United States Patent Application: 0120231948
As we've explained and documented in several previous reports, such as, more recently:
West Virginia Coal Association | France Efficient CO2 to Carbon Monoxide Conversion | Research & Development; concerning: "United States Patent Application 20030113244 - Method for Producing Carbon Monoxide by Reverse Conversion with an Adapted Catalyst; 2003; Assignee: Air Liquide (France); Abstract: The invention concerns a method for producing carbon monoxide by reverse conversion, in gas phase, of carbonic acid gas and gaseous hydrogen while minimising the production of methane (and) is preferably carried out continuously and comprises preferably the following steps which consist in: preparing a gas mixture rich in carbon dioxide and in hydrogen (and) reacting said gas mixture, forming carbon monoxide and water vapour, by passing said mixture through a catalytic bed based on zinc oxide and chromium oxide. The invention relates to a process for the production of carbon monoxide by reverse conversion, in the gas phase, of hydrogen and carbon dioxide";
there exists a chemical process known as the "reverse water gas shift reaction", "RWGS", or, more simply, "reverse conversion", in which elemental, molecular Hydrogen reacts with CO2 to form Carbon Monoxide.
The reaction is easy to promote, actually, and the greatest challenge, as indicated above, to using it to produce Carbon Monoxide from Carbon Dioxide is to prevent, or perhaps preferably, as we will in a future report see, just to limit somewhat the competing Sabatier reaction, explained in:
West Virginia Coal Association | CO2 Solution Wins Nobel Prize - in 1912 | Research & Development; concerning: "Paul Sabatier; The Nobel Prize in Chemistry 1912; Nobel Lecture, December 11, 1912"; wherein Sabatier explains that with Hydrogen, "carbon dioxide" can be "changed immediately into methane, which can therefore be synthesized with the greatest ease".
As useful as Methane, "synthesized with the greatest ease" from Carbon Dioxide might be, there are good reasons why, in some cases, we would prefer to have more of the Carbon Monoxide, as we'll explain further on and, again, in a report or two to follow.
First, to remind you, there have been technologies developed recently in several nations around the world wherein Hydrogen, as required for the chemical reduction of Carbon Dioxide by the RWGS reaction, can be extracted from plain old Water using nothing but sunlight to drive the process. Some of them are referred to and summarized in our report of
West Virginia Coal Association | Panasonic Sunshine Extracts Even More Hydrogen from H2O | Research & Development; which itself concerns, primarily, with:"United States Patent Application 20130075250 - Hydrogen Production Device; 2013; Assignee: Panasonic Corporation (Japan); The present invention relates to a hydrogen production device for producing hydrogen through decomposition of water in a cell by irradiating an electrode including at least a photocatalytic semiconductor with light. (Hydrogen) production using a photocatalyst is a system for producing hydrogen directly from water and sunlight, and can convert the solar energy effectively into hydrogen energy".
Japan, as above, has developed other similar means of employing environmental energy to extract Hydrogen from Water, as well; as we'll remind you following excerpts from the initial link in this dispatch, which demonstrate that Japan has developed their own RWGS technology for using Hydrogen to convert Carbon Dioxide into the more reactive, and more valuable, Carbon Monoxide, and, consequently, with more Hydrogen, into hydrocarbon synthesis gas:
"United States Patent Application 20120231948 - Catalyst for Reverse Shift Reaction and Method for Producing Synthesis Gas Using the Same
Date: September 13, 2012
Inventor: Yoshinori Saito, Japan
Assignee: Murata Manufacturing Company, Ltd., Japan
Abstract: There are provided a catalyst for reverse shift reaction which has excellent durability at a high temperature, can suppress generation of a methanation reaction, and can efficiently generate a reverse shift reaction to produce a synthesis gas including carbon monoxide and unreacted hydrogen with a reduced methane content, and a method for producing a synthesis gas using the catalyst for reverse shift reaction. The composition of the catalyst for the reverse shift reaction includes a composite oxide containing at least one alkali earth metal selected from the group consisting of Ca (Calcium), Sr (Strontium) and Ba (Barium) and at least one transition metal selected from the group consisting of Ti (Titanium) and Zr (Zirconium).
A raw material gas containing carbon dioxide and hydrogen is contacted with the catalyst for reverse shift reaction at a temperature of 700 C or higher.
(The temperature needed, as above, to drive the Reverse Water Gas Shift reaction seems quite high; and, it does demand energy. There are, however, as we indicated in our introductory comments, other factors, such as the competing Sabatier reaction, which can be, and by others have been, assimilated into technology closely related to that disclosed by the Murata Manufacturing Company herein; and, those other factors greatly reduce the demand for energy to be supplied from outside the process, from external sources. And, in fact, a study of the various RWGS processes which have been developed reveals that various catalysts can be employed to adjust, or vary, as desired, the proportional mix of final products, that is, Carbon Monoxide, Methane and Water, keeping in mind that some Hydrogen, if enough is made available, will remain un-reacted and also pass through into the product mix.)
Claims: A method for producing a synthesis gas, comprising contacting a raw material gas comprising carbon dioxide and hydrogen with a catalyst for reverse shift reaction which comprises a composite oxide containing at least one alkali earth metal selected from the group consisting of Calcium, Strontium, and Barium, and at least one transition metal selected from the group consisting of Titanium and Zirconium at a temperature of 700 C or higher.
The method for producing a synthesis gas ... in which the raw material gas has a hydrogen to carbon dioxide volume ratio greater than 1:1 (and) further comprising separating at least one of CO2 and H2O from the synthesis gas resulting from the reverse shift reaction.
(Concerning the above, not all the CO2 will be converted to Carbon Monoxide; and, again, "H2O" is one of the products of the Reverse Water Gas Shift Reaction.)
The method for producing a synthesis gas ... wherein the composite oxide is a perovskite.
(Concerning the exotic-sounding "perovskite", see:
Perovskite - Wikipedia, the free encyclopedia; "Perovskite is a calcium titanium oxide mineral species composed of calcium titanate, with the chemical formula CaTiO3. Perovskite is found in contact carbonate skarns at Magnet Cove, Arkansas".
And, although it isn't the most common mineral in the world, it can, as seen in:
Calcium titanate - Wikipedia, the free encyclopedia; "CaTiO3 can be prepared by the combination of CaO and TiO2 at temperatures (greater than) 1300 C. Sol-gel processes has been used to make a more pure substance, as well as lowering the synthesis temperature";
be synthesized. Further, even though some significant energy would be needed for that synthesis, to generate temperatures higher than "1300 C", the "Perovskite"/"CaTiO3" acts as a catalyst and wouldn't be used up or consumed to an appreciable extent in the RWGS, CO2-to-CO, reaction. So, the costs of making the Perovskite would be more of a capital investment than an ongoing, raw material expense.)
The method for producing a synthesis gas ... wherein the alkali earth metal comprises Calcium (or) Strontium (or) Barium (and) wherein the transition metal comprises Titanium (or) Zirconium (and) wherein the catalyst is SrTiO3 (or) BaZrO3 (or) CaZrO3.
The method for producing a synthesis gas ... wherein the composite oxide is a mixture of two different perovskites (and) wherein the perovskites are SrTiO3 and SrZrO3.
The method for producing a synthesis gas ... in which the temperature is 700 C to 1100 C.
A catalyst for reverse shift reaction generating carbon monoxide and water vapor from carbon dioxide and hydrogen which comprises a composite oxide containing at least one alkali earth metal selected from the group consisting of Ca, Sr and Ba and at least one transition metal selected from the group consisting of Ti and Zr.
(The repetition of the various metals is tedious; but, they are attempting to thoroughly define the catalyst, and to establish their claim to it, in both the broadest and the most concrete terms possible.)
Background and Field: The present invention relates to a catalyst for a reverse shift reaction, which is active for a reaction for generating carbon monoxide and water vapor from carbon dioxide and hydrogen, the reaction being a reaction reverse to the shift reaction for generating carbon dioxide and hydrogen from carbon monoxide and water vapor, and a method for producing a synthesis gas using the same.(There) has been proposed a method in which a reverse shift reaction is carried out using hydrogen and carbon dioxide to produce a synthesis gas comprising generated carbon monoxide and unreacted hydrogen.
Many catalysts have been put to use ... for promoting a shift reaction represented by Formula (1) described below, i.e., catalysts for shift reaction, for the purpose of producing hydrogen.
(Formula (1):) CO + H2O = CO2 + H2
Many of the catalysts for promoting a shift reaction are considered to have an activity as a catalyst for the reverse shift reaction represented by Formula (2) described below.
(Formula (2):) CO2 + H2 = CO + H2O
It is desirable that the reverse shift reaction be carried out at a high temperature of 600 C or higher in consideration of the equilibrium composition of the synthesis gas generated by the reaction. However, since the temperature of 600 C or higher is much higher than the temperature for carrying out a shift reaction in general, it is actually difficult to use these common catalysts for shift reaction.
A reverse shift reaction can proceed in a common water vapor reforming catalyst, but there is the problem that under pressurized conditions, a methanation which is described by Formula (3) below, occurs. This is a reaction reverse to the water vapor reforming reaction, and the methane generated reduces the concentration of carbon monoxide.
(Formula (3):) CO + 3H2 = CH4 + H2O
(Note that the combination of "Formula (2)" and "Formula (3)" comprise, in essence, when proceeding concurrently, in the same reaction space, the Sabatier process, as noted in our introductory comments and as explained most recently in our report of:
West Virginia Coal Association | NASA Improves CO2 to Methane Conversion | Research & Development; concerning: "United States Patent Application 20120029095 - Sabatier Process and Apparatus for Controlling Exothermic Reaction; 2012; Inventors: Christian Junaedi, et. al., Connecticut; Abstract: A Sabatier process involving contacting carbon dioxide and hydrogen in a first reaction zone with a first catalyst bed at a temperature greater than a first designated temperature; feeding the effluent from the first reaction zone into a second reaction zone, and contacting the effluent with a second catalyst bed at a temperature equal to or less than a second designated temperature, so as to produce a product stream comprising water and methane. The first and second catalyst beds each individually comprise an ultra-short-channel-length metal substrate. An apparatus for controlling temperature in an exothermic reaction, such as the Sabatier reaction, is disclosed. Government Interests: This invention was made with support from the U.S. government under U.S. Contract No. NNX10CF25P sponsored by the National Aeronautics and Space Administration.The U.S. Government holds certain rights in this invention".)
Summary: The present invention has been made ... and an object thereof is to provide a catalyst for a reverse shift reaction which can be used at a high temperature, suppresses generation of a methanation reaction to efficiently generate a reverse shift reaction, thus making it possible to obtain a synthesis gas comprising carbon monoxide and hydrogen with the reduced methane content, and a method for producing a synthesis gas using the catalyst for reverse shift reaction.
(A) catalyst according to the present invention for a reverse shift reaction used for generating carbon monoxide and water vapor from carbon dioxide and hydrogen, is a composite oxide containing at least one alkali earth metal selected from the group consisting of Ca, Sr and Ba and at least one transition metal selected from the group consisting of Ti and Zr.
A method for producing a synthesis gas according to the present invention comprises contacting a raw material gas containing carbon dioxide and hydrogen with the catalyst for reverse shift reaction under a temperature condition of 700 C or higher to carry out the reverse shift reaction.
The catalyst for reverse shift reaction according to the present invention comprises a composite oxide containing at least one alkali earth metal selected from the group consisting of Ca, Sr, and Ba, and at least a component selected from the group consisting of Ti and Zr. A perovskite compound containing an alkali earth metal, like the catalyst for reverse shift reaction according to the present invention, acts as a basic catalyst and therefore has high affinity with CO2, and undergoes oxidation and reduction by oxygen in a lattice and therefore has a high catalytic activity in a reverse shift reaction using CO2.
Consequently, a reverse shift reaction of hydrogen and carbon dioxide can be efficiently promoted while suppressing a methanation reaction under a high-temperature condition by using the catalyst for reverse shift reaction, thus making it possible to efficiently produce a synthetic gas containing carbon monoxide and hydrogen.
Accordingly, if it is desired to obtain a synthesis gas with a high concentration of CO using H2 and CO2 as a raw material, the reverse shift reaction of Formula (2) may be allowed to proceed at a temperature higher than that of a normal shift reaction process (and, for) obtaining a synthesis gas, unreacted CO2 and generated H2O may be removed from a gas after reaction.
The ratio of H2 in the synthesis gas can be increased as the ratio of H2 in the raw material gas increases.
(In other words, almost obviously, we can adjust the Hydrogen-Carbon Monoxide ratio in the finished synthesis gas, to make it more or less suitable for various synthesis processes, such as for the production of alcohols or, via processes like the Fischer-Tropsch synthesis, of hydrocarbons, by adding more or less Hydrogen from an external source to the starting blend of Carbon Dioxide and Hydrogen - or, one would suppose, to the product synthesis gas itself.)
The catalyst for reverse shift reaction according to the present invention has an activity as a catalyst that causes the Formula (2) reaction at a high temperature, such as a temperature higher than 700 C (for example, 700 C to 1100 C).
As in the method for producing a synthesis gas according to the present invention, a raw material gas containing carbon dioxide and hydrogen is contacted with the catalyst for reverse shift reaction under a temperature condition of 700 C or higher to carry out a reverse shift reaction, whereby a synthesis gas of high utility value can be efficiently produced.
From the (results of experiments described and illustrated), it was found that the catalysts which meet the requirements of the present invention (perovskite compounds with an alkali earth metal) have such excellent properties that they have a high activity as a catalyst for reverse shift reaction and do not produce methanation in a side reaction.
[t is known that generally the conversion increases as the synthesis pressure becomes higher in liquid fuel chemical synthesis and the like using a synthesis gas as a raw material. Thus, employment of a pressurization process is desired also in a process of producing a synthesis gas (reverse shift reaction process) in a front stage of the chemical synthesis process, and the desire can be met according to the present invention. That is, while methanation is likely to occur in the a reverse shift reaction under pressure, when using the catalyst for reverse shift reaction according to the present invention, the pressurization process can be employed without the possibility of causing methanation. Therefore, it can be said that the catalyst according to the present invention and the method for producing a synthesis gas according to the present invention, which can suppress generation of methane (CH4) even under high-temperature and pressurized conditions to efficiently produce a synthesis gas having the reduced methane content and containing carbon monoxide and hydrogen at a high ratio, are very useful."
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Well, given that we can, as seen for yet another example in:
West Virginia Coal Association | Japan Hydrogen from Water and Sunlight | Research & Development; concerning yet another light-driven water-splitting Hydrogen production technology from Japan's Panasonic Corporation: "United States Patent 7,909,979 - Water Photolysis System and Process; 2011; Assignee: Panasonic Corporation; Abstract: The present invention provides a water photolysis system comprising: a casing into which incident sunlight can enter (and in which water) vapor is decomposed into hydrogen and oxygen by the photocatalyst particles, which are excited by the sunlight";
generate the Hydrogen required by the process of our subject herein, "United States Patent Application 20120231948 - Catalyst for Reverse Shift Reaction and Method for Producing Synthesis Gas Using the Same", to convert Carbon Dioxide, as collected from whatever convenient source, into Carbon Monoxide, or, rather, into an adjustable-ratio blend of Carbon Monoxide and more or less added Hydrogen, we could then, depending upon our preference and how much Hydrogen we added, direct the Synthesis Gas, made from Carbon Dioxide, into a process like that explained in:
Fischer–Tropsch process - Wikipedia, the free encyclopedia; "The Fischer–Tropsch process, or Fischer–Tropsch synthesis, is a collection of chemical reactions that converts a mixture of carbon monoxide and hydrogen into liquid hydrocarbons. It was first developed by Franz Fischer and Hans Tropsch ... in 1925";
and thereby manufacture any or all of the liquid hydrocarbon fuels we now indenture our grandchildren's futures to the tender mercies of OPEC to keep ourselves supplied with in the here and now.
Or, we could use that Carbon Dioxide-derived synthesis gas blend of Carbon Monoxide and Hydrogen in other processes, like those described in:
West Virginia Coal Association | WVU Makes Alcohol from Coal for USDOE | Research & Development; concerning: "The Economical Production of Alcohol from Coal-derived Synthesis Gas; Contract Number DE-AC22-91PC91034; 1998; Submitted to: USDOE, Pittsburgh Energy Technology Center; Submitted by: West Virginia University Research Corporation on behalf of West Virginia University";
and thereby synthesize a wide variety of alcohols, valuable both as fuels and as feedstock for the plastics manufacturing industry.
Or, we could recycle the Hydrogen back into the Carbon Dioxide reduction process of "United States Patent Application 20120231948" and use just the Carbon Monoxide made from the CO2, as seen for one example in:
West Virginia Coal Association | Standard Oil Carbon Monoxide + Water = Gasoline | Research & Development; concerning: "United States Patent 4,559,363 - Process for Reacting Carbon Monoxide and Water (Patent US4559363 - Process for reacting carbon monoxide and water - Google Patents; Process for reacting carbon monoxide and water - Standard Oil Company (Indiana)); 1985; (Original Assignee: Standard Oil Company of Indiana); Abstract: A process for reacting carbon monoxide and water in the presence of a cadmium-containing catalyst is disclosed. A method for the production of hydrocarbons by reacting carbon monoxide and water ... . It is a general object of the present invention to provide a method for the direct production of gasoline"
and rather directly manufacture Gasoline - a commodity which, if US workers could make it on US soil from a scorned US resource like Carbon Dioxide, would seem to have some special value.
In sum: Carbon Dioxide - - which some wish to tax our Coal-fired electric power producers and, by extension, the consumers of that abundant Coal-based electric power, for making a little of as a byproduct - - is a valuable raw material resource from which, perhaps via the process of our subject herein, "United States Patent Application 20120231948 - Catalyst for Reverse Shift Reaction and Method for Producing Synthesis Gas Using the Same", we can manufacture a hydrocarbon "Synthesis Gas" of variable composition, and, through that "Synthesis Gas", any and all of the hydrocarbons we now squander our national wealth, and mortgage our grandchildren's future, to keep ourselves supplied with in the here and now by purchasing from the often inimical nations of OPEC.
And, for all our readers, as a closing thought, as said decades ago by Mahatma Mohandas Gandhi:
"Silence becomes cowardice when occasion demands speaking out the whole truth and acting accordingly."