One-step process for producing hydrocarbons from carbon dioxide

Abstract

The present invention is a new and improved method and catalyst that can efficiently promote the direct conversion of hydrogen and carbon dioxide to hydrocarbons in a single reactor at temperatures below 450°C, more preferably between 250°C and 325°C. Carbon dioxide is utilized from a stationary source or direct air capture. Hydrogen is produced by electrolysis of water using renewable or low-carbon electricity.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 474,544, filed August 22, 2022, which is incorporated herein by reference in its entirety.

[0002] The field of this invention is the production of hydrocarbons, including sustainable aviation fuel (SAF) or diesel fuel, from CO2 by using a new low-temperature CO2C reaction in a new direct integrated process for producing hydrocarbons. [Background technology]

[0003] Increasing concentrations of carbon dioxide (CO2) in the world's atmosphere have been linked to global climate change. Burning fossil fuels in various engines and heaters produces atmospheric CO2. Concerns about climate change have led to a major societal shift towards renewable or low-carbon electricity, which has also led to increased efforts to decarbonize the economy.

[0004] Electricity can be used to produce synthetic methane, kerosene, methanol, or other chemicals, either gases or liquids, also known as power-to-gas, power-to-chemical, or more commonly, power-to-X (PtX, P2X) methods. Electricity generated from solar, wind, or other sustainable sources is commonly referred to as decarbonized electricity. Fuels and chemicals produced using decarbonized electricity have low, zero, or negative CO2 emissions overall. The raw materials (feedstocks) distinguish e-fuels from biofuels. Biofuels are primarily produced from biomass, which often includes food feedstocks or environmentally harmful feedstocks (e.g., canola oil, palm oil, etc.).

[0005] State-of-the-art processes convert hydrogen from electrolysis with CO2 to produce syngas, a mixture of carbon monoxide and hydrogen, which can then be used to generate fuels and chemicals. The thermodynamics of the RWGS reaction require high temperatures of approximately 800–900°C at the inlet of the RWGS reactor to drive the reaction. Because the syngas production reaction is highly endothermic (i.e., requires significant continuous heat input), this process often requires large electric heaters with significant electrical demands. Furthermore, the subsequent reaction of syngas to fuels (including hydrocarbons and / or alcohols) is highly exothermic, releasing heat of reaction that must be continuously removed from the reactor system. Therefore, state-of-the-art processes must simultaneously provide heat input in the syngas production step and heat removal in the syngas conversion step. While the latter partially offsets the former, the net requirement is heat input to drive the integrated process. Furthermore, managing these two thermal process effects of great practical importance presents engineering and operational challenges that adversely affect both process efficiency and capital cost requirements.

[0006] Various Power to X (PtX) concepts rely on using renewable or low-carbon electricity to produce hydrogen through the electrolysis of water, which can be used directly as the final energy carrier or converted, for example, into methane, syngas, liquid fuels, electricity, or chemicals.

[0007] At temperatures below 450°C 5+ Some limited research has been done on carrying out the CO2C reaction on hydrocarbons.

[0008] Most efforts to convert CO2 to liquid hydrocarbon fuels in one step (usually manifesting as a single reactor) have focused on developing catalysts that first produce CO from CO2 by hydrogenation, and then react with H2 to produce liquid hydrocarbons on the same catalyst or on tandem catalysts (physically close together). Ideally, the proximity of the two reaction sites is close enough that the benefits of heat integration can be realized, at least in part, directly.

[0009] To date, most research has focused on the use of iron-based catalysts active for the reverse water-gas shift reaction and FT chemistry (National Academy of Sciences, 2019).

[0010] Pan et al. (2007) reported that in a tubular reaction, Rh catalyst supported on carbon nanotubes was used for approximately 13 hours. -1 described the production of ethanol from a mixture of CO2 and H2 at a very low space velocity of 1000 sq. m. The catalyst produced a complex mixture of oxygenated hydrocarbons, including methanol, acetaldehyde, acetone, isopropanol, and acetic acid, in addition to ethanol. The problem with this catalyst is that it is not suitable for commercial scale-up due to the high pressure drop in the catalytic reactor, the very low space velocity, and the complex mixture of oxygenated hydrocarbons produced, which requires significant workup to produce specific products viable for the commercial market.

[0011] Wang et al. (2019) described an Fe / ZrO catalyst for catalyzing CO hydrogenation, which mainly produced CH and C2–C4 paraffins. The selectivity for the production of liquid-phase hydrocarbons was very low.

[0012] Landau et al. (2015) described a 20% Fe2O3 catalyst on iron-spinel. The particle size of the catalyst was varied from 100 μm to 3.0 mm. The catalyst was used at H2 / CO2 ratios of 2.0 to 3.0 / 1.0 and space velocities of approximately 2.0 h -1The temperature range was 325-350°C and the pressure range was 20-40 atmospheres. The maximum CO2 conversion was 36%. The product selectivity was 13% CO, 9% CH4, 44% C2-C5, and 44% C6-C6. 27 The HC of the 25%. 6+ The olefin / paraffin ratio of the hydrocarbons was about 5 / 1. This catalyst was used at a very low space velocity (2.0 hr -1 ), and is therefore not commercially viable.

[0013] Wei et al. (2018) described an iron-based catalyst for the one-step conversion of CO2 to isoparaffins. The CO2 conversion efficiency was only 26%, and the CO selectivity was low at about 17%. Coke (carbon) deposited in the catalyst pores caused a rapid decline in the isoparaffin yield over time.

[0014] Williamson et al. (2019) described the performance of a one-step catalyst containing iron nanoparticles deposited on carbon nanotubes. The catalyst was calcinated in air at 400 °C for 1 h or at 570 °C for 40 min and activated with H2 at 400 °C for 3 h. The catalyst was tested in a laboratory reactor at 370 °C and 221 psi using a 3.0 / 1.0 H2 / CO2 mixture. The average CO2 conversion was 54%, with selectivities to CO and hydrocarbons of 30% and 70%, respectively. The average composition of the hydrocarbon products was, by mass, 43% CH4, 55% C2-C4, and 2.0% C. 5+ It was a hydrocarbon.

[0015] Wang et al. (2021) described a single-step, plasma-assisted catalytic method for converting CO2 to hydrocarbons. They found that this method could convert CO2 at approximately 70% higher conversion at approximately 250 °C, with approximately 45% higher hydrocarbon selectivity. However, only C1-C5 hydrocarbons were produced, with methane selectivity of 65-70% and C2-C5 selectivity of 30-35%. The large amount of methane produced limited the practical value of this approach.

[0016] Shen et al. (2022) synthesized a nickel-cerium solid solution catalyst and found that it produced CO with high selectivity (>95%) at 300 °C. However, only 10% of the CO2 was converted to CO, and this conversion rate decreased over approximately 100 h.

[0017] Yao et al. (2020) reported that a mixture of CO2 and H2 was 5+ An Fe-Mn-K catalyst for the direct conversion of hydrocarbons was synthesized. This catalyst was tested at 300°C, 150 psi, and a space velocity of 2,400 h O at a H / CO ratio of 3 / 1. -1 The CO2 conversion rate decreased from 37-34% over the 75-hour test period, suggesting catalyst deactivation. 5+ The yield of hydrocarbons was about 22%. Summary of the Invention [Problem to be solved by the invention]

[0018] It is an object of the present invention to utilize new and improved methods and catalysts that can promote the direct CO conversion (COC) reaction to hydrocarbons at temperatures below 450°C, and more preferably at temperatures between 250°C and 325°C. [Means for solving the problem]

[0019] The present invention is an improved method for producing low carbon fuels and chemicals utilizing a new and improved catalyst capable of carrying out the CO2C reaction at temperatures between 250°C and 325°C.

[0020] In one embodiment, a method for producing hydrocarbons is provided, the method comprising: mixing a first feed stream comprising CO with a second feed stream comprising renewable H, thereby generating a CO reactor feed stream; and feeding the CO reactor feed stream into a CO conversion reactor, the CO conversion reactor comprising two catalysts, thereby generating a C 5+and producing a reactor product stream comprising hydrocarbons, H2O, and unreacted H2, CO, and CO2.

[0021] In another embodiment, a method for producing hydrocarbons is provided, the method comprising: mixing a first feed stream comprising CO with a second feed stream comprising renewable H, thereby generating a CO reactor feed stream; and feeding the CO reactor feed stream into a CO conversion reactor, the CO conversion reactor being a multi-tubular fixed-bed reactor, the CO conversion reactor comprising two catalysts, one of which comprises copper-impregnated FeO, thereby producing a C 5+ and producing a reactor product stream comprising hydrocarbons, H2O, and unreacted H2, CO, and CO2. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 illustrates a process for converting CO2 and hydrogen to hydrocarbons using a CO2C reactor, and includes the following components: Stream 1: Low Carbon Power, Stream 2: Water, Stream 3: H2, Stream 4: O2, Stream 5: CO2, Stream 6: CO2C Reactor Feed, Stream 7: CO2C Product, Stream 8: Portion of the CO2C Product, Stream 9: Hydrocarbons, Stream 10: Water, Stream 11: CO2 and Other Recycle to Unit 2, Unit 1: Electrolyzer, Unit 2: CO2C Reactor, and Unit 3: Product Processing Unit.

[0023] [Figure 2]2 shows the CO2C process described in Example 2, and includes the following components: Unit 200: CO2C Reactor, Unit 201: Water Knockout, Unit 202: Amine Contactor, Unit 203: Amine Regenerator, Unit 401: Syngas Methanation Reactor System, Unit 402: Methanation Reactor Product Separator, Stream 301: Feed to CO2C Rx, 302: Reactor Effluent, 303: Water, 304: Methane, H2, CO2, 305: Methane-H2 Feed to 401, 306: CO2, 307: Methanation Reactor Effluent, 308: Methane, 309: CO2, 310: Water Produced by Methanation, 311: CO2 / Amine Solution, 312: Amine to Contactor, 313: Medium Pressure Stream. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hydrocarbons refer to a class of organic compounds composed only of the elements carbon and hydrogen. Hydrogen atoms are attached to carbon atoms in many different arrangements. Hydrocarbons are classified as either aliphatic or aromatic. Aliphatic hydrocarbons are classified as alkanes, alkenes, and alkynes. Aromatic hydrocarbons are classified as arenes, which contain a benzene ring as a structural unit, or non-benzenoid aromatic hydrocarbons, which lack a benzene ring as a structural unit.

[0025] C1-C5 Hydrocarbons refers to hydrocarbons containing between one and five carbon atoms.

[0026] C2-C5 Hydrocarbons refers to hydrocarbons containing between two and five carbon atoms.

[0027] C 5+ Hydrocarbons (C 5+ Hydrocarbons refers to hydrocarbons containing five or more carbon atoms.

[0028] Renewable Electric Power refers to energy sources that are not fossil carbon based and may include solar, wind, biomass, geothermal, landfill gas, wave, tidal and ocean thermal technologies. Nuclear energy itself is a renewable energy source, but the materials used in nuclear power plants are not reusable unless the spent nuclear fuel is reusable. Currently, approximately 96% of spent nuclear fuel in nuclear reactors is recycled.

[0029] Low-carbon electric power refers to electricity that is produced with significantly fewer greenhouse gas emissions than traditional fossil fuel power generation.

[0030] Precious metals are naturally occurring rare metallic chemical elements of high economic value. Precious metals include gold, silver, platinum, palladium, ruthenium, rhodium, osmium, and iridium.

[0031] Natural magnetite refers to a naturally occurring iron oxide mineral. It is composed primarily of Fe3O4 with trace amounts of precious metals. It is the most magnetic of any naturally occurring mineral on Earth, making it a natural magnet. Magnetite-rich "black sands" are commonly found in gold mining operations. Precious metals are often present in magnetic concentrates as individual mineral particles, as inclusions in the magnetite, and as atoms dispersed within the magnetite lattice. Precious metal content may vary from a few ppm to 1,500 ppm depending on the mineral source.

[0032] Synthetic Magnetite refers to synthetic Fe3O4 impregnated with up to 1,500 ppm of various precious metals followed by calcination at up to about 2,100°F. Figure 1 shows an integrated process for producing hydrocarbons. Feed Stream 1 is low-carbon electricity. Low-carbon electricity includes, but is not limited to, wind, solar, nuclear, power generation from biomass or renewable natural gas, and hydropower. Feed Stream 2 is water. These two feeds are used in Unit 1, which is an electrolyzer. Water and low-carbon energy are used in the electrolyzer to produce hydrogen and oxygen. Hydrogen is produced by the electrolysis of water.

[0033] [ka]

[0034] An electrolyzer consists of an anode and a cathode separated by an electrolyte. Different electrolyzers function slightly differently. Different electrolyzer designs are used in the various electrolysis technologies in use, including alkaline electrolysis, polymer electrolyte membrane (PEM) electrolysis, solid oxide electrolysis, high temperature electrolysis, and other newer types of electrolysis.

[0035] The products from the electrolyzer are a hydrogen-containing stream, designated Stream 3 in Figure 1, and an oxygen-containing stream, designated Stream 4. The electrolyzer produces green hydrogen from renewable or low-carbon energy sources. Other forms of hydrogen production using renewable or non-renewable energy sources may also be used, including methane pyrolysis, steam reforming of hydrocarbons with or without carbon capture, biomass gasification, renewable natural gas (RNG) reforming, or hydrogen supply from geological sources. Each of these options may require steam purification to produce hydrogen for use in the process.

[0036] In FIG. 1, Stream 5 is a CO2-containing stream. CO2 can be obtained from several sources. Power plants that generate electricity from various carbonaceous sources produce large amounts of CO2. Industrial manufacturing plants that produce ammonia for fertilizer produce large amounts of CO2. Ethanol plants that convert corn or wheat to ethanol produce large amounts of CO2 through fermentation. Other industrial fermentation processes also produce large amounts of CO2. Municipal wastewater treatment systems that use aerobic and anaerobic digestion of sludge produce large amounts of CO2. CO2 utilization or conversion as described herein generally involves separating and purifying CO2 from gas (e.g., exhaust gas) streams in which CO2 is not the only, and often not the major, component. Typically, alkylamines are used to remove CO2 from gas streams. Alkylamines used in this process include monoethanolamine, diethanolamine, methidiethanolamine, diisopropylamine, aminoethoxyethanol, or combinations thereof. Metal organic framework (MOF) materials have also been used as a means of capturing CO2 from dilute streams, using chemisorption or physisorption to separate CO2 from the stream. Another method for obtaining concentrated CO2 is chemical looping combustion, where a circulating metal oxide material captures the CO2 produced during the combustion process. CO2 can also be captured from the atmosphere, a process known as direct air capture (DAC). Methods for capturing CO2 often involve regeneration of the capture material. Alkylamines are typically regenerated by heating with low-pressure steam.

[0037] The captured CO2 is converted into useful products such as fuels (e.g., synthetic natural gas, diesel fuel, gasoline blend stocks, jet fuel, etc.) and chemicals (e.g., solvents, olefins, alcohols, aromatics, polymers (for fibers, packaging, structural materials, etc.)) that replace fuels and chemicals made from fossil resources such as oil and natural gas, reducing the total net emissions of CO2 into the atmosphere. This is what is meant by low-carbon, ultra-low-carbon, zero-carbon, or negative-carbon fuels and chemicals.

[0038] CO streams from industrial or biological processes, or CO streams captured from the atmosphere, or available from commercial CO pipelines are generally not pure CO. These CO streams available from industrial facilities or pipelines may contain zero to 2,000 ppm by weight of sulfur-containing compounds and zero to 10% by volume of hydrocarbons. Purification of CO, including removal of sulfur-containing compounds and hydrocarbons, is necessary to avoid problems in downstream processing. After purification, the purified CO is suitable for use in producing low- or zero-carbon fuels and chemicals according to the present invention.

[0039] At least a portion of hydrogen-containing stream 3 is mixed with CO2-containing stream 5 to produce stream 6, or CO2C reactor product stream. The H2 / CO2 ratio is from 2 to 6, or preferably from 3 to 4. The CO2 and hydrogen in stream 6 react to form products in the CO2C reactor, shown as unit 2 in Figure 1. The CO2C reactor operates at a temperature of 250 to 425°C, more preferably from 275 to 350°C, and even more preferably at a temperature of about 300°C. The main reactions that may occur in the CO2C reactor are:

[0040] [ka]

[0041] The first reaction, equation 1, is the reverse water gas shift reaction. At standard temperatures, this reaction is endothermic and requires temperatures much higher than would otherwise be desirable in a CO2C reactor. The second reaction, equation 2, is the methanation reaction, which reacts CO and hydrogen gas to produce methane and water. The methanation reaction is highly exothermic, as indicated by its highly negative enthalpy of reaction. The third reaction, equation 3, is the desired Fischer-Tropsch (FT) reaction. This FT reaction is also highly exothermic.

[0042] Catalysts are used in CO2C reactors to promote chemical reactions. A variety of catalysts can be used in CO2C reactors. Catalysts contain multiple components with different functionalities. Catalysts can be monofunctional, bifunctional, or multifunctional compounds containing many different elements, including nickel, magnesium, aluminum, iron, copper, cobalt, indium, sodium, silicon, manganese, zinc, chromium, rhodium, carbon, cerium, titanium, and zirconium. Specifically, the catalysts include unsupported Ni2Mg solid solution catalyst, Mg / Mg-aluminate catalyst, rhodium on gamma alumina, CuFeO2, Fe-Co / K / Al2O3, In2O3 / HZSM-5, Na-Fe3O4 / HZSM-5, FeNa, Na-Fe2O4 / HMCM-22, Fe2O3, Co6 / MnO4, Zn-Cr / Hy, Fe-Zn-Zr / HZSM-5, Fe-Mn-K, and other catalysts mentioned in the review article by Tan et al. (2022) or Yao et al. (2020).

[0043] The product from the CO2C reactor is shown in Figure 1 as Stream 7. At least a portion of Stream 7 becomes Stream 8 and is fed to the Product Processing Unit, Unit 3 in Figure 1. This Product Processing Unit can be a combination of various methods that allow for the separation or further processing of the CO2C reactor product stream. Various embodiments are created depending on the products, yields, and selectivities observed in the CO2C reactor. Each reaction that occurs in the CO2C reactor produces water. Therefore, the first step in the Product Processing Unit is to reduce the temperature of the reactor product stream. This can be done by many different means, including heat exchange with a cooler feed stream, heat exchange with another cooler stream, and a cooling water heat exchanger. The purpose of this cooling is to reduce the water and / or C that may be produced in the CO2C. 5+ The purpose is to enable the condensation of hydrocarbons. As is well known, C 5+ Hydrocarbons are generally insoluble in water. After the effluent stream is cooled, a three-phase separator or sequential two-phase separators can be used. This separates the water and C from the reactor effluent. 5+ This allows the separation of

[0044] In one embodiment, the CO conversion in the COC reactor is less than about 90%, and the unreacted CO is converted to water and C 5+It is removed after hydrocarbon removal and before further processing. CO2 removal from streams can be accomplished by any number of available techniques. Removal methods include the use of physical solvents, such as chilled methanol used in the Rectisol process and the Solexol process, which uses dimethyl ether of polyethylene glycol to capture CO2 from gas streams. Other means include the use of selective membranes for CO2 removal. Another method for CO2 removal is the chemical capture of CO2 using aqueous solutions of alkylamines (called amines). An amine contactor captures the CO2 in solution. The overhead from this amine contactor is a CO2-free gas, and the CO2-laden amine solution is heated in an amine regenerator to release the CO2 and return it to the contactor for reuse. A variety of amines can be used, such as diethanolamine (DEA), monoethanolamine (MEA), methyl-diethanolamine (MDEA), and diisopranolamine (DIPA).

[0045] The CO2 stream recovered from the CO2 capture unit is shown in Figure 1 as stream 11. This stream is compressed, recycled, and mixed with the CO2 feed stream, shown in Figure 1 as stream 5.

[0046] In one embodiment, the CO2C hydrocarbon product stream comprises n-alkanes having carbon numbers between 6 and 23 and is fed to a CO2C separation unit that produces at least three product fractions. The CO2C separation can be any separation method, such as absorption, adsorption, filtration, or distillation, or a combination of these methods. Distillation is the preferred separation method. The light CO2C separation product comprises n-alkanes having carbon numbers between 5 and 9. The medium CO2C separation product comprises n-alkanes having carbon numbers between 9 and 15.

[0047] The heavy CO2C separation product comprises n-alkanes having carbon numbers from 16 to 23. The hydrocarbons produced in the CO2C reactor are represented (collectively) as Stream 9 in Figure 1.

[0048] In one embodiment of the present invention, the CO2C reactor is a mixture of two different catalysts capable of producing hydrocarbons from a mixture of CO2 and H2.

[0049] The first catalyst, Catalyst #1, is a CO2 hydrogenation catalyst, and is operated at 300°C, with a H2 / CO2 feed ratio of about 3.0-3.5 / 1.0, a pressure of 250-350 psig, and a space velocity of 2,000-3,000 hr. -1 This catalyst has a CO2 conversion efficiency of about 25% and a high CO selectivity (>90%). 298 = approximately +40 kJ / mol), which requires heat input.

[0050] The second catalyst, catalyst #2, can be any FT catalyst capable of producing hydrocarbons at 300°C. Iron-based catalysts are well known to be active for FT at this temperature. One particularly useful catalyst is a magnetite-based catalyst that operates in the same temperature range as catalyst #1 (300°C). This is an exothermic catalyst (ΔH 298= approximately -200 kJ / mole of CO) to produce hydrocarbons from CO and H produced from catalyst #1. This catalyst was used at a H / CO feed ratio of approximately 1.5-2.0 / 1.0, a pressure of 250-350 psi, and a space velocity of 2,000-3,000 h -1 It works by.

[0051] The first and second catalysts are mixed in a ratio and in physical proximity such that heat generation from catalyst #2 is directly transferred to the adjacent endothermic catalyst #1. A catalyst #1 to #2 ratio of 4-5 to 1 is estimated to be desirable to maintain isothermal catalyst beds and allow sufficient CO2 to be supplied from catalyst #1 to catalyst #2. The catalytic reactor is maintained under adiabatic conditions through the use of sufficient insulation and heat to maintain the catalyst bed at 300°C.

[0052] Any suitable CO hydrogenation catalyst may be used as catalyst #1. Titanium oxide has the highest surface acidity of any catalyst support, so TiO is preferred as the support for catalyst #1. Zirconium oxide also has high surface acidity, but it is less than that of titanium oxide.

[0053] Impregnating the catalyst #1 support with certain metals, such as Cu on TiO2, improves the reaction rate. Approximately 2,000-3,000 hours -1 With a space velocity of 0.15, high CO selectivity and minimal CH4 production at 300°C, a CO2 conversion of about 25% is desirable.

[0054] Because the CO produced by Catalyst #1 evolves rapidly, a highly efficient oligomerization (chain propagating) catalyst (Catalyst #2) must be mixed or placed in tandem (in close proximity) with the hydrogenation catalyst, Catalyst #1. Furthermore, this chain propagating catalyst must operate efficiently at 300°C.

[0055] In one embodiment, a magnetite or iron-based catalyst is used for Catalyst #2. Depending on the source, natural magnetite may contain about 50-1,500 ppm of precious metals and may be used as a catalyst. In other embodiments, synthetic magnetite or iron catalysts are used, with desired promoters incorporated into the catalyst, which may contain precious metals. The precious metals in magnetite are used to convert H2 from H2. * It significantly increases the production of radicals and reduces the probability of free radical chain propagation, thereby reducing the production of higher molecular weight hydrocarbon species.

[0056] In one embodiment of the present invention, the CO2C reactor is a multi-tubular fixed-bed reactor. The internal reactor tubes are filled with a mixture of steam and water. The heat of reaction is removed by the production of steam in the reactor shell. The inner diameter of the tubes is between 18 and 50 mm. The tubes are filled with catalyst particles, the size of which is optimized to optimize the tradeoff between conversion and pressure drop across the reactor. The small diameter of the reactor tubes means that when the feed gas reacts over the catalyst, heat must be transferred to the heat transfer surface from no more than 9 to 25 mm (half the diameter of the tube). On the outside of the tubes, a mixture of steam and water allows heat transfer primarily via nucleation as liquid water vaporizes to steam. This water comes from the steam drum. Boiler feed water (BFW) is fed to the steam drum and circulates through the system. The pressure of the steam system controls the temperature of the steam / water mixture. Steam pressures range from 200 to 1,600 psig. The temperature of saturated steam at 1,200 psig (82.7 barg) is 298°C. The temperature of saturated steam at 1,100 psig (75.8 barg) is 292°C. The temperature of saturated steam at 1,000 psig (69.0 barg) is 285°C. As such, saturated steam at 1,000 to 1,200 psig is an ideal quenching fluid for the CO₂C reaction, which occurs at 300°C. Typically, water is fed from the steam drum to the water inlet of the reactor shell, and a mixture of about 50% steam and 50% water is at the steam outlet of the reactor shell that returns to the steam drum.

[0057] In one embodiment, heat transfer is achieved through a hot oil system. Oil, as the working fluid, is pumped into the reactor shell. Heat is transferred through the tubes to the oil, raising the oil temperature. The oil circulation rate is controlled by the pumping speed, which regulates the rate of heat removal. The hot oil exiting the reactor shell is cooled in an external heat exchanger. Cooling water, cold water, or propylene glycol, or other suitable material, can be used on the cold side of the external heat exchanger to lower the temperature of the hot oil back to the desired reactor shell inlet temperature. The cooled hot oil is then pumped back into the reactor shell. Some suitable oils have operating temperatures that are useful for this application and include Therminol XP, Therminol 55, Therminol SP, Therminol 59, or any equivalent or similar oil working fluid.

[0058] In one embodiment, the catalyst inside the CO2C reactor can be diluted with other non-reactive solids. Diluting the catalyst aids in heat transfer, thereby reducing the amount of heat generated per unit volume and thus the local temperature rise. Suitable diluents include alumina, silicon carbide, spinel, or other refractory materials. Silicon carbide has the advantage of high thermal conductivity and thus allows for fast heat transfer from the heat generated. However, any material that is not catalytically active can be used as a diluent.

[0059] In one embodiment, a metal partition can be installed inside the CO2C reactor tube prior to adding the catalyst so that there is a metal passage or connection from the center of the tube to the wall of the tube. This aids in heat transfer as the high thermal conductivity of metal increases the rate of heat transfer from the hot tube center to the cooled tube wall.

[0060] In one embodiment of the present invention, the feed gas to the CO2C reactor can be diluted with a non-reactive gas. Diluting the feed gas aids in heat transfer and temperature control in several ways. This reduces the heat of reaction generated per unit volume per unit time. It also adds additional mass flow that acts as a heat sink. A variety of dilution gases can be used. An ideal dilution gas is easily separable from the reactor effluent. Low-pressure steam can be used as the dilution gas feed to the CO2C reactor. As the reactor effluent cools, condensed steam can be easily removed from the effluent by a knockout vessel or separator, and because steam is a reaction product, the only design change involves increasing the size of the separator.

[0061] In one embodiment, the CO2C reactor is a series of adiabatic reactors or reactor beds. The length or residence time of each reactor bed is set so that the maximum possible conversion keeps the bed temperature rise below 50°C, preferably below 25°C, and more preferably below a set temperature rise of 10°C. Dilution of the catalyst and feed gases can also be used to keep the temperature rise within set limits. The effluent gas at the outlet of the reactor bed is cooled in a heat exchanger that produces high-pressure saturated steam in the range of 1,000 to 1,200 psig. This cools the reactor effluent to a temperature close to the inlet temperature of the previous bed. The cooled effluent is then fed to the subsequent bed. The total number of beds is selected to obtain the desired overall CO2 conversion. Optionally, additional hydrogen, or hydrogen and CO2, can be added to the subsequent bed feed gas.

[0062] In one embodiment, heat transfer and thermal management in the reactor are controlled using continuous H injection. The initial H / CO ratio is lower than the stoichiometric ratio for the net reaction. This keeps the CO conversion low and the reactor bed temperature rise low. H is added to the end of the reactor bed at a temperature significantly lower than the reactor bed temperature. This cold H reduces the overall gas temperature to around the inlet temperature of the previous bed. This added hydrogen reacts in subsequent beds with the CO from the previous bed. In essence, the conversion is spread out over a longer effective bed depth (or bed number), reducing the amount of heat generated per reactor area or volume and making heat removal more manageable. Adding the number of reactor beds and cold hydrogen adjusts the overall CO conversion.

[0063] In one embodiment, the CO2C reactor is operated with low CO2 conversion but a high overall gas recycle. This allows the temperature in the reactor bed to be controlled and the temperature rise to be within acceptable limits. The space velocity or residence time in the reactor bed is high so that the conversion is low. Gas dilution and catalyst dilution can be used to aid in temperature control. The CO2 conversion per pass is kept below 30%, preferably below 20%, and more preferably below 10%. The reactor effluent is fed to a product processing unit where water in the effluent is removed by cooling and separation, and unreacted CO2 and H2 are removed, compressed, recycled, and mixed with the fresh feed to the CO2C reactor. [Example]

[0064] Example 1

[0065] In this example, two different catalysts were mixed in a CO2C reactor. Catalyst #1 was a high surface area copper aluminate (CuAl2O4) spinel modified by impregnation with 0.05-5.0 wt% Cu, pressed into pellets, and calcined. Catalyst #2 was a natural magnetite-based catalyst pressed into pellets and calcined. These catalysts were placed very close to each other in the reactor. Catalyst #1 operated endothermically (requiring heat), while Catalyst #2 operated exothermically (generating heat).

[0066] These catalysts were mixed in predetermined ratios to operate isothermally throughout the catalytic reactor, and H2 produced from the electrolysis of water using renewable or low-carbon electricity was mixed with the captured CO2.

[0067] Because the catalyst in the catalytic reactor operates under isothermal or near-isothermal conditions, the CO2C reactor design can be one of many currently available isothermal reactor designs, including multi-tubular fixed-bed reactors.

[0068] H2 and CO2 were each heated to a desired temperature of about 315°C and mixed in a specific ratio before being introduced into the catalytic reactor.

[0069] The manufacturing and composition details for Catalyst #1 and Catalyst #2 are as follows:

[0070] Catalyst #1 was a copper aluminate (CuAl2O4) spinel formed by mixing copper salts with high surface area gamma-alumina powder. Sufficient excess copper was added so that the resulting catalyst was a copper aluminate spinel with 0.05-5.0 wt.% copper distributed on the spinel. Copper salts may include copper acetate, copper nitrate, or other water-soluble copper salts. This mixture was then pressed into tablets under high pressure. These tablets were calcined at approximately 950°C to form CuAl2O4 spinel. The resulting CuAl2O4 catalyst had a BET surface area of ​​10 m 2 / g, preferably 25m 2 / g, more preferably 50m 2 / g.

[0071] An alternative approach to preparing the catalyst is to dissolve copper acetate in water and add enough of the solution to a copper aluminate spinel to produce 0.05-10.0 wt. % Cu impregnated onto the copper aluminate (CuAl2O4) spinel.

[0072] This Cu-CuAl2O4 catalyst was used at 300°C, a CO2 / H2 feed molar ratio of 3.5 / 1.0, and a space velocity of 3,000 h -1 At 300 psi and a pressure of 300 psi, a mixture of CO2 / H2 was converted with a CO2 conversion of about 25% and a CO selectivity of over 90% (Table 3).

[0073] [Table 3]

[0074] Catalyst #2 is a magnetite catalyst based on naturally occurring magnetite found in selected regions of North America. This natural magnetite contains small amounts of precious metals and is typically a by-product of gold mining. The magnetite is pressed into tablets under high pressure. These tablets are then calcined at approximately 950°C. In this example, the magnetite had a composition of 94.4% FeO, 3.2% AlO, 1.8% TiO, 0.22% CuO, 0.17% MnO, 0.10% MgO, and approximately 850 ppm precious metals. In other embodiments, the catalyst was generally synthesized to the desired composition. The precious metals, in order of decreasing abundance, were Au, Ag, Pt, and Pd. These precious metals were widely dispersed throughout the Fe3O4 matrix in clusters of 100-250 Å, which were distributed primarily on the surface of the magnetite crystals. The surface area of ​​this magnetite catalyst was 3-4 m 2 / g and had pores in the size range of 10-100 angstroms (1-10 nanometers). The magnetite catalyst was reduced in a catalytic reactor with H2 at 300 °C.

[0075] The effect of temperature on the performance of this magnetite catalyst (Catalyst #2) in a Fischer-Tropsch-like oligomerization reaction is summarized in Table 4. At 300 °C, C 5+ Hydrocarbon production accounts for approximately 39%, with the remaining carbon-containing products (CH4, CO2, C2-C5 hydrocarbons and C 24+ The carbon dioxide (CO₂) and hydrogen (hydrocarbons) accounted for 61% of the total energy produced. When this exothermic catalyst was coupled with the endothermic catalyst, Catalyst #1, on a short length scale, the result was the direct conversion of CO₂ and hydrogen to hydrocarbons. In this example, hydrogen was produced from the electrolysis of water. Additionally, oxygen was produced by an electrolyzer.

[0076] Catalyst #1 catalyzes an endothermic reaction (approximately +50 kJ / mol) that requires heating, while catalyst #2 catalyzes an exothermic reaction (approximately -175 kJ / mol) that generates heat. Catalyst #1 and catalyst #2 were mixed in the appropriate ratio so that the heat generated by catalyst #2 was used to heat catalyst #1. Therefore, the masses of the first and second catalysts were adjusted so that the catalytic reactor operated isothermally at approximately 300°C. Based on thermodynamics, a catalyst #1 / catalyst #2 mass ratio of 3.0-5.0 / 1.0 resulted in near thermal equilibrium within the catalytic reactor.

[0077] Because catalyst #1 was 3-5 times more abundant than catalyst #2, more CO was produced than could be used by catalyst #2, even though the conversion efficiency of CO2 to CO for catalyst #1 was only about 25%.

[0078] Catalyst #2 produces CO2, while the first catalyst converts CO2 further to CO. As a result, the product composition from the two catalysts in the catalytic reactor averaged 30% CH4, 24% C2-C5, and 56% C6-C6 over three passes. 24 Additionally, there was some CO2, CO, and H2 in the tail gas.

[0079] In this example, the CO2C reactor effluent was cooled. Water was removed by water knockout. 5+ The hydrocarbons were condensed and separated. 5+ After the hydrocarbons were condensed and collected, the remaining CO2 and C1-C5 (44% total) in the tail gas were recycled by being sent to an oxyfuel combustor, where the hydrocarbons and any remaining hydrogen and other combustibles were converted to additional CO2 using oxygen produced in the electrolysis unit. This CO2 was then used as the recycled feed to the catalytic CO2C reactor. Thus, after about three recycle loops, more than about 90% of the carbon in the CO2 was converted to C 5+ The product was a mixture of hydrocarbons. Depending on the reactor operating conditions, up to 30% by volume of the liquid product was C3-C6. 11 The remainder of the liquid product was composed of C5 to C6 α-olefins and hydroxyalkanes (alcohols). 24 It was composed of normal alkanes and a small fraction of isoalkanes.

[0080] The CH4, C2-C5, CO and H2 contained in the tail gas can be used as energy for the process or can be converted using oxy-combustion to produce further CO2 and CO.

[0081] The oxyfuel combustor used in this example functions as follows: CO2 was mixed with oxygen as the oxidant for the combustor. The fuel to the combustor was the CO2C effluent, which contained CO2, H2, and the C1-C5 fraction produced by the CO2C reactor. The combustion products were water and CO2. The combustion products were cooled and the water removed. CO2 was recycled and mixed with oxygen to produce the oxidant stream for the combustor. Alternatively, CO2 could be mixed with the feed to the CO2C reactor.

[0082] [Table 4]

[0083] Example 2

[0084] In this example, two catalysts were implemented for use in the CO2C reactor. Catalyst #1 consisted of Cu impregnated on a high surface area titanium dioxide (TiO2) support (e.g., Cu-TiO2) instead of copper aluminate. Catalyst #2 was the same as that described above in Example 1.

[0085] Catalyst #1 was prepared by wet impregnation. Copper salt was suspended in a solvent. A high surface area TiO2 support was added to this solution. The solvent was removed by evaporation, and copper was precipitated onto the support. The mixture was then pressed into tablets under high pressure. These tablets were calcined at approximately 950°C to form the Cu-TiO2 catalyst. The resulting Cu-TiO2 catalyst was then heated to 1000°C. 2 / g, preferably 25m 2 / g, more preferably 50m 2 / g.

[0086] Another approach to producing the catalyst is to dissolve copper acetate in water and add enough of the solution to copper Cu-TiO2 to produce 0.05-10.0 wt% Cu impregnation on the Cu-TiO2 material.

[0087] The CO2C reactor was operated as described in Example 1, and after recycling, more than about 90% of the carbon in the CO2 was converted to C 5+ The product was a mixture of hydrocarbons. Depending on the reactor operating conditions, up to 30% by volume of the liquid product was C3-C6. 11 The remainder of the liquid products consisted of C5-C6 α-olefins and hydroxyalkanes (alcohols). 24 It was composed of normal alkanes and a small fraction of isoalkanes.

[0088] The CH4, C2-C5, CO and H2 in the tail gas can be used as energy for the process or may be converted using oxy-combustion to further produce CO2 and CO.

[0089] Example 3

[0090] In this example, the catalyst used in the CO2C reactor was Fe3O4 (magnetite) catalyst impregnated with 0.1-10.0 wt% copper. The reactor was a multi-tubular fixed-bed reactor, and hot oil was used to help maintain a constant catalyst temperature. The H2 / CO2 ratio in the feed to the CO2C reactor was 3.0-4.0, the pressure was 250-350 psi, and the reactor was operated at 300°C. The CO2 conversion was 38%, the CH4 selectivity was 10.4%, the C2-C5 selectivity was 27.7%, and the C 5+ The selectivity was 61.9%. The effluent of this CO2C reactor consisted of hydrogen, CO, CO2, C1-C5 hydrocarbons and C 5+ Downstream of this CO2C reactor, C 5+ The majority of the hydrocarbons were condensed to liquid via a cooling water exchanger and knockout vessel and sent to product storage. The remaining H2, CO, CO2, and C1-C2 streams were sent to a CO2 removal unit, typically an amine unit, where the CO2 was removed. This CO2-rich stream was compressed and recycled to the inlet of the CO2C reactor. Additional hydrogen was fed to this reactor to maintain a feed H2 / CO ratio of 3.0-4.0. The CO, H2, and C1-C5 streams were further separated and either used as plant fuel gas, converted to additional CO2 and CO, or sold as fuel products.

[0091] References

[0092] Landau et al., AU 2015203898 B2 (2015).

[0093] NationalAcademy of Sciences, Chemical Utilization of CO2into Chemicals andFuels, Gaseous Carbon Waste Streams Utilization: Statusand Research Needs, National Academies Press, Washington D.C. (2019).

[0094] Pan,et al., Enhanced Ethanol Production InsideCarbon Nanotube Reactors Containing Catalytic Particles, Nature Materials,Volume 6 (2007).

[0095] Shenet al., Identifying the Roles of Ce 3+ -OH and Ce-H in the ReverseWater-Gas Shift Reaction Over Highly Active Ni-doped CeO2Catalyst,Xi'an Key Laboratory Functional Organic Porous Materials, School of Chemistryand Chemical Engineering, Northwestern Polytechnical University, Xi'an 710129,China (2022).

[0096] Tan,et al., Current Developments in Catalytic Methanation of Carbon Dioxide - AReview, Frontiers in Energy Research (2022).

[0097] Wanget al., High Performance M a ZrO x (Ma =Cd, Ga)Solid-Solution Catalysts for CO2Hydrogenation to Methanol, StateKey Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China (2019).

[0098] Wanget al., One-Step Plasma-Enabled Catalytic Carbon Dioxide Hydrogenation toHigher Hydrocarbons: Significance ofCatalyst-Bed Configuration, Green Chemistry (2021).

[0099] Weiet al., Catalytic Hydrogenation of CO2to Isoparaffins over Fe-BasedMultifunctional Catalysts, Dalian National Laboratory for Clean Energy, DalianInstitute of Chemical Physics, Chinese Academy of Sciences, Dalian, China(2018).

[0100] Williamsonet al., N-Doped Fe@CNT for Combined RWGS / FT CO2Hydrogenation, ACS Sustainable Chemical Engineering (2019).

[0101] Yao,et al, Transforming Carbon Dioxide into Jet Fuel Using an Organic Combustion-SynthesizedFe-Mn-K Catalyst, Nature Communications, 11, 6395 (2020).

Claims

1. a.CO ２ a first feed stream comprising renewable H ２ and mixing the second feed stream containing CO ２ generating a reactor feed stream; b. The CO ２ The reactor feed stream is ２ into a conversion reactor, ２ The conversion reactor contains two catalysts, whereby C ５＋ Hydrocarbons, H ２ O and unreacted H ２ , CO and CO ２ generating a reactor product stream comprising:

1. A method for producing hydrocarbons, comprising:

2. The reactor product stream is subjected to a separation step to produce a purified product stream comprising a liquid product and a vapor phase product, the liquid product being C ５＋ and the gas phase product comprises a C １ ~C ５ Hydrocarbons, CO ２ , H ２ O, CO and H ２ 10. The method of claim 1, comprising:

3. The H in the second feed stream ２ is a renewable or low-carbon electricity source. ２ 10. The method of claim 1, wherein the oxygen is produced from the electrolysis of O.

4. the CO in the first feed stream ２ The method of claim 1 , wherein is collected from a stationary source or ambient air.

5. The CO ２ 10. The method of claim 1, wherein the conversion reactor is an isothermal catalytic reactor that is insulated to prevent heat loss.

6. The first feed stream and the second feed stream are separately heated to between 310°C and 320°C, and then the CO ２ 6. The method of claim 5, wherein the components are mixed at a volume / volume ratio of between 3.0 and 5.0 before being charged into the conversion reactor.

7. The CO ２ One catalyst in the conversion reactor is an endothermic catalyst, the endothermic catalyst comprising 0.05 to 10 wt. % copper impregnated in copper aluminate spinel or titanium oxide, the catalyst having a thickness of 10 m ２ 6. The method of claim 5, wherein the surface area of ​​the cellulose acylate is greater than 1 / g.

8. The CO ２ One catalyst in the conversion reactor is an exothermic catalyst, the exothermic catalyst comprising magnetite, the magnetite comprising between 94% and 99.9% by weight of Fe. ３ O ４ and between 50 ppm and 500 ppm of a precious metal.

9. The CO ２ One catalyst in the conversion reactor is an exothermic catalyst, the exothermic catalyst comprising between 99% and 99.9% by weight of Fe. ３ O ４ 6. The method of claim 5, wherein the catalyst is impregnated with between 1 ppm and 2,000 ppm gold.

10. The CO ２ A first catalyst and a second catalyst are present in the conversion reactor, the first catalyst being an endothermic catalyst and the second catalyst being an exothermic catalyst, and the exothermic catalyst is ２ 6. The method of claim 5, wherein the exothermic catalyst generates heat when reacting with a reactor feed stream, the heat generated from the exothermic catalyst being used to heat the endothermic catalyst, and wherein producing the product stream using the endothermic catalyst and the exothermic catalyst is isothermal.

11. 3. The method of claim 2, wherein the reactor product stream is fed to a product processing unit that separates the liquid product from the vapor phase product.

12. The vapor phase product is recycled back into the isothermal catalytic reactor, thereby providing additional C ５＋ 12. The method of claim 11, wherein a hydrocarbon product is produced.

13. The H in the second feed stream ２ uses renewable or low-carbon electricity ２ O, the gas phase products being mixed with oxygen generated from the electrolysis to provide an oxygenated mixture, which when fed into an oxy-combustor produces additional CO ２ and CO, and said additional CO ２ and CO are recycled back into the isothermal catalytic reactor to produce additional liquid C ５＋ 12. The method of claim 11, wherein a hydrocarbon product is produced.

14. CO ２ 13. The process of claim 12, wherein the conversion efficiency of the above to liquid hydrocarbon products is between 30% and 95%.

15. CO ２ 14. The process of claim 13, wherein the conversion efficiency of the above to liquid hydrocarbon products is between 30% and 95%.

16. The CO ２ 10. The method of claim 1, wherein the conversion reactor is a fixed bed catalytic reactor.

17. The CO ２ 10. The method of claim 1, wherein one of the catalysts in the conversion reactor comprises natural magnetite impregnated with 0.10 to 10.0 wt. % copper.

18. The CO ２ 10. The method of claim 1, wherein one of the catalysts in the conversion reactor comprises synthetic magnetite impregnated with 0.10 to 10.0 wt. % copper.

19. 20. The method of claim 17, wherein the natural magnetite impregnated catalyst maintains operating temperatures by producing steam outside the reactor tubes.

20. 20. The method of claim 18, wherein the synthetic magnetite impregnated catalyst maintains operating temperatures by producing steam outside the reactor tubes.

21. 20. The method of claim 17, wherein the natural magnetite impregnated catalyst is maintained at operating temperature using a hot oil system outside the reactor tubes.

22. 20. The method of claim 18, wherein the synthetic magnetite impregnated catalyst is maintained at operating temperature using a hot oil system outside the reactor tubes.

23. The CO ２ The reactor feed stream contains additional H in excess of the stoichiometric ratio. ２ 18. The method of claim 17, wherein the solution is diluted with

24. The CO ２ The reactor feed stream contains additional H in excess of the stoichiometric ratio. ２ 19. The method of claim 18, wherein the solution is diluted with

25. a.CO ２ a first feed stream comprising renewable H ２ and mixing the second feed stream containing CO ２ generating a reactor feed stream; b. The CO ２ The reactor feed stream is ２ into a conversion reactor, ２ The conversion reactor is a multi-tubular fixed bed reactor, and the CO ２ The conversion reactor contains two catalysts, one of which is copper-impregnated Fe ３ O ４ whereby C ５＋ Hydrocarbons, H ２ O and unreacted H ２ , CO and CO ２ generating a reactor product stream comprising:

1. A method for producing hydrocarbons, comprising:

26. 26. The method of claim 25, wherein the multi-tubular fixed bed reactor uses hot oil to maintain a constant temperature.

27. H in the reactor feed stream ２ / CO ２ 27. The method of claim 26, wherein the ratio is between 2.75 and 4.

25.

28. CO ２ and there is a conversion of between 30% and 45% and there is a selectivity for product production of C ５＋ 28. The method of claim 27, wherein the selectivity of product production with respect to hydrocarbons is between 50% and 70%.

29. 30. The method of claim 28, wherein the other catalyst comprises a copper aluminate spinel.

30. The method is carried out for 2,000 hours. －１ From 4,000 hours －１ 30. The process of claim 29, wherein the process is operated at a space velocity between

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