Production of synthesis gas from carbon dioxide via methanol

Abstract

The present disclosure relates generally to a method for producing synthesis gas. In particular, the disclosure relates to a method that includes providing a first feed stream comprising H and CO, contacting the first feed stream with a hydrogenation catalyst to form a first product stream comprising methanol, providing a second feed stream comprising at least a portion of the methanol of the first product stream, and contacting the second feed stream with a methanolcracking catalyst to form a second product stream comprising synthesis gas.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority from European Patent Application No. 22190307.3, filed August 12, 2022, which is incorporated herein by reference in its entirety. [Technical Field]

[0002] The present disclosure relates to an integrated process for producing synthesis gas from carbon dioxide via a methanol intermediate. [Background technology]

[0003] The conversion of synthesis gas (i.e., a mixture of carbon monoxide and hydrogen, also known as syngas) to hydrocarbons via the Fischer-Tropsch process has been known for decades, but historically, its performance has lagged compared to other hydrocarbon synthesis technologies. With the growing importance of alternative energy sources, the Fischer-Tropsch (FT) process has attracted renewed interest because it enables a direct and environmentally acceptable route to high-quality fuels and feedstock chemicals. The Fischer-Tropsch process uses synthesis gas (syngas), a mixture of CO and H2 gases, as a starting material. Syngas is traditionally produced from fossil fuel sources, primarily by coal gasification. However, synthesis gas suffers from poor handling characteristics, as it must be transported in its low-density vapor phase or liquefied under high pressure.

[0004] The FT process is known to produce linear hydrocarbons for use in fuels, as well as oxygenates that can be useful in fuels and also serve as valuable feedstock chemicals. Hydrocarbon fuels derived from the FT process can better meet increasingly stringent environmental regulations compared to fuels produced in conventional refineries because FT-derived fuels typically contain lower amounts of sulfur, nitrogen, and aromatic compounds, which contribute to the emission of potent pollutants such as SO2, NOx, and particulates. Products derived from the FT process often have higher octane numbers than hydrocarbons and therefore burn more completely, thereby reducing the environmental impact of such fuels. The resulting alcohols, olefins, and other oxygenates can also be used as reagents in other processes, such as the synthesis of lubricants.

[0005] Therefore, there is a need to develop improved protocols for the production and handling of syngas. Summary of the Invention

[0006] The present inventors have identified a method for the efficient conversion of CO2 to synthesis gas via methanol (MeOH) mediation. Advantageously, this method can proceed at lower temperatures compared to traditional synthesis routes and does not require the reverse water-gas shift (rWGS) process.

[0007] Thus, in one aspect, the present disclosure provides an integrated process for producing synthesis gas, the method comprising: Providing the first supply logistics including H2 and CO2, contacting the first feed stream with a hydrogenation catalyst (e.g., in a hydrogenation reaction zone) to hydrogenate at least a portion of the CO to form a first product stream comprising methanol; providing a second feed stream comprising at least a portion of the methanol of the first product stream; contacting the second feed stream with a methanol decomposition catalyst (e.g., in a methanol decomposition reaction zone) to decompose at least a portion of the methanol to form a second product stream comprising synthesis gas (e.g., comprising CO and H2).

[0008] Other aspects of the present disclosure will be apparent to those skilled in the art in view of the following description. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a method according to an exemplary embodiment of the present disclosure. [Figure 2] FIG. 2 is a schematic diagram of a method according to an exemplary embodiment of the present disclosure. [Figure 3] FIG. 3 is a schematic diagram of a method according to an exemplary embodiment of the present disclosure. [Figure 4] FIG. 4 is a schematic diagram of a method according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0010] This disclosure relates to techniques for preparing syngas from carbon dioxide. Carbon dioxide is a widely available gas (currently present at approximately 400 ppm in the atmosphere) that is inert to many transformations. Furthermore, due to its tendency to absorb infrared radiation, carbon dioxide has been designated a greenhouse gas. Therefore, there is a need to develop economical methods to utilize carbon dioxide, especially waste carbon dioxide, which would otherwise add to the ever-increasing concentration of carbon dioxide in the atmosphere. Carbon dioxide is produced by many industries and can be captured as a point source to be used as a feedstock, for example, from facilities involved in steelmaking, fossil fuel power generation, cement production, fermentation processes, or fertilizer production. Carbon dioxide may also be sourced from direct air capture projects. Advantageously, processes that use synthesis gas, such as Fischer-Tropsch hydrocarbon synthesis, and waste carbon dioxide as a feedstock have the potential to be low-carbon, carbon-neutral, or even have a negative carbon footprint. One way to achieve this is to convert carbon dioxide and hydrogen to methanol. Methanol, which is a liquid at ambient temperature and pressure, can optionally be transported through low-pressure pipelines, ships, or trucks, thus generally allowing for increased transportation efficiency as a liquid. The methanol can then be subjected to a methanol cracking process to produce H2 and CO in a 2:1 ratio. This mixture of H2 and CO is commonly referred to as "syngas" and finds widespread utility. At least the CO from the methanol cracking product can then be utilized in a Fischer-Tropsch synthesis reaction to produce hydrocarbons, and the H2 from the methanol cracking is also desirably used in the Fischer-Tropsch synthesis. For example, some Fischer-Tropsch processes operate at H2:CO ratios of 2:1 or greater, e.g., 2.2:1 or 3:1. In such cases, the H2 and CO mixture from the methanol cracking process may be supplemented with a hydrogen source, such as from a recycle stream or green hydrogen generated from renewable energy, to form the Fischer-Tropsch reaction mixture.

[0011] Thus, in one aspect, the present disclosure provides an integrated process for producing synthesis gas, the method comprising: Providing the first supply logistics including H2 and CO2, contacting the first feed stream with a hydrogenation catalyst (e.g., in a hydrogenation reaction zone) to hydrogenate at least a portion of the CO to form a first product stream comprising methanol; providing a second feed stream comprising at least a portion of the methanol of the first product stream; contacting the second feed stream with a methanol decomposition catalyst (e.g., in a methanol decomposition reaction zone) to decompose at least a portion of the methanol to form a second product stream comprising synthesis gas (e.g., comprising CO and H2).

[0012] As used herein, a "feed stream" is used to mean all materials input to a process step, e.g., CO2 hydrogenation or methanolysis, whether provided in a single physical stream or multiple physical streams and whether through a single inlet or multiple inlets. For example, the H2 and CO2 of a first feed stream can be provided to a hydrogenation reactor in a single physical stream (e.g., a single pipe to the reactor) or in multiple physical streams (e.g., separate inlets for CO2 and H2, or one inlet for fresh CO2 and H2 and another inlet for recycled CO2 and / or H2). Similarly, a "product stream" is used to mean all materials output from a process step, e.g., carbon dioxide hydrogenation or methanolysis, whether provided in a single physical stream or multiple physical streams and whether through a single reactor outlet or multiple reactor outlets.

[0013] As used herein, the term "syngas" refers to a mixture of CO and H, where CO and H are present in a molar ratio ranging from 0.2:1 to 10:1, and where the combined CO and H constitute 10% to 80% by volume of the mixture. Syngas is a gas at standard temperature and pressure, but can be liquefied at elevated pressures and / or temperatures.

[0014] Advantageously, the integrated processes described herein can be substantially asymmetric in nature: methanol can be synthesized from carbon species that are primarily CO, which can then be decomposed into a stream having CO as the predominant carbon species. This is in contrast to symmetric processes, in which the streams entering methanol synthesis and exiting methanol decomposition have similar carbon compositions. Because most of the reactions described herein are equilibrium processes, they naturally lend themselves to being symmetrically integrated. However, the inventors have discovered that asymmetric processes such as those disclosed herein allow for improved control over stream composition and increased process efficiency.

[0015] The first feed stream comprises H and CO for subsequent contact with a hydrogenation catalyst to produce methanol. Thus, in various embodiments described elsewhere herein, the first feed stream comprises at least 10 mol% H. For example, in various embodiments, the first feed stream comprises at least 20 mol% H, e.g., at least 30 mol% H. In various embodiments described elsewhere herein, the first feed stream comprises at least 5 mol% CO. For example, in various embodiments, the first feed stream comprises at least 10 mol% CO, e.g., at least 15 mol% CO.

[0016] Generally, CO hydrogenation to produce methanol proceeds according to the reaction: CO + 3H → CHOH + HO. Thus, in various embodiments described elsewhere herein, the H:CO ratio of the first feed stream is at least 1:1, e.g., at least 1.5:1, on a molar basis. For example, in various embodiments described elsewhere herein, the H:CO ratio of the first feed stream is at least 2:1, e.g., at least 2.5:1, or at least 3:1, or at least 4:1, or at least 5:1, or at least 6:1, or at least 8:1. In certain embodiments, the H:CO ratio of the first feed stream is 25:1 or less, e.g., 20:1 or less, or 15:1 or less, or 12:1 or less.

[0017] In some embodiments, the first feed stream includes other gases in addition to CO and H. For example, in various embodiments, the first feed stream further includes one or more of CO, CH, and N. For example, in certain embodiments, the first feed stream includes, in addition to CO and H, other gases (e.g., one or more of CO, CH, and N) in an amount of up to 70 mol%. In various embodiments, the first feed stream includes 1% or less O, e.g., 0.1% or less O, or 0.01% or less O, or is substantially free of O. In various embodiments, the first feed stream includes 20 mol% or less CO, e.g., 15 mol% or less CO, or 10 mol% or less CO, or even 5 mol% or less CO.

[0018] As described elsewhere herein, the first feed stream is contacted with a hydrogenation catalyst. The hydrogenation catalyst may be selected by one skilled in the art. Examples of suitable catalysts include Cu / ZnO catalysts supported on aluminum oxide or zirconium oxide, for example.

[0019] Advantageously, the CO hydrogenation reaction may be carried out at relatively low temperatures, resulting in increased energy efficiency and overall process integration. For example, in various embodiments described elsewhere herein, contacting the first feed stream with the hydrogenation catalyst is carried out at a temperature in the range of 200-500°C, e.g., 200-450°C, or 200-400°C, or 200-350°C, or 200-300°C, or 250-500°C, or 250-450°C, or 250-400°C, or 250-300°C, or 300-500°C, or 300-450°C, or 300-400°C. In various embodiments, contacting the first feed stream with the hydrogenation catalyst is carried out at a pressure of 100 bar or less, e.g., 80 bar or less, or 60 bar or less.

[0020] As described herein, the hydrogenation of CO advantageously produces methanol with high selectivity. Thus, in various embodiments described elsewhere herein, the hydrogenation of CO is carried out with a selectivity to methanol of at least 50%, e.g., at least 55%, or at least 60%. For example, in certain embodiments, the hydrogenation of CO is carried out with a selectivity to methanol of at least 65% (e.g., at least 70%, or at least 75%, or at least 80% to methanol). Advantageously, the hydrogenation of CO can be carried out with a low selectivity to methane. In various embodiments described elsewhere herein, the hydrogenation of CO is carried out with a selectivity to methane of 20% or less, e.g., 10% or less, or 5% or less to methane. As one of ordinary skill in the art will understand, "selectivity" for a given species is the fraction of the reacted carbon-containing reactant that is converted to that species, i.e., not counting unreacted material.

[0021] Importantly, the CO hydrogenation reaction described herein is not a reverse water gas shift reaction. As known in the art, the reverse water gas shift reaction converts CO and H to CO and HO. Thus, in various embodiments described elsewhere herein, the hydrogenation of CO is carried out at a selectivity to CO of 20% or less, e.g., 10% or less to CO, or 5% or less. In certain embodiments, the hydrogenation of CO is carried out at a selectivity to CO of 2% or less, or 1% or less to CO.

[0022] During the CO hydrogenation reaction, at least a portion of the CO is hydrogenated to MeOH and HO. Advantageously, the process can be carried out at a relatively high conversion of CO. Thus, in various embodiments described elsewhere herein, the hydrogenation of CO is carried out at a conversion of at least 25%, e.g., at least 35%, e.g., at least 45% or at least 50% of CO.

[0023] Those skilled in the art will be familiar with catalytic methods for hydrogenating carbon dioxide to methanol.Various examples of catalysts and catalytic processes are described in R. Guil-Lopez et al., Materials, 12, 3902 (2019); Xiao et al., In; Aresta et al. (eds.) An Economy Based on Carbon Dioxide and Water (2019); Marlin et al., Front. Chem. (2018); Rodriguez et al., ACS Cat. 5(11), 6696 (2015); Choundhury, Chem. Cat. Chem. 4(5), 609 (2012), each of which is incorporated herein by reference in its entirety.

[0024] CO hydrogenation produces a first product stream. In various embodiments described elsewhere herein, the first product stream comprises at least 15 mol% methanol, e.g., at least 25 mol%, or at least 35 mol% methanol. As described herein, CO hydrogenation also advantageously has low selectivity to other products, such as methane and / or carbon monoxide. Accordingly, in various embodiments described elsewhere herein, the first product stream comprises 10 mol% or less methane, e.g., 5 mol% or less methane, or 2 mol% or less methane. In various embodiments described elsewhere herein, the first product stream comprises 10 mol% or less CO, e.g., 5 mol% or less CO, or 2 mol% or less CO. Of course, in some embodiments, more methane and / or CO may be present, for example, when provided as part of the first feed stream. As will be understood by one of skill in the art, the composition of the first product stream disclosed herein is calculated excluding inert gases or unreacted CO and / or H.

[0025] As described herein, the CO hydrogenation step produces both methanol and water. In some embodiments, the water formed can be harmful to subsequent processes. For example, excess water present in a methanol decomposition process step can undesirably convert CO back to CO via the water-gas shift reaction. Furthermore, extraneous water can react with methanol in a methanol steam reforming reaction to form CO and hydrogen, reducing process efficiency. Accordingly, in various embodiments described elsewhere herein, the method further includes separating at least a portion of the water from the first product stream. For example, in certain embodiments, the method further includes separating at least 50%, or at least 75%, or at least 90%, or at least 95%, or at least 99%, or at least 99.5% of the water in the first product stream. In various embodiments described elsewhere herein, the portion of the first product stream included in the second feed stream has a water content of 10 mol% or less, e.g., 2 mol% or less, or 1 mol% or less, or 0.5 mol% or less.

[0026] In embodiments in which water is separated from the CO hydrogenation process, the water may be disposed of as waste or recycled to other processes. For example, in various embodiments, the separated water is sent to an electrolysis reactor for the formation of H gas, for example, for use in this or other processes. In certain embodiments, the separated water is subjected to a purification step before being introduced into the electrolysis reactor.

[0027] In various embodiments described elsewhere herein, not all H gas input to the CO hydrogenation is reacted. Accordingly, in such embodiments, the method may further include separating at least a portion of the H from the first product stream. For example, in certain embodiments described elsewhere herein, the method further includes separating at least 50%, or at least 60%, or at least 75%, or at least 90%, or at least 95% of the H in the first product stream. The separated H may optionally be purified and then optionally recycled. In various embodiments, at least a portion of the separated H may be recycled to the first feed stream and / or directed to another reactor. For example, in various embodiments, at least a portion of the separated H is sent to a Fischer-Tropsch reactor feed stream. In certain embodiments, the method further includes activating a Fischer-Tropsch catalyst using at least a portion of the H separated from the first product stream. Additionally or alternatively, at least a portion of the H separated from the first product stream may be used to activate a methanol cracking catalyst.

[0028] Advantageously, some processes described herein may be integrated to increase efficiency. For example, in various embodiments described elsewhere herein, contacting the second feed stream with a methanol cracking catalyst and contacting the first feed stream with a hydrogenation catalyst occur in the same plant. As will be understood by those skilled in the art, "same plant" means that the two processes occur within a small geographic area or region, such that it is economical to directly connect the two without significant intervening transportation steps. For example, in certain embodiments described elsewhere herein, at least a portion of the methanol of the first product stream may be provided directly to the second feed stream.

[0029] As described herein, there are many uses for hydrogen from the first product stream. Any or all of them may be utilized in certain real-world processes. In particular, the inventors recognize that the presence of hydrogen in the second feed stream may work against the conversion of methanol to carbon monoxide (i.e., because hydrogen is a by-product in that reaction, the presence of hydrogen in the second feed stream would force the equilibrium in an undesirable reverse direction). Thus, in various embodiments, the portion of the first product stream provided to the second feed stream comprises no more than 50% of the hydrogen in the first product stream, e.g., no more than 25%, no more than 10%, or no more than 5% of the hydrogen in the first product stream.

[0030] The portion of the first product stream provided to the second feed stream may advantageously be at elevated temperature and / or pressure. This can reduce capital costs by alleviating the need to heat and / or pressurize the second feed stream. Thus, in various embodiments described elsewhere herein, the portion of the first product stream provided to the second feed stream has a temperature in the range of 200-500°C, e.g., 200-450°C, or 200-400°C, or 200-350°C, or 200-300°C, or 250-500°C, or 250-450°C, or 250-400°C, or 250-300°C, or 300-500°C, or 300-450°C, or 300-400°C. In certain embodiments, the portion of the first product stream provided to the second feed stream is at a pressure of 0-50 barg, e.g., 1-50 barg.

[0031] Compared to gaseous compositions, compositions that are liquid at ambient temperature and pressure generally require lower capital expenditures for handling due to their increased density and reduced need for high pressure and / or low temperature. The inventors have noted that the methanol product of CO2 hydrogenation can be easily stored and / or transported. Accordingly, in various embodiments described elsewhere herein, contacting the second feed stream with the methanol cracking catalyst and contacting the first feed stream with the dehydrogenation catalyst occur in different plants. As used herein, a different "plant" is not simply a different catalyst bed or a different vessel, but rather a different facility from the facility where carbon dioxide hydrogenation occurs. In such embodiments, the plant may be, for example, at least 1 km away from the facility where hydrogenation occurs. In various such embodiments, the methanol from the first product stream may be stored and / or transported before being provided to the second feed stream.

[0032] In various embodiments described elsewhere herein, at least a portion of the methanol of the first product stream is stored (e.g., in one or more tanks) before being provided to the second feed stream. The storage can be for any suitable time. In various embodiments, the stored portion of the methanol of the first product stream is stored for at least 1 day, e.g., at least 2 days, or at least 3 days, or at least 1 week. In certain embodiments, the stored portion of the methanol is transported at least 1 km, e.g., at least 2 km, or at least 10 km, during storage. In some embodiments, the methanol may be transported via a pipeline.

[0033] The second feed stream introduces methanol for decomposition into CO and H. Methanol decomposition is a different process than methanol reforming, which reacts methanol with water to produce CO and H. Thus, in various embodiments as described elsewhere herein, methanol reforming is not utilized. For example, in certain embodiments, 10% or less (e.g., 5% or less, or 1% or less) of the H is derived from methanol reforming.

[0034] The water-gas shift reaction is another method for producing H by reacting carbon monoxide with water. The reaction is reversible; carbon dioxide can also react with hydrogen to form carbon monoxide and water. Both of these reactions are conventionally used in the art. Advantageously, the disclosed method avoids the use of both the water-gas shift reaction and the reverse water-gas shift reaction. Thus, in various embodiments described elsewhere herein, less than 10% (e.g., less than 5%, or less than 2%) of each of the H, CO, and CO of the process is produced by the water-gas shift reaction or the reverse water-gas shift reaction, as appropriate. In various processes disclosed herein, a dedicated water-gas shift or reverse water-gas shift reactor is not used (however, as will be understood by those skilled in the art, the water-gas shift or reverse water-gas shift reaction may act to a small extent as a side reaction during certain processes).

[0035] As described herein, methanol decomposition is utilized to form a product stream comprising CO and H. Accordingly, in various embodiments described elsewhere herein, the second feed stream comprises at least 5 mol% methanol. For example, in certain embodiments, the second feed stream comprises at least 7.5% methanol, e.g., at least 10% methanol, or at least 15% methanol, or at least 20% methanol, or at least 25 mol% methanol.

[0036] Optionally, the second feed stream may include one or more additional gases, which may be inert or reactive. In such embodiments, the second feed stream may further include one or more of H, CO, CH, CO, and N. In certain embodiments, the second feed stream includes an inert carrier gas, which includes one or more of CH, CO, and N. Additionally or alternatively, H and / or CO may be added to the second feed stream to adjust the decomposition reaction. In such embodiments, the second feed stream further includes H and / or CO. In various embodiments described elsewhere herein, one or more of H, CO, CH, CO, and N are present in the second feed stream in an amount ranging from up to 50 mol%, e.g., up to 40 mol%, or up to 30 mol%.

[0037] In various embodiments, the second feed stream has a low water content. Water present can react with CO and be at least partially converted to CO and H through the water-gas shift reaction, and water can also react with methanol via reforming to provide H and CO. According to the reaction equilibrium of methanol decomposition, the produced H is antithetical to the decomposition of methanol to CO and H. Thus, in various embodiments described elsewhere herein, the second feed stream has a water concentration of 5 mol% or less, e.g., 2 mol% or less, or 1 mol% or less, or 0.5 mol% or less, or 0.3 mol% or less, or 0.2 mol% or less, or 0.1 mol% or less.

[0038] The second feed stream may be provided at an elevated temperature. For example, in various embodiments described elsewhere herein, the second feed stream has a temperature in the range of 200-500°C, e.g., 200-450°C, or 200-400°C, or 200-350°C, or 200-300°C, or 250-500°C, or 250-450°C, or 250-400°C, or 250-300°C, or 300-500°C, or 300-450°C, or 300-400°C.

[0039] The second feed stream is contacted with a methanol decomposition catalyst. Any suitable decomposition catalyst can be used, and a variety are known in the art. For example, the decomposition catalyst can include a transition metal, such as one or more transition metals selected from Groups 7-11 of the periodic table. In certain embodiments, the methanol decomposition catalyst includes one or more of Cr, Fe, Co, Ni, Cu, Zn, Ru, Rh, Pd, Ir, or Pt, or mixtures thereof. In some embodiments, the decomposition catalyst can include an intermetallic compound or alloy. For example, the catalyst can further include one or more of Sc, Y, Ti, Zr, Ce, B, Al, Ga, In, Si, Ge, Sn, or Sb. The decomposition catalyst can be a supported catalyst, where the support is a refractory oxide such as diamond oxide, silica, zirconia, ceria, titania, alumina, lanthanum oxide, or magnesia. In some embodiments, the methanol decomposition catalyst is, for example, a copper / zinc oxide catalyst on alumina.

[0040] Those skilled in the art will be familiar with catalytic methods for decomposing methanol into CO and H. Various examples of catalysts and catalytic processes are described in U.S. Pat. Nos. 6,541,142, 9,833,773, and 4,716,859, as well as Usami et al., "Catalytic methanol decomposition at low temperatures over palladium supported on metal oxides." Appl. Cat. A 171(1):123-130 (1998), each of which is incorporated herein by reference in its entirety.

[0041] Contacting the second feed stream with the methanol decomposition catalyst is carried out at a temperature suitable for efficient methanol decomposition. In various embodiments described elsewhere herein, contacting the second feed stream with the methanol decomposition catalyst is carried out at a temperature ranging from 200 to 500°C, e.g., 200 to 450°C, or 200 to 400°C, or 200 to 350°C, or 200 to 300°C, or 250 to 500°C, or 250 to 450°C, or 250 to 400°C, or 250 to 300°C, or 300 to 500°C, or 300 to 450°C, or 300 to 400°C. Contacting can be carried out at various suitable pressures, e.g., ranging from 0 to 50 barg. Thus, in such embodiments, contacting with the methanol decomposition catalyst can be carried out at relatively high pressures, e.g., up to 50 barg, e.g., in the range of 20 to 40 barg.

[0042] As described herein, contacting the second feed stream with the methanol decomposition catalyst may be carried out in the same plant as contacting the first feed stream with the hydrogenation catalyst. In such instances, it may be advantageous to adjust the temperatures of the methanol decomposition and hydrogenation reactions to avoid excessive heating and cooling capital and energy costs. Thus, in certain embodiments described elsewhere herein, contacting the second feed stream with the methanol decomposition catalyst is carried out at a temperature within 75° C., e.g., within 50° C., of the temperature of contacting the first feed stream with the hydrogenation catalyst.

[0043] The methanol decomposition reaction ideally produces CO and H2, with minimal other products. Thus, in various embodiments described elsewhere herein, the decomposition of methanol is carried out at a carbon product selectivity of at least 50% relative to CO, e.g., at least 60%, or at least 70%, or at least 80%, or at least 90% relative to CO2. Advantageously, in various embodiments, the decomposition of methanol is carried out at a selectivity of 20% or less relative to CO2, e.g., 15% or less, or 10% or less, or 5% or less. In various embodiments described elsewhere herein, the decomposition of methanol is carried out at a methanol conversion of at least 30%, e.g., at least 40%, or at least 50%, or at least 60%, or at least 65%, or at least 70%, or at least 75%.

[0044] As described herein, the decomposition of methanol produces CO and H. Thus, in various embodiments described elsewhere herein, the second product stream comprises at least 20 mol %, e.g., at least 35 mol %, or at least 50 mol %, or at least 65 mol % of the sum of CO and H. Without being bound by theory, methanol decomposition under these conditions is expected to produce 2 moles of H per mole of CO. Thus, in various embodiments described elsewhere herein, the second product stream has a molar ratio of hydrogen to carbon monoxide ranging from 0.5:1 to 5:1, e.g., from 1:1 to 3:1, or from 1.5:1 to 2.5:1, or from 1.5:1 to 3.5:1. Of course, in other embodiments, this molar ratio may be different, for example, as a result of including H or CO in the second feed stream.

[0045] In various embodiments, the second product stream comprises 20 mol% or less of CO, e.g., 15 mol% or less of CO, or 10 mol% or less of CO, or 5 mol% or less of CO, excluding CO not derived from methanol decomposition (e.g., excluding any CO present in the second feed stream, such as unreacted CO from methanol synthesis).

[0046] Advantageously, a portion of the methanol is consumed during the methanolysis reaction. Thus, in various embodiments described elsewhere herein, the second product stream comprises 75 mol% or less methanol, e.g., 60 mol% or less methanol, 50 mol% or less methanol, or 25 mol% or less methanol.

[0047] In some embodiments, further removal of methanol from the second product stream is desirable. For example, in various embodiments described elsewhere herein, the method further includes separating at least a portion of the methanol from the second product stream, e.g., separating at least 50%, or at least 75%, or at least 90%, or at least 95% of the methanol from the second product stream. Advantageously, at least a portion of the methanol in the second product stream, e.g., the methanol separated from the second product stream, may be transferred or recycled to other processes. For example, in various embodiments described elsewhere herein, the method further includes recycling at least a portion of the methanol separated from the second product stream to the second feed stream.

[0048] As described herein, the methanol decomposition reaction theoretically produces CO and H in a 2:1 molar ratio, although actual reaction output can vary. This can result in excess hydrogen for subsequent processes, depending on the desired ratio. And, particularly, hydrogen may be present in the second feed stream, further increasing the ratio in the second product stream. Accordingly, in various embodiments described elsewhere herein, the method further includes separating at least a portion of the H from the second product stream. The separated H is suitable for various processes. For example, in certain embodiments, at least a portion of the H separated from the second product stream is provided to the first feed stream. Additionally or alternatively, in various embodiments described elsewhere herein, the method further includes activating a methanol decomposition catalyst using at least a portion of the H separated from the second product stream.

[0049] The inventors have noted that carbon dioxide is the primary carbon input to the processes described herein, and that the carbon dioxide can be advantageously provided by a variety of sources. Importantly, at least a portion (e.g., at least 50%, at least 75%, at least 90%, or at least 95%) of the carbon dioxide in the first feed stream can be derived from renewable sources.

[0050] Carbon dioxide is a common waste product, and it is often desirable to remove it from waste streams rather than release it into the atmosphere. Such capture of carbon dioxide is important to the implementation of many renewable initiatives, as it helps lower the carbon dioxide footprint of the associated processes. Advantageously, the carbon dioxide utilized in the methods described herein can be carbon dioxide collected from the atmosphere or carbon dioxide that would otherwise be released into the atmosphere, for example, from combustion or other industrial processes. Carbon dioxide may be captured when it is recovered or absorbed after being released from an industrial process, or it may be taken directly from the atmosphere. Methods of carbon dioxide capture are known to those skilled in the art. In various embodiments, at least a portion of the CO2 of the first feed stream is from direct air capture. Additionally, or alternatively, carbon dioxide is often scrubbed from industrial wastewater, particularly from processes that produce large amounts of carbon dioxide as a by-product. Accordingly, in various embodiments described elsewhere herein, at least a portion (e.g., at least 50%, at least 75%, at least 90%, or at least 95%) of the CO2 of the first feed stream is captured from a manufacturing plant, such as a bioethanol plant, steel mill, or cement plant.

[0051] As mentioned above, renewable sources can be used to provide CO2 for the claimed methods. For example, biomass is an attractive source of renewable carbon dioxide for use in the methods described herein. One source of biomass is agricultural products in the form of dedicated energy crops such as switchgrass, miscanthus, bamboo, sorghum, tall fescue, kochia, wheatgrass, poplar, willow, silver maple, eastern cottonwood, green ash (ash), black walnut, sweetgum (gum), and sycamore. Another source of biomass is agricultural waste or agricultural crop residues. Conventional agricultural activities, including the production of food, feed, fiber, and forest products, generate large amounts of waste plant material. Examples of such materials include corn stover, wheat straw, oat straw, barley straw, sorghum stubble, and rice straw. A third source of biomass comes from forestry residues left after timber operations. Biomass can also be in the form of commercial waste, industrial waste, sewage sludge, and municipal waste, including commercial and residential trash, including yard trimmings, paper and paperboard, plastics, rubber, leather, textiles, and food waste. Accordingly, in various embodiments described elsewhere herein, at least a portion of the CO2 of the first feed stream is derived from renewable resources. For example, in certain embodiments, at least a portion (e.g., at least 50%, at least 75%, at least 90%, or at least 95%) of the CO2 of the first feed stream is derived from biomass, e.g., agricultural biomass or municipal waste biomass. Additional sources of agricultural biomass will be apparent to those skilled in the art, as determined by local availability, economics, and process suitability.

[0052] To produce carbon dioxide from carbon-containing materials such as biomass, the material is typically subjected to gasification. Gasification involves heating the material under controlled conditions to produce a gaseous stream of carbon monoxide, hydrogen, and carbon dioxide. Controlled amounts of other reactants, such as oxygen and / or steam, can be used to adjust the process. Gasification conditions are adjusted according to the carbon-containing material being gasified to efficiently produce gaseous products. In various embodiments, the carbon dioxide in the first feed stream comprises carbon dioxide from the gasification of biomass, e.g., at least 50%, at least 75%, at least 90%, or at least 95% of the carbon dioxide is from the gasification of biomass. The biomass can be from any source, as described above, or can be combined from multiple sources.

[0053] Conventional H gas is most commonly obtained from natural gas, often through methane steam reforming, partial oxidation of hydrocarbons, and / or coal gasification. However, each of these processes, as conventionally practiced, releases significant amounts of CO into the atmosphere and relies on fossil fuels as starting materials and / or energy sources. In contrast, other H sources are known that are preferable from an environmental standpoint. Accordingly, in various embodiments described elsewhere herein, at least a portion (e.g., at least 50%, at least 75%, at least 90%, or at least 95%) of the H in the first feed stream and / or the second feed stream is from a renewable resource.

[0054] As is known in the art, hydrogen can be named based on its color depending on its source. Example types of hydrogen include green hydrogen, blue hydrogen, gray hydrogen, black hydrogen, brown hydrogen, pink hydrogen, turquoise hydrogen, yellow hydrogen, and / or white hydrogen.

[0055] One potential source of green hydrogen is through water electrolysis. Numerous electrolysis methods are known in the art. For example, electrolysis may be performed on pure water to produce hydrogen gas and oxygen gas, or on other solutions, such as saline solution, to produce hydrogen gas and another product (e.g., chlorine gas). In certain embodiments, hydrogen is formed through the electrolysis of saline solution. Water electrolysis is further described in U.S. Pat. No. 4,312,720, U.S. Pat. No. 4,021,323, and U.S. Pat. No. 4,094,751, each of which is incorporated by reference in its entirety.

[0056] To qualify as green hydrogen, the electricity used for water electrolysis must come from a renewable source, i.e., a source that does not rely on the combustion of fossil fuels. Examples of renewable electricity sources include solar power via photovoltaic capture or solar thermal technology, wind power, geothermal energy capture, hydroelectric energy, or other renewable sources. Hydrogen generated using solar energy for water electrolysis is sometimes referred to as yellow hydrogen. Suitable renewable energy sources are known to those skilled in the art and may be optionally selected through certification by an appropriate authority. Thus, in various embodiments described elsewhere herein, at least a portion of the H2 in the first feed stream is green hydrogen and / or yellow hydrogen. For example, in certain embodiments, the method further includes providing at least a portion of the H2 in the first feed stream by water electrolysis. In various embodiments, the water electrolysis is performed using electricity obtained at least in part from a renewable resource.

[0057] Blue hydrogen is defined as hydrogen gas produced in a process that relies somewhat on fossil fuels for production but is entirely carbon-neutral (i.e., does not result in any net introduction of carbon dioxide into the atmosphere). In various embodiments described elsewhere herein, the hydrogen utilized in the methods described elsewhere herein includes blue hydrogen. An example of blue hydrogen is hydrogen gas produced from fossil-fuel-derived hydrocarbons, such as methane gas, with the resulting carbon product captured or otherwise utilized. For example, steam reforming of methane can be performed to produce three moles of hydrogen gas and one mole of carbon monoxide per mole of methane. Methane steam reforming is highly endothermic and requires a significant energy input. Of course, the energy required to carry out these methods must come from renewable sources or sources with appropriate carbon capture technology. Thus, in various embodiments as described elsewhere herein, at least a portion (e.g., at least 50%, at least 75%, at least 90%, or at least 95%) of the hydrogen is formed by steam reforming of methane. Steam reforming of methane to produce hydrogen is described in International Patent Application Publication No. 2004 / 022480, which is incorporated herein by reference in its entirety. Thus, in various embodiments as described elsewhere herein, at least a portion of the H2 in the first feed stream is blue hydrogen.

[0058] Grey hydrogen is the most common source of H. Grey hydrogen is produced from natural gas / methane by steam reforming, but in contrast to blue hydrogen, the resulting greenhouse gases (e.g., CO) are not captured. In various embodiments described elsewhere herein, at least a portion of the H in the first feed stream is grey hydrogen.

[0059] Black hydrogen and brown hydrogen are produced from black or lignite coal, respectively, often by gasification thereof without carbon capture. In various embodiments as described elsewhere herein, at least a portion of the H2 in the first feed stream is black hydrogen and / or brown hydrogen.

[0060] Pink hydrogen is produced by water electrolysis, with the energy required for electrolysis being generated by nuclear power. In various embodiments described elsewhere herein, at least a portion of the H2 in the first feed stream is pink hydrogen. Pink hydrogen is also known as purple hydrogen or red hydrogen.

[0061] Turquoise hydrogen is produced by methane pyrolysis, with the by-products being hydrogen gas and solid elemental carbon. In various embodiments described elsewhere herein, at least a portion of the H2 in the first feed stream is turquoise hydrogen.

[0062] White hydrogen is naturally occurring hydrogen that can be released by fracking. In various embodiments as described elsewhere herein, at least a portion of the H2 in the first feed stream is white hydrogen.

[0063] As described herein, the disclosed methods, in various embodiments, involve two central reactions: CO hydrogenation and methanol decomposition. As described herein, these reactions can be advantageously carried out in different spatial configurations relative to one another. As known in the art, a reaction zone consists of one or more catalyst beds, and one or more reaction zones may be located within the same plant. Different plants are typically geographically separated, such that feedstocks cannot be transferred between them without intervening transportation and storage steps. Thus, in various embodiments described elsewhere herein, the first reaction zone includes a first reactor in which a hydrogenation catalyst is disposed, and the second reaction zone includes a second reactor in which a methanol decomposition catalyst is disposed. In various embodiments described elsewhere herein, the first reaction zone includes a first catalyst bed in which a hydrogenation catalyst is disposed, and the second reaction zone includes a second catalyst bed in which a methanol decomposition catalyst is disposed. For example, in certain embodiments, the first catalyst bed and the second catalyst bed are located within the same reactor, e.g., in a catalyst stack or catalyst bed section. In certain embodiments, the first reactor is located in a first plant and the second reactor is located in a second plant.

[0064] As described herein, in some embodiments, various catalyst beds may be located in different reactors. Placing catalyst beds in separate reactors can have various process advantages. For example, such separation allows individual units to experience reactor downtime (e.g., for maintenance) independently of one another. Furthermore, reactors can be maintained at different temperatures to maximize individual process selectivity and efficiency. Exothermic and endothermic chemical reactions require temperature control to maintain stable operating temperatures. Because different catalysts change activity at different rates over time, separate processes performed in separate reactors simplify temperature control. Thus, in certain embodiments as described elsewhere herein, the first and second catalyst beds are immiscible. Catalyst intermixing occurs when catalysts for different processes share the same catalyst bed. As used herein, two different catalyst beds within one reactor are immiscible. In certain embodiments as described elsewhere herein, the first and second catalyst beds are located in separate reactors.

[0065] An exemplary embodiment is shown in the schematic diagram of FIG. 1, which depicts a process 100 contained within a single plant 141. A first feed stream 111 comprising H and CO is sent to a hydrogenation reaction zone 110 (here, a hydrogenation reactor) where it is contacted with a hydrogenation catalyst 113 under conditions suitable to produce a first product stream 112 comprising methanol. The first product stream typically contains other materials as well. For example, in the embodiment of FIG. 1, the first product stream comprises CO, and at least a portion of the CO is separated from the first product stream and recycled to the first feed stream 111 via CO recycle 114. Similarly, the first product stream may comprise H (e.g., unreacted H) and / or CO. Here, at least a portion of the H and / or CO is separated from the first product stream and recycled to the first feed stream 111 via H and / or CO recycle stream 115. Any water present can be removed from the first product stream 112 by a water separation stream 116 to provide a primarily dry second feed stream (121); optionally, the water feed stream 116 can be fed to an electrolysis reactor 160.

[0066] 1, the remaining portion of first product stream 112 (i.e., after the separations described above) is provided to second feed stream 121. Second feed stream 121, which comprises at least a portion of the methanol from the first product stream, is sent to a methanol decomposition reaction zone 120 (here, a methanol decomposition reactor) where it contacts a methanol decomposition catalyst 123 to decompose at least a portion of the methanol and form a second product stream 122 comprising CO and H. Second feed stream 121 can also be augmented by introducing other gases, such as CO and / or H, through an augmentation feed (not shown). H gas from electrolysis reactor 160 is returned to the first feed stream via electrolysis H stream 117.

[0067] As described above, methanol can be formed via the hydrogenation of carbon dioxide in a first plant and then transported (e.g., via vehicle or pipeline) to a second plant where the methanol is cracked and the resulting carbon monoxide and / or H can be utilized in downstream processes. An example of such an embodiment is shown in the schematic diagram of FIG. 2, where the carbon dioxide hydrogenation step of process 200 occurs in first plant 241. A first feed stream 211 comprising carbon dioxide and hydrogen is directed to a hydrogenation reaction zone 210 (here, a hydrogenation reactor) containing a CO hydrogenation catalyst 213. The first feed stream 211 contacts the CO hydrogenation catalyst 213 to hydrogenate at least a portion of the CO to produce a first product stream 212 comprising methanol. The first product stream 212 can be subjected to various separations (not shown) as described herein, and the methanol of the first product stream can then be stored for later use and / or transported to another plant. 1, at least a portion of first product stream 212, the portion comprising methanol, is charged to storage tank 217 and then transported thereto by truck 218 to second plant 243. A portion of the first product stream is provided to second feed stream 221, which is directed to methanol decomposition reaction zone 220 where it contacts methanol decomposition catalyst 223 to produce second product stream 222 comprising CO and H.

[0068] Another illustrative embodiment is shown in the schematic diagram of Figure 3, where in process 301, a first feed stream 311 is delivered to a first reaction zone 310 and contacted with a CO2 hydrogenation catalyst 313 to hydrogenate at least a portion of the CO2 in the first feed stream to form a first product stream 312 comprising methanol. The first product stream 312 is directed from the first reaction zone 310, an additional gas stream 324 is added, and the resulting mixture is provided as a second feed stream 321. The second feed stream 321 is directed to a methanol decomposition reaction zone 320, where it is coupled with a methanol decomposition catalyst 323 to provide a second product stream 322. Here, the second product stream 322 is directed from the methanol decomposition reaction zone, and unreacted methanol is substantially separated from the second product stream (e.g., at least 50%, at least 75%, at least 90%, or at least 95%) and recycled to the second feed stream 321 via a methanol recycle 325. In particular, at least a portion of the H2 in second product stream 322 may be separated and recycled to first feed stream 311 via H2 recycle 326. At least a portion of the H2 in second product stream 322 may also or alternatively be provided to an external reactor or process through H2 stream 327.

[0069] In some embodiments, the conversion of CO to hydrocarbons via a methanol intermediate may be carried out in a single reactor, for example, with various catalysts arranged in series. In the embodiment of Figure 4, process 400 utilizes a syngas source stream 412 that enters reactor 425 as a first feed stream 421 in zone 420. First feed stream 421 contacts a hydrogenation catalyst 413 and then passes directly to a methanol cracking catalyst 423. The resulting gas mixture is recovered from zone 430 as a second product stream 432. Recycle stream 413 draws off CO gas, in any mixture with other gases, for recycling to CO source stream 412.

[0070] Various exemplary embodiments of the present disclosure include, but are not limited to, the enumerated embodiments listed below, which can be combined in any number and in any combination that is not technically or logically consistent.

[0071] Embodiment 1: A method for producing synthesis gas, comprising: Providing the first supply logistics including H2 and CO2, contacting the first feed stream with a hydrogenation catalyst (e.g., in a hydrogenation reaction zone) to hydrogenate at least a portion of the CO to form a first product stream comprising methanol; providing a second feed stream comprising at least a portion of the methanol of the first product stream; contacting the second feed stream with a methanol decomposition catalyst (e.g., in a methanol decomposition reaction zone) to decompose at least a portion of the methanol to form a second product stream comprising synthesis gas (e.g., comprising CO and H2).

[0072] Embodiment 2: The method of embodiment 1, wherein the first feed stream comprises at least 10 mol% H2, e.g., at least 20 mol% H2, or at least 30 mol% H2.

[0073] Embodiment 3: The method of embodiment 1 or embodiment 2, wherein the first feed stream comprises at least 5 mol% CO2, e.g., at least 10 mol% CO2, or at least 15 mol% CO2.

[0074] Embodiment 4: The method of any of embodiments 1-3, wherein the H2:CO2 ratio of the first feed stream is at least 1:1, e.g., at least 1.5:1, at least 2:1, at least 2.5:1, at least 3:1, or at least 4:1.

[0075] Embodiment 5: The method of any of embodiments 1-4, wherein the first feed stream further comprises one or more of CO, CH4, and N2.

[0076] Embodiment 6: The method of any one of embodiments 1-5, wherein the first feed stream comprises 20 mol% or less CO, e.g., 15 mol% or less CO, or 10 mol% or less CO, or 5 mol% or less CO.

[0077] Embodiment 7: The method of any one of embodiments 1-6, wherein the hydrogenation catalyst is a copper / zinc oxide catalyst, for example, supported on aluminum oxide or zirconium oxide.

[0078] Embodiment 8: The method of any of embodiments 1 to 7, wherein the contacting of the first feed stream with the hydrogenation catalyst is carried out at a temperature in the range of 200 to 500°C, e.g., 200 to 450°C, or 200 to 400°C, or 200 to 350°C, or 200 to 300°C, or 250 to 500°C, or 250 to 450°C, or 250 to 400°C, or 250 to 300°C, or 300 to 500°C, or 300 to 450°C, or 300 to 400°C.

[0079] Embodiment 9: The method of any of embodiments 1-8, wherein the hydrogenation of CO2 is carried out with a selectivity to methanol of at least 50%, e.g., at least 65% or at least 80%.

[0080] Embodiment 10: The method of any one of embodiments 1-9, wherein the hydrogenation of CO2 is carried out at a selectivity to methane of 20% or less, such as 10% or less, or 5% or less.

[0081] Embodiment 11: The method of any one of embodiments 1 to 10, wherein the hydrogenation of CO2 is carried out at a selectivity to CO of 20% or less, such as 10% or less, or 5% or less.

[0082] Embodiment 12: The method of any of embodiments 1 to 11, wherein the hydrogenation of CO2 is carried out to a conversion of CO2 of at least 25%, such as at least 35%, such as at least 45% or at least 50%.

[0083] Embodiment 13: The method of any of embodiments 1-12, wherein the first product stream comprises at least 15 mol% methanol, e.g., at least 25 mol%, or at least 35 mol% methanol.

[0084] Embodiment 14: The method of any one of embodiments 1-13, wherein the first product stream comprises 10 mol% or less methane, e.g., 5 mol% or less methane, or 2 mol% or less methane.

[0085] Embodiment 15: The method of any one of embodiments 1-14, wherein the first product stream comprises 10 mol% or less CO, e.g., 5 mol% or less CO, or 2 mol% or less CO.

[0086] Embodiment 16: The method of any of embodiments 1-15, further comprising separating at least a portion of the water from the first product stream (e.g., at least 50%, at least 75%, or at least 90% of the water in the first product stream).

[0087] Embodiment 17: The method of any one of embodiments 1-16, wherein the portion of the first product stream included in the second feed stream has a water content of 10 mol % or less, e.g., or 2 mol % or less, or 0.5 mol % or less.

[0088] Embodiment 18: The method of any one of embodiments 1-16, further comprising separating at least a portion of the H2 (e.g., at least 50%, or at least 60%, or at least 75%, or at least 90%, or at least 95% of the H2 in the first product stream) from the first product stream.

[0089] Embodiment 19: The method of embodiment 18, further comprising recycling at least a portion of the H2 separated from the first product stream to the first feed stream.

[0090] Embodiment 20: The method of any of embodiments 16-19, further comprising using at least a portion of the H2 separated from the first product stream to activate a methanol decomposition catalyst.

[0091] Embodiment 21: The method of any one of embodiments 1-20, wherein the portion of the first product stream provided to the second feed stream comprises no more than 50% of the hydrogen in the first product stream, e.g., no more than 25%, no more than 10%, or no more than 5% of the hydrogen in the first product stream.

[0092] Embodiment 22: The process of any one of embodiments 1 to 21, wherein the contacting of the second feed stream with the methanolic decomposition catalyst and the contacting of the first feed stream with the hydrogenation catalyst occur in the same plant.

[0093] Embodiment 23: The process of any one of Embodiments 1-22, wherein at least a portion of the methanol of the first product stream is fed directly to the second feed stream.

[0094] Embodiment 24: The method of embodiment 23, wherein the portion of the first product stream that is fed to the second feed stream has a temperature in the range of 200 to 500°C, e.g., 200 to 450°C, or 200 to 400°C, or 200 to 350°C, or 200 to 300°C, or 250 to 500°C, or 250 to 450°C, or 250 to 400°C, or 250 to 300°C, or 300 to 500°C, or 300 to 450°C, or 300 to 400°C.

[0095] Embodiment 25: The process of any one of embodiments 1 to 24, wherein the contacting of the second feed stream with the methanolic decomposition catalyst and the contacting of the first feed stream with the hydrogenation catalyst occur in different plants.

[0096] Embodiment 26: The method of any of embodiments 1-25, wherein at least a portion of the methanol of the first product stream is stored (e.g., in one or more tanks) before being fed to the second feed stream.

[0097] Embodiment 27: The method of embodiment 26, wherein the stored portion of the methanol of the first product stream is stored for at least 1 day, such as at least 2 days or at least 1 week.

[0098] Embodiment 28: The method of embodiment 26, wherein the stored portion of methanol is transported at least 1 km, such as at least 2 km or at least 10 km during storage.

[0099] Embodiment 29: The method of any of embodiments 1-28, wherein the second feed stream comprises at least 5 mol% methanol, e.g., at least 7.5% methanol, or at least 10 mol% methanol, or at least 15% methanol, or at least 20% methanol, or at least 25 mol% methanol.

[0100] Embodiment 30: The method of any of embodiments 1-29, wherein the second feed stream further comprises one or more of H2, CO, CH4, CO2, and N2.

[0101] Embodiment 31: The method of any one of embodiments 1 to 30, wherein the second feed stream has a water concentration of 5 mol% or less, e.g., 2 mol% or less, or 1 mol% or less.

[0102] Embodiment 32: The method of any one of embodiments 1 to 31, wherein the second feed stream has a temperature in the range of 200 to 500°C, e.g., 200 to 450°C, or 200 to 400°C, or 200 to 350°C, or 200 to 300°C, or 250 to 500°C, or 250 to 450°C, or 250 to 400°C, or 250 to 300°C, or 300 to 500°C, or 300 to 450°C, or 300 to 400°C.

[0103] Embodiment 33: The method of any one of embodiments 1 to 32, wherein the methanol decomposition catalyst is, for example, a copper / zinc oxide on alumina catalyst.

[0104] Embodiment 34: The process of any one of embodiments 1 to 33, wherein contacting the second feed stream with the methanol decomposition catalyst is conducted at a temperature in the range of 200 to 500°C, e.g., 200 to 450°C, or 200 to 400°C, or 200 to 350°C, or 200 to 300°C, or 250 to 500°C, or 250 to 450°C, or 250 to 400°C, or 250 to 300°C, or 300 to 500°C, or 300 to 450°C, or 300 to 400°C.

[0105] Embodiment 35: The process of any one of Embodiments 1 to 34, wherein contacting the second feed stream with the methanolic decomposition catalyst is conducted at a temperature within 75° C., e.g., within 50° C., of the temperature of contacting the first feed stream with the hydrogenation catalyst.

[0106] Embodiment 36: The method of any of embodiments 1-35, wherein the decomposition of methanol is carried out at a carbon product selectivity relative to CO of at least 50%, e.g., at least 60%, or at least 70%, or at least 80%, or at least 90%.

[0107] Embodiment 37: The method of any one of embodiments 1 to 36, wherein the decomposition of methanol is carried out at a selectivity to CO of 20% or less, e.g., 15% or less, 10% or less, or 5% or less.

[0108] Embodiment 38: The method of any one of embodiments 1 to 36, wherein the decomposition of methanol is carried out to a conversion of methanol of at least 30%, e.g., at least 40%, or at least 50%, or at least 60%, or at least 65%, or at least 70%, or at least 75%.

[0109] Embodiment 39: The method of any of embodiments 1-37, wherein the second product stream comprises at least 20 mol % CO and H2 in total, e.g., at least 35 mol %, or at least 50 mol %, or at least 65 mol %.

[0110] Embodiment 40: The method of any of embodiments 1-39, wherein the second product stream comprises 20 mol% or less CO2, e.g., 15 mol% or less CO2, or 10 mol% or less CO2, or 5 mol% or less CO2, excluding CO2 not derived from methanol decomposition.

[0111] Embodiment 41: The method of any one of embodiments 1 to 40, wherein the second product stream has a molar ratio of hydrogen to carbon monoxide in the range of 0.5:1 to 5:1, e.g., 1:1 to 3:1, e.g., 1.5:1 to 2.5:1.

[0112] Embodiment 42: The method of any one of embodiments 1-41, wherein the second product stream comprises 75 mol% or less methanol, e.g., 60 mol% or less methanol, or 50 mol% or less methanol, or 25 mol% or less methanol.

[0113] Embodiment 43: The method of any one of Embodiments 1-42, further comprising separating at least a portion of the methanol from the second product stream (e.g., at least 50%, at least 75%, or at least 90% of the methanol in the second product stream).

[0114] Embodiment 44: The method of embodiment 43, further comprising recycling at least a portion of the methanol separated from the second product stream, e.g., at least 50%, or at least 75%, or at least 90%, or at least 95% of the methanol from the second product stream, to the second feed stream.

[0115] Embodiment 45: The method of any one of embodiments 1 to 44, further comprising separating at least a portion of the H2 from the second product stream.

[0116] Embodiment 46: The method of embodiment 45, further comprising providing H2 separated from the second product stream to the first feed stream.

[0117] Embodiment 47: The method of any of embodiments 1-46, wherein at least a portion of the CO2 of the first feed stream is from a renewable source.

[0118] Embodiment 48: The method of any of embodiments 1-47, wherein at least a portion of the CO2 of the first feed stream is from direct air capture.

[0119] Embodiment 49: The method of any of embodiments 1 to 48, wherein at least a portion of the CO2 of the first feed stream is captured from a manufacturing plant, such as a bioethanol plant, a steel mill, or a cement factory.

[0120] Embodiment 50: The method of any one of embodiments 1 to 49, wherein at least a portion of the H2 of the first feed stream is from renewable resources.

[0121] Embodiment 51: The method of any one of embodiments 1 to 50, wherein at least a portion of the hydrogen in the first feed stream is green hydrogen.

[0122] Embodiment 52: The method of any one of embodiments 1 to 51, wherein at least a portion of the hydrogen in the first feed stream is blue hydrogen.

[0123] Embodiment 53: The method of any one of embodiments 1 to 52, wherein at least a portion of the hydrogen in the first feed stream is gray hydrogen, black hydrogen, brown hydrogen, pink hydrogen, turquoise hydrogen, yellow hydrogen, and / or white hydrogen.

[0124] Embodiment 54: The method of any one of embodiments 1 to 53, further comprising providing at least a portion of the H2 to the first feed stream by water electrolysis.

[0125] Embodiment 55: The method of embodiment 54, wherein the water electrolysis is performed using electricity derived at least in part from renewable resources.

[0126] Embodiment 56: The method of any one of embodiments 1-55, wherein the first reaction zone comprises a first reactor disposed with a hydrogenation catalyst, and the second reaction zone comprises a second reactor disposed with a methanol decomposition catalyst.

[0127] Embodiment 57: The process of any one of embodiments 1-56, wherein the first reaction zone comprises a first catalyst bed disposed with a hydrogenation catalyst, and the second reaction zone comprises a second catalyst bed disposed with a methanol decomposition catalyst.

[0128] Embodiment 58: The method of embodiment 57, wherein the first catalyst bed and the second catalyst bed are immiscible.

[0129] Embodiment 59: The method of embodiment 57 or embodiment 58, wherein the first catalyst bed and the second catalyst bed are disposed in separate reactors.

[0130] Embodiment 60: The method of embodiment 57, wherein the first catalyst bed and the second catalyst bed are disposed within the same reactor in a catalyst stack or bed section.

[0131] The details set forth herein are presented by way of example only for purposes of illustrative discussion of various embodiments of the present disclosure and to provide what is believed to be the most useful and readily understood explanation of the principles and conceptual aspects of various embodiments of the present disclosure. In this regard, no attempt is made to show details related to the methods of the present disclosure in more detail than is necessary for a fundamental understanding of the methods described herein; the description, taken together with the examples, will make clear to those skilled in the art how some forms of the methods of the present disclosure can be actually embodied. Therefore, before the disclosed methods and devices are described, it should be understood that the aspects described herein are not limited to specific embodiments, apparatus, or configurations, which may, of course, vary. It should also be understood that the terminology used herein is intended to describe particular aspects only and is not intended to be limiting unless specifically defined herein.

[0132] As used in the context of describing the methods of the present disclosure (particularly in the context of the embodiments and claims that follow), the terms "a," "an," "the," and similar referents should be construed to encompass both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context.

[0133] All methods described herein can be performed in any suitable order of steps, unless otherwise indicated herein or clearly contradicted by context. Any and all examples provided herein, or the use of exemplary language (e.g., "etc."), are intended merely to better clarify the methods of the present disclosure and do not impose limitations on the scope of the disclosure. No language in the present specification should be construed as indicating any non-claimed element essential to the practice of the methods of the present disclosure.

[0134] Unless the context clearly dictates otherwise, throughout this specification and the claims, words like "comprise," "comprising," and the like are to be construed in an inclusive sense, i.e., "including, but not limited to," rather than an exclusive or exhaustive sense. Words using the singular or plural also include the plural and singular, respectively. Furthermore, the words "herein," "above," and "below," and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of this application.

[0135] As will be understood by one of ordinary skill in the art, each embodiment disclosed herein can comprise, consist essentially of, or consist of its specified recited elements, steps, ingredients, or components. As used herein, the transitional phrases "comprise" or "comprises" mean including, but not limited to, and allow for the inclusion of unspecified elements, steps, ingredients, or components, even if they amount to a large amount. The transitional phrase "consisting of" excludes any unspecified element, step, ingredient, or component. The transitional phrase "consisting essentially of" limits the scope of the embodiment to the specified elements, steps, ingredients, or components, and those that do not materially affect the embodiment.

[0136] All percentages, ratios and proportions herein are by weight unless otherwise specified.

[0137] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the disclosure are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. However, any numerical value inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

[0138] Groupings of alternative elements or embodiments of the present disclosure should not be construed as limiting. Each group member may be referred to and claimed individually or in any combination with other members of the group or other elements found herein. It is anticipated that one or more members of a group may be included in, or deleted from, a group for reasons of convenience and / or patentability. When any such inclusion or deletion occurs, the specification is deemed to include the modified group and thus satisfy the written description of all Markush groups used in the appended claims.

[0139] Several embodiments of various aspects of the present disclosure are described herein, including the best mode known to the inventors for carrying out the methods described herein. Of course, variations of these described embodiments will become apparent to those skilled in the art upon reading the foregoing description. Those skilled in the art will employ such variations as appropriate, and thus the methods of the present disclosure can be carried out in ways other than those specifically described herein. Accordingly, the scope of the present disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Furthermore, any combination of the above-described elements in all possible variations thereof is encompassed by the present disclosure unless otherwise indicated herein or clearly contradicted by context.

[0140] As used herein, the phrase "at least a portion" is used to mean that at least a partial amount, up to the total possible amount, is required.

[0141] Finally, it should be understood that the various embodiments herein are illustrative of the methods of the present disclosure. Other modifications that may be employed are within the scope of the present disclosure. Thus, by way of example, and not of limitation, alternative configurations of the methods may be utilized in accordance with the teachings herein. Thus, the methods of the present disclosure are not limited to that precisely as shown and described.

Claims

1. 1. A method for producing synthesis gas, comprising: Providing the first supply logistics including H2 and CO2, contacting the first feed stream with a hydrogenation catalyst (e.g., in a hydrogenation reaction zone) to hydrogenate at least a portion of the CO to form a first product stream comprising methanol; providing a second feed stream comprising at least a portion of the methanol of the first product stream; contacting the second feed stream with a methanol decomposition catalyst (e.g., in a methanol decomposition reaction zone) to decompose at least a portion of the methanol to form a second product stream comprising synthesis gas (e.g., comprising CO and H2).

2. 10. The method of claim 1, wherein the first feed stream comprises at least 10 mol% H2, e.g., at least 20 mol% H2, or at least 30 mol% H2.

3. 3. The method of claim 1 or claim 2, wherein the first feed stream comprises at least 5 mol% CO2, such as at least 10 mol% CO2, or at least 15 mol% CO2.

4. 4. The method of any one of claims 1 to 3, wherein the H2:CO2 ratio of the first feed stream is at least 1:1, such as at least 1.5:1, at least 2:1, at least 2.5:1, at least 3:1, or at least 4:

1.

5. 5. The process according to any one of claims 1 to 4, wherein the hydrogenation of CO2 is carried out with a selectivity to methanol of at least 50%, such as at least 65% or at least 80%.

6. 6. The method of any one of claims 1 to 5, further comprising separating at least a portion of the water from the first product stream (e.g., at least 50%, at least 75%, or at least 90% of the water in the first product stream).

7. 7. The method of any one of claims 1 to 6, wherein the portion of the first product stream included in the second feed stream has a water content of 10 mol% or less, such as, or 2 mol% or less, or 0.5 mol% or less.

8. 8. The method of any one of claims 1 to 7, wherein the second feed stream comprises at least 5 mol% methanol, e.g., at least 7.5% methanol, or at least 10 mol% methanol, or at least 15% methanol, or at least 20% methanol, or at least 25 mol% methanol.

9. The method of any one of claims 1 to 8, wherein the second feed stream has a water concentration of 5 mol% or less, such as 2 mol% or less, or 1 mol% or less.

10. 10. The process of any one of claims 1 to 9, wherein contacting the second feed stream with the methanol decomposition catalyst is conducted at a temperature within 75°C, e.g., within 50°C, of the temperature of contacting the first feed stream with the hydrogenation catalyst.

11. 11. The method of any one of claims 1 to 10, wherein the decomposition of methanol is carried out with a carbon product selectivity relative to CO of at least 50%, such as at least 60%, or at least 70%, or at least 80%, or at least 90%.

12. 12. The method of any one of claims 1 to 11, wherein the decomposition of methanol is carried out at a selectivity to CO of 20% or less, such as 15% or less, 10% or less, or 5% or less.

13. 13. The method of any one of claims 1 to 12, wherein the second product stream comprises a sum of CO and H2 of at least 20 mol%, e.g., at least 35 mol%, or at least 50 mol%, or at least 65 mol%.

14. 14. The method of any one of claims 1 to 13, wherein the second product stream has a molar ratio of hydrogen to carbon monoxide in the range of from 0.5:1 to 5:1, e.g., from 1:1 to 3:1, from 1.5:1 to 2.5:1, or from 1.5:1 to 3.5:

1.

15. 15. The method of any one of claims 1 to 14, further comprising separating at least a portion of the H2 from the second product stream and providing the H2 separated from the second product stream to the first feed stream.

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