Systems and Methods of Converting Fuel
Systems and methods for converting fuel are provided wherein the system comprises at least reactors configured to conduct oxidation-reduction reactions. The first reactor comprises a plurality of ceramic composite particles, wherein the ceramic composite particles comprises at least one metal oxide disposed on a support. The first reactor is configured to reduce the least one metal oxide with a fuel to produce a reduced metal or a reduced metal oxide. The second reactor is configured to oxidize the reduced metal or reduced metal oxide to produce a metal oxide intermediate. The system may also comprise a third reactor configured to oxidize the metal oxide intermediate to regenerate the metal oxide of the ceramic composite particles.
The present invention is generally directed to systems and methods of converting fuel, and is generally directed to oxidation-reduction reactor systems used in fuel conversion.
There is a constant need for clean and efficient energy generation systems. Most of the commercial processes that generate energy carriers such as steam, hydrogen, synthesis gas (syngas), liquid fuels and/or electricity are based on fossil fuels. Furthermore, the dependence on fossil fuels is expected to continue in the foreseeable future due to the much lower costs compared to renewable sources. Currently, the conversion of carbonaceous fuels such as coal, natural gas, petroleum coke is usually conducted through a combustion or reforming process. However, combustion of carbonaceous fuels, especially coal, is a carbon intensive process that emits large quantities of carbon dioxide to the environment. Sulfur and nitrogen compounds are also generated in this process due to the complex content in coal.
Chemical reactions between metal oxides and carbonaceous fuels, on the other hand, may provide a better way to recover the energy stored in the fuels. Several processes are based on the reaction of metal oxide particles with carbonaceous fuels to produce useful energy carriers. For example, Ishida et al. U.S. Pat. No. 5,447,024 describes processes wherein nickel oxide particles are used to convert natural gas through a chemical looping process into heat, which may be used in a turbine. However, recyclability of pure metal oxides is poor and constitutes an impediment for its use in commercial and industrial processes. Moreover, this technology has limited applicability, because it can only convert natural gas, which is more costly than other fossil fuels. Another well known process is a steam-iron process, wherein coal derived producer gas is reacted with iron oxide particles in a fluidized bed reactor to be later regenerated with steam to produce hydrogen gas. This process however suffers from poor gas conversion rates due to improper contact between reacting solids and gases, and is incapable of producing a hydrogen rich stream.
As demands increase for cleaner and more efficient systems of converting fuel, the need arises for improved systems, and system components therein, which will convert fuel effectively, while reducing pollutants.
In one embodiment of the present invention, a system for converting fuel is provided. The system comprises a first reactor comprising a plurality of ceramic composite particles, wherein the ceramic composite particles comprise at least one metal oxide disposed on a support. The first reactor is configured to reduce at least one metal oxide with a fuel to produce a reduced metal or a reduced metal oxide. The system also comprises a second reactor configured to oxidize the reduced metal or reduced metal oxide to produce a metal oxide intermediate, and a third reactor configured to regenerate at least one metal oxide by oxidizing the metal oxide intermediate.
In another embodiment of the present invention, a method of converting fuel to hydrogen, CO, or syngas is provided. The method comprises the steps of: reducing a metal oxide in a reduction reaction between a fuel and a metal oxide to a reduced metal or a reduced metal oxide; oxidizing the reduced metal or reduced metal oxide with an oxidant to a metal oxide intermediate, while also producing hydrogen, CO, or syngas; and regenerating the at least one metal oxide by oxidizing the metal oxide intermediate.
In yet another embodiment, a system comprising a Fischer-Tropsch reactor is provided. The Fischer-Tropsch reactor is configured to produce hydrocarbon fuel from a feed mixture comprising gaseous fuel. The system also comprises a first reactor comprising a plurality of ceramic composite particles, wherein the ceramic composite particles comprise at least one metal oxide disposed on a support. The first reactor is configured to reduce the metal oxides with a gaseous fuel to a reduced metal or a reduced metal oxide, wherein the gaseous fuel comprises at least partially the hydrocarbon fuel produced by the Fischer-Tropsch reactor. The system also comprises a second reactor configured to oxidize the reduced metal or reduced metal oxide with steam to produce metal oxide intermediates.
In another embodiment, a method of preparing ceramic composite particles is provided. The method comprises reacting a metal oxide with a support material; heat treating the mixture of metal oxide and support material at temperatures of between about 200 to about 1500° C. to produce ceramic composite powders; converting the ceramic composite powders into ceramic composite particles; and reducing and oxidizing the ceramic composite particles prior to use in a reactor.
Additional features and advantages provided by embodiments of the present invention will be more fully understood in view of the following detailed description.
The following detailed description of the illustrative embodiments of the present invention can be best understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:
Referring generally to
The third alternative method includes the step of physically mixing a metal oxide with a ceramic support material. Optionally, a promoter material may be added to the mixture of metal oxides and support material. After mixing, the mixture is heat treated at temperatures of between about 200 to about 1500° C. to produce ceramic composite powders. Heat treating may occur in the presence of inert gas, steam, oxygen, air, H2, and combinations thereof at a pressure of between vacuum pressure and about 10 atm. The method may also include a chemical treatment step, wherein the mixture of metal oxides and support material are treated with an acid, base, or both to activate the ceramic composite powder. After powder production, the ceramic composite powders may be converted into ceramic composite particles by methods known to one of ordinary skill in the art. These methods may include, but are not limited to, extrusion, granulation, and, pressurization methods such as pelletization. The particle may comprise various shapes and forms, for example, pellets, monoliths, or blocks.
The method then includes the step of reducing and oxidizing the ceramic composite particles prior to use in a reactor. This cycle is important for the ceramic composite particles because this mixing process may produce a particle with increased activity, strength and stability. This cycle is important for the ceramic composite particles to increase their activity, strength and stability. This treatment also leads to a reduced porosity (0.1-50 m2/g) as well as crystal structure changes that make the particle readily reducible and oxidizable without loosing its activity for multiple such reaction cycles. The porosity in Thomas patent is not reported but it is stated that the particle was porous and had mesopores. Although the description of particle synthesis in this application is limited to spray dry, co-precipitation, and direct mixing approach, ceramic composite particles produced by other techniques such as sol-gel, wet impregnation, and other methods known to one of ordinary skill in the art are also operable in the reactors of the present system.
The metal oxide of the ceramic composite comprises a metal selected from the group consisting of Fe, Cu, Ni, Sn, Co, Mn, and combinations thereof. Although various compositions are contemplated herein, the ceramic composite typically comprises at least 40% by weight of the metal oxide. The support material comprises at least one component selected from the group consisting of SiC, oxides of Al, Zr, Ti, Y, Si, La, Sr, Ba, and combinations thereof. The ceramic composite comprises at least 5% by weight of the support material. In further embodiments, the particle comprises a promoter material. The promoter comprises a pure metal, a metal oxide, a metal sulfide, or combinations thereof. These metal based compounds comprise one or more elements from the group consisting of Fe, Ni, Sn, Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba, , B, P, V, Cr, Mn, Co, Cu, Zn, Ga, Mo, Rh, Pt, Pd, Ag, and Ru. The ceramic composite comprises up to 40% by weight of the promoter material. In an exemplary embodiment of the ceramic composite, the metal oxide comprises Fe2O3 supported on a TiO2 support, and specifically a support comprising a mixture of TiO2 and Al2O3. In another exemplary embodiment, the ceramic composite may also comprise Fe2O3 supported on an YSZ (Yittria stabilized Zirconia) support.
Referring back to the reduction reaction of the first reactor 1, the first reactor 1 receives a fuel, which is utilized to reduce the at least one metal oxide of the ceramic composite to produce a reduced metal or a reduced metal oxide. As defined herein, “fuel” may include: a solid carbonaceous composition such as coal, tars, oil shales, oil sands, tar sand, biomass, wax, coke etc; a liquid carbonaceous composition such as gasoline, oil, petroleum, diesel, jet fuel, ethanol etc; and a gaseous composition such as syngas, carbon monoxide, hydrogen, methane, gaseous hydrocarbon gases (C1-C6), hydrocarbon vapors, etc. For example, and not by way of limitation, the following equation illustrates possible reduction reactions:
Fe2O3+2CO→2Fe+2CO2
16Fe2O3+3C5H12→32Fe+15CO2+18H2O
In this example, the metal oxide of the ceramic composite, Fe2O3, is reduced by a fuel, for example, CO, to produce a reduced metal oxide, Fe. Although Fe is the predominant reduced composition produced in the reduction reaction of the first reactor 1, FeO or other reduced metal oxides with a higher oxidation state are also contemplated herein.
The first reactor 1 and second reactor 2 may include various suitable reactors to allow an overall countercurrent contacting between gas and solids. Such may be achieved using a moving bed reactor, a series of fluidized bed reactors, a rotatory kiln, a fixed bed reactor, combinations thereof, or others known to one of ordinary skill in the art.
As shown in
The first reactor 1 may be constructed with various durable materials suitable to withstand temperatures of up at least 1200° C. The reactor may comprises carbon steel with a layer of refractory on the inside to minimize heat loss. This construction also allows the surface temperature of the reactor to be fairly low, thereby improving the creep resistance of the carbon steel. Other alloys suitable for the environments existing in various reactors may also be employed, especially if they are used as internal components configured to aid in solids flow or to enhance heat transfer within a moving bed embodiment. The interconnects for the various reactors can be of lock hopper design or rotary/star valve design to provide for a good seal. Other interconnects as can be determined easily by a person skilled in the art may also be used.
After reduction in the first reactor 1, the reduced metal or reduced metal oxide particles are then delivered to the second reactor 2 to undergo an oxidation reaction. The second reactor 2, which may comprise the same reactor type or a different reactor type than the first reactor 1, is configured to oxidize the reduced metal or reduced metal oxide to produce a metal oxide intermediate. As used herein, “metal oxide intermediate” refers to a metal oxide having a higher oxidation state than the reduced metal or metal oxide, and a lower oxidation state than the metal oxide of the ceramic composite. For example, and not by way of limitation, the following equation illustrates possible oxidation reactions:
3Fe+4H2O→Fe3O4 +4H2
3Fe+4CO2→Fe3O4+4CO
In this example which centers on ceramic composites that utilize Fe2O3 as the metal oxide, oxidation in the second reactor using steam will produce a resultant mixture that includes metal oxide intermediates comprising predominantly Fe3O4. Fe2O3 and FeO may also present. Furthermore, although H2O, specifically steam, is the oxidant in this example, numerous other oxidants are contemplated, for example, CO, O2, air, and other compositions familiar to one of ordinary skill in the art.
Referring to the solid fuel conversion embodiment of
The char formed on devolatilization of coal will then react with partially reduced iron oxide as it flows downwardly in the first reactor 1. To enhance the char reaction with iron oxide, a small amount of hydrogen is introduced at the bottom of the moving bed to result in the formation of H2O on its reaction with partially reduced iron oxide. The H2O produced will react with downwardly flowing char leading to its gasification into H2 and CO. The hydrogen formed will then react with the partially reduced iron oxide in order to further reduce the reduced iron oxide, thereby enhancing the char-iron oxide reaction rates. The hydrogen introduced at the bottom of the reactor will also ensure that the iron oxide particles are greatly reduced to Fe as they exit the first reactor 1. In some cases, some carbon is intentionally left unconverted in the particle to generate CO using steam in the second reactor. In yet some other cases, an excess of ceramic composite particles comprising Fe2O3 may be inserted into the first reactor 1 in order to enhance reaction rates.
The exiting reduced Fe containing particles may then be introduced into the second reactor 1. Like in the first reactor 1, the second reactor 2 may also comprise a moving bed with a countercurrent contacting pattern of gas and solids. Steam is introduced at the bottom of the reactor and it oxidizes the reduced Fe containing particles as the particles move downwardly inside the second reactor 2. In this embodiment, the product formed is hydrogen, which is subsequently discharged from the top of the second reactor 2. It will be shown in further embodiments that products such as CO and syngas are possible in addition to hydrogen. Though Fe2O3 formation is possible in the second reactor 2, the solid product from this reactor is expected to be mainly metal oxide intermediate, Fe3O4. The amount of Fe2O3 produced in the second reactor 2 depends on the oxidant used, as well as the amount of oxidant fed to the second reactor 2. The steam present in the hydrogen product of reactor 2 may then be condensed in order to provide for a hydrogen rich stream. At least part of this hydrogen rich stream may be recycled back to the first reactor 1 as described above. In addition to utilizing the same reactor type as the first reactor 1, the second reactor 2 may similarly operate at a temperature between about 400 to about 1200° C. and pressure of about 1 to about 150 atm.
To regenerate the metal oxide of the ceramic composite, the system utilizes a third reactor 3, which is configured to oxidize the metal oxide intermediate to the metal oxide of the composite. Referring to the embodiment
2Fe3O4+0.5O2→3Fe2O3
Referring to the embodiment of
The iron particles exiting the first reactor 1 may also contain ash and other unwanted byproducts. If the ash is not removed after the first 1 or second reactor 2 stages, the ash may keep building up in the system. Numerous devices and mechanisms for ash removal would be familiar to one of ordinary skill in the art. For example, ash may be removed based on the size of ash with respect to the iron oxide particles from any of the solid streams in the system. If pulverized coal is used as the fuel source, it will yield fine ash particles, typically lower than 100 μm in size. The size of the ceramic composite particles may vary based on the metal components used and the oxidation-reduction reaction in which the ceramic composite is utilized. In one embodiment, the particle comprises a size between about 0.5 to about 50 mm. As a result, simple sieving, for example, simple sieving at high temperatures, may result in removal of ash. Simple sieving uses the size and density differences between the wanted and unwanted solid particles in the separation process. Other methods, for example, mechanical methods, and methods based on weight, or magnetic properties, may be used to separate ash and unwanted materials. Separation devices, such as cyclones, will be further discussed in later embodiments.
Heat integration and heat recovery within the system and all system components is highly desirable. Heat integration in the system is specifically focused on generating the steam for the steam requirements of the second reactor 2. This steam can easily be generated using the high grade heat available in the hydrogen, CO2 and depleted air streams exiting reactors 1, 2, 3, respectively. In the process described above, there is also a desire to generate pure oxygen. To generate this pure oxygen, at least part of the hydrogen may be utilized.
The residence time in each reactor is dependent upon the size and composition of individual ceramic composite particles, as would be familiar to one or ordinary skill in the art. For example, the residence time for a reactor comprising Fe based metal oxides may range from about 0.1 to about 20 hours.
As stated above, additional unwanted elements may be present in addition to ash. Trace elements like Hg, As, Se are not expected to react with Fe2O3 at the high temperatures of the process. As a result they are expected to be present in the CO2 stream produced. If CO2 is to be used as a marketable product, these trace elements must be removed from the stream. Various cleanup units, such as mercury removal units are contemplated herein. Similar options will need to be exercised in case the CO2 stream is let out into the atmosphere, depending upon the rules and regulations existing at that time. If it is decided to sequester the CO2 for long term benign storage, e.g. in a deep geological formation, there may not be a need to remove these unwanted elements. Moreover, CO2 may be sequestered via mineral sequestration, which may be more desirable than geological storage, because it is safer and more manageable. Additionally sequestering CO2 has an economic advantage for global CO2 credit trading, which may be highly lucrative.
Furthermore, sulfur may constitute another unwanted element, which must be accounted for in the system. In a solid fuel conversion embodiment, sulfur, which is present in coal, is expected to react with Fe2O3 and form FeS. This will be liberated on reaction with steam in reactor 2 as H2S and will contaminate the hydrogen stream. During the condensation of water from this steam, most of this H2S will condense out. The remaining H2S can be removed using conventional techniques like amine scrubbing or high temperature removal using a Zn, Fe or a Cu based sorbent. Another method for removing sulfur would include the introduction of sorbents, for example, CaO, MgO, etc. Additionally, as shown in the embodiment of
Although the embodiments of the present system are directed to producing hydrogen, it may be desirable for further treatment to produce ultra-high purity hydrogen. As would be familiar to one of ordinary skill in the art, some carbon or its derivatives may carry over from reactor 1 to 2 and contaminate the hydrogen stream. Depending upon the purity of the hydrogen required, it may be necessary to use a pressure swing adsorption (PSA) unit for hydrogen to achieve ultra high purities. The off gas from the PSA unit may comprise value as a fuel and may be recycled into the first reactor 1 along with coal, in solid fuel conversion embodiments, in order to improve the efficiency of hydrogen production in the system.
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In the F-T embodiment of
In all the F-T embodiments, part of the steam generated in the F-T reactor may be superheated by high temperature streams from the chemical looping system of the present invention or gasifiers. The superheated steam may comprise various uses, for example, driving a steam turbine for parasitic energy or as a feed stock in reactor 2.
In the embodiment of
Referring to
It is noted that terms like “preferably, ” “generally”, “commonly,” and “typically” are not utilized herein to limit the scope of the claimed invention or to imply that certain features are critical, essential, or even important to the structure or function of the claimed invention. Rather, these terms are merely intended to highlight alternative or additional features that may or may not be utilized in a particular embodiment of the present invention.
For the purposes of describing and defining the present invention it is noted that the term “substantially” is utilized herein to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. The term “substantially” is also utilized herein to represent the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue.
Having described the invention in detail and by reference to specific embodiments thereof, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims. More specifically, although some aspects of the present invention are identified herein as preferred or particularly advantageous, it is contemplated that the present invention is not necessarily limited to these preferred aspects of the invention.
Claims
1. A system for converting fuel comprising:
- a first reactor comprising a plurality of ceramic composite particles, the ceramic composite particles comprising at least one metal oxide dispersed on a support, wherein the first reactor is configured to reduce the at least one metal oxide with a fuel to produce a reduced metal or a reduced metal oxide, and is further configured to produce carbon dioxide, steam, or combinations thereof;
- a second reactor configured to oxidize at least a portion of the reduced metal or reduced metal oxide from the first reactor to produce a metal oxide intermediate, and is further configured to produce hydrogen, carbon monoxide, syngas, heat or combinations thereof wherein the oxidant utilized in the oxidizing steps comprises steam, carbon dioxide, air, oxygen, or combinations thereof, wherein the oxidants being configured to produce the syngas in the second reactor; and
- a third reactor in communication with the first reactor, the second reactor or both that is configured to regenerate the at least one metal oxide by oxidizing the metal oxide intermediate of the second reactor, and is further configured to produce heat in the third reactor.
2. A system according to claim 1 wherein the second reactor is also configured to produce H2, CO, heat, or combinations thereof.
3. A system according to claim 1 wherein the H2/CO ratio of the syngas is controlled by recycling part of the second reactor product, or controlling the amount of CO2 and steam oxidants inputted into the second reactor.
4. A system according to claim 1 wherein the ceramic composite particles comprise a promoter.
5. A system according to claim 1 wherein the fuel comprises a solid fuel, a liquid fuel, a gaseous fuel, or combinations thereof.
6. A system according to claim 1 further comprising a separation unit configured to remove ash, char, or unwanted materials from a product stream of the second reactor, the third reactor, or both.
7. A system according to claim 8 wherein the ash separator comprises a cyclone, a sieve, a particle classifier, or combinations thereof.
8. A system according to claim 1 wherein the first and second reactors are configured to operate at a pressure of between about 1 atm to about 150 atm.
9. A system according to claim 1 wherein the first and second reactors are configured to operate at a temperature of between about 400 to about 1200 C.
10. A system according to claim 1 wherein the metal oxide comprises a metal selected from the group consisting of Fe, Cu, Ni, Sn, Co, Mn, and combinations thereof, and the support material comprises at least one component selected from the group consisting of SiC, oxides of Al, Zr, Ti, Y, Si, La, Sr, Ba, and combination thereof.
11. A system according to claim 1 further comprising a power generation section configured to produce electricity from a product of the second reactor.
12. A system according to claim 1 further comprising at least one heat exchanger configured to heat a feed comprising water, steam and combinations thereof.
13. A system according to claim 1 wherein the first reactor and the second reactor comprise at least one moving bed reactor, a series of fluidized bed reactors, a rotatory kiln, a fixed bed reactor, or combinations thereof.
14. A system according to claim 13 wherein the first reactor and the second reactor defines a countercurrent contacting pattern between gas and solids.
15. A system according to claim 1 wherein the first reactor is a moving bed reactor comprising a mixing device inserted in the moving bed to radially distribute the ceramic composite particles and mix unconverted fuel with the ceramic composite particles.
16. A system according to claim 1 wherein the first reactor is a moving bed reactor defines an annular region created around the moving bed, the annular region being location where a fuel is introduced.
17. A system according to claim 1 further comprising a conveyor or pneumatic feeding device configured to deliver the solid fuel to the first reactor.
18. A system according to claim 1 further comprising a solid fuel gasifier, a candle filter, a mercury removal unit, a gas cleanup component, a pressure swing absorption unit, a water gas shift reactor, or combinations thereof.
19. A system according to claim 1 wherein the first reactor comprises metal carbonates, metal oxides, or metal hydroxides configured to capture pollutants, heavy metals, or combinations thereof.
20. A system according to claim 1 wherein the first reactor is operable to receive a recycled H2 stream at a bottom portion of the reactor.
21. A system according to claim 1 wherein the first reactor is operable to receive the fuel at a first reactor region below a feed region of the ceramic composite particles.
22. A system according to claim 1 wherein the first reactor is operable to receive feeds including oxygen, CO2, air, steam, and combinations thereof at a location adjacent the middle region in which the fuel is fed.
23. A system according to claim 1 wherein the system is coupled to a solid oxide fuel cell.
24. A system according to claim 1 wherein the system is in fluid communication with a Fischer-Tropsch reactor.
25. A system according to claim 24 further comprising a refining section.
26. A system according to claim 1 wherein the first and second reactors comprise packed beds in the form of portable cassettes, wherein the portable cassettes are configured to generate and store hydrogen in a vehicle.
27. A system comprising:
- a Fischer-Tropsch reactor configured to produce hydrocarbon fuel from a feed mixture comprising fuel;
- a first reactor comprising a plurality of ceramic composite particles, the ceramic composite particles comprising at least one metal oxide disposed on a support, wherein the first reactor is configured to reduce the at least one metal oxide with fuel to a reduced metal or a reduced metal oxide, the fuel being comprised at least partially of the hydrocarbon product of the Fischer-Tropsch reactor; and
- a second reactor configured to oxidize the reduced metal or reduced metal oxide with steam to produce metal oxide intermediates,
- wherein the second reactor is also configured to produce syngas.
28. A system according to claim 27 further comprising:
- a gaseous fuel feed source;
- a refining system to treat the hydrocarbon products generated in the system.
29. A system according to claim 27, wherein the oxidant is steam, CO, air, O2, or combinations thereof.
30. A system according to claim 27, wherein the steam utilized in the second reactor comprises at least partially steam generated in a Fischer-Tropsch reactor or a gasifier.
31. A system according to claim 27 further comprising a third reactor in communication with the first reactor and configured to regenerate the at least one metal oxide by oxidizing the metal oxide intermediates.
32. A system according to claim 27 wherein the second reactor is also configured to produce hydrogen.
33. A system according to claim 27 wherein the fuel fed to the first reactor comprises at least partially syngas produced by gasification of a hydrocarbon fuel.
34. A system according to claim 27 wherein byproducts of the Fischer-Tropsch reactor are recycled to the first reactor.
35. A system according to claim 27 further comprising a steam turbine configured to produce electricity from steam generated in the system.
36. A system according to claim 27 further a gaseous fuel mixing location, wherein a gaseous fuel feed and a hydrogen containing product from the second reactor are operable to mix to produce a gaseous fuel having a molar ratio of hydrogen to carbon monoxide equal to about 2 to 1, the gaseous fuel being used in the feed mixture of the Fischer-Tropsch reactor.
37. A method of preparing ceramic composite particles comprising the steps of reacting a metal oxide with a support material;
- heat treating the mixture of metal oxide and support material at temperatures of between about 200 to about 1500° C. to produce ceramic composite powders;
- converting the ceramic composite powders into ceramic composite particles;
- reducing and oxidizing the ceramic composite particles prior to use in a reactor.
38. A method according to claim 37 further comprising adding a promoter material to the mixture of metal oxide and support material.
39. A method according to claim 37 wherein heat treating occurs in the presence of inert gas, steam, oxygen, air, H2, and combinations thereof at a pressure of between vacuum pressure and about 10 atm.
40. A method according to claim 37 further comprising chemically treating the mixture of metal oxide and promoter to activate a ceramic composite powder.
41. A method according to claim 37 wherein the reacting step occurs via spray drying, direct mixing, co-impregnation, or combinations thereof.
42. A method according to claim 37 wherein the conversion of ceramic composite powders occurs via extrusion, granulation, pelletization, and combinations thereof.
43. A particle produced by the method of claim 37.
44. A particle according to claim 43 wherein the metal oxide comprises a metal selected from the group consisting of Fe, Cu, Ni, Sn, Co, Mn, and combinations thereof.
45. A particle according to claim 43 wherein the ceramic composite comprises at least 40% by weight of the metal oxide.
46. A particle according to claim 43 wherein the support material comprises at least one component selected from the group consisting of SiC, oxides of Al, Zr, Ti, Y, Si, La, Sr, Ba, and combination thereof.
47. A particle according to claim 43 wherein the ceramic composite comprises at least 5% by weight of the support material.
48. A particle according to claim 43 wherein the particle comprises a promoter comprising a pure metal, a metal oxide, a metal sulfide, or combinations thereof, wherein the metal comprises one or more from the group consisting of Fe, Ni, Sn, Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba, B, P, V, Cr, Mn, Co, Cu, Zn, Ga, Mo, Rh, Pt, Pd, Ag, and Ru.
49. A particle according to claim 48 wherein the ceramic composite comprises up to 40% by weight of the promoter material.
50. A method according to claim 37 wherein the ceramic composite particles are in the form of pellets, monoliths, blocks, or combinations thereof.
51. A method according to claim 37 wherein the particle is operable to maintain activity after 10 or more regeneration cycles.
Type: Application
Filed: Jan 12, 2007
Publication Date: Jan 1, 2009
Inventors: Liang-Shih Fan (Columbus, OH), Puneet Gupta (Houston, TX), Luis Gilberto Velazquez Vargas (Columbus, OH), Fanxing Li (Columbus, OH)
Application Number: 12/160,803
International Classification: C10J 1/20 (20060101);