Improved catalytic reactor system and catalyst for converting captured CO2 and renewable H2 to low-carbon syngas

Abstract

The present invention describes an improved catalytic reactor system with an improved catalyst that converts CO2 and low carbon H2 to low carbon syngas with greater than 80% CO2 conversion efficiency, resulting in reduced plant capital and operating costs compared to processes described in the current art. The inner surfaces of the adiabatic catalytic reactor are covered with an adiabatic non-reactive surface that does not react with the syngas and does not affect catalyst performance. The improved catalyst is robust, has high CO2 conversion efficiency, and shows little or no performance degradation over extended periods of operation. The low carbon syngas is used to produce low carbon fuels (such as diesel fuel, jet fuel, gasoline, kerosene, etc.), low carbon chemicals, and other products, resulting in significant reductions in greenhouse gas emissions compared to fossil fuel-derived products.

Description

[Technical Field]

[0001] The present invention describes an improved catalytic reactor system, which may include a single reactor or a series of reactors, with an improved catalyst that converts captured CO and renewable H to low-carbon syngas with a CO conversion efficiency greater than 80%. The improved catalyst is robust, has high CO conversion efficiency, and exhibits little or no performance degradation over extended periods of operation. The low-carbon syngas can be used to produce low-carbon fuels (e.g., diesel fuel, jet fuel, gasoline, kerosene, etc.), low-carbon chemicals (methanol, alcohols, olefins, solvents, etc.), and other products, resulting in significant reductions in greenhouse gas emissions compared to fossil fuel-derived products. [Background technology]

[0002] Carbon dioxide is produced by many industrial and biological processes. It is typically released into the atmosphere. However, it has been identified as an important greenhouse gas, and therefore, carbon dioxide emissions from these processes need to be reduced (Shukla et al. (2019) and Schuetzle (2020)). In limited cases, carbon dioxide is used to enhance oil and gas recovery from oil wells, and small amounts are used in the beverage industry and for other applications. However, most carbon dioxide is emitted into the atmosphere. A desirable way to deal with carbon dioxide is to efficiently capture and utilize it and convert it into useful products, such as fuels and chemicals. Such products can replace fuels and chemicals produced from fossil resources, such as oil and natural gas, thereby reducing the total net carbon dioxide emissions into the atmosphere (Hepburn et al. (2019)).

[0003] One of the reactions that has been investigated for utilizing carbon dioxide is the reverse water gas shift (RWGS) reaction, which is often referred to as the hydrogenation of carbon dioxide (Equation 1). CO2+ H2= CO + H2O Equation 1 This reaction converts CO and H to CO and HO. The reaction is endothermic at room temperature and requires heat to proceed. High temperatures and an efficient catalyst are required to achieve significant conversion of carbon dioxide to carbon monoxide with minimal or no coking (carbon formation).

[0004] Hydrogen can be produced from many sources, including natural gas, or more preferably, from water by electrolysis or other means (Equation 2). H2O = H2+ 1 / 2O2 formula 2 The CO from the RWGS reaction and the H from the electrolysis of water can be used to produce fuels and chemicals. The mixture of H and CO is called synthesis gas or syngas. Syngas can be used as a feedstock to produce a wide range of chemical products, including liquid and gaseous hydrocarbon fuels, alcohols, acetic acid, dimethyl ether, and many other chemical products (Olah (2009), Centi (2009), Jian (2010), Fischer (2016), Li (2019), National Academy of Sciences (2019)).

[0005] [RWGS catalyst] The most widely described approach in current technology employs a catalytic process to convert a mixture of CO2 and H2 into syngas. This method is usually referred to as "CO2 hydrogenation" or "reverse water gas shift (RWGS)" (Daza et al. (2016), Vogt et al. (2019)). A second emerging approach involves an electrolysis process to convert a mixture of CO2 and HO into syngas (Wang et al. (2016)).

[0006] Many patent applications, patents, and publications describe the development of RWGS catalysts for the conversion of mixtures of H2 and CO2 to syngas. This technology is evaluated with respect to the quality and performance specifications outlined in Table 1.

[0007] Table 1. Quality and performance requirements for effective catalytic conversion of H2 / CO2 mixtures to syngas 1. The catalyst contains low-cost components (no (or few) rare metals). 2. It can be produced economically in multi-ton quantities. 3. The catalyst is robust (e.g., Rockwell hardness greater than Mohr 03-04). 4. Chemically and physically stable up to approximately 2,100°F. 5. It can be easily packed into catalytic reactors (such as tubular reactors or packed bed reactors). 6. The pressure drop from top to bottom of the catalytic reactor is acceptable (preferably less than 50 psi). 7. Catalyst activation (e.g., reduction with H2) can be performed in situ. 8. The CO2 to CO conversion efficiency is approximately 5,000 hours -1 greater than about 65%, preferably greater than about 75% per pass at space velocities greater than about 100%. 9. The selectivity for CO production (from CO2) is greater than about 90%, preferably greater than about 95%. 10. The catalyst does not coke (e.g., does not form carbon deposits). 11. Long life (less than 0.5% activity loss per 1,000 hours of operation) and no systematic reactivation (reduction) is required.

[0008] The above indicators are important for the RWGS catalyst system to meet the commercial economics of the CO conversion system. Therefore, the standard RWGS catalyst described in the current technology is evaluated by adopting these quality and performance specifications as described in Table 1.

[0009] (1995) developed a catalyst containing transition metals and rare metals (Ni, Fe, Ru, Rh, Pt, W, Pd, Mo, etc.) on zinc oxide for the conversion of a mixture of CO2 and H2 to CO. They achieved a relatively low conversion rate of up to 37% after 150 hours without a significant decrease in catalytic activity, but did not perform longer-term tests.

[0010] Dupont et al. (2003) developed a catalyst consisting of 0.78% ZnO / 0.21% CrO / 0.01% NiO for the conversion of a mixture of H / CO (3.5 / 1.0 (v / v)) to CO. The catalyst was operated at 950°F, 580 psi, and a space velocity of 5.0 hr. -1 The CO conversion efficiency at 1000kJ / s was 36%, with 92% CO and 8% CH. No data was presented on the catalyst's efficiency over time. This catalyst does not meet any of the criteria outlined in Table 1.

[0011] Chen et al. (2015) reported that a nano-intermetallic catalyst (InNiCo) exhibited activity and selectivity for the RWGS reaction. 0.5 reported the synthesis of a catalyst called In-Ni intermetallic base. This catalyst was prepared by carburization of an In-Ni intermetallic base, which produced dual active sites on the catalyst surface. This catalyst was found to have a catalytic activity of 30,000 hours. -1 At a high gas flow rate of 1125°F for 150 hours, a moderate CO2 conversion of 52-53% was achieved. Based on its structure, this catalyst has the potential to meet criteria #3 and #7. Manufacturing this catalyst in multi-ton quantities (criterion #2) is difficult, and it is unclear whether it can be used commercially in conventional catalytic reactors (criterion #5 and #6). This catalyst does not meet the CO2 conversion efficiency (criterion #8) or selectivity for CO production (criterion #9). Because this catalyst was only tested for 150 hours, its stability and lifetime (criterion #4, #10, and #11) are unknown.

[0012] Bahmanpour et al. (2019) studied in situ formed Cu-Al spinel as an active catalyst for the hydrogenation of CO with H to syngas. They used coprecipitation followed by hydrotreating to form Cu-Al spinel at various weight ratios. A Cu to Al ratio of 4:1 was found to be efficient for CO conversion. They maintained a relatively low CO conversion of 47% at 600 °C at a relatively high space velocity, with no detectable deactivation after a 40-hour test.

[0013] This catalyst meets criterion #1 and may meet criteria #2, #3, #5, #6, and #7. However, copper-containing catalysts tend to deactivate over time due to sintering at high temperatures. Furthermore, this catalyst formulation requires a 1,000-hour test to evaluate long-term life (criterion #10).

[0014] Daza and Kuhn (2016) developed a La / Sr (3.0 / 1.0 (w / w)) catalyst impregnated on an FeO substrate. They observed 16% conversion of H2 / CO2 (1.0 / 1.0 (v / v)) to CO with 95% selectivity at 1,200°F and 15 psi. The CO2 conversion efficiency and CO selectivity remained relatively constant throughout the 150-hour test period. This catalyst met criteria #1, #7, and #9 listed in Table 1. Because this catalyst was only operated for 150 hours, its long-term life (#10) is unknown.

[0015] Table 2 summarizes these and other technologies for catalyzing the hydrogenation of CO to CO. In summary, the catalysts described in these technologies do not meet even half of the quality and performance required for the effective, commercial conversion of H / CO mixtures to syngas. In contrast, the improved catalysts and catalytic conversion systems described herein meet all of the requirements set forth in Table 1.

[0016] [Table 2-1]

[0017] [Table 2-2]

[0018] [RWGS catalytic reactor technology] The use of catalytic reactors, including single reactors and reactors in series, has been used for decades to boost feedstock conversion efficiency, improve yields, and enhance product selectivity (Du et al. (2019), Wikipedia (2021), Repasky et al. (2021)). For this reason, the use of reactors in series for RWGS is well known to those skilled in the art, and these reactors in series are not considered a revolutionary improvement.

[0019] The catalytic reactor described herein is improved by adding an insulating, non-reactive surface to the catalyst inner wall that does not react with the syngas and affect catalyst performance. Other catalytic reactor systems and configurations using RWGS catalysts are described. Summary of the Invention

[0020] The present invention relates to a method for converting a feed gas containing a mixture of H and CO to a syngas containing H and CO in various ratios. The feed gas is preheated to an inlet temperature greater than 1,500°F, preferably greater than 1,600°F, to produce a heated feed gas. The feed gases may be heated individually and then mixed, or may be mixed and then heated together. An electric preheater (Q1) heats the feed gas using renewable electricity, although a furnace configuration may also be used. The heated feed gas is sent to an improved RWGS catalyst in a first catalytic reactor. The improved catalyst comprises one or more Group 1 and Group 2 metals impregnated on a metallic alumina spinel. The gas from the first catalytic reactor is reheated (Q2) to the desired operating temperature of the RWGS catalyst before being sent to a second RWGS catalytic reactor containing the improved catalyst. The resulting CO conversion efficiency is greater than about 80%, and the selectivity for CO production is greater than about 95%. [Brief explanation of the drawings]

[0021] [Figure 1] Figure 1 illustrates a flow diagram of a method for converting H and CO into low-carbon fuels and chemical products. The main parts of the system include: 1) an electrolysis system 101 that produces H and O from water; 2) captured CO 102; and 3) a catalytic conversion system 104 that includes an improved catalyst (Catalyst #1) in series catalytic reactors A 105 and B 106 to efficiently produce syngas from the H / CO mixture. Catalyst #2 108 produces liquid hydrocarbons (or other chemical products) from the syngas. The resulting low-carbon fuel products and high-value chemical products are separated and / or purified by distillation and / or other separation processes 114.

[0022] The general layout of an intrinsic catalytic conversion system 104 is illustrated in FIG. 1. A mixture of H and CO 103 is heated (Q1) to the desired operating temperature before entering reactor A 105, which contains an improved RWGS catalyst (Catalyst #1). The reactant streams may be heated as a gas mixture or individually. Because the catalytic conversion of H and CO is endothermic, the temperature of the gas exiting reactor A will be lower than the inlet temperature. Therefore, the gas is reheated (Q2) to the desired operating temperature before entering reactor B 106. System configurations can also include the use of a single reactor system in which heating is performed throughout the length of the reactor to maintain a nearly constant temperature. Following the RWGS reactor system, a heat exchanger is used to reduce the temperature of the gas from reactor B to the desired operating temperature of catalyst #2 108 for producing fuels and chemicals. Water is removed at this stage.

[0023] Thermal design and optimization for RWGS reactors is particularly important in the commercial synthesis of fuels and chemicals. This series reactor design results in approximately 80% or greater conversion of CO2 to CO, eliminating the need to recycle the product gas / syngas stream before entering the next stage of the process. DETAILED DESCRIPTION OF THE INVENTION

[0024] Renewable H2 is produced by electrolysis 101 of water using renewable electricity. H2O = H2+ 1 / 2O2 equation 1 Other sources of low-carbon or renewable H2 can also be used, including renewable H2, which can be produced by steam reforming of biomass to produce syngas with a H2 / CO ratio of approximately 2.0 (Schuetzle et al. (2015)), or renewable H2, which can be produced from flare gas containing primarily methane (Equation 2) (Tan et al., 2018). CH4+ H2O = 3H2+ CO Equation 2

[0025] CO2 can be captured from many industrial and natural sources. CO2 is often found in natural gas deposits. CO2 is emitted from many biological processes, such as anaerobic digestion. Many other processes (e.g., power plants, cement plants, ethanol production, oil refineries, chemical plants, etc.) produce CO2, which is typically released into the atmosphere. CO2 can also be captured from the atmosphere. CO2 can be captured from these biological, industrial, and atmospheric processes using many known techniques and used as a feedstock for the present invention (Hepburn et al. (2019)). H2 and CO2 are mixed in a desired volumetric ratio to form stream 103 in Figure 1. The H2 / CO2 ratio is between 2.5 and 4.0, more preferably between 3.0 and 3.7. This gas mixture is then indirectly heated to temperatures above 1,500°F, preferably above 1,600°F. It is important that this heating be done using renewable electricity or other renewable resources in order to achieve acceptable carbon intensities for the resulting end product.

[0026]

number

[0027] Electrical heating of the feed gas can be accomplished in many ways. One method is to use an electrically heated radiant furnace. In this embodiment, at least a portion of the gas mixture passes through a heating coil within the furnace. Within the furnace, the heating coil is surrounded by radiant electric heating elements. In another embodiment of the invention, the gas passes directly over the heating elements, which heat the gas by convective heat transfer. Electric heating elements can be made from many materials. The most common heating element is a nickel-chromium alloy. These elements can be wound strip or wire, or cast in a zigzag shape. These elements are typically secured within an insulated container, where ceramic fiber is used for insulation. Radiant elements can be divided into multiple sections to allow for control of the heating pattern. Multiple coils and multiple sections may be required to provide the energy to generate the heated feed gas. In a radiant furnace, the heating elements and fluid coils must be properly designed to ensure good view factors and good heat transfer. The power usage by the radiant furnace should be as low as possible: less than 0.5 MWh (megawatt hours) of power per MT (metric tonnes) of CO in the feed gas, more preferably less than 0.40 MWh / MT, and even more preferably less than 0.20 MWh / MT.

[0028] Catalytic reactors A and B are constructed of high temperature Inconel steel or Hastelloy, insulated to limit heat loss. The advantage of this series reactor design is that catalytic reactors A and B only need to be insulated and not heated. It is only necessary to heat the gas prior to catalytic reactors A and B. In the alternative, a single catalytic reactor system may be used, in which case a heater is used within the reactor system to maintain a near constant temperature within the system to maximize conversion. The reactor system may be a packed vessel or a shell-and-tube reactor system, both of which are well known in the art.

[0029] It is not acceptable to construct the catalytic reactor using stainless steel or ceramic materials containing silica, because it has been found that after the silica reacts with the syngas to produce silicon hydride, silicates deposit on the catalyst, significantly reducing the catalyst's life and efficiency. Stainless steel is also not acceptable because it reacts with the syngas. Preferably, the catalytic reactor is made from high-temperature Inconel or Hastelloy.

[0030] The interior surfaces of the Inconel or Hastelloy are coated with a thermally insulating, non-reactive surface coating that does not react with syngas and does not affect catalytic performance. Examples of acceptable surface coatings include, for example, magnesium aluminate and spinels such as yttria-stabilized zirconia (YSZ). These coatings can be applied using a thermal spray process.

[0031] The improved RWGS catalyst (Catalyst #1 in Reactor A 105 and Reactor B 106) is placed inside the catalytic conversion system 104. The catalyst can be in the form of granules, pellets, spheres, trilobes, quadra-lobes, monoliths, or any other designed shape to minimize pressure drop across the reactor. Ideally, the shape and size of the catalyst particles are controlled so that the pressure drop across the reactor is less than 50 psi, and more preferably less than 20 psi. The size of the catalyst form can have a characteristic dimension between 1 mm and 10 mm. The catalyst particles have an internal surface area of ​​about 15 m. 2 / g, more preferably about 30m 2 / g or larger porous material.

[0032] The improved catalyst used in this improved process comprises a metal alumina spinel impregnated with one or more elements in a total concentration of between 1 and 35 parts by weight, the metal alumina spinel being selected from the group consisting of magnesium aluminate, calcium aluminate, strontium aluminate, potassium aluminate, and sodium aluminate, and the impregnated elements being selected from the group consisting of Ba, Ca, Co, Fe, Mg, Ni, and Zn.

[0033] The weight hourly space velocity (WHSV) per unit time is calculated by dividing the mass flow rate of reactants (H2 + CO2) per hour by the mass of catalyst in reactors A and B. -1 From 50,000 hours -1 and more preferably between 10,000 hours -1 From 30,000 hours -1 It is between.

[0034] The gas exiting the main reactor vessel is product gas. Product gas includes syngas (a H2 / CO mixture), unreacted CO2, and H2O. Additionally, product gas may include small amounts of methane (CH4) produced by side reactions within the main reactor vessel. In one embodiment, methane production is preferably less than 10%, more preferably less than 5%, and even more preferably less than 1%.

[0035] The syngas can be used in a variety of ways at this point in the process: It can be cooled and compressed using heat exchanger 107, as characterized by a catalyst 108, which is used to produce fuels and chemicals.

[0036] After producing fuels or chemicals, the products (including the methane-rich tail gas) are separated 109 and the taigas are recycled to an autothermal reformer 111 for further conversion. The autothermal reformer uses the oxygen produced from the electrolysis step 101.

[0037] The liquid hydrocarbon products 113 may be distilled and / or processed 114 to produce diesel, naphtha, kerosene, jet fuel, gasoline or other fuel products, or low carbon specialty chemical products such as solvents, waxes, n-paraffins, olefins and other products. [Example]

[0038] Below are examples for the conversion of H2 and CO2 mixtures to syngas using various catalytic conversion system designs and operating specifications.

[0039] [Example #1] In this example, catalytic reactor A 105 and reactor B 106 are the same size and operated under the same conditions of pressure, temperature, and space velocity. A H2 / CO2 mixture (3.4 / 1.0 (v / v)) is heated to 1,650°F, compressed to 300 psi, and run for approximately 17,000 hours. -1The mixture was fed into the catalytic reactor A105 at a space velocity of 0.05 MPa.

[0040] Because the catalytic conversion of the H2 / CO2 mixture to syngas is endothermic, the temperatures of the gas reactants and products decrease and the CO2 conversion efficiency decreases as the gas passes through the reactor. Figure 1 illustrates the relationship between CO2 conversion efficiency and gas temperature. The CO2 conversion efficiency at the inlet to the catalyst bed is 82%, and the selectivity for CO production is greater than 99%.

[0041] The exit temperature of the unreacted and product gases from Reactor A will be approximately 1,375°F. Therefore, the average gas temperature in Reactor A is approximately 1,510°F. The average CO2 conversion efficiency is approximately 68% at this average temperature of the catalyst bed. The gas exiting Reactor A contains approximately 32% unconverted CO2. The gas exiting Reactor A is reheated to 1,650°F before entering Reactor B (Q2 in Figure 1). The gas exit temperature from Reactor B is approximately 1,615°F, with an average CO2 conversion efficiency of 78%. As a result, with this improved series reactor design, the CO2 conversion efficiency is greater than 80%. Therefore, catalyst tail gas recycle is not necessary. The composition (dry) of the syngas exiting Reactor B is 54% H2, 27% CO, and 19% CO2.

[0042] Therefore, a 2.0 / 1.0 ratio of H2 / CO is ideal for the direct production of fuels (Schuetzle et al., 2013, 2014, 2015, 2016, 2017, 2019), ethanol (Schuetzle et al., 2010), methanol (National Energy Technology Laboratory, 2021), and other products.

[0043] [US Patent Application Literature] 2003 / 0113244A1, June 2003, DuPont et al.

[0044] [US Patent Documents] 7,718,832B1, May 2010, Schuetzle et al. 8,394,862B1, March 2013, Schuetzle et al. 8,741,001B1, June 2014, Schuetzle et al. 9,090,831B2, July 2015, Schuetzle et al. 9,476,002B1, October 2016, Schuetzle et al. 9,611,145B1, April 2017, Schuetzle et al. 9,631,147B1, April 2017, Schuetzle et al. 10,478,806B1, November 2019, Schuetzle et al.

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[0047] Bahmanpour, A.M., Heroguel, F., Kilic, M., Baranowski, C.J., Artiglia, L.: Cu-Al spinel as a highly active and catalyst for the reverse water gas shift reaction. ACS Catal., 9, 6243-6251 (2019).

[0048] Centi, G., Perathoner, S.: Opportunities and prospects in the chemical recycling of carbon dioxide to fuels. Catalysis Today, 148, 191-205 (2009).

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[0050] Daza, Y.A., Kuhn, J.N.: CO2conversion by reverse water gas shift catalysis: Comparison of catalysts, mechanisms, and their consequences for CO2conversion to liquid fuels, Royal Society of Chemistry Advances, 6, 49, 675-49,691 (2016).

[0051] Fischer, N., Claeys, M., Van Steen, E., Niemantsverdriet, H., Vosloo, M.: Syngas convention - fuels and chemicals from synthesis gas: state of the art, 2, 1-200 (2016).

[0052] Hepburn, C., Adlen, E., Beddington, J., Carter, E.A., Fuss, S., Dowell, N.M., Minx, J. C., Smith, P., Williams, C.K.: The technological and economic prospects for CO2utilization and removal, Nature, 575, 87-97 (2019).

[0053] Jiang, Z., Xiao, T., Kuznetsov, V.L., Edwards, P.P.: Turning carbon dioxide into fuel. Phil. Trans. R. Soc. A, 368, 3343-3364 (2010).

[0054] Li, W., Wang, H., Jiang, X., Zhu, J., Liu, Z., Guo, X., Song, C.: A short review of recent advances in CO2hydrogenation to hydrocarbons over heterogeneous catalysts, RSC Adv., 8, 7651 (2018).

[0055] Lortie, M.: Reverse water gas shift reaction over supported Cu-Ni nanoparticle catalysts, Department of Chemical and Biological Engineering M.S. Thesis, University of Ottawa, Ottawa, Canada (2014).

[0056] National Academy of Sciences, Chemical Utilization of CO2into Chemicals and Fuels, Gaseous Carbon Waste Streams Utilization: Status and Research Needs, National Academies Press, Washington D.C. (2019).

[0057] National Energy Technology Laboratory: Syngas conversion to methanol, www.netl.doe.gov) (2021).

[0058] Olah, G. A., Goeppert, A., Surya Prakash, G. K.: Chemical recycling of carbon dioxide to methanol and dimethyl ether - from greenhouse gas to renewable, environmentally carbon neutral fuels and synthetic hydrocarbons. J. Org. Chem., 74, 487-498 (2009).

[0059] Ruckenstein, E., Hu, Y.H.: Combination of CO2reforming and partial oxidation of methane over NiO / MgO Solid Solution, Industrial & Engineering Chemistry Research, 37, 1744-1747 (1998).

[0060] Schuetzle, D., Tamblyn, G., Caldwell, M., Schuetzle, R.: Solar reforming of carbon dioxide to produce diesel fuel. U.S. Department of Energy report #DE-FE0002558 (2010).

[0061] Schuetzle, D., Tamblyn, G., Caldwell, M., Hanbury, O., Schuetzle, R., Rodriquez, R., Johnson, A., Deichert, F., Jorgensen, R., Struble, D: Demonstration of a pilot integrated biorefinery for the efficient, direct conversion of biomass to diesel fuel. DOE Technical Report #DE-EE0002876, U.S. Department of Energy Bioenergy Technologies Office (DOE-BTO), Golden, CO, 1-261 (May 2015) (www.researchgate.net)

[0062] Schuetzle, D.: Historical and predicted global climate changes and some potential accelerated climate moderation approaches, 2018 Global Climate Action Summit, San Francisco, CA, 1-42 (2020) (www.researchgate.net).

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[0064] Tan, E.C.D., Schuetzle, D., Zhang, Y., Hanbury, O., Schuetzle, R.: Reduction of greenhouse gas and criteria pollutant emissions by direct conversion of associated flare gas to synthetic fuels at oil wellheads, International Journal of Energy and Environmental Engineering, 9: 305-321 (2018)

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Claims

1. 1. A method for producing syngas, comprising: H ２ and CO ２ into a first catalytic reactor having an interior surface and an exterior surface, wherein the interior surface of the first catalytic reactor is ２ , CO or CO ２ the first catalytic reactor is coated with an inert insulating material that does not react with the first catalytic reactor, and the exterior surface of the first catalytic reactor is insulated to minimize heat loss during adiabatic operation; This produces syngas.

2. The first catalytic reactor is used in series with a second catalytic reactor having an inner surface and an outer surface, the inner surface of the second catalytic reactor being heated to a temperature of 1000 K. ２ , CO or CO ２ the second catalytic reactor is coated with an inert insulating material that does not react with the second catalytic reactor, and the outer surface of the second catalytic reactor is insulated to minimize heat loss during adiabatic operation; CO, H ２ and CO ２ a mixture of CO ２ and H ２ to syngas, and CO ２ The conversion efficiency is between 80% and 100%.

10. The method of claim 1.

3. H introduced into the first reactor ２ CO ２ 2. The method of claim 1, wherein the volume ratio of 0.1 to 0.5 is between 1.5 and 5.

0.

4. 3. The method of claim 2, wherein the first and second catalytic reactors are operated at 1.034 MPa (150 psi) to 2.413 MPa (350 psi).

5. 3. The method of claim 2, wherein the first and second catalytic reactors are operated at 871°C (1,600°F) to 926°C (1,700°F).

6. 3. The method of claim 2, wherein the second catalytic reactor is operated at a pressure within 20 psi of the pressure of the first catalytic reactor.

7. Renewable electricity is ２ and CO ２ 10. The method of claim 1, wherein the first catalytic reactor is heated prior to introduction of the first catalytic reactor.

8. 2. The method of claim 1, wherein the catalyst in the first catalytic reactor comprises a metal alumina spinel impregnated with one or more elements in a total concentration of between 1 part and 35 parts by weight, the metal alumina spinel being selected from the group consisting of magnesium aluminate, calcium aluminate, strontium aluminate, potassium aluminate, and sodium aluminate, and the one or more elements being selected from the group consisting of Ba, Ca, Co, Fe, Mg, Ni, and Zn.

9. The CO, H introduced into the second catalytic reactor ２ and CO ２ is introduced into the first catalytic reactor ２ and CO ２ 3. The method of claim 2, wherein the temperature is preheated to about the same temperature as

10. CO ２ 2. The process of claim 1, wherein the selectivity for CO production from is between 90% and 100%.

11. CO ２ 10. The method of claim 1, wherein the efficiency of conversion of CO to CO decreases between 0% and 1% over 1,000 hours.

12. The H ２ and CO ２ before being introduced into the first catalytic reactor. ２ and CO ２ a preheater used to heat the CO introduced into the first catalytic reactor; ２ 10. The method of claim 1, wherein the method uses less than 0.6 MWh of renewable electricity per metric ton of water.

13. H of the produced syngas ２ 2. The method of claim 1, wherein the ratio of CO to CO is from 1.5 to 3.

0.

14. The H introduced into the first reactor ２ and CO ２ 10. The method of claim 1, wherein the mixture further comprises methane.

15. The methane is CO ２ 15. The method of claim 14, wherein the amount of the hydroxybenzoate is between 0.1 volume percent and 10 volume percent of the hydroxybenzoate.

16. 15. The method of claim 14, wherein 80% to 100% by volume of the methane is converted to CO.

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