oxidative coupling of methane.
The combination of the (described and illustrated) reactions ... has the result, considering the reactants, that methane can be converted by means of one endothermic and one exothermic process to longer-chain hydrocarbons with a combined process.
Typically, such hydrocarbons are nowadays prepared from methane by means of preparation of synthesis gas and subsequent Fischer-Tropsch synthesis, especially supplying the preparation of synthesis gas with the heat of reaction needed by firing, for instance by the combustion of methane, the methane being converted to carbon dioxide and water in the course of firing, and the carbon dioxide usually being released into the atmosphere as an environmentally damaging gas. In addition to environmental damage, however, it is disadvantageous to proceed in such a way in particular because the carbon dioxide constitutes an essentially inert gas which cannot easily be used widely in such a manner as to deliver value. This firing thus also constitutes an economic disadvantage.
It would thus be advantageous overall if the methane ... is not used solely for the generation of heat, but if an integrated process were to form both heat and a product of value which can be used in equivalent further processes.
(It) would thus be advantageous to provide a process for simultaneous preparation of hydrogen and carbon monoxide (synthesis gas), and for simultaneous preparation of ethylene, which can be performed in simple reaction apparatus and which enables exact, simple temperature control of the two processes, such that it allows high conversions of methane with maximum purities of the products while maintaining desired yields and/or selectivities. Such simple reaction apparatus would be easily convertible to an industrial scale and are inexpensive and robust in all sizes.
It has been found that, surprisingly, this object is achieved by a process for coproducing synthesis gas by means of endothermic, heterogeneously catalysed gas phase reaction and ethylene by means of exothermic, heterogeneously catalysed, oxidative coupling of methane, characterized in that the endothermic, heterogeneously catalysed preparation of synthesis gas and the exothermic, heterogeneously catalysed, oxidative coupling of methane are performed in at least three separate series-connected pairs of adiabatic reaction zones, a heat exchange zone being present between each pair of adiabatic reaction zones, in which the heat of reaction of the exothermic, heterogeneously catalysed, oxidative coupling of methane from the upstream reaction zone is supplied at least partly through one wall to the process gases of the endothermic, heterogeneously catalysed gas phase reaction to give synthesis gas which have been cooled in the upstream reaction zone.
In the context of the present invention, synthesis gas refers to a process gas which comprises essentially the substances carbon monoxide and hydrogen. The synthesis gas may also comprise proportions of carbon dioxide, steam and hydrocarbons.
In the context of the present invention, hydrocarbons refer to substances present as process gas, consisting of carbon, hydrogen and optionally oxygen. Essentially, such hydrocarbons, however, consist of carbon and hydrogen.
Preferred hydrocarbons which are used as a feedstock in the process according to the invention are those selected from the list consisting of alkanes, alkenes and alkynes. Particularly preferred hydrocarbons are alkanes. Preferred alkanes are those comprising not more than six carbon atoms, particular preference being given to methane, ethane, propane and butane, very particular preference to methane.
In the process according to the invention, the synthesis gas is formed in the reaction zones by endothermic, heterogeneously catalysed gas phase reaction of hydrocarbons with steam and carbon dioxide.
(Again, of the :hydrocarbons", "very particular preference" is given "to methane".)
Moreover, the ethane and/or ethylene is formed in the process according to the invention by exothermic, heterogeneously catalysed, oxidative coupling of methane with oxygen.
The hydrocarbons used in the process according to the invention, the steam, the oxygen, the methane as the hydrocarbon, the constituents of the synthesis gas and the synthesis gas, and the ethylene and/or ethane, are also referred to hereinafter collectively as process gases.
In addition to the essential components of the process gases, they may also comprise secondary components. Non-exclusive examples of secondary components which may be present in the process gases are, for instance, ... carbon dioxide.
According to the invention, the performance of the process under adiabatic conditions means that essentially no heat is supplied actively to, nor is heat withdrawn from, the reaction zone from outside. ... In the context of the present invention, "adiabatic" ... means that no measures for supply or removal of heat are taken.
(Again, the economies implied by the above should be noted.)
One advantage of the inventive adiabatic mode of operation of at least three series-connected pairs of reaction zones over a nonadiabatic mode of operation is that no means of heat supply need be provided in the reaction zones, which implies a considerable simplification of the construction. This gives rise, more particularly, to simplifications in the manufacture of the reactor and in the scaleability of the process, and a rise in the reaction conversions.
A further advantage of the process according to the invention is the possibility of very exact temperature control, by virtue of a close graduation of adiabatic reaction zones and heat exchange zones. It is thus possible to establish and control a temperature which is advantageous in the reaction progress in each reaction zone.
Moreover, the heat of reaction of the exothermic, heterogeneously catalysed, oxidative coupling of methane with oxygen can be used in an advantageous manner in order to supply the endothermic heterogeneously catalysed gas phase reaction to synthesis gas with the heat of reaction needed.
(The above reiteration of energy economy is so important that it is repeated multiple times, in multiple ways, throughout the Disclosure.)
Catalyst materials which are (appropriate to the specified conditions) to give synthesis gas are, for example, catalysts which comprise nickel or nickel compounds.
The differences between the temperatures of process gases in the exothermic, heterogeneously catalysed, oxidative coupling of methane with oxygen, and the endothermic, heterogeneously catalysed gas phase reaction to give synthesis gas give rise to a significant advantage of the present invention. The processes involve preparing products which can be used together in similar subsequent processes, but one involves an endothermic reaction at temperatures which are significantly lower than in the case of the exothermic reaction. Thermal integration of the two processes can thus be effected in an advantageous manner by the process presented here.
In (a) preferred embodiment of the process, the residence time of the process gas in all reaction zones of the endothermic, heterogeneously catalysed gas phase reaction to give synthesis gas together is between 0.05 and 60 s, preferably between 0.1 and 5 s, more preferably between 0.5 and 3 s.
(The syngas can be made in under three seconds, in other words. It can be a rapid, continuous process since things don't have to "cook".)
The hydrocarbon (i.e., the Methane), the carbon dioxide and the steam are typically supplied to the endothermic, heterogeneously catalysed gas phase reaction to give synthesis gas only upstream of the first reaction zone.
However, it is also possible to meter carbon dioxide and/or steam into the process gas if required upstream of one or more of the reaction zones which follow the first reaction zone.
The methane and the oxygen are typically supplied to the exothermic, heterogeneously catalysed, oxidative coupling of methane with oxygen only upstream of the first reaction zone. This has the advantage that the entire process gas is available for the absorption of heat of reaction in all reaction zones.
Moreover, such a procedure can ... reduce the mass of catalyst needed.
The supply of the process gases between the reaction zones can additionally control the temperature and the conversion. This is especially advantageous when the metered addition of individual process gases is to regulate the heat transfer in the downstream heat exchange zones. For this purpose, it is possible to meter in only process gases of the endothermic, heterogeneously catalysed gas phase reaction to give synthesis gas or only process gases of the exothermic, heterogeneously catalysed, oxidative coupling of methane with oxygen distributed upstream of the subsequent reaction zones. Alternatively, it is also possible, for particularly good temperature control, to meter in the process gases of both reactions distributed over the subsequent reaction zones, which is preferred.
The heat exchange zones act as heat exchangers between the process gases of the reactions, which generally transfers heat from the process gases of the exothermic reaction to those of the endothermic reaction.
The process according to the invention is thus notable for high space-time yields for the individual reactions, associated with a reduction in the apparatus sizes and a simplification of the apparatus or reactors. This surprisingly high space-time yield is enabled by the interplay of the inventive and preferred embodiments of the novel process. Especially the interplay of graduated, adiabatic reaction zones with heat exchange zones in between and the defined residence times enables exact control of the process and the resulting high space-time yields, and a reduction in the by-products formed.
(The) overall process is notable for an advantageous utilization of the reactants and an advantageous utilization of heat, which leads to a significant reduction in ... carbon dioxide."
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We, here, with our limitations, cannot do an assured job of fully interpreting the complete Disclosure for you.
It is nowhere clearly stated that Carbon Dioxide can be consumed in enough quantity so that amounts of it in addition to that which might be co-produced in the "catalysed, oxidative coupling of methane with oxygen" and in the, not herein fully-described, "subsequent Fischer-Tropsch synthesis" - there will be some - can be imported into the system from external sources.
We believe that would be the case, however; and, especially so if the "Fischer-Tropsch synthesis" were, as it can be, and if enough Hydrogen is available, set up and catalyzed so as to produce, preferentially, more oxygenated hydrocarbons, that is, alcohols, which would consume Oxygen, as opposed to Bayer's specified, and perhaps more valuable, "longer chain hydrocarbons".
However, as in our introductory comment citation of our earlier report concerning "United States Patent 4,609,440 - Electrochemical Synthesis of Methane", and, as seen separately in our report of:
West Virginia Coal Association | 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 and other hydrocarbons is achieved";
the Methane needed by the process of our subject, Bayer's "US Patent Application 20110240926 - Method for Oxidative Coupling of Methane and Producing Syngas", through the use of freely-available environmental energy, can itself be synthesized from Carbon Dioxide.
So, via the no-external-energy-needed process of "US Patent Application 20110240926", as herein, and the subsequent "Fischer-Tropsch synthesis", in combination with a process like that described, as above, by Penn State, we can produce both commercially valuable "ethylene" and "longer-chain hydrocarbons" out of nothing, essentially, but "water vapor" and, as reclaimed from whatever handy source, Carbon Dioxide.
