Production of syngas from carbon dioxide via methanol

Abstract

The present disclosure generally relates to methods of producing syngas. In particular, the present disclosure relates to a process comprising: providing a first feed stream comprising H2 and CO2; 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; the second feed stream is contacted with a methanol decomposition catalyst to form a second product stream comprising syngas.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority of European patent application No. 22190307.3 filed on August 12, 2022, the entire contents of which are incorporated herein by reference.

[0003] Public background Technical Field

[0004] The present disclosure relates to an integrated process for producing synthesis gas from carbon dioxide via a methanol intermediate. Background Art

[0005] The conversion of synthesis gas (i.e., a mixture of carbon monoxide and hydrogen, also referred to as synthesis gas (syngas)) into hydrocarbons by the Fischer-Tropsch process has been known for decades, but has historically lagged behind other hydrocarbon synthesis technologies. The growing importance of alternative energy sources has led to a renewed interest in the Fischer-Tropsch (FT) process because it enables the acquisition of high quality fuels and feedstock chemicals in a direct and environmentally acceptable manner. The Fischer-Tropsch process uses synthesis gas as a starting material, wherein synthesis gas is a mixture of CO and H2 gases. Synthesis gas is conventionally produced from fossil fuel sources, primarily by gasification of coal. However, the handling properties of synthesis gas are poor because it must be transported in a low density gas phase, or liquefied at high pressure.

[0006] The FT process is known for producing straight chain hydrocarbons for fuels, as well as oxygenates that can be used in fuels and can also serve as valuable feedstock chemicals. Hydrocarbon fuels derived from the FT process are generally better able to meet increasingly stringent environmental regulations than conventional refinery-produced fuels because FT-derived fuels generally have lower levels of sulfur, nitrogen, and aromatic compounds that contribute to potent pollutants such as SO2, NO x The products derived from the FT process generally have a higher octane rating 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 in the synthesis of lubricants.

[0007] Therefore, there is a need to develop improved solutions for producing and handling syngas. Summary of the invention

[0008] The present inventors have identified a method for efficiently converting CO2 to synthesis gas via a methanol (MeOH) intermediate. Advantageously, this method can be carried out at lower temperatures than conventional synthesis routes and does not require a reverse water gas shift (rWGS) process.

[0009] Thus, in one aspect, the present disclosure provides an integrated method for producing synthesis gas, the method comprising:

[0010] Providing a first feed stream comprising H2 and CO2;

[0011] contacting the first feed stream with a hydrogenation catalyst (e.g., in a hydrogenation reaction zone) to hydrogenate at least a portion of the CO2 to form a first product stream comprising methanol;

[0012] providing a second feed stream comprising at least a portion of the methanol of the first product stream;

[0013] The second feed stream is contacted with a methanolysis catalyst (eg, in a methanolysis reaction zone) to decompose at least a portion of the methanol to form a second product stream comprising syngas (eg, comprising CO and H2).

[0014] Other aspects of the present disclosure will be apparent to those skilled in the art based on the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1-4 A schematic diagram of a process according to an exemplary embodiment of the present disclosure is provided. DETAILED DESCRIPTION

[0016] The present disclosure relates to the technology of preparing synthesis gas from carbon dioxide. Carbon dioxide is a widely available gas (currently present in the atmosphere at about 400ppm), which is inert to many conversions. In addition, the tendency of carbon dioxide to absorb infrared radiation has led to its designation as a greenhouse gas. Therefore, it is necessary to develop economical methods for utilizing carbon dioxide, especially waste carbon dioxide that would otherwise increase the rising carbon dioxide concentration in the atmosphere. Carbon dioxide is produced by many industries, where it can be captured as a point source for use as a raw material, such as from places involved in steel production, fossil fuel power generation, cement production, fermentation processes or fertilizer production. Carbon dioxide can also be derived from direct air capture projects. Advantageously, methods of using synthesis gas (such as Fischer-Tropsch hydrocarbon synthesis) using waste carbon dioxide as a feed 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 into methanol. Methanol, which is a liquid at ambient temperature and pressure, can optionally be transported by low-pressure pipelines, ships or trucks, so as a liquid, it is generally possible to improve transportation efficiency. Methanol can then be subjected to a methanol decomposition step to generate H2 and CO in a 2:1 ratio. A mixture of H2 and CO is often referred to as "syngas" and has a wide range of uses. At least the CO of the methanol decomposition product can then be used in a Fischer-Tropsch synthesis reaction to produce hydrocarbons; the H2 from the methanol decomposition is also ideal for use in Fischer-Tropsch synthesis. For example, some Fischer-Tropsch processes operate at a H2:CO ratio of 2:1 or greater, such as 2.2:1 or 3:1. In such cases, the H2 and CO mixture from the methanol decomposition can be supplemented by a hydrogen source (such as green hydrogen from a recycled feed stream or produced with renewable energy) to form a Fischer-Tropsch reaction mixture.

[0017] Accordingly, in one aspect, the present disclosure provides an integrated method for producing synthesis gas, the method comprising:

[0018] Providing a first feed stream comprising H2 and CO2;

[0019] contacting the first feed stream with a hydrogenation catalyst (e.g., in a hydrogenation reaction zone) to hydrogenate at least a portion of the CO2 to form a first product stream comprising methanol;

[0020] providing a second feed stream comprising at least a portion of the methanol of the first product stream;

[0021] The second feed stream is contacted with a methanolysis catalyst (eg, in a methanolysis reaction zone) to decompose at least a portion of the methanol to form a second product stream comprising syngas (eg, comprising CO and H2).

[0022] As used herein, "feed stream" is used to represent the total material input to a process step, such as CO2 hydrogenation or methanol decomposition, whether provided as a single physical stream or multiple physical streams, and whether provided via a single inlet or multiple inlets. For example, the H2 and CO2 of the first feed stream can be provided to the hydrogenation reactor in a single physical stream (e.g., in a single pipeline leading 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 recycling CO2 and / or H2). Similarly, "product stream" is used to represent the total material output from a process step, such as hydrogenation of carbon dioxide or methanol decomposition, whether provided as a single physical stream or multiple physical streams, and whether provided via a single reactor outlet or multiple reactor outlets.

[0023] As used herein, the term "synthesis gas" refers to a mixture of CO and H2, wherein the molar ratio of CO to H2 is in the range of 0.2:1 to 10:1, and the combination of CO and H2 accounts for 10% to 80% by volume of the mixture. Synthesis gas is gaseous at standard temperature and pressure, but can be liquefied at elevated pressure and / or reduced temperature.

[0024] Advantageously, the integrated process as described herein can be substantially asymmetric in nature: while methanol can be synthesized from a carbon species that is primarily CO2, it can subsequently be decomposed into a stream having CO as the primary carbon species. This is in contrast to symmetric processes, in which the streams entering methanol synthesis and leaving methanol decomposition have similar carbon compositions. Since most of the reactions described herein are equilibrium processes, they are naturally suitable for symmetric integration. However, the inventors have discovered that asymmetric processes, such as the asymmetric processes disclosed herein, can enhance control over stream composition and improve process efficiency.

[0025] The first feed stream comprises H2 and CO2 for subsequent contact with a hydrogenation catalyst to produce methanol. Thus, in various embodiments as further described herein, the first feed stream comprises at least 10 mol % H2. For example, in various embodiments, the first feed stream comprises at least 20 mol % H2, such as at least 30 mol % H2. In various embodiments as further described herein, the first feed stream comprises at least 5 mol % CO2. For example, in various embodiments, the first feed stream comprises at least 10 mol % CO2, such as at least 15 mol % CO2.

[0026] In general, CO2 is hydrogenated to produce methanol according to the following reaction: CO2+3H2→CH3OH+H2O. Thus, in various embodiments as otherwise described herein, the ratio of H2:CO2 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 as otherwise described herein, the ratio of H2:CO2 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 specific embodiments, the ratio of H2:CO2 of the first feed stream is no greater than 25:1, e.g., no greater than 20:1, or no greater than 15:1, or 12:1.

[0027] In some embodiments, the first feed stream comprises other gases in addition to CO2 and H2. For example, in various embodiments, the first feed stream further comprises one or more of CO, CH4 and N2. For example, in specific embodiments, the first feed stream comprises other gases (e.g., one or more of CO, CH4 and N2) in an amount of up to 70 mol%. In various embodiments, the first feed stream comprises no more than 1% O2, such as no more than 0.1% O2, or no more than 0.01% O2, or substantially free of O2. In various embodiments, the first feed stream comprises no more than 20 mol% CO, such as no more than 15 mol% CO, or no more than 10 mol% CO, or even no more than 5 mol% CO.

[0028] As described herein, the first feed stream is contacted with a hydrogenation catalyst. The hydrogenation catalyst can be selected by one of ordinary skill in the art. Examples of suitable catalysts include Cu / ZnO catalysts, such as Cu / ZnO catalysts supported on alumina or zirconium oxide.

[0029] Advantageously, the CO2 hydrogenation reaction can be carried out at relatively low temperatures to improve the energy efficiency and integration of the entire process. For example, in various embodiments as described herein, the contact of the first feed stream with the hydrogenation catalyst is carried out at a temperature in the range of 200-500°C, such as 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, the contact of the first feed stream with the hydrogenation catalyst is carried out at a pressure of not more than 100 bar, such as not more than 80 bar or not more than 60 bar.

[0030] As described herein, CO2 hydrogenation advantageously produces methanol with high selectivity. Therefore, in various embodiments as described in addition herein, CO2 hydrogenation is carried out with a selectivity of at least 50%, for example at least 55% or at least 60% to methanol. For example, in specific embodiments, CO2 hydrogenation is carried out with a selectivity of at least 65% (for example, at least 70%, or at least 75%, or at least 80%) to methanol. Advantageously, CO2 hydrogenation can be carried out with a low selectivity to methane. In various embodiments as described in addition herein, CO2 hydrogenation is carried out with a selectivity of not more than 20%, for example not more than 10% or not more than 5% to methane. As will be understood by those of ordinary skill in the art, "selectivity" to a given species is the fraction of the carbonaceous reactant of the reaction converted into the species, i.e., unreacted material is not counted.

[0031] Importantly, the CO2 hydrogenation reaction as described herein is not a reverse water gas shift reaction. As is known in the art, the reverse water gas shift reaction converts CO2 and H2 into CO and H2O. Thus, in various embodiments as otherwise described herein, the hydrogenation of CO2 is performed with a selectivity to CO of no more than 20%, e.g., no more than 10% or no more than 5% to CO. In specific embodiments, the hydrogenation of CO2 is performed with a selectivity to CO of no more than 2% or no more than 1% to CO.

[0032] During the CO2 hydrogenation reaction, at least a portion of the CO2 is hydrogenated to MeOH and H2O. Advantageously, the method can be performed with a relatively high CO2 conversion rate. Therefore, in various embodiments as further described herein, the hydrogenation of CO2 is performed with a CO2 conversion rate of at least 25%, such as at least 35%, such as at least 45% or at least 50%.

[0033] Those of ordinary skill in the art are familiar with catalytic methods for hydrogenating carbon dioxide to methanol. Various examples of catalysts and catalytic methods are described in R. Guil-López 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.

[0034] CO2 hydrogenation produces a first product stream. In various embodiments as described in addition herein, the first product stream comprises at least 15 mol % methanol, for example at least 25 mol % or at least 35 mol % methanol. As described herein, CO2 hydrogenation also advantageously has low selectivity to other products such as methane and / or carbon monoxide. Therefore, in various embodiments as described in addition herein, the first product stream comprises no more than 10 mol % methane, for example no more than 5 mol % methane or no more than 2 mol % methane. In various embodiments as described in addition herein, the first product stream comprises no more than 10 mol % CO, for example no more than 5 mol % CO or no more than 2 mol % CO. Of course, in some embodiments, there may be more methane and / or CO, for example, as part of the first feed stream. As will be appreciated by the technician, the composition of the first product stream as disclosed herein does not include inert gases or unreacted CO2 and / or H2.

[0035] As described herein, the CO2 hydrogenation step produces methanol and water. In some embodiments, the water formed may be harmful to subsequent processes. For example, the excess water present in the methanol decomposition process step may undesirably cause CO to be converted back to CO2 via the water-gas shift reaction. In addition, external water may react with methanol in the methanol steam reforming reaction to form CO2 and hydrogen, thereby destroying process efficiency. Therefore, in various embodiments as described herein in addition, the method further includes separating at least a portion of water from the first product stream. For example, in specific 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 as described herein in addition, the portion of the first product stream included in the second feed stream has a water content of not more than 10 mol%, such as not more than 2 mol%, or not more than 1 mol%, or not more than 0.5 mol%.

[0036] In embodiments where water from the CO2 hydrogenation step is separated, the water can be disposed of as waste, or recycled into other processes. For example, in various embodiments, the separated water is directed to an electrolysis reactor to form H2 gas, for example for use in this integrated process or for use in other processes. In certain embodiments, the separated water is subjected to a purification step prior to introduction into the electrolysis reactor.

[0037] In various embodiments as described in addition herein, not all H2 gases input to the CO2 hydrogenation react. Therefore, in such embodiments, the method may further include separating at least a portion of H2 from the first product stream. For example, in specific embodiments as described in addition 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 H2 in the first product stream. The separated H2 can be optionally purified and then optionally recycled. In various embodiments, at least a portion of the separated H2 can be recycled to the first feed stream, and / or can be directed to another reactor. For example, in various embodiments, at least a portion of the separated H2 is directed to the Fischer-Tropsch reactor feed stream. In specific embodiments, the method further includes activating the Fischer-Tropsch catalyst using at least a portion of the H2 separated from the first product stream. Additionally or alternatively, at least a portion of the H2 separated from the first product stream can be used to activate the methanol decomposition catalyst.

[0038] Advantageously, some processes described herein can be integrated to improve efficiency. For example, in various embodiments as described in addition herein, the contact of the second feed stream with the methanol decomposition catalyst and the contact of the first feed stream with the hydrogenation catalyst are carried out in the same manufacturing plant (plant). As those of ordinary skill in the art will recognize, "same manufacturing plant" means that the two processes are carried out in a small geographic area or real estate (property), so that the two will be economically directly connected without obvious intermediate transportation steps. For example, in a specific embodiment as described in addition herein, at least a portion of the methanol of the first product stream can be directly supplied to the second feed stream.

[0039] As described herein, there are many uses for hydrogen from the first product stream. Any or all of them can be utilized in a specific real-world process. It is noteworthy that the inventors recognize that the presence of the hydrogen in the second feed stream may be detrimental to the conversion of methanol into carbon monoxide (that is, because hydrogen is a co-product in the reaction, the presence of the hydrogen in the second feed stream will force the balance to the undesirable reverse direction). Therefore, in various embodiments, the part of the first product stream supplied to the second feed stream includes no more than 50% of the hydrogen of the first product stream, such as no more than 25%, no more than 10% or no more than 5% of the hydrogen of the first product stream.

[0040] The part of the first product stream supplied to the second feed stream can be advantageously at elevated temperature and / or pressure. This can reduce capital costs by alleviating the heating and / or pressurization requirements of the second feed stream. Therefore, in various embodiments as described herein in addition, the part of the first product stream supplied to the second feed stream has a temperature in the range of 200-500 ° C, such as 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 a particular embodiment, the part of the first product stream supplied to the second feed stream is at a pressure of 0 to 50 barg, such as 1 to 50 barg.

[0041] Compared with gaseous compositions, compositions that are liquid at ambient temperature and pressure generally have lower operating capital expenditures due to their increased density and reduced demand for high pressure and / or low temperature. The inventors have noted that the methanol product of the CO2 hydrogenation can be simply stored and / or transported. Therefore, in various embodiments as described in addition herein, the contact of the second feed stream with the methanol decomposition catalyst and the contact of the first feed stream with the dehydrogenation catalyst are carried out in different manufacturing plants. As used herein, different "manufacturing plants" are not just different catalyst beds or different containers, but places different from the places where carbon dioxide hydrogenation is carried out. In such embodiments, the manufacturing plant can be, for example, at least 1 km away from the place where hydrogenation is carried out. In various such embodiments, the methanol from the first product stream can be stored and / or transported before being supplied to the second feed stream.

[0042] In various embodiments as described in addition herein, at least a portion of the methanol of the first product stream is stored (e.g., in one or more tanks) before being supplied to the second feed stream. This storage can last any suitable time. In various embodiments, the storage portion of the methanol of the first product stream is stored for at least one day, e.g., at least two days, or at least three days, or at least 1 week. In a specific embodiment, the storage portion of methanol is transported at least 1 km during storage, e.g., at least 2 km or at least 10 km. In some embodiments, methanol can be transported via pipeline.

[0043] The second feed stream introduces methanol to decompose into CO and H2. Methanol decomposition is a process different from methanol reforming. In methanol reforming, methanol and water react to produce CO2 and H2. Therefore, in various embodiments as described herein, methanol reforming is not used. For example, in specific embodiments, no more than 10% of the H2 is derived from methanol reforming (e.g., no more than 5% or no more than 1%).

[0044] The water-gas shift reaction is another method of generating H2 by reacting carbon monoxide with water. The reaction is also reversible, in which carbon dioxide can react with hydrogen to form carbon monoxide and water. Both reactions are conventionally used in the art. Advantageously, the method of the present disclosure avoids the use of the water-gas shift reaction and the reverse water-gas shift reaction. Therefore, in various embodiments as described herein, less than 10% (e.g., less than 5% or less than 2%) of each of the H2, CO, and CO2 of the method is generated by the water-gas shift reaction or the reverse water-gas shift reaction, as appropriate. In the various methods disclosed herein, no dedicated water-gas shift reactor or reverse water-gas shift reactor is used (however, as one of ordinary skill in the art will recognize, the water-gas shift reaction or the reverse water-gas shift reaction can be operated to a lesser extent as a side reaction during certain processes).

[0045] As described herein, methanolysis is utilized to form a product stream comprising CO and H. Thus, in various embodiments as otherwise described herein, the second feed stream comprises at least 5 mol% methanol. For example, in specific 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.

[0046] Optionally, the second feed stream may also include one or more additional gases, which may be inert or reactive. In such an embodiment, the second feed stream may further include one or more of H2, CO, CH4, CO2 and N2. In a particular embodiment, the second feed stream comprises an inert carrier gas, wherein the inert carrier gas comprises one or more of CH4, CO2 and N2. Additionally or alternatively, H2 and / or CO may be added to the second feed stream to regulate the decomposition reaction. In such an embodiment, the second feed stream further comprises H2 and / or CO. In various embodiments as further described herein, one or more of H2, CO, CH4, CO2 and N2 are present in the second feed stream in an amount of up to 50 mol %, for example, up to 40 mol % or up to 30 mol %.

[0047] In various embodiments, the second feed stream has a low water content. Any water present can react with CO to be converted into CO2 and H2 at least partially by a water-gas shift reaction, and water can also react with methanol by reforming to provide H2 and CO2. The generated H2 is not conducive to the decomposition of methanol into CO and H2 according to the reaction equilibrium of methanol decomposition. Therefore, in various embodiments as described herein, the second feed stream has a water concentration of not more than 5 mol%, for example, not more than 2 mol%, or not more than 1 mol%, or not more than 0.5 mol%, or not more than 0.3 mol%, or not more than 0.2 mol%, or not more than 0.1 mol%.

[0048] The second feed stream can be provided at an elevated temperature. For example, in various embodiments as otherwise described 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.

[0049] The second feed stream is contacted with a methanol decomposition catalyst. Any suitable decomposition catalyst may be used; a variety of which are known in the art. For example, the decomposition catalyst may include a transition metal, such as one or more transition metals selected from Groups 7-11 of the periodic table. In a particular embodiment, the methanol decomposition catalyst comprises one or more of Cr, Fe, Co, Ni, Cu, Zn, Ru, Rh, Pd, Ir, or Pt, or a mixture thereof. In some embodiments, the decomposition catalyst may comprise an intermetallic compound or alloy. For example, the catalyst may further comprise one or more of Sc, Y, Ti, Zr, Ce, B, Al, Ga, In, Si, Ge, Sn, or Sb. The decomposition catalyst may be a supported catalyst in which the carrier is a refractory oxide, such as diamond oxide, silicon dioxide, zirconium oxide, cerium dioxide, titanium dioxide, aluminum oxide, lanthanum oxide, or magnesium oxide. In some embodiments, the methanol decomposition catalyst is a copper / zinc oxide catalyst, such as on aluminum oxide.

[0050] Those of ordinary skill in the art are familiar with catalytic processes for decomposing methanol into CO and H. Various examples of catalysts and catalytic processes are described in U.S. Pat. No. 6,541,142, U.S. Pat. No. 9,833,773, and U.S. Pat. No. 4,716,859 and Usami et al., "Catalytic methanol decomposition at low temperatures overpalladium supported on metal oxides." Appl. Cat. A 171(1):123-130 (1998), each of which is incorporated herein by reference in its entirety.

[0051] The contact of the second feed stream with the methanol decomposition catalyst is carried out at a temperature suitable for implementing efficient methanol decomposition. In various embodiments as described herein, the contact of the second feed stream with the methanol decomposition catalyst is carried out at a temperature in the range of 200-500°C, such as 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. The contact can be carried out at various suitable pressures in the range of, for example, 0 to 50 barg. Therefore, in such an embodiment, the contact with the methanol decomposition catalyst can be carried out at a relatively high pressure, such as at most 50 barg, such as in the range of 20 to 40 barg.

[0052] As described herein, the contacting of the second feed stream with the methanol decomposition catalyst can be carried out in the same manufacturing plant as the contacting of the first feed stream with the hydrogenation catalyst. In such an example, it may be advantageous to coordinate the temperatures of the methanol decomposition reaction and the hydrogenation reaction to avoid excessive heating and cooling capital costs and energy costs. Therefore, in a specific embodiment as otherwise described herein, the contacting of the second feed stream with the methanol decomposition catalyst is carried out at a temperature within 75°C, such as within 50°C, of ​​the contacting temperature of the first feed stream with the hydrogenation catalyst.

[0053] The methanol decomposition reaction generates CO and H2, ideally with very few other products. Therefore, in various embodiments as described herein, the decomposition of methanol is carried out with a carbon product selectivity of at least 50% for CO, for example, at least 60%, or at least 70%, or at least 80%, or at least 90% for CO. Advantageously, in various embodiments, the decomposition of methanol is carried out with a selectivity of no more than 20%, for example, no more than 15%, or no more than 10%, or no more than 5% for CO2. In various embodiments as described herein, the decomposition of methanol is carried out with a methanol conversion rate of at least 30%, for example, at least 40%, or at least 50%, or at least 60%, or at least 65%, or at least 70%, or at least 75%.

[0054] As described herein, the decomposition of methanol generates CO and H2. Thus, in various embodiments as further described herein, the second product stream comprises a total of at least 20 mol% CO and H2, such as at least 35 mol%, or at least 50 mol%, or at least 65 mol%. Without wishing to be bound by theory, the decomposition of methanol under these conditions is expected to generate 2 mol H2 / mol CO. Thus, in various embodiments as further described herein, the second product stream has a hydrogen / carbon monoxide molar ratio in the range of 0.5:1 to 5:1, such as 1:1 to 3:1, or 1.5:1 to 2.5:1, or 1.5:1 to 3.5:1. Of course, in other embodiments, this molar ratio may be different, such as due to the inclusion of H2 or CO in the second feed stream.

[0055] In various embodiments, the second product stream contains no greater than 20 mol % CO2, e.g., no greater than 15 mol % CO2, or no greater than 10 mol % CO2, or no greater than 5 mol % CO2, excluding CO2 not derived from methanol decomposition (e.g., excluding any CO2 present in the second feed stream, such as unreacted CO2 from methanol synthesis).

[0056] Advantageously, a proportion of the methanol is consumed during the methanolysis reaction. Thus, in various embodiments as otherwise described herein, the second product stream comprises no greater than 75 mol % methanol, e.g., no greater than 60 mol % methanol, no greater than 50 mol % methanol, or no greater than 25 mol % methanol.

[0057] In some embodiments, it is necessary to further remove methanol from the second product stream. For example, in various embodiments as described in addition herein, the method further includes separating at least a portion of methanol from the second product stream, for example, 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, the methanol of the second product stream, for example, at least a portion of the methanol separated from the second product stream, can be transferred or recycled to other processes. For example, in various embodiments as described in addition herein, the method further includes recycling at least a portion of the methanol separated from the second product stream to the second feed stream.

[0058] As described herein, the methanol decomposition reaction produces CO and H2 in a 2: 1 theoretical molar ratio, although the actual reaction output may be different. Depending on the desired ratio, this may result in excess hydrogen for subsequent processes. It is also worth noting that hydrogen may be present in the second feed stream to further increase the ratio in the second product stream. Therefore, in various embodiments as further described herein, the method further includes separating at least a portion of H2 from the second product stream. The separated H2 may be suitable for various processes. For example, in a specific embodiment, at least a portion of the H2 separated from the second product stream is supplied to the first feed stream. Additionally or alternatively, in various embodiments as further described herein, the method further includes activating the methanol decomposition catalyst using at least a portion of the H2 separated from the second product stream.

[0059] The inventors have noted that carbon dioxide is the main input of carbon for the methods described herein, and carbon dioxide can be advantageously provided by a variety of sources. Importantly, at least a portion of the carbon dioxide (e.g., at least 50%, at least 75%, at least 90%, or at least 95%) of the first feed stream can come from a renewable source.

[0060] Carbon dioxide is a common waste material, and it is usually desirable to remove it from waste streams rather than discharge it into the atmosphere. This capture of carbon dioxide is crucial for the implementation of many renewable measures because it helps to reduce the carbon footprint of related processes. Advantageously, the carbon dioxide utilized in the method described herein can be carbon dioxide collected from the atmosphere or carbon dioxide that would otherwise be released into the atmosphere, such as from combustion or other industrial processes. Carbon dioxide can be captured, wherein it is collected or absorbed after being released from an industrial process, or harvested directly from the atmosphere. Carbon dioxide capture methods are known to those skilled in the art. In various embodiments, at least a portion of the CO2 of the first feed stream comes from direct air capture. Additionally or alternatively, carbon dioxide is typically washed from industrial effluents, especially processes that generate a large amount of carbon dioxide as a by-product. Therefore, in various embodiments as described herein in addition, at least a portion of the CO2 of the first feed stream (e.g., at least 50%, at least 75%, at least 90% or at least 95%) is captured from a manufacturing plant, such as a bioethanol plant, a steel plant or a cement plant.

[0061] As mentioned above, renewable sources can be used to provide CO to the claimed method. For example, biomass is an attractive source of renewable carbon dioxide for 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 scoparia, wheatgrass, poplar, willow, silver maple, eastern cottonwood, green ash, black walnut, sweetgum and sycamore. Another biomass source is agricultural waste or crop residues. Conventional agricultural activities, including the production of food, feed, fiber and forest products, generate a large amount of waste plant materials. Examples of such materials include corn stalks, wheat stalks, oat stalks, barley stalks, sorghum stubble and straw. The third biomass source is the 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 garbage, including yard trimming waste, paper and cardboard, plastics, rubber, leather, textiles and food waste. Therefore, in various embodiments as described herein, at least a portion of the CO2 of the first feed stream is derived from a renewable source. For example, in a specific embodiment, at least a portion of the CO2 of the first feed stream (e.g., at least 50%, at least 75%, at least 90% or at least 95%) is derived from biomass, such as agricultural biomass or municipal waste biomass. The other source of agricultural biomass is obvious to those skilled in the art, depending on local availability, economics and process compatibility.

[0062] In order to generate carbon dioxide from carbonaceous materials such as biomass, the material is usually gasified. Gasification involves heating the material under controlled conditions to generate a gas stream of carbon monoxide, hydrogen and carbon dioxide. Other reactants of controlled amounts can be used, such as oxygen and / or steam to regulate the process. Gasification conditions are adjusted according to the carbonaceous material of gasification to efficiently generate gaseous products. In various embodiments, the carbon dioxide of the first feed stream includes carbon dioxide from biomass gasification, such as at least 50%, at least 75%, at least 90% or at least 95% of the carbon dioxide from biomass gasification. Biomass can be any source as described above, or can be combined from a variety of sources.

[0063] Conventional H2 gas is most commonly derived from natural gas, typically by steam reforming of methane, partial oxidation of hydrocarbons, and / or gasification of coal. However, as conventionally performed, these methods each release a large amount of CO2 into the atmosphere and rely on fossil fuels as starting materials and / or energy sources. In contrast, other H2 sources that are preferred from an environmental perspective are known. Therefore, in various embodiments as otherwise described herein, at least a portion of the H2 (e.g., at least 50%, at least 75%, at least 90%, or at least 95%) of the first feed stream and / or the second feed stream is from renewable resources.

[0064] As is known in the art, hydrogen can be provided with color-based names depending on its production source. Examples of hydrogen types include green hydrogen, blue hydrogen, gray hydrogen, black hydrogen, brown hydrogen, pink hydrogen, turquoise hydrogen, yellow hydrogen, and / or white hydrogen.

[0065] One potential source of green hydrogen is through water electrolysis. Many electrolysis methods are known in the art. For example, pure water can be electrolyzed to produce hydrogen and oxygen, or other solutions, such as salt solutions, can be electrolyzed to produce hydrogen and another product (e.g., chlorine). In a particular embodiment, hydrogen is formed by electrolysis of a salt solution. Water electrolysis is further described in U.S. Patent No. 4,312,720, U.S. Patent No. 4,021,323, and U.S. Patent No. 4,094,751, each of which is incorporated herein by reference in its entirety.

[0066] In order 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. Exemplary sources of renewable power include solar power through photovoltaic capture or solar thermal technology, wind power, geothermal energy capture, hydroelectric energy, or other renewable sources. Hydrogen produced using solar power for water electrolysis is sometimes referred to as yellow hydrogen. Suitable renewable energy sources are known to those skilled in the art and may optionally be selected through certification by appropriate agencies. Therefore, in various embodiments as further described herein, at least a portion of the H2 of the first feed stream is green hydrogen and / or yellow hydrogen. For example, in specific embodiments, the method further includes providing at least a portion of the H2 of the first feed stream by electrolysis of water. In various embodiments, the electrolysis of water is performed using electricity derived at least in part from a renewable source.

[0067] Blue hydrogen is defined as hydrogen made in a process that is dependent to some extent on fossil fuels but is overall carbon neutral (i.e., does not result in any net introduction of carbon dioxide into the atmosphere). In various embodiments as described herein, the hydrogen used in the method as described herein comprises blue hydrogen. An example of blue hydrogen is hydrogen made from fossil fuel-derived hydrocarbons such as methane gas, wherein the resulting carbon product is captured or otherwise utilized. For example, steam reforming of methane can be performed to produce 3 moles of hydrogen and 1 mole of carbon monoxide for each mole of methane. Steam reforming of methane is highly endothermic and requires a large amount of energy input. Of course, the energy required to carry out these processes must come from a renewable source, or a source with sufficient carbon capture technology. Therefore, in various embodiments as described herein, at least a portion of the hydrogen (e.g., at least 50%, at least 75%, at least 90%, or at least 95%) is formed by steam reforming of methane. Steam reforming of methane to produce hydrogen is discussed in International Patent Application Publication No. 2004 / 022480, the entire text of which is incorporated herein by reference. Thus, in various embodiments as otherwise described herein, at least a portion of the H2 of the first feed stream is blue hydrogen.

[0068] Gray hydrogen is the most conventional source of H2. Gray hydrogen is made from natural gas / methane by steam reforming, but compared to blue hydrogen, the greenhouse gases (e.g., CO2) produced are not captured. In various embodiments as otherwise described herein, at least a portion of the H2 of the first feed stream is gray hydrogen.

[0069] Black hydrogen and brown hydrogen are made from black coal or lignite, respectively, typically by gasification thereof without any carbon capture. In various embodiments as otherwise described herein, at least a portion of the H2 of the first feed stream is black hydrogen and / or brown hydrogen.

[0070] Powdered hydrogen is generated by water electrolysis, wherein the energy required for electrolysis is generated by nuclear energy. In various embodiments as further described herein, at least a portion of the H2 of the first feed stream is powdered hydrogen. Powdered hydrogen is also known as purple hydrogen or red hydrogen.

[0071] Blue green hydrogen is produced by pyrolysis of methane, wherein the byproducts are hydrogen and solid elemental carbon. In various embodiments as otherwise described herein, at least a portion of the H2 of the first feed stream is blue green hydrogen.

[0072] White hydrogen is naturally occurring hydrogen that can be released by hydraulic fracturing. In various embodiments as otherwise described herein, at least a portion of the H2 of the first feed stream is white hydrogen.

[0073] As described herein, the disclosed method includes two central reactions in various embodiments: hydrogenation of CO2 and methanol decomposition. As described herein, these reactions can be advantageously carried out in different spatial arrangements relative to each other. As known in the art, the reaction zone consists of one or more catalyst beds, and one or more reaction zones can be in the same manufacturing plant. Different manufacturing plants are usually geographically separated so that raw materials cannot be transferred between them without intermediate transportation and storage steps. Therefore, in various embodiments as described herein, the first reaction zone includes a first reactor in which a hydrogenation catalyst is arranged, and the second reaction zone includes a second reactor in which a methanol decomposition catalyst is arranged. In various embodiments as described herein, the first reaction zone includes a first catalyst bed in which a hydrogenation catalyst is arranged, and the second reaction zone includes a second catalyst bed in which a methanol decomposition catalyst is arranged. For example, in a specific embodiment, the first catalyst bed and the second catalyst bed are arranged in the same reactor, for example, in a catalyst stack or a catalyst bed section. In a specific embodiment, the first reactor is located in the first manufacturing plant, and the second reactor is located in the second manufacturing plant.

[0074] As described herein, in some embodiments, various catalyst beds may be located in different reactors. Positioning the catalyst beds in separate reactors may have various process advantages. For example, this separation enables each unit to experience reactor downtime (e.g., for maintenance) independently of each other. In addition, the reactors can be maintained at different temperatures to maximize the selectivity and efficiency of each process. Exothermic and endothermic chemical reactions require temperature control to maintain a stable operating temperature. The separate processes carried out in separate reactors simplify temperature control because different catalysts will change activity at different rates over time. Therefore, in certain embodiments as described in addition herein, the first catalyst bed and the second catalyst bed are not blended. When catalysts for different processes share the same catalyst bed, blending of catalysts occurs. As used herein, two different catalyst beds in a reactor are not blended. In certain embodiments as described in addition herein, the first catalyst bed and the second catalyst bed are arranged in separate reactors.

[0075] An exemplary embodiment is shown in a diagrammatic view. Figure 1 , which depicts a process 100 contained within a single manufacturing plant 141. A first feed stream 111 comprising H2 and CO2 is directed to a hydrogenation reaction zone 110 (here, a hydrogenation reactor) and is contacted with a hydrogenation catalyst 113 under conditions suitable for producing a first product stream 112 comprising methanol. The first product stream typically also contains other substances. For example, in Figure 1In an embodiment of the present invention, the first product stream comprises CO2; at least a portion of the CO2 is separated from the first product stream and recycled to the first feed stream 111 via the CO2 recycle 114. Similarly, the first product stream may comprise H2 (e.g., unreacted H2) and / or CO. Here, at least a portion of the H2 and / or CO is separated from the first product stream and recycled to the first feed stream 111 via the H2 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 obtain a predominantly dry second feed stream (121), and the water feed stream 116 can optionally be fed to the electrolysis reactor 160.

[0076] exist Figure 1 In an embodiment of the present invention, the remaining portion of the first product stream 112 (i.e., after the above separation) is supplied to the second feed stream 121. The second feed stream 121 includes at least a portion of the methanol of the first product stream and is directed to the methanol decomposition reaction zone 120 (here, a methanol decomposition reactor), where it is contacted with a methanol decomposition catalyst 123 to decompose at least a portion of the methanol to form a second product stream 122 comprising CO and H2. The second feed stream 121 can also be supplemented by introducing other gases, such as CO and / or H2, via a supplementary feed (not shown). The H2 gas from the electrolysis reactor 160 is sent back to the first feed stream by electrolyzing the H2 stream 117.

[0077] As described above, methanol can be formed by hydrogenation of carbon dioxide in a first manufacturing plant and then transported (e.g., via a vehicle or pipeline) to a second manufacturing plant where the methanol is decomposed and the resulting carbon monoxide and / or H2 is used in downstream processes. An example of such an embodiment is shown in a schematic view at Figure 2 Here, the carbon dioxide hydrogenation step of method 200 is carried out in a first manufacturing 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 CO2 hydrogenation catalyst 213. The first feed stream 211 is contacted with the CO2 hydrogenation catalyst 213 to hydrogenate at least a portion of the CO2 to generate a first product stream 212 comprising methanol. The first product stream 212 may be subjected to various separations as described herein (not shown), and the methanol of the first product stream may then be stored for later use, and / or transported to another manufacturing plant. For example, in Figure 1In the embodiment of the present invention, at least a portion of the first product stream 212 (the portion containing methanol) is loaded into a storage tank 217 and then transported there to a second manufacturing plant 243 by a truck 218. This portion of the first product stream is supplied to a second feed stream 221, which is directed to a methanol decomposition reaction zone 220 where it is contacted with a methanol decomposition catalyst 223 to generate a second product stream 222 comprising CO and H2.

[0078] Another exemplary embodiment is shown in a diagrammatic view. Figure 3 Here, in the method 300, a first feed stream 311 is directed to a first reaction zone 310 and contacted with a CO2 hydrogenation catalyst 313 to hydrogenate at least a portion of the CO2 of the first feed stream to form a first product stream 312 comprising methanol. The first product stream 312 is withdrawn from the first reaction zone 310 and added to an additional gas stream 324, 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 a second product stream 322 is provided with a methanol decomposition catalyst 323. Here, the second product stream 322 is withdrawn from the methanol decomposition reaction zone, and unreacted methanol (e.g., at least 50%, at least 75%, at least 90%, or at least 95%) is substantially separated from the second product stream and recycled to the second feed stream 321 via a methanol recycle 325. Notably, at least a portion of the H2 of the second product stream 322 may be separated and recycled to the first feed stream 311 via H2 recycle 326. At least a portion of the H2 of the second product stream 322 may also or alternatively be supplied to an external reactor or process via H2 stream 327. . .

[0079] In some embodiments, the conversion of CO2 to hydrocarbons via a methanol intermediate can be carried out in a single reactor with various catalysts arranged, for example, in series. Figure 4 In an embodiment of the present invention, the process 400 utilizes a synthesis gas source stream 412, which enters the reactor 425 as a first feed stream 421 at a zone 420. The first feed stream 421 is contacted with a hydrogenation catalyst 413 and then passed directly to a methanol decomposition catalyst 423. The resulting gas mixture is discharged from the zone 430 as a third product stream 432. The recycle stream 413 removes CO2 gas, optionally mixed with light hydrocarbons and other gases, and is recycled to the CO2 source stream 412.

[0080] Various exemplary embodiments of the present disclosure include, but are not limited to, the embodiments listed below, which may be combined in any number and in any combination that are not technically or logically contradictory.

[0081] Embodiment 1. A method for producing synthesis gas, the method comprising:

[0082] Providing a first feed stream comprising H2 and CO2;

[0083] contacting the first feed stream with a hydrogenation catalyst (e.g., in a hydrogenation reaction zone) to hydrogenate at least a portion of the CO2 to form a first product stream comprising methanol;

[0084] providing a second feed stream comprising at least a portion of the methanol of the first product stream;

[0085] 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 syngas (e.g., comprising CO and H2);

[0086] Embodiment 2. A process according to 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.

[0087] Embodiment 3. A process according to Embodiment 1 or Embodiment 2, wherein the first feed stream comprises at least 5 mol % CO 2 , eg, at least 10 mol % CO 2 , or at least 15 mol % CO 2 .

[0088] Embodiment 4. A method according to any of Embodiments 1-3, wherein the ratio of H2:CO2 of the first feed stream is at least 1:1, for example at least 1.5:1, at least 2:1, at least 2.5:1, at least 3:1, or at least 4:1.

[0089] Embodiment 5. A method according to any of Embodiments 1-4, wherein the first feed stream further comprises one or more of CO, CH4 and N2.

[0090] Embodiment 6. A process according to any of Embodiments 1-5, wherein the first feed stream comprises no greater than 20 mol % CO, e.g., no greater than 15 mol % CO, or no greater than 10 mol % CO, or no greater than 5 mol % CO.

[0091] Embodiment 7. The method according to any of Embodiments 1-6, wherein the hydrogenation catalyst is a copper / zinc oxide catalyst, for example supported on alumina or zirconia.

[0092] Embodiment 8. A method according to any of Embodiments 1-7, wherein contacting of 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.

[0093] Embodiment 9. A process according to any one of Embodiments 1-8, wherein the hydrogenation of CO2 is carried out with a selectivity to methanol of at least 50%, eg, at least 65% or at least 80%.

[0094] Embodiment 10. The process according to any of Embodiments 1-9, wherein the hydrogenation of CO2 is carried out with a selectivity to methane of not more than 20%, eg, not more than 10% or not more than 5%.

[0095] Embodiment 11. A process according to any of Embodiments 1-10, wherein the hydrogenation of CO2 is carried out with a selectivity to CO of not more than 20%, eg, not more than 10% or not more than 5%.

[0096] Embodiment 12. A method according to any of Embodiments 1-11, wherein the hydrogenation of CO2 is carried out at a CO2 conversion of at least 25%, such as at least 35%, such as at least 45% or at least 50%.

[0097] Embodiment 13. The process of any of Embodiments 1-12, wherein the first product stream comprises at least 15 mol% methanol, eg, at least 25 mol% or at least 35 mol% methanol.

[0098] Embodiment 14. The method of any of Embodiments 1-13, wherein the first product stream comprises no greater than 10 mol% methane, eg, no greater than 5 mol% methane or no greater than 2 mol% methane.

[0099] Embodiment 15. The method of any of Embodiments 1-14, wherein the first product stream comprises no greater than 10 mol % CO, eg, no greater than 5 mol % CO or no greater than 2 mol % CO.

[0100] 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).

[0101] Embodiment 17. The method of any of Embodiments 1-16, wherein the portion of the first product stream included in the second feed stream has a water content of no greater than 10 mol %, eg, no greater than 2 mol % or no greater than 0.5 mol %.

[0102] Embodiment 18. A method according to any of Embodiments 1-16, further comprising separating at least a portion of the H2 from the first product stream (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).

[0103] 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.

[0104] Embodiment 20. The method of any of Embodiments 16-19, further comprising activating the methanol decomposition catalyst using at least a portion of the H2 separated from the first product stream.

[0105] Embodiment 21. The method of any of Embodiments 1-20, wherein the portion of the first product stream supplied to the second feed stream comprises no more than 50% of the hydrogen of the first product stream, e.g., no more than 25%, no more than 10%, or no more than 5% of the hydrogen of the first product stream.

[0106] Embodiment 22. The method of any of Embodiments 1-21, wherein the contacting of the second feed stream with the methanol decomposition catalyst and the contacting of the first feed stream with the hydrogenation catalyst are performed in the same manufacturing plant.

[0107] Embodiment 23. The method of any of Embodiments 1-22, wherein at least a portion of the methanol of the first product stream is supplied directly to the second feed stream.

[0108] Embodiment 24. A process according to Embodiment 23, wherein the portion of the first product stream supplied 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.

[0109] Embodiment 25. The method according to any of Embodiments 1-24, wherein the contacting of the second feed stream with the methanol decomposition catalyst and the contacting of the first feed stream with the hydrogenation catalyst are performed in different manufacturing plants.

[0110] 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 (eg, in one or more tanks) prior to being supplied to the second feed stream.

[0111] Embodiment 27. The method according to Embodiment 26, wherein the stored portion of the methanol of the first product stream is stored for at least one day, such as at least two days or at least 1 week.

[0112] Embodiment 28. A method according to embodiment 26 or embodiment 26, wherein the stored portion of the methanol is transported at least 1 km, such as at least 2 km or at least 10 km during storage.

[0113] Embodiment 29. A method according to 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.

[0114] Embodiment 30. A method according to any of Embodiments 1-29, wherein the second feed stream further comprises one or more of H2, CO, CH4, CO2 and N2.

[0115] Embodiment 31. The method of any of Embodiments 1-30, wherein the second feed stream has a water concentration of no greater than 5 mol%, eg, no greater than 2 mol% or no greater than 1 mol%.

[0116] Embodiment 32. A method according to any of Embodiments 1-31, wherein the second feed stream has a temperature in the range of 200-500°C, for example 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.

[0117] Embodiment 33. The method of any of Embodiments 1-32, wherein the methanol decomposition catalyst is a copper / zinc oxide catalyst, such as on alumina.

[0118] Embodiment 34. A method according to any of Embodiments 1-33, wherein contacting the second feed stream with the methanol decomposition 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.

[0119] Embodiment 35. The process of any of Embodiments 1-34, wherein contacting the second feed stream with the methanol decomposition catalyst is carried out at a temperature within 75°C, eg, within 50°C, of ​​the contacting temperature of the first feed stream with the hydrogenation catalyst.

[0120] Embodiment 36. A method according to any of Embodiments 1-35, wherein the decomposition of methanol is carried out with a carbon product selectivity to CO of at least 50%, e.g., at least 60%, or at least 70%, or at least 80%, or at least 90%.

[0121] Embodiment 37. A method according to any of Embodiments 1-36, wherein the decomposition of methanol is carried out with a selectivity to CO2 of not more than 20%, eg, not more than 15%, not more than 10% or not more than 5%.

[0122] Embodiment 38. A method according to any of Embodiments 1-36, wherein the decomposition of methanol is carried out at a methanol conversion rate of at least 30%, such as at least 40%, or at least 50%, or at least 60%, or at least 65%, or at least 70%, or at least 75%.

[0123] Embodiment 39. A method according to any of Embodiments 1-37, wherein the second product stream comprises a total of at least 20 mol% CO and H2, for example at least 35 mol%, or at least 50 mol%, or at least 65 mol%.

[0124] Embodiment 40. A method according to any of Embodiments 1-39, wherein the second product feed stream contains no more than 20 mol% CO2, for example no more than 15 mol% CO2, or no more than 10 mol% CO2, or no more than 5 mol% CO2, excluding CO2 not derived from methanol decomposition.

[0125] Embodiment 41. The method of any of Embodiments 1-40, wherein the second product stream has a hydrogen / carbon monoxide molar ratio in the range of 0.5:1 to 5:1, eg, 1:1 to 3:1, 1.5:1 to 2.5:1.

[0126] Embodiment 42. A method according to any of Embodiments 1-41, wherein the second product stream comprises no greater than 75 mol% methanol, e.g., no greater than 60 mol% methanol, or no greater than 50 mol% methanol, or no greater than 25 mol% methanol.

[0127] Embodiment 43. The method of any 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).

[0128] Embodiment 44. The method of Embodiment 43 further comprises recycling at least a portion of the methanol separated from the second product stream, for example 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.

[0129] Embodiment 45. The method of any of Embodiments 1-44, further comprising separating at least a portion of the H2 from the second product stream.

[0130] Embodiment 46. The method of Embodiment 45, further comprising supplying H2 separated from the second product stream to the first feed stream.

[0131] Embodiment 47. The method of any of Embodiments 1-46, wherein at least a portion of the CO2 of the first feed stream comes from a renewable source.

[0132] Embodiment 48. The method of any of Embodiments 1-47, wherein at least a portion of the CO2 of the first feed stream comes from direct air capture.

[0133] Embodiment 49. The method of any of Embodiments 1-48, 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 plant, or a cement plant.

[0134] Embodiment 50. The method of any of Embodiments 1-49, wherein at least a portion of the H2 of the first feed stream is from a renewable source.

[0135] Embodiment 51. The method of any of Embodiments 1-50, wherein at least a portion of the hydrogen in the first feed stream is green hydrogen.

[0136] Embodiment 52. The method of any of Embodiments 1-51, wherein at least a portion of the hydrogen in the first feed stream is blue hydrogen.

[0137] Embodiment 53. The method of any of Embodiments 1-52, wherein at least a portion of the hydrogen in the first feed stream is gray hydrogen, black hydrogen, brown hydrogen, pink hydrogen, blue-green hydrogen, yellow hydrogen and / or white hydrogen.

[0138] Embodiment 54. The method of any of Embodiments 1-53, further comprising providing at least a portion of the H2 to the first feed stream by electrolysis of water.

[0139] Embodiment 55. The method of Embodiment 54, wherein the electrolysis of water is performed using electricity derived at least in part from a renewable source.

[0140] Embodiment 56. The method of any of Embodiments 1-55, wherein the first reaction zone comprises a first reactor in which a hydrogenation catalyst is disposed, and the second reaction zone comprises a second reactor in which a methanol decomposition catalyst is disposed.

[0141] Embodiment 57. The method of any of Embodiments 1-56, wherein the first reaction zone comprises a first catalyst bed in which a hydrogenation catalyst is disposed, and wherein the second reaction zone comprises a second catalyst bed in which a methanol decomposition catalyst is disposed.

[0142] Embodiment 58. The method of any of Embodiment 57, wherein the first catalyst bed and the second catalyst bed are not intermixed.

[0143] 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.

[0144] Embodiment 60. The method of any of Embodiment 57, wherein the first catalyst bed and the second catalyst bed are arranged in the same reactor as a catalyst stack or bed section.

[0145] The details shown herein are provided as examples and only for the purpose of illustrative discussion of various embodiments of the present disclosure, and are given in order to provide the most useful and understandable description of the principles and concepts of various embodiments of the present disclosure. In this regard, no attempt is made to display the details related to the methods of the present disclosure to a level of detail necessary for a basic understanding of the methods described herein, and the descriptions made in conjunction with the examples make it clear to those skilled in the art how several forms of the methods of the present disclosure can be specifically implemented in practice. Therefore, before describing the disclosed methods and apparatus, it is to be understood that the aspects described herein are not limited to specific embodiments, apparatuses, or configurations, and therefore can certainly vary. It is also to be understood that the terms used herein are only for the purpose of describing specific aspects, and are not intended to be limiting unless specifically defined herein.

[0146] The terms “a” and “an” and “the” and similar referents used in the context of describing the methods of the present disclosure (especially in the context of the following embodiments and claims) should be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context.

[0147] Unless otherwise specified herein or clearly contradictory to the context, all methods described herein can be performed in any suitable order of steps. The use of any and all examples or exemplary wordings (e.g., "such as") provided herein is intended only to better illustrate the methods of the present disclosure rather than to impose limitations on the scope of the present disclosure. The wording in the specification should not be interpreted as indicating that any unclaimed element is essential to the practice of the methods of the present disclosure.

[0148] Unless the context clearly requires otherwise, throughout the specification and claims, the words "comprises" or "including" and the like should be interpreted in an inclusive sense rather than an exclusive or exhaustive sense; that is, in the sense of "including but not limited to". Words using the singular or plural number also include the plural and singular, respectively. In addition, when used in this application, the words "herein," "above," and "below," and words of similar meaning shall refer to this application as a whole and not to any particular portion of this application.

[0149] As will be understood by those of ordinary skill in the art, each embodiment disclosed herein may comprise, consist essentially of, or consist of its specific specified elements, steps, ingredients, or components. As used herein, the transitional terms "comprising" or "including" are meant to include, but are not limited to, and allow for the inclusion of unspecified elements, steps, ingredients, or components, even in major amounts. The transitional phrase "consisting of" does not include any unspecified elements, steps, ingredients, or components. 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 substantially affect the embodiment.

[0150] All percentages, ratios and proportions herein are by weight unless otherwise specified.

[0151] 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. Any numerical value, however, inherently contains various errors necessarily resulting from the standard deviation found in their respective testing measurements.

[0152] The grouping of alternative elements or embodiments of the present disclosure should not be construed as limiting. Each group member may be mentioned and claimed individually or in any combination with other members of the group or other elements found herein. It is estimated that one or more members in the group may join the group or delete from the group for convenience and / or patentability reasons. When any such addition or deletion occurs, this specification is considered to contain the modified group, so the written description of all Markush groups used in the appended claims is met.

[0153] Some embodiments of various aspects of the present disclosure are described herein, including the best mode known to the inventors for implementing the methods described herein. Of course, the changes to these described embodiments will be apparent to those of ordinary skill in the art after reading the above description. The technician will utilize such changes as appropriate, so the method of the present disclosure can be implemented differently from the specific description herein. Therefore, the scope of the present disclosure includes all modifications and equivalents of the subject items listed in the claims attached hereto as permitted by applicable law. In addition, unless otherwise specified herein or clearly contradictory to the context, the present disclosure covers any combination of the above-mentioned elements under all possible changes thereof.

[0154] As used herein, the phrase "at least a portion" is used to mean at least a desired fractional amount, up to a full possible amount.

[0155] Finally, it is to be understood that the various embodiments herein illustrate the method of the present disclosure. Other modifications that may be employed are within the scope of the present disclosure. Therefore, by way of example and not limitation, alternative configurations of the method may be utilized according to the teachings herein. Therefore, the method of the present disclosure is not limited to being exactly as shown and described.

Claims

1. A method for producing synthesis gas, the method comprising: Providing a first feed stream comprising 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 CO2 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; The second feed stream is contacted with a methanolysis catalyst (eg, in a methanolysis reaction zone) to decompose at least a portion of the methanol to form a second product stream comprising syngas (eg, comprising CO and H2).

2. The process of claim 1, wherein the first feed stream comprises at least 10 mol % H2, such as at least 20 mol % H2, or at least 30 mol % H2.

3. A process according to 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. A process according to any one of claims 1 to 3, wherein the ratio of H2:CO2 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.

5. A 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. The method of any one of claims 1-5, 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. The process 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 no greater than 10 mol%, eg, no greater than 2 mol% or no greater than 0.5 mol%.

8. The process 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 process of any one of claims 1 to 8, wherein the second feed stream has a water concentration of no greater than 5 mol%, eg, no greater than 2 mol% or no greater than 1 mol%.

10. A process according to any one of claims 1 to 9, wherein contacting the second feed stream with the methanol decomposition catalyst is carried out at a temperature within 75°C, such as within 50°C, of ​​the contacting temperature of the first feed stream with the hydrogenation catalyst.

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

12. A process according to any one of claims 1 to 11, wherein the decomposition of methanol is carried out with a selectivity to CO2 of not more than 20%, such as not more than 15%, not more than 10% or not more than 5%.

13. The process of any one of claims 1 to 12, wherein the second product stream comprises at least 20 mol% CO and H2 in total, such as at least 35 mol%, or at least 50 mol%, or at least 65 mol%.

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

1.

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

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