A catalytic process using ammonia as a hydrogen source for carbon dioxide conversion.

Abstract

Provided herein is a process for producing synthesis gas and / or hydrocarbons. The process comprises reacting ammonia and carbon dioxide in a single reactor in the presence of a catalyst.

Description

[Technical Field]

[0001] The present invention relates to a process (method) for producing one or more reaction products from ammonia and carbon dioxide, wherein the reaction products are selected from carbon monoxide, one or more C1-C3 hydrocarbons, and hydrogen. [Background technology]

[0002] Syngas (also known as synthesis gas) is a mixture of hydrogen and carbon monoxide, sometimes containing carbon dioxide and methane, which can exist in various proportions.

[0003] Syngas is industrially useful in the production of numerous important chemicals, including synthetic fuels, ammonia fertilizers, polymer monomers, and methanol. Furthermore, syngas is also used as an intermediate in hydrogen production via the water-gas shift reaction (1) described below. TIFF2026516199000002.tif15164

[0004] Current industrial methods for producing syngas include steam methane reforming or coal gasification, as shown in reactions (2) and (3) below. TIFF2026516199000003.tif29164

[0005] However, because these reactions are endothermic, process heating and exhaust gases generate large amounts of greenhouse gases, significantly contributing to the 1.5 gigatons of CO2 emissions in the chemical industry. Furthermore, synthetic fuels produced from syngas derived from fossil fuels result in even greater CO2 emissions. Therefore, there is a need to produce syngas and its downstream products from non-fossil fuel sources. The development of such processes will play a significant role in reducing future CO2 emissions.

[0006] There are two main methods for directly producing syngas from CO2, neither of which has reached commercial megatons / year scale and is net-zero. First, the reverse water-gas shift (RWGS) reaction reacts excess hydrogen with CO2 to produce carbon monoxide (CO) (reaction (4) below). The resulting CO is further mixed with hydrogen to obtain a composition suitable for downstream use (usually an H2 / CO ratio of 2-3), and the water is removed by condensation. In this case, if hydrogen cannot be obtained from a net-zero source (e.g., electrolysis using carbon-free electricity), net CO2 emissions still occur. Second, the dry reforming method reacts CO2 with CH4 to theoretically produce a 1:1 mixture of CO and H2 (reaction (5) below). This mixture is similarly mixed with added hydrogen. In this case, converting methane raw materials to CO results in net CO2 emissions from the downstream use of CO. TIFF2026516199000004.tif29164

[0007] Therefore, hydrogenating CO2 to form syngas is a potentially viable method for producing net-zero syngas (and downstream chemicals), insofar as hydrogen is obtained in a carbon-free manner. For example, "green" hydrogen can be obtained from the electrolysis of water driven by solar, wind, or nuclear energy. However, hydrogen is extremely difficult to store and has an extremely low density (0.0899 kg / m³) at standard conditions. 3 ) has liquid hydrogen (71 kg / m³ 3 Hydrogen has the drawbacks of high liquefaction costs and a boil-off rate of approximately 1% per day. Furthermore, its flammability and explosiveness raise safety concerns during storage and transport, increasing costs.

[0008] Ammonia is a promising liquid hydrogen carrier due to its high hydrogen density, high density when liquefied, and the ability to liquefy at relatively high temperatures (-33°C). Ammonia can be transported far more efficiently, easily, and safely than liquid hydrogen. Green ammonia can also be commercially obtained from multiple sources.

[0009] However, when used as a hydrogen carrier, ammonia must be broken down (cracked) to regenerate hydrogen, as shown in reaction (6) below. TIFF2026516199000005.tif15164

[0010] Current methods for decomposing ammonia are energy-intensive and uncost-effective due to their small scale and the high costs of purifying, storing, and transporting the resulting hydrogen. This is especially true for industries requiring high hydrogen purity, such as fuel cells. Even if the resulting hydrogen is used in reactions where nitrogen is inert, very large ammonia decomposition plants must be provided on-site for the production of relatively small amounts of hydrogen, which increases the on-site footprint and reduces economic viability compared to existing methane reforming (which is not green). Furthermore, since ammonia conversion and CO2 conversion occur under different process conditions (e.g., temperature and pressure) and are carried out using different catalysts, the use of ammonia as a hydrogen source for syngas preparation remains a costly multi-step process.

[0011] A simplified process is needed to address some or all of the problems associated with existing methods for producing syngas / hydrocarbons. [Overview of the project]

[0012] Despite concerns in the field regarding the purification and storage of hydrogen, the presence of nitrogen in the environment is not a problem in reactions (4) and (5) above. Therefore, in the production of syngas, ammonia can be decomposed to produce hydrogen and nitrogen, and the subsequent gas stream can be used directly in the production of syngas in reactions (4) and (5) above.

[0013] Remarkably, the inventors have found that this can be carried out as an integrated process in a single reactor using a single catalyst. Thus, depending on the catalyst, the present invention can convert ammonia (NH3) and carbon dioxide (CO2) into an outlet stream containing a syngas (containing carbon monoxide and hydrogen) and / or hydrocarbons such as methane. Examples of possible reactions are shown in reactions (7) and (8) below. TIFF2026516199000006.tif29164

[0014] Therefore, the present invention allows for the direct use of green ammonia as a liquefied hydrogen carrier in CO2 conversion, advantageously reducing the costs of individually regenerating, purifying, storing, and transporting hydrogen (H2) gas. Advantageously, this process can be used as a greener alternative to the production of syngas derived from fossils or hydrocarbons. The green syngas obtained by the present invention can be used for decarbonization of downstream chemical applications such as synthetic fuels and industrial chemicals, while green hydrocarbons can be used as a substitute for fossil fuels during the green fuel transition.

[0015] Therefore, the present invention provides the following embodiments. Appearance 1 A process for producing one or more reaction products, comprising the following steps: (i) supplying ammonia and carbon dioxide to a reactor containing a transition metal catalyst; and (ii) React ammonia and carbon dioxide in the presence of a transition metal catalyst to produce carbon monoxide, 1 or more C 1-3 Forming one or more reaction products selected from the group consisting of hydrocarbons and hydrogen. The process includes step (ii), which is carried out in a single reactor. Appearance 2 The process according to embodiment 1, wherein the transition metal catalyst comprises one or more transition metals from groups 8 to 11 of the periodic table. Appearance 3 The transition metal catalyst contains one or more transition metals selected from the group consisting of Co, Fe, Cu, Ni, Ru, and Pt, In some cases, the transition metal catalyst contains Co, in the process according to Embodiment 1 or 2. Embodiment 4 The transition metal catalyst is in the form of a solid metal catalyst, in the process according to any one of Embodiments 1 to 3. Embodiment 5 The transition metal catalyst is in the form of a solid metal catalyst supported on a solid support, in the process according to any one of Embodiments 1 to 4. Embodiment 6 The solid support contains one or more selected from the group consisting of silica, alumina, carbon, ceria, zirconia, gallium oxide, indium oxide, and magnesium oxide, Optionally, the solid support contains silica, in the process according to Embodiment 5. Embodiment 7 The transition metal catalyst is the following: (a) coprecipitation of a transition metal salt and a solid support precursor; and (b) calcination or reduction of the resulting product, obtained by a process including, optionally, the solid support contains silica and the solid support precursor contains tetraethyl orthosilicate, in the process according to any one of Embodiments 1 to 6. Embodiment 8 The transition metal catalyst contains 1 wt% to 70 wt% of a transition metal, in the process according to Embodiment 5, or in the process according to Embodiment 6 or 7 dependent on Embodiment 5. Embodiment 9 The molar ratio of ammonia:carbon dioxide is from about 0.67:1 to about 10:1, Optionally, it is from about 1:1 to about 4:1, in the process according to any one of Embodiments 1 to 8. Embodiment 10 Step (ii) is carried out at a temperature of about 250°C to about 1000°C, Optionally, it is carried out at about 300°C to about 700°C, and further optionally, it is carried out at about 400°C to about 650°C, for example at about 500°C to about 600°C, in the process according to any one of Embodiments 1 to 9. Appearance 11 Step (ii) is performed at a pressure of atmospheric pressure to approximately 3,000 kPa. The process described in embodiment 10, which may be carried out at atmospheric pressure ~ approximately 500 kPa depending on the circumstances. Appearance 12 (iii) Cool the product from step (ii) in a gas-liquid separator to remove carbon monoxide, 1 or more C 1-3 The method further includes obtaining a gas stream containing one or more hydrocarbons and hydrogen, The process according to any one of embodiments 1 to 11, wherein, in some cases, the gas stream is subjected to a separation process to remove at least a portion of the gaseous nitrogen present in the gas stream. Appearance 13 The process according to embodiment 12, wherein step (iii) is carried out at a temperature of approximately 1°C to approximately 40°C, and optionally at approximately 10°C to approximately 30°C, for example, at approximately 25°C. Appearance 14 Step (iii) also provides a liquid stream containing one or more of ammonium carbonate, ammonium bicarbonate, and ammonium carbamate. (iv) Regenerate ammonia and carbon dioxide by passing a liquid stream containing one or more of ammonium carbonate, ammonium bicarbonate, and ammonium carbamate through an evaporator. The process according to embodiment 12 or 13, further comprising the above. Appearance 15 Step (iv) is carried out at a temperature of approximately 40°C to approximately 80°C, for example, at approximately 60°C, according to the process according to embodiment 14. Appearance 16 The process according to any one of embodiments 1 to 15, wherein step (ii) is carried out in an atmosphere containing less than 1 volume% of O2, optionally in an atmosphere containing less than 0.1 volume% of O2, and further optionally in an atmosphere containing less than 0.01 volume% of O2. Appearance 17 The following preliminary steps: (A) Obtaining a gas stream containing carbon dioxide from a carbon capture process or a liquid carbon dioxide source; and (B) Obtaining a gas stream containing ammonia from a liquid ammonia source. A process according to any one of embodiments 1 to 16, which includes one or both of the above. Appearance 18 The process according to any one of embodiments 1 to 17, wherein step (ii) is carried out in a reactor heated by a source selected from fuel (e.g., natural gas or ammonia), electric heating or waste heat. Appearance 19 1 or more C 1-3 The hydrocarbons consist of one or more selected from the group consisting of methane, ethane, ethene, and propane. Depending on the case, 1 or more C 1-3 The process according to any one of embodiments 1 to 18, wherein the hydrocarbon includes methane. Appearance 20 1 or more C 1-3 Hydrocarbons include methane; A transition metal catalyst is a solid metal catalyst supported on a solid support, comprising one or more transition metals selected from the group consisting of Co, Fe, Cu, Ni, Ru, and Pt; also, Step (ii) is performed at a temperature of approximately 300°C to approximately 700°C. The process described in any one of embodiments 1 to 19. Appearance 21 The process then proceeds to the following steps: (iii) Cool the product from step (ii) in a gas-liquid separator to remove carbon monoxide, 1 or more C 1-3 To provide a gas stream containing one or more hydrocarbons and hydrogen, and a liquid stream containing one or more ammonium carbonate, ammonium bicarbonate, and ammonium carbamate; and, (iv) Regenerate ammonia and carbon dioxide by passing a liquid stream containing one or more of ammonium carbonate, ammonium bicarbonate, and ammonium carbamate through an evaporator. The process according to embodiment 20, which includes, optionally, step (iii) subjecting the gas stream to a separation process to remove at least a portion of the gaseous nitrogen present in the gas stream. Appearance 22 The transition metal catalyst contains 0.1% to 20% by weight of alkali metals. Although optional, the alkali metal is selected from one or more of the group consisting of lithium, sodium, potassium, and rubidium. The process according to any one of embodiments 1 to 21, wherein the alkali metal is optionally selected from one or more of the group consisting of sodium and potassium. Appearance 23 An apparatus for carrying out the process described in any one of embodiments 1 to 22, (a) Carbon dioxide storage tanks for storing carbon dioxide in liquid form; (b) Ammonia storage tanks for storing ammonia in liquid form; (c) A packed-bed catalytic reactor comprising a transition metal catalyst in the form of a solid metal supported on a solid carrier, suitable for converting carbon dioxide and ammonia into one or more carbon monoxide and methane; (d) A thermal energy source for heating a packed-bed catalytic reactor; (e) gas-liquid separator; and (f) Evaporator, A device including a device. [Brief explanation of the drawing]

[0016] [Figure 1] This shows the steps involved in the production of green cinnamon. [Figure 2] This shows the NH3 decomposition (cracking) performance of various catalysts. [Figure 3] The results of long-term tests exceeding 340 hours using a Co@SiO2 catalyst are shown. [Figure 4] The thermogravimetric analysis (TGA) of the used Co@SiO2 catalyst is shown. [Figure 5]The X-ray diffraction results of urea, ammonium carbamate, ammonium carbonate, ammonium bicarbonate, and the solid obtained using the process of the present invention are shown.

[0017] Detailed Description of the Invention The present invention provides a process for producing one or more reaction products, the process comprising the following: (i) Supplying ammonia and carbon dioxide to a reactor containing a transition metal catalyst; and (ii) Reacting ammonia and carbon dioxide in the presence of the transition metal catalyst to form one or more reaction products selected from the group consisting of carbon monoxide, one or more C 1-3 hydrocarbons, and hydrogen. Step (ii) is carried out in a single reactor.

[0018] As used herein, the term "ammonia" may be used interchangeably with its chemical formula "NH3". Similarly, the term "carbon dioxide" may be used interchangeably with its chemical formula "CO2", and the term "carbon monoxide" may be used interchangeably with its chemical formula "CO". The chemical formula "H2" may be used, for example, to indicate molecular hydrogen such as gaseous hydrogen.

[0019] The present invention also provides an apparatus for carrying out the process according to the present invention, the apparatus comprising: (a) A carbon dioxide storage tank for storing carbon dioxide in a liquid state; (b) An ammonia storage tank for storing ammonia in a liquid state; (c) A packed bed catalytic reactor containing a transition metal catalyst in the form of a solid metal provided on a solid support, the packed bed catalytic reactor being suitable for converting carbon dioxide and ammonia into one or more of carbon monoxide and methane; (d) A heat energy source for heating the packed bed catalytic reactor; (e) A gas-liquid separator; and (f) An evaporator.

[0020] In the embodiments herein, the term “comprising” may be interpreted as requiring the described features, but not as limiting the presence of other features. Alternatively, the term “comprising” may also be relevant when it is intended that only the described components / features exist (for example, the term “comprising” can be replaced with the phrases “consists of” or “consists essentially of”). In all aspects and embodiments of the present invention, it is explicitly intended that both broad and narrow interpretations may apply. In other words, “comprising” and its synonyms can be replaced with the phrases “consists of” or “consists essentially of” or their synonyms, and vice versa.

[0021] As used herein, the phrase "consists essentially of" and its synonyms may be interpreted as referring to a material that may contain trace amounts of impurities. For example, the material may have a purity of 90% or more, e.g., more than 95%, e.g., more than 97%, e.g., more than 99%, e.g., more than 99.9%, e.g., more than 99.99%, e.g., more than 99.999%, or e.g., 100%.

[0022] In this specification, the singular forms "a," "an," and "the" refer to multiple objects unless the context clearly indicates otherwise. Therefore, for example, the phrase "a composition" refers to a mixture of two or more such compositions, and the phrase "a metal" refers to a mixture of two or more such metals, etc.

[0023] One or more reaction products produced by the process of the present invention are carbon monoxide, one or more C10 1-3 The reaction products are selected from the group consisting of hydrocarbons and hydrogen. As those skilled in the art will understand, the composition ratio of the reaction products can be changed by altering the process conditions (e.g., catalyst, temperature, ammonia:carbon dioxide ratio). Thus, the process of the present invention can be used to produce syngas, one or more hydrocarbons (e.g., methane), or both syngas and hydrocarbons. In this context, those skilled in the art will understand that the description herein relating to the production of syngas refers to the production of a gas containing both carbon monoxide and hydrogen, but may also include hydrocarbons such as methane.

[0024] The process of the present invention involves 1 or more C 1-3 Hydrocarbons can be produced. As those skilled in the art will understand, depending on the reaction conditions, one or more hydrocarbons selected from the group consisting of methane, ethane, ethene, and propane can be produced. In specific embodiments of the present invention that may be referred to herein, one or more C 1-3 Hydrocarbons may include methane.

[0025] The present invention includes the step of supplying ammonia and carbon dioxide to a reactor containing a transition metal catalyst. The ammonia and carbon dioxide may be supplied to the reactor as a single mixed stream or as two separate streams. Since both gases may be mixed in the reactor, it is not a concern whether they are mixed before being introduced into the reactor. The molar ratio of ammonia to carbon dioxide can be adjusted as needed and is not particularly limited. In some embodiments of the present invention that may be referred to herein, the ammonia:carbon dioxide molar ratio may be from about 0.67:1 to about 10:1, for example, from about 1:1 to about 4:1.

[0026] To avoid any doubt, the ammonia and carbon dioxide used in the process of the present invention may or may not be obtained from “green” renewable or environmentally friendly sources. The origin of these gases is not important to the process of the present invention, and the process of the present invention can be carried out using ammonia and carbon dioxide obtained from any source. Nevertheless, one of the advantages of the present invention is that syngas and / or hydrocarbons can be produced from green sources.

[0027] As used herein, the term "about" may mean that a value may vary by up to 20% from the stated quantity. For example, a value may vary by up to 20%, 18%, 15%, 13%, 10%, 9%, 8%, 7%, 6%, or 5%.

[0028] Subsequently, the present invention reacts ammonia and carbon dioxide in the presence of a transition metal catalyst to produce carbon monoxide, 1 or more C 1-3 The process includes forming one or more reaction products selected from the group consisting of hydrocarbons and hydrogen (i.e., syngas and / or hydrocarbons). This step will be described in more detail below.

[0029] NH3 and CO2 gases may be mixed in a heated reactor (e.g., a packed-bed reactor) containing a solid powder catalyst with one or more transition metals. The one or more transition metals may or may not be supported on one or more inert catalyst supports. At high temperatures, the catalyst decomposes NH3 to produce hydrogen gas, which reacts with CO2 to form syngas and / or hydrocarbons, with water and nitrogen as byproducts. The water can be condensed, and unreacted ammonia and carbon dioxide can be collected and recycled in aqueous solutions as ammonium carbonate / ammonium bicarbonate or ammonium carbamate. Trace amounts of ammonia can be removed by adsorption, resulting in a high-purity exhaust gas stream. By adjusting the catalyst and reaction conditions, high selectivity for either syngas or methane can be obtained.

[0030] By combining CO2 and NH3 as direct feedstocks for a syngas / metany reactor with catalysts and process conditions suitable for syngas or methane production, the following characteristics and advantages can be obtained. (a) By combining the decomposition of NH3 and the hydrogenation of CO2 in a single integrated reactor, syngas and methane can be produced, improving cost and process efficiency. In a conventional two-reactor series system, NH3 is decomposed into H2 in one reactor, and in between, costly H2 purification and storage processes are carried out. Then, in the other reactor, CO2 and H2 are reacted to produce syngas and methane. Therefore, according to the present invention, the equipment and operating costs of one reactor, as well as the intermediate costs related to H2 purification and storage, can be saved (compared to a two-reactor configuration). (b) In this process, NH3 is used as the reducing agent instead of H2, and since NH3 can be liquefied much more easily than H2, the energy density of the raw materials is higher, and more efficient storage is possible. (c) The use of NH3 in this process results in NO x It does not generate (zero NO x For comparison, if turbine power generation is performed using NH3, and that electricity is used to drive a turbine for hydrogen production by electrolysis or direct electrochemical CO2 reduction, a considerable amount of NO is released. x There is a risk of pollutants being generated. (d) A simple separation / purification process to facilitate the removal and recycling of unreacted NH3 and CO2. When the two processes of NH3 decomposition and CO2 hydrogenation are carried out separately, the H2 derived from NH3 needs to be purified by pressure swing adsorption, and the unreacted CO2 also needs to be purified by amine adsorption. However, in the present invention, both unreacted NH3 and CO2 are automatically collected as ammonium bicarbonate in the water stream of the discharged liquid phase. (e) The catalyst enables a new production pathway for useful chemicals from NH3 and CO2. Existing technologies for reacting both NH3 and CO2 are non-catalytic and only produce urea under high temperature and pressure. Instead, the present invention uses a catalyst to produce syngas and methane.

[0031] Figure 1 shows the steps involved in the green preparation of syngas / methane from ammonia and carbon dioxide. • CO2 supply may be obtained from CO2 capture as gas (a). Meanwhile, ammonia (b) may be stored in liquid form and regasified before entering the reactor (c). The catalyst used in (c) may be in the form of a solid powder or pellets. Reactors are typically powered by heat, and the heat source is flexible. Examples include fuels such as natural gas or ammonia, electric heating, or waste heat. The discharged high-temperature gas may be cooled in a gas-liquid separator (d), which removes the generated water and unreacted CO2 and NH3 as aqueous ammonium carbonate / aqueous ammonium bicarbonate. Thus, the exhaust gas consists of gases selected from CO, H2, CH4, inert N2 and CO2, and trace amounts of NH3, which can be used directly in downstream applications or further purified if necessary. The ammonium carbonate aqueous solution may pass through evaporator (e) to release NH3 and CO2 gases, which can be returned to the reactor feed system for recycling, while the wastewater can be discarded.

[0032] The process of the present invention uses a transition metal catalyst. In some embodiments of the present invention that may be referenced herein, the transition metal catalyst may comprise one or more transition metals from groups 8 to 11 of the periodic table. For example, the transition metal catalyst may comprise one or more transition metals selected from the group consisting of Co, Fe, Cu, Ni, Ru, and Pt. In a particular embodiment of the present invention, the transition metal catalyst may comprise Co.

[0033] In some embodiments of the present invention that may be referenced herein, the transition metal catalyst may be provided in the form of a solid metal catalyst, i.e., in the form of the metal itself with an oxidation state of 0. As those skilled in the art will understand, catalysts are usually provided in the form of a powder, pellet or high-surface-area supported form to maximize the surface area available for the reaction to occur.

[0034] Accordingly, in some embodiments of the present invention that may be referenced herein, the transition metal catalyst may be in the form of a solid metal catalyst supplied on a solid support. A suitable solid support comprises any material known to function as an inert catalyst support under the reaction conditions of the process of the present invention. Accordingly, in some embodiments that may be referenced herein, the solid support may comprise one or more of the group consisting of silica, alumina, carbon, ceria, zirconia, gallium oxide, indium oxide, and magnesium oxide. In certain embodiments, the solid support may comprise silica. Typically, the transition metal catalyst may be in the form of a powder. In some embodiments, the catalyst may be, for example, about 50 to about 400 m 2 It may have a surface area in the range of / g.

[0035] The transition metal catalyst can be obtained by a process that includes the following: (a) Coprecipitation of transition metal salts and solid support precursors; and (b) Calcination or reduction of the product obtained.

[0036] In some embodiments of the present invention, the product obtained from step (a) or (b) may be ground into a powder. Thus, in some embodiments of the present invention, the transition metal catalyst of the present invention may be in powder form. The transition metal catalyst contains a transition metal present in a solid support matrix.

[0037] If the solid support contains silica, the solid support precursor may contain tetraethyl orthosilicate.

[0038] If the transition metal catalyst includes a solid support, the transition metal catalyst may contain either an appropriate amount of the transition metal and either an appropriate amount of the solid support. For example, in some embodiments of the present invention that may be referenced herein, the transition metal catalyst may contain 1% to 70% by weight of the transition metal.

[0039] The transition metal catalyst may further contain one or more alkali metals. While not bound by theory, the inclusion of alkali metals is thought to contribute to an increase in the amount of CO2, an acidic gas, adsorbed onto the catalyst surface during the process of the present invention. Accordingly, in some embodiments of the present invention that may be referred to herein, the transition metal catalyst may contain 0.1% to 20% by weight of alkali metals. Suitable alkali metals that may be referred to herein include lithium, sodium, potassium, and rubidium (e.g., sodium and potassium).

[0040] Step (ii) of the process of the present invention may be carried out at any suitable temperature. For example, in some embodiments of the present invention that may be referenced herein, step (ii) may be carried out at a temperature of about 250°C to about 1000°C. In further embodiments of the present invention that may be referenced herein, step (ii) may be carried out at a temperature of about 300°C to about 700°C. In further embodiments of the present invention that may be referenced herein, step (ii) may be carried out at a temperature of about 400°C to about 650°C. In further embodiments of the present invention that may be referenced herein, step (ii) may be carried out at a temperature of about 500°C to about 600°C.

[0041] To avoid misunderstanding, any endpoint of any range mentioned herein may be combined with any endpoint of any other range with respect to the same variable. Therefore, the following ranges are explicitly assumed in this specification for the above temperatures. Approximately 250°C to 300°C, approximately 250°C to 400°C, approximately 250°C to 500°C, approximately 250°C to 600°C, approximately 250°C to 700°C, approximately 250°C to 1000°C; Approximately 300°C to 400°C, approximately 300°C to 500°C, approximately 300°C to 600°C, approximately 300°C to 700°C, approximately 300°C to 1000°C; Approximately 400°C to 500°C, approximately 400°C to 600°C, approximately 400°C to 700°C, approximately 400°C to 1000°C; Approximately 500°C to 600°C, approximately 500°C to 700°C, approximately 500°C to 1000°C; Approximately 600°C to approximately 700°C, approximately 600°C to approximately 1000°C; and Approximately 700°C to 1000°C.

[0042] Step (ii) of the process of the present invention may be carried out at any suitable pressure. For example, in some embodiments of the present invention that may be referenced herein, step (ii) can be carried out at a pressure of atmospheric pressure to about 3,000 kPa. In further embodiments of the present invention that may be referenced herein, step (ii) can be carried out at a pressure of atmospheric pressure to about 500 kPa.

[0043] The process of the present invention may further include the following: (iii) Cool the product discharged from step (ii) in a gas-liquid separator, and remove carbon monoxide, 1 or more C 1-3 To provide a gas stream containing one or more hydrocarbons and hydrogen.

[0044] This cooling step (iii) may be carried out at any suitable temperature. For example, in some embodiments of the invention as referenced herein, step (iii) may be carried out at a temperature of about 1°C to about 40°C. In further embodiments of the invention as referenced herein, step (iii) may be carried out at a temperature of about 10°C to about 30°C. In further embodiments of the invention as referenced herein, step (iii) may be carried out at a temperature of about 25°C.

[0045] The gas stream obtained from step (iii) may be further subjected to a separation process to remove at least a portion of all gaseous nitrogen that may be present in the gas stream.

[0046] The cooling step (iii) may also provide a stream of liquid (e.g., aqueous) containing one or more of ammonium carbonate, ammonium bicarbonate, and ammonium carbamate. Thus, the process of the present invention may further include: (iv) Pass a liquid stream containing one or more of ammonium carbonate, ammonium bicarbonate, and ammonium carbamate through the evaporator to regenerate ammonia and carbon dioxide.

[0047] The evaporation step (iv) may be carried out at any suitable temperature. For example, in some embodiments of the invention that may be referenced herein, step (iv) may be carried out at a temperature of about 40°C to about 80°C, for example, about 60°C. As those skilled in the art will understand, in order to increase the evaporation rate of the liquid (e.g., water) in step (iv), this step may be carried out under reduced pressure.

[0048] As those skilled in the art will understand, step (ii) may be advantageously carried out in an atmosphere with reduced oxygen content, for example, under anaerobic conditions. This improves the lifetime and efficiency of the catalyst and, otherwise, minimizes the amount of nitrogen oxides that may be produced at the temperature and pressure of the reaction. Accordingly, in some embodiments that may be referenced herein, step (ii) may be carried out in an atmosphere with less than 1 vol.% O2. In further embodiments of the present invention that may be referenced herein, step (ii) may be carried out in an atmosphere with less than 0.1 vol.% O2. In further embodiments that may be referenced herein, step (ii) may be carried out in an atmosphere with less than 0.01 vol.% O2.

[0049] As described herein, the process of the present invention is advantageous in that it provides a green (i.e., environmentally friendly) process for preparing syngas and / or hydrocarbons. Accordingly, the process may include a precursor (or pre-step) step of obtaining carbon dioxide from a carbon capture (or capture) process. Alternatively, it may be preferable, though not essential, to use a liquid carbon dioxide feedstock, which may be obtained by a carbon capture process.

[0050] Accordingly, in some embodiments of the present invention that may be referenced herein, the process may include the following preliminary steps: (A) Obtain a gas stream containing carbon dioxide from a carbon capture process or a liquid carbon dioxide source.

[0051] This process may also include a preliminary step of obtaining a gaseous ammonia stream from a liquid ammonia source. Therefore, in some embodiments referred to herein, this process may include the following preliminary steps: (B) Obtain a gas stream containing ammonia from a liquid ammonia source.

[0052] As described herein, the reaction process may be carried out by raising the temperature inside a reactor (e.g., inside a packed-bed reactor). Thus, in some embodiments that may be referenced herein, step (ii) can be carried out inside a reactor heated by a source selected from fuel (e.g., natural gas or ammonia), electric heating or waste heat.

[0053] In certain embodiments of the present invention as referred to herein: 1 or more C 1-3 Hydrocarbons may include methane if present; The transition metal catalyst may include one or more transition metals selected from the group consisting of Co, Fe, Cu, Ni, Ru, and Pt in the form of a solid metal catalyst supplied on a solid support; and Step (ii) may be carried out at a temperature of approximately 300°C to approximately 700°C.

[0054] In a particular example of this embodiment, the present invention may include the following steps: (iii) Cool the product discharged from step (ii) in a gas-liquid separator to remove carbon monoxide, 1 or more C 1-3 A step of providing a gas stream containing one or more hydrocarbons and hydrogen, and a liquid stream containing one or more ammonium carbonate, ammonium bicarbonate, and ammonium carbamate; and (iv) A step of regenerating ammonia and carbon dioxide by passing a liquid stream containing one or more of ammonium carbonate, ammonium bicarbonate, and ammonium carbamate through an evaporator.

[0055] In a particular example of this particular embodiment, step (iii) may include subjecting the gas stream to a separation process in order to remove at least a portion of all gaseous nitrogen present in the gas stream.

[0056] As described herein, the present invention also provides an apparatus for carrying out the process according to the present invention, the apparatus including: (a) Carbon dioxide storage tanks for storing carbon dioxide in liquid form; (b) Ammonia storage tanks for storing ammonia in liquid form; (c) A packed-bed catalytic reactor comprising a transition metal catalyst in the form of a solid metal supplied on a solid support, suitable for converting carbon dioxide and ammonia into one or more carbon monoxide and methane; (d) A thermal energy source for heating a packed-bed catalytic reactor; (e) gas-liquid separator; and (f) Evaporator.

[0057] Components (a) to (f) may be any suitable components known to those skilled in the art and conforming to the above disclosure.

[0058] Examples Source of raw materials Co / Fe / Cu / Ni containing catalyst: Copper(II) nitrate hemi(pentahydrate), Cu(NO3)2·2.5H2O, >98%), Alfa Aesar Nickel(II) nitrate hexahydrate, Ni(NO3)2·6H2O, >98%, Alfa Aesar Iron(III) nitrate nonahydrate (Fe(NO3)3·9H2O, >98%), Sigma-Aldrich Co. Ltd. Cobalt(II) nitrate hexahydrate, Co(NO3)2·6H2O, >98%), Sigma-Aldrich Co. Ltd. Cetrimonium chloride 25 wt.% (in water) (CTAC, Sigma-Aldrich Co. Ltd.) Sodium hydroxide pellets for analysis (NaOH, >99.9%), Merck KGaA Tetraethyl orthosilicate (TEOS, Si(OC2H5)4, >98%), Alfa Aesar Anhydrous ethanol (Ethanol absolute), EtOH, analytical reagent (C2H5OH, >99.8%), VWR BDH chemical

[0059] Ru and Pt-containing catalysts: Ruthenium(III) chloride hydrate (RuCl3·xH2O, >99.8%), Sigma-Aldrich Co. Ltd. Chloroplatinic acid hexahydrate, H2PtCl6·6H2O, Pt standard >37.5%), Sigma-Aldrich Co. Ltd. Sodium hydroxide pellets for analysis (NaOH, >99.9%), Merck KGaA Ethylene glycol (C2H6O2, anhydrous, 99.8%), Sigma-Aldrich Co. Ltd. Anhydrous ethanol (Ethanol absolute, EtOH, C2H5OH, >99.8%), VWR BDH chemical Hexadecyltrimethylammonium chloride (in water) (25 wt.% in H2O, CTACl), Sigma-Aldrich Co. Ltd. Triethanolamine (TEA, N(CH2CH2OH)3, analytical grade GR, >99.9%), Merck KGaA Tetraethyl orthosilicate (TEOS, Si(OC2H5)4, >98%), Alfa Aesar

[0060] Preparation example: Catalyst synthesis Metal-doped silica-supported catalysts are prepared by coprecipitation, and all synthesis can be scaled up simply by increasing the amount of reagents used. The notation "M@SiO2" is used to refer to the developed catalyst supported on SiO2, where M is the metal used.

[0061] Typically, for Co / Fe / Cu / Ni metals, 50 wt% of the precursor nitrate (based on the metal oxides CuO, Fe2O3, Co3O4, and NiO), i.e., 6.1 g of Cu(NO3)2·2.5H2O (hemi pentahydrate), 10.3 g of Fe(NO3)3·9H2O, 7.42 g of Co(NO3)2·6H2O, or 7.8 g of Ni(NO3)2·6H2O, is dissolved in a mixture of 3.51 mL of 25% CTAC (cetrimonium chloride) in 400 mL of water. Then, 80 mL of 1.25 M NaOH solution is added and the mixture is stirred for several hours. The precipitate is collected by centrifugation, redispersed in 320 mL of water, and the pH is adjusted to above 12 using NaOH solution. Then, a mixture of 7.6 mL of TEOS (tetraethyl orthosilicate) and 80 mL of ethanol is added dropwise, and the resulting mixture is stirred for 48 hours. The final solid is separated by centrifugation, dried overnight at 80°C, and calcined in still air at 500°C for 2 hours.

[0062] For Ru and Pt metals, 2 wt% of the precursor RuCl3·xH2O (0.2 g) or H2PtCl6·6H2O (0.5 g) is added to a mixture of 0.4 mL of NaOH and 100 mL of ethylene glycol. The solution is heated to 80°C and held for 30 minutes to completely dissolve, then heated under reflux at 160°C for 3 hours, and cooled to room temperature to form a colloidal suspension. Next, 75 mL of this colloidal suspension is added to a mixture of 195 mL of water, 15 mL of ethanol, 30 mL of 25% CTACl, and 7.5 mL of triethanolamine. Then, 7.5 mL of TEOS is added dropwise with stirring, and the mixture is heated at 60°C for 2 hours. The final solid is centrifuged, washed with ethanol, dried overnight at 80°C, and calcined in N2 at 400°C for 6 hours.

[0063] General Method 1: Catalytic Process Conditions In a typical single-pass (i.e., non-recycle) reaction operation, CO2 and NH3 gases are supplied via a mass flowmeter to a 0.25-inch stainless steel (SS316) tube packed with 200 mg of catalyst, and heated in an electric furnace. The catalyst is first reduced by flowing pure H2 at 20 mL / min for 2 hours at 250–600°C (metal-dependent). The temperature is then adjusted to a reaction temperature of 600°C, first under a flow of NH3, and then under a flow of CO2. An NH3 / CO2 ratio of 1–4 is used (NH3 flow rate of 20–80 mL / min). An inert gas such as argon may be added to measure the reaction conversion rate and product yield. In a single-pass configuration, aqueous ammonium carbonate is collected in a glass condenser, while the exhausted gas can be analyzed in a gas chromatograph equipped with a thermal conductivity detector (TCD) and Porapak Q and MolSieve 5A columns (with appropriate valve switching to allow both NH3 and CO2 to bypass the MolSieve 5A column).

[0064] Driving example Catalytic performance: Decomposition of ammonia To confirm the monofunctional activity of the catalyst, the single-pass catalytic performance in the case of decomposition of pure NH3 (i.e., CO2 / NH3=0) was first tested at various temperatures using the steps described in General Method 1, and the results are shown in Figure 2.

[0065] Catalytic performance: Syngas / hydrocarbon production Next, the single-pass catalytic performance of various catalysts was tested for the NH3-CO2 reaction, and the results are summarized in Table 1 below (General Method 1, 200 mg of catalyst, Ar:NH3 = 10:20 mL / min flow rate ratio, 20 hours time-on-stream).

[0066] [Table 1]

[0067] Furthermore, long-term single-pass experiments exceeding 340 hours using the Co@SiO2 catalyst demonstrated high stability and excellent performance over extended periods, as shown in Table 2 and Figure 3 below. This catalyst was selected because it possessed a good balance of high NH3 conversion rate, CO2 conversion rate, and CO selectivity. The highest CO yield achieved was 72.8%, and the highest NH3 conversion rate was 93.3%. At a flow rate of NH3:CO2 = 40:20 mL / min, this performance corresponds to the production of 77.7 L / day of syngas with an H2 / CO ratio of 2.7 (or an H2 / [CO+CO2] ratio of 2).

[0068] [Table 2]

[0069] Furthermore, since all reactions were carried out anaerobically (i.e., without oxygen), NO was produced in all of the reactions. x It was not detected.

[0070] Thermogravimetric analysis (TGA) of the spent Co@SiO2 catalyst showed no carbon deposits on the catalyst. The only changes observed were a 0.5% mass loss below 200°C, which is thought to be due to the desorption of adsorbed water, and a 12.9% mass increase around 350–500°C, which is thought to be due to the reoxidation of Co metal to an oxide. The results are shown in Figure 4.

[0071] Recovery of ammonium carbonate / ammonium carbamate for recycling Depending on whether water was present or not, different white powders could be recovered from the reactor outlet via a gas-liquid separator after cooling and drying. Powder identification was performed by X-ray diffraction (XRD) analysis, confirming that ammonium bicarbonate (possibly in equilibrium with ammonium carbonate) was recovered in the presence of water, while in the absence of water, the solid was mainly ammonium carbonate (Figure 5).

[0072] Although not bound by theory, it is thought that small amounts of ammonium carbamate are also present, and that ammonium carbonate, ammonium bicarbonate, and ammonium carbamate are each in equilibrium with each other in solid or aqueous solution.

[0073] The recyclability of ammonia and carbon dioxide from the gas-liquid separator was confirmed by heating the aqueous condensate in the reactor to 60°C. At this temperature, aqueous ammonium ions and carbonate / bicarbonate ions completely decomposed, releasing NH3 and CO2 gases, leaving water behind.

Claims

1. A process for producing one or more reaction products, comprising the following steps: (i) supplying ammonia and carbon dioxide to a reactor containing a transition metal catalyst; and (ii) React ammonia and carbon dioxide in the presence of a transition metal catalyst to produce carbon monoxide, 1 or more C １－３ Forming one or more reaction products selected from the group consisting of hydrocarbons and hydrogen. The process includes step (ii), which is carried out in a single reactor.

2. The process according to claim 1, wherein the transition metal catalyst comprises one or more transition metals from groups 8 to 11 of the periodic table.

3. The transition metal catalyst comprises one or more transition metals selected from the group consisting of Co, Fe, Cu, Ni, Ru, and Pt. The process according to claim 1 or 2, wherein the transition metal catalyst optionally includes Co.

4. The process according to any one of claims 1 to 3, wherein the transition metal catalyst is in the form of a solid metal catalyst.

5. The process according to any one of claims 1 to 4, wherein the transition metal catalyst is in the form of a solid metal catalyst supported on a solid support.

6. The solid support comprises one or more selected from the group consisting of silica, alumina, carbon, ceria, zirconia, gallium oxide, indium oxide, and magnesium oxide. The process according to claim 5, wherein the solid support optionally includes silica.

7. Transition metal catalysts have the following characteristics: (a) Coprecipitation of transition metal salts and solid support precursors; and (b) Calcination or reduction of the product obtained The process according to any one of claims 1 to 6, wherein the process is obtained by a process comprising, optionally, the solid support comprising silica and the solid support precursor comprising tetraethyl orthosilicate.

8. The transition metal catalyst comprises 1% to 70% by weight of a transition metal, the process according to claim 5, or the process according to claim 6 or 7 dependent on claim 5.

9. The molar ratio of ammonia to carbon dioxide is approximately 0.67:1 to approximately 10:

1. The process according to any one of claims 1 to 8, wherein the ratio is, depending on the circumstances, approximately 1:1 to approximately 4:

1.

10. Step (ii) is performed at a temperature of approximately 250°C to approximately 1000°C. The process according to any one of claims 1 to 9, which may be carried out at approximately 300°C to approximately 700°C, and may be carried out at approximately 400°C to approximately 650°C, for example, at approximately 500°C to approximately 600°C.

11. Step (ii) is performed at a pressure ranging from atmospheric pressure to approximately 3,000 kPa. The process according to claim 10, which may be carried out at atmospheric pressure to approximately 500 kPa depending on the circumstances.

12. (iii) The product from step (ii) is cooled in a gas-liquid separator to remove carbon monoxide, 1 or more C １－３ The method further includes obtaining a gas stream containing one or more hydrocarbons and hydrogen, The process according to any one of claims 1 to 11, wherein, in some cases, the gas stream is subjected to a separation process to remove at least a portion of the gaseous nitrogen present in the gas stream.

13. The process according to claim 12, wherein step (iii) is carried out at a temperature of about 1°C to about 40°C, and optionally at about 10°C to about 30°C, for example at about 25°C.

14. Step (iii) also provides a liquid stream containing one or more of ammonium carbonate, ammonium bicarbonate, and ammonium carbamate. (iv) Regenerating ammonia and carbon dioxide by passing a liquid stream containing one or more of ammonium carbonate, ammonium bicarbonate, and ammonium carbamate through an evaporator. The process according to claim 12 or 13, further comprising:

15. The process according to claim 14, wherein step (iv) is carried out at a temperature of about 40°C to about 80°C, for example, at about 60°C.

16. Step (ii) is less than 1 volume% ２ The process is carried out in an atmosphere containing, and in some cases, less than 0.1 volume% of O ２ The process is carried out in an atmosphere containing, and in some cases, less than 0.01 volume% of O ２ The process according to any one of claims 1 to 15, carried out in an atmosphere containing

17. The following preliminary steps: (A) Obtaining a gas stream containing carbon dioxide from a carbon capture process or a liquid carbon dioxide source; and (B) Obtaining a gas stream containing ammonia from a liquid ammonia source. The process according to any one of claims 1 to 16, comprising one or both of the above.

18. The process according to any one of claims 1 to 17, wherein step (ii) is carried out in a reactor heated by a source selected from fuel (e.g., natural gas or ammonia), electric heating or waste heat.

19. 1 or more C １－３ The hydrocarbon comprises one or more selected from the group consisting of methane, ethane, ethene, and propane. Depending on the case, 1 or more C １－３ The process according to any one of claims 1 to 18, wherein the hydrocarbon includes methane.

20. 1 or more C １－３ Hydrocarbons include methane; The transition metal catalyst is in the form of a solid metal catalyst supported on a solid support and comprises one or more transition metals selected from the group consisting of Co, Fe, Cu, Ni, Ru, and Pt; also, Step (ii) is performed at a temperature of approximately 300°C to approximately 700°C. The process according to any one of claims 1 to 19.

21. The process then proceeds to the following steps: (iii) Cooling the product from step (ii) in a gas-liquid separator to provide a gas stream containing carbon monoxide, one or more C １－３ hydrocarbons and one or more of hydrogen, and a liquid stream containing one or more of ammonium carbonate, ammonium bicarbonate and ammonium carbamate; and, (iv) Regenerating ammonia and carbon dioxide by passing a liquid stream containing one or more of ammonium carbonate, ammonium bicarbonate, and ammonium carbamate through an evaporator. The process according to claim 20, wherein step (iii), which is optional, comprises subjecting the gas stream to a separation process to remove at least a portion of the gaseous nitrogen present in the gas stream.

22. The transition metal catalyst contains 0.1% to 20% by weight of alkali metal. Although optional, the alkali metal is selected from one or more of the group consisting of lithium, sodium, potassium, and rubidium. The process according to any one of claims 1 to 21, wherein the alkali metal is optionally selected from one or more of the group consisting of sodium and potassium.

23. An apparatus for carrying out the process described in any one of claims 1 to 22, (a) Carbon dioxide storage tanks for storing carbon dioxide in liquid form; (b) Ammonia storage tanks for storing ammonia in liquid form; (c) A packed-bed catalytic reactor comprising a transition metal catalyst in the form of a solid metal supported on a solid carrier, suitable for converting carbon dioxide and ammonia into one or more carbon monoxide and methane; (d) A thermal energy source for heating the packed-bed catalytic reactor; (e) gas-liquid separator; and (f) Evaporator, A device including a device.

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