A process and apparatus for the production of ethanol in two steps

Abstract

The application provides a method and device for producing ethanol in two steps, which comprises the following steps: step S1: carrying out a reaction of decomposing water to produce hydrogen under the action of a metal oxide catalyst at a normal pressure and at a reaction temperature of 500 DEG C to 1300 DEG C; and step S2: carrying out a reaction of the hydrogen prepared in step S1 with carbon dioxide to produce ethanol under the action of a composite metal oxide catalyst at a reaction pressure of 1 to 10 standard atmospheres. The application can meet the need of producing a large amount of ethanol, save electric energy, improve the utilization rate of heat energy and has great environmental value.

Description

Technical Field

[0001] This invention belongs to the fields of chemical engineering and energy chemical technology, and in particular relates to a two-step method and apparatus for producing ethanol. Background Technology

[0002] Ethanol is a bulk chemical used in beverages, food, and industrial production to manufacture ethylene and acetate products. It is also a liquid fuel used to blend gasoline into ethanol gasoline, which reduces carbon emissions. my country consumes 150 million tons of gasoline annually; at a 10% blending rate, this would require 15 million tons annually, with fuel ethanol alone being insufficient to meet the massive demand. Summary of the Invention

[0003] The present invention provides a two-step method and apparatus for producing ethanol, achieving at least one of the following objectives: meeting the needs of large-scale ethanol production.

[0004] To achieve the above and other related objectives, the present invention provides the following technical solution:

[0005] In a first aspect, the present invention provides a metal oxide catalyst for hydrogen production by water splitting, wherein the metal oxide catalyst has the structural formula: M1+(M2O)a(M3O)b, wherein M1 is selected from at least one of gold, silver, copper, palladium, and platinum; M2O represents an oxide of metal M2, M2 is selected from at least one of calcium, magnesium, strontium, titanium, molybdenum, tungsten, zirconium, gadolinium, samarium, bismuth, and erbium; M3O represents an oxide of metal M3, M3 is selected from at least one of iron, cobalt, nickel, cerium, manganese, indium, and tin; a = 0.0-0.5 mol, b = 0.6-0.80 mol.

[0006] Furthermore, the metal M1 in the metal oxide catalyst exists in the form of nanoparticles with a particle size of 2-100 nm. Preferably, the amount of metal M1 is 1%-20% of the sum of the mass of M2O and M3O in the metal oxide catalyst.

[0007] Furthermore, the metal oxide catalyst also includes a support, the amount of which is 1%-10% of the total mass of the catalyst. Preferably, the support is alumina.

[0008] In a second aspect, the present invention provides a composite metal oxide catalyst for the production of ethanol, wherein the composite metal oxide catalyst has the structural formula: Cu+M4+(M5O)c(M6O)d(M7O)e+Na+-beta zeolite, wherein...

[0009] M4 is selected from at least one of gold, silver, palladium, and platinum;

[0010] M5O represents an oxide of metal M5, where M5 is selected from at least one of calcium, magnesium, and strontium.

[0011] M6O represents an oxide of metal M6, where M6 is selected from at least one of titanium, molybdenum, tungsten, zirconium, gadolinium, samarium, and bismuth.

[0012] M7O represents the oxide of metal M7, where M7 is selected from at least one of iron, cobalt, nickel, cerium, manganese, indium, and tin.

[0013] c represents the sum of the moles of M6O and M7O, d = 0.01-0.5 mol, e = 0.5-0.8 mol.

[0014] Furthermore, the amount of Na+-beta zeolite used is 1-6 times the total volume of the metal and oxide.

[0015] Furthermore, the active components in the composite metal oxide catalyst include Cu, M4, M5O, M6O, and M7O, and the Na+-beta zeolite covers the surface of the active components.

[0016] The present invention also provides a method for preparing the above-mentioned metal oxide catalyst for hydrogen production by water splitting, comprising the following steps: mixing the materials evenly according to the proportions in the structural formula of the metal oxide catalyst for hydrogen production by water splitting, adding a binder and a pore-forming agent, dispersing by ball milling, and then sintering at a sintering temperature range of 700-900℃, and obtaining the composite metal oxide catalyst for ethanol production after cooling.

[0017] The present invention also provides a method for preparing the above-mentioned composite metal oxide catalyst for ethanol production, comprising the following steps: mixing the materials evenly according to the proportions in the structural formula of the composite metal oxide catalyst for ethanol production, adding a binder and a pore-forming agent, dispersing by ball milling, and then sintering at a sintering temperature range of 700-900℃, and obtaining the composite metal oxide catalyst for ethanol production after cooling.

[0018] A third aspect of the present invention provides a two-step method for producing ethanol, comprising the following steps:

[0019] Step S1: Under normal pressure, the reaction of splitting water to produce hydrogen is carried out under the action of the metal oxide catalyst used for splitting water to produce hydrogen. The reaction temperature range is 500℃-1300℃.

[0020] Step S2: Under the action of the composite metal oxide catalyst used to produce ethanol, the hydrogen gas prepared in step S1 is reacted with carbon dioxide to produce ethanol at a reaction pressure of 1-10 standard atmospheres.

[0021] Furthermore, step S1 includes:

[0022] S11: The above-mentioned metal oxide catalyst is decomposed at 500℃-1300℃ to obtain an intermediate and oxygen. The oxygen is removed by purging with inert gas.

[0023] S12: The intermediate reacts with water vapor to obtain the metal oxide catalyst and hydrogen.

[0024] Further, in step S1 or step S11, the reaction temperature is controlled within the range of 500℃-1300℃ under at least one of the following heating conditions: light energy heating, microwave heating, high-frequency inductive heating, and low-temperature plasma heating. Preferably, the heating power is greater than or equal to 10 kW / kg catalyst.

[0025] Furthermore, in step S2, the reaction temperature for hydrogen to react with carbon dioxide to produce ethanol is 100-200℃.

[0026] Furthermore, in step S2, the desired reaction temperature is controlled under at least one of the following heating conditions: light energy heating, microwave heating, high-frequency inductive heating, and low-temperature plasma heating. Preferably, the heating power is greater than or equal to 10 kW / kg catalyst.

[0027] Furthermore, it also includes step S3: discharging the reaction products containing ethanol and carbon dioxide, condensing the reaction products containing ethanol and carbon dioxide to obtain high-purity ethanol and a mixed gas containing carbon dioxide and hydrogen, and returning the mixed gas containing carbon dioxide and hydrogen to step S2 for recycling.

[0028] Furthermore, the inert gas includes at least one of argon, helium, neon, and nitrogen.

[0029] A fourth aspect of the present invention provides an apparatus for a two-step process to produce ethanol, comprising:

[0030] The system comprises a first reaction vessel, a first heating mechanism, and a condensation mechanism. The first reaction vessel has a hydrogen inlet, a carbon dioxide inlet, and a first mixed gas outlet. The first heating mechanism is used to heat the first reaction vessel. The condensation mechanism includes a condensation inlet, a condensation outlet, and a condensate outlet. The condensation inlet of the condensation mechanism is connected to the first mixed gas outlet of the first reaction vessel, and the condensation outlet is connected to the carbon dioxide inlet of the first reaction vessel.

[0031] The second reaction vessel and the second heating mechanism are provided. The second reaction vessel has an inert gas inlet, a water vapor inlet, an oxygen outlet, and a hydrogen outlet. The hydrogen outlet is connected to the hydrogen inlet of the first reaction vessel.

[0032] Furthermore, the first heating mechanism employs at least one of the following heating methods: light energy heating, microwave heating, high-frequency inductive heating, and low-temperature plasma heating.

[0033] Furthermore, the interior of the first reaction vessel is coated with a first catalyst, which is the aforementioned composite metal oxide catalyst for producing ethanol.

[0034] Furthermore, the first reaction vessel is made of a high-temperature resistant and highly transparent material, and the internal pressure of the first reaction vessel is 1-10 standard atmospheres.

[0035] Furthermore, the interior of the second reaction vessel is coated with the aforementioned second catalyst, which is the aforementioned metal oxide catalyst used for water splitting to produce hydrogen.

[0036] Furthermore, the second reaction vessel is made of a high-temperature resistant and highly transparent material.

[0037] Furthermore, the second heating mechanism employs at least one of the following heating methods: light energy heating, microwave heating, high-frequency inductive heating, and low-temperature plasma heating.

[0038] This invention enables the production of hydrogen from water by catalyst reduction and the production of ethanol from carbon dioxide hydrogenation, which can meet the needs of large-scale ethanol production. At the same time, it can save electricity and improve the utilization rate of thermal energy, and has significant environmental value. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of an apparatus for producing ethanol in a two-step process according to an embodiment of the present invention. Detailed Implementation

[0040] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0041] It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding and reading. They are not intended to limit the implementation conditions of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effectiveness and objectives of the invention, should still fall within the scope of the technical content disclosed in the invention. Furthermore, the terms "first," "second," and "third" in this specification are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0042] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0043] According to a first aspect, some embodiments of the present invention provide a metal oxide catalyst for hydrogen production by water splitting, wherein the metal oxide catalyst has the structural formula: M1+(M2O)a(M3O)b, wherein M1 is selected from at least one of gold, silver, copper, palladium, and platinum; M2O represents an oxide of metal M2, M2 is selected from at least one of calcium, magnesium, strontium, titanium, molybdenum, tungsten, zirconium, gadolinium, samarium, bismuth, and erbium; M3O represents an oxide of metal M3, M3 is selected from at least one of iron, cobalt, nickel, cerium, manganese, indium, and tin; a = 0.0-0.5 mol, b = 0.6-0.80 mol.

[0044] In this invention, the metal M1 in the metal oxide catalyst exists in the form of nanoparticles with a particle size of 2-100 nm. Preferably, the amount of metal M1 is 1%-20% of the sum of the mass of M2O and M3O in the metal oxide catalyst.

[0045] In this invention, the metal oxide catalyst further includes a support, the amount of which is 1%-10% of the total mass of the catalyst. Preferably, the support is alumina.

[0046] In this invention, a metal oxide catalyst for water splitting to produce hydrogen is provided, wherein the metal M1 is a nanoparticle with a particle size of 2-100 nm, the metal oxide M2O is cerium dioxide, and the metal oxide M3O includes, but is not limited to, at least one of gadolinium oxide, samarium oxide, calcium oxide, strontium oxide, zirconium dioxide, bismuth oxide, and erbium oxide.

[0047] In this invention, the metal oxide composite (M2O+M3O) includes cerium dioxide, cerium dioxide doped with 1%-20% gadolinium oxide by mass, cerium dioxide doped with 1%-20% samarium oxide by mass, cerium dioxide doped with both 1%-10% samarium oxide and 1%-10% gadolinium oxide by mass, cerium dioxide doped with 1%-20% calcium oxide, cerium dioxide doped with 1%-20% strontium oxide, cerium dioxide doped with 1%-20% zirconium dioxide, cerium dioxide doped with both 1%-10% oxometalate, 1%-10% erbium oxide and 1%-10% samarium oxide, etc.

[0048] The present invention also provides a method for preparing the above-mentioned metal oxide catalyst for hydrogen production by water splitting, comprising the following steps: mixing the materials evenly according to the proportions in the structural formula of the metal oxide catalyst for hydrogen production by water splitting, adding a binder and a pore-forming agent, dispersing by ball milling, and then sintering at a sintering temperature range of 700-900℃, and obtaining the composite metal oxide catalyst for ethanol production after cooling.

[0049] According to a second aspect, some embodiments of the present invention provide a composite metal oxide catalyst for the production of ethanol, the composite metal oxide catalyst having the structural formula: Cu+M4+(M5O)c(M6O)d(M7O)e+Na+-beta zeolite, wherein,

[0050] M4 is selected from at least one of gold, silver, palladium, and platinum;

[0051] M5O represents an oxide of metal M5, where M5 is selected from at least one of calcium, magnesium, and strontium.

[0052] M6O represents an oxide of metal M6, where M6 is selected from at least one of titanium, molybdenum, tungsten, zirconium, gadolinium, samarium, and bismuth.

[0053] M7O represents the oxide of metal M7, where M7 is selected from at least one of iron, cobalt, nickel, cerium, manganese, indium, and tin.

[0054] c represents the sum of the moles of M6O and M7O, d = 0.01-0.5 mol, e = 0.5-0.8 mol.

[0055] Furthermore, the amount of Na+-beta zeolite used is 1-6 times the total volume of the metal and oxide.

[0056] Furthermore, the active components in the composite metal oxide catalyst include Cu, M4, M5O, M6O, and M7O, and the Na+-beta zeolite covers the surface of the active components.

[0057] This invention provides a composite metal oxide catalyst for ethanol production, comprising a composite metal oxide supported on composite nano-metals, or a perovskite supported on nano-metals. The composite nano-metals (Cu+M4) include copper-palladium composites, copper-silver-palladium composites, copper-aluminum-palladium composites, or copper-aluminum composites, wherein the copper content is above 50 wt%. The composite metal oxides (M5O+M6O+M7O) are mainly composed of cerium oxide, doped with at least one of gadolinium oxide, samarium oxide, zirconium oxide, bismuth oxide, erbium oxide, indium oxide, and gallium oxide, with a doping ratio of 0.5-20 wt%. The surface of the composite metal oxide supported on the composite nano-metals is covered with sodium-stabilized zeolite, i.e., sodium-stabilized zeolite covers the surface of the active component.

[0058] The present invention also provides a method for preparing the above-mentioned composite metal oxide catalyst for ethanol production, comprising the following steps: mixing the materials evenly according to the proportions in the structural formula of the composite metal oxide catalyst for ethanol production, adding a binder and a pore-forming agent, dispersing by ball milling, and then sintering at a sintering temperature range of 700-900℃, and obtaining the composite metal oxide catalyst for ethanol production after cooling.

[0059] According to a third aspect, the present invention provides a two-step method for producing ethanol, comprising the following steps:

[0060] Step S11: Under normal pressure, the above-mentioned metal oxide catalyst for water splitting to produce hydrogen is decomposed in the range of 500-1300℃ to obtain intermediates and oxygen, and the oxygen is discharged by purging with inert gas.

[0061] Step S12: The intermediate reacts with water vapor to obtain the original catalyst and hydrogen.

[0062] Step S2: Under the action of the composite metal oxide catalyst used to produce ethanol, the hydrogen gas prepared in step S1 is reacted with carbon dioxide to produce ethanol. The reaction pressure is 1-10 standard atmospheres and the reaction temperature is 100-200℃.

[0063] Step S3: The reaction products containing ethanol and carbon dioxide are discharged. The reaction products containing ethanol and carbon dioxide are condensed to obtain high-purity ethanol and a mixed gas containing carbon dioxide and hydrogen. The mixed gas is returned to step S2 for recycling.

[0064] In this invention, in step S11, the reaction temperature is controlled below 700°C under at least one of the following heating conditions: light energy heating, microwave heating, high-frequency inductive heating, and low-temperature plasma heating. Preferably, the heating power is greater than or equal to 10 kW / kg of catalyst. In some embodiments, the heating method includes microwaves of 900-2500 MHz, or a medium-to-high frequency induction heater of 1-100 kHz, and sunlight, visible light, ultraviolet light, and infrared light irradiating the catalyst surface.

[0065] In this invention, one can choose to perform light energy heating and microwave heating simultaneously, or perform light energy heating and high-frequency inductive heating simultaneously, or perform low-temperature plasma heating and microwave heating simultaneously.

[0066] In this invention, in step S2, the desired reaction temperature is controlled under at least one heating condition selected from light energy heating, microwave heating, high-frequency inductive heating, and low-temperature plasma heating. Preferably, the heating power is greater than or equal to 10 kW / kg catalyst. In this invention, the heating method includes microwaves of 900-2500 MHz, or a medium-to-high frequency induction heater of 1-100 kHz, and sunlight, visible light, ultraviolet light, and infrared light irradiating the catalyst surface.

[0067] In this invention, in step S11, the device can first use light energy to heat the device for a period of time, and then use microwaves to heat it for a period of time. For example, it can use sunlight to heat the device for 20 minutes and then use microwaves to heat it for 5 minutes. This can increase the reaction rate and the amount of hydrogen produced per unit time.

[0068] Furthermore, the inert gas described in this invention includes at least one of argon, helium, neon, and nitrogen.

[0069] According to a fourth aspect, some embodiments of the present invention provide an ethanol production apparatus 100, see [link to previous document]. Figure 1 It includes a first reaction unit 10 and a second reaction unit 20.

[0070] The first reaction unit 10 is used for carbon dioxide hydrogenation reaction and includes a first reaction vessel 11, a first heating mechanism 12 and a condensation mechanism 13. The first reaction vessel 11 has a hydrogen inlet 111, a carbon dioxide inlet 112 and a first mixed gas outlet 113. The interior of the first reaction vessel 11 is coated with a first catalyst. The first reaction vessel 11 is made of a high-temperature resistant and high-transmittance material. The internal pressure of the first reaction vessel 11 is 1-10 standard atmospheres.

[0071] The first heating mechanism 12 is used to heat the first reaction vessel 11. The first heating mechanism 12 adopts at least one of light energy heating, microwave heating, high frequency inductive heating, and low temperature plasma heating.

[0072] The condensation mechanism 13 includes a condensation inlet 131, a condensation outlet 132, and a condensate outlet 133.

[0073] The condenser inlet 131 is connected to the first mixed outlet 113, and the condenser outlet 132 is connected to the carbon dioxide inlet 112.

[0074] The second reaction unit 20 is used for photoelectric synergistic water splitting to produce hydrogen, including a second reaction container 21 and a second heating mechanism 22. The second reaction container 21 has an inert gas inlet 211, a water vapor inlet 212, an oxygen outlet 213, and a hydrogen outlet 214, which is connected to the hydrogen inlet 111. The interior of the second reaction container 21 is coated with a second catalyst, and the second reaction container 21 is made of a high-temperature resistant and high-transmittance material.

[0075] The second heating mechanism 22 is used to heat the second reaction vessel 21. The second heating mechanism 22 adopts at least one of light energy heating, microwave heating, high frequency inductive heating, and low temperature plasma heating.

[0076] In this invention, the heating device is composed of light energy heating and microwave heating, or light energy heating and high-frequency inductive heating, or low-temperature plasma heating and microwave heating.

[0077] In this invention, the heating method includes microwaves of 900-2500MHz or medium-high frequency induction heaters of 1-100KHz, and sunlight, visible light, ultraviolet light and infrared light irradiating the catalyst surface.

[0078] The photoelectric synergistic water splitting hydrogen production reaction uses light energy and electrical energy to heat the second catalyst, nanoparticles, and support, causing the catalyst in the second reaction vessel 21 to decompose at 500-1300℃ to produce hydrogen and release oxygen.

[0079] In this embodiment, when sunlight shines on the second reaction vessel 21 and the catalyst inside is heated to above 110 degrees Celsius, microwave heating or high-frequency inductive heating is initiated. Simultaneously, inert gas is introduced through the inert gas inlet 211 to carry away the oxygen released by the catalyst, which is then discharged through the oxygen outlet 213 to prevent re-oxidation and reduced energy conversion efficiency. After 30 minutes of reaction, the inert gas inlet 211 is closed, and water vapor is introduced through the water vapor inlet 212 to combine with the catalyst and produce hydrogen.

[0080] During heating, inert gas is introduced through the inert gas inlet 211, and the released oxygen is discharged through the oxygen outlet 213. The inert gas includes, but is not limited to, at least one of argon, helium, neon, and nitrogen. When not heating, the inert gas supply is stopped, and then water vapor is introduced through the water vapor inlet 212 into the second reaction vessel 21 to react and generate hydrogen.

[0081] Hydrogen enters the first reaction vessel 11 and reacts with carbon dioxide under the action of a catalyst to form ethanol. The ethanol is collected by the condensation mechanism 13 and then recycled.

[0082] Hydrogen gas discharged from hydrogen outlet 214 enters the first reaction vessel 11 through hydrogen inlet 111, and carbon dioxide gas enters the first reaction vessel 11 through carbon dioxide inlet 112. In the first reaction vessel 11, hydrogen and carbon dioxide react under the action of a catalyst to produce ethanol. The mixed gas containing ethanol, hydrogen and carbon dioxide discharged from the first mixed gas outlet 113 enters the condensation mechanism 13 through condensation inlet 131. After condensation by the condensation mechanism 13, the ethanol in the mixed gas becomes liquid and flows out from the condensate outlet 133 for collection and reuse. The remaining mixed gas of hydrogen and carbon dioxide flows out from the condensation outlet 132 and enters the first reaction vessel 11 through carbon dioxide inlet 112 for reuse.

[0083] The first catalyst is the aforementioned composite metal oxide catalyst for producing ethanol, and the second catalyst is the aforementioned composite metal oxide catalyst for producing ethanol, which will not be described in detail here.

[0084] The embodiments of the present invention can realize the production of hydrogen from water by reducing water and the production of ethanol by hydrogenating carbon dioxide using solar energy, electrical energy and thermal energy, saving electrical energy, improving thermal energy utilization, and having significant environmental value.

[0085] The present invention will be further described below with reference to specific embodiments:

[0086] Example 1: Two-step method for producing hydrogen from water via thermochemical splitting and hydrogenation of carbon dioxide to produce ethanol.

[0087] Preparation of a metal oxide catalyst for water splitting to produce hydrogen: 2 g of nano-copper powder (10 nm particle size), 0.1 mol of calcium oxide, 0.05 mol of titanium dioxide, and 0.05 mol of manganese dioxide were ball-milled until uniform. 10 g of the metal oxide was then taken, along with a binder and a pore-forming agent. After ball milling and dispersion, the mixture was coated inside a first quartz glass tube and sintered at a maximum temperature of 800 degrees Celsius. After cooling, it was ready for use.

[0088] A composite metal oxide catalyst for ethanol production was prepared by ball milling 0.1 mol of calcium oxide, 0.05 mol of titanium dioxide, and 0.05 mol of manganese dioxide. 10 g of the metal oxide was then mixed with 1 g of nano-copper powder, 0.5 g of palladium powder, and 0.5 g of silver powder, and 3 times the volume ratio of Na was added. + The amount of beta zeolite, along with binder and pore-forming agent, is dispersed by ball milling, coated inside a second quartz glass tube, sintered at a maximum temperature of 800 degrees Celsius, and then cooled.

[0089] The first quartz glass tube (second reaction vessel) was heated using a solar concentrator while high-purity, oxygen-free nitrogen gas was introduced. Once the temperature reached 700 degrees Celsius, microwave heating was initiated to maintain the temperature between 700-1000 degrees Celsius. The heating power was 10 kW / kg of catalyst (10 W / g power). After 30 minutes of reaction, nitrogen gas was introduced for another 5 minutes. Then, nitrogen gas was stopped, the gas was evacuated, and water vapor was introduced. After removing the water vapor from the outlet gas, it was introduced into the second quartz glass tube (first reaction vessel) for the production of ethanol from carbon dioxide hydrogenation. Simultaneously, a mixture of 2 parts carbon dioxide and 6 parts hydrogen gas was introduced. The catalyst inside the second quartz glass tube was irradiated using a solar concentrator. After 1 hour, the reaction temperature reached 200 degrees Celsius. Ethanol was collected after condensation in a condenser, and the ethanol yield was determined.

[0090] Analysis showed that the hydrogen production rate was 1.1 ml per gram of catalyst per hour. After removing water vapor, the hydrogen was mixed with carbon dioxide and fed into a reactor coated with a carbon dioxide hydrogenation catalyst at a rate of 224 ml per minute. The reaction was carried out for 1 hour, and the cycle was repeated 3 times. 0.12 grams of ethanol were collected. After 3 cycles, the ethanol conversion rate was 27%.

[0091] Example 2: Two-step method for producing hydrogen from water via thermochemical splitting and hydrogenation of carbon dioxide to produce ethanol.

[0092] Preparation of metal oxide catalysts for water splitting to produce hydrogen: Perovskite oxide with a ratio of 0.1 mol calcium oxide, 0.05 mol titanium dioxide, and 0.05 mol manganese dioxide was prepared by sol-gel method. 10 g of metal oxide was taken, and 1 g of nano copper powder and 1 g of palladium powder with a particle size of 10 nanometers were added. A binder and a pore-forming agent were added, and the mixture was dispersed by ball milling. The mixture was then coated into the inside of a first quartz glass tube and sintered at a maximum temperature of 800 degrees Celsius. After cooling, it was ready for use.

[0093] Preparation of a composite metal oxide catalyst for ethanol production: A perovskite oxide with a ratio of 0.1 mol calcium oxide, 0.05 mol titanium dioxide, and 0.05 mol manganese dioxide was prepared by the sol-gel method. 10 g of the metal oxide was mixed with 1 g of nano-copper powder and 1 g of palladium powder, and then 6 times the volume ratio of Na was added. + The amount of beta zeolite, along with binder and pore-forming agent, is dispersed by ball milling, coated inside a second quartz glass tube, sintered at a maximum temperature of 800 degrees Celsius, and then cooled.

[0094] The first quartz tube was heated using a solar concentrator while high-purity, oxygen-free nitrogen was introduced. Once the temperature reached 700 degrees Celsius, high-frequency inductive heating at 100 kHz was initiated, controlling the reaction temperature between 700-1000 degrees Celsius. The heating power was 10 kW / kg of catalyst (10 W / g power). After 30 minutes of reaction, nitrogen was introduced for another 5 minutes. Nitrogen was then stopped, and the gas was evacuated before introducing water vapor. After removing the water vapor from the outlet gas, it was introduced into the quartz tube for the hydrogenation of carbon dioxide to ethanol, while simultaneously introducing a mixture of 2 parts carbon dioxide and 6 parts hydrogen. The catalyst in the second quartz tube was irradiated with a solar concentrator for 1 hour, and finally, microwave heating was applied for 5 minutes to reach 200 degrees Celsius. Ethanol was collected after condensation in a condenser, and the ethanol yield was determined.

[0095] Analysis showed that the hydrogen production rate was 0.6 ml per gram of catalyst per hour. After removing water vapor, the hydrogen was mixed with carbon dioxide and fed into a reactor coated with a carbon dioxide hydrogenation catalyst at a rate of 112 ml per minute. The reaction was carried out for 1 hour, and the cycle was repeated 3 times. 0.07 g of ethanol was collected. After 3 cycles, the ethanol conversion rate was 30.3%.

[0096] Example 3: Two-step method for producing hydrogen from water via thermochemical splitting and hydrogenation of carbon dioxide to produce ethanol.

[0097] Preparation of metal oxide catalysts for water splitting to produce hydrogen: 0.2 moles of zirconium dioxide and 0.8 moles of cerium dioxide were prepared by ball milling. 10 g of metal oxide was taken and 1 g of nano copper powder, 0.5 g of palladium powder, and 0.5 g of silver powder with a particle size of 10 nanometers were added. A binder and a pore-forming agent were added, and the mixture was dispersed by ball milling. The mixture was then coated inside a first quartz glass tube and sintered at a maximum temperature of 800 degrees Celsius. After cooling, it was ready for use.

[0098] Preparation of a composite metal oxide catalyst for ethanol production: An oxide mixture of 0.02 mol gadolinium trioxide, 0.08 mol samarium trioxide, and 0.8 mol cerium dioxide was prepared via a sol-gel method. 10 g of the metal oxide was mixed with 1 g of nano-copper powder, 0.5 g of palladium powder, and 0.5 g of silver powder, and then 6 times the volume ratio of Na was added. + The amount of beta zeolite, along with binder and pore-forming agent, is dispersed by ball milling, coated inside a second quartz glass tube, sintered at a maximum temperature of 800 degrees Celsius, and then cooled.

[0099] The first quartz glass tube was heated using a solar concentrator while high-purity, oxygen-free nitrogen gas was introduced. Once the temperature reached 110 degrees Celsius, microwave heating at 2450 MHz was initiated, raising the temperature to 500-700 degrees Celsius. The heating power was 10 kW / kg of catalyst (10 W / g power). After 30 minutes of reaction, nitrogen gas was introduced for another 5 minutes. Nitrogen gas was then stopped, and the gas was evacuated before introducing water vapor. After removing the water vapor from the outlet gas, it was introduced into the quartz tube for the hydrogenation of carbon dioxide to ethanol, while simultaneously introducing a mixture of 2 parts carbon dioxide and 6 parts hydrogen gas. The catalyst in the second quartz glass tube was irradiated using a solar concentrator for 30 minutes, followed by microwave heating for 5 minutes to 200 degrees Celsius. The ethanol was collected after condensation in a condenser, and the ethanol yield was determined.

[0100] The hydrogen production rate was 0.3 mL per gram of catalyst per hour. After removing water vapor, the hydrogen was mixed with carbon dioxide and fed into a reactor coated with a carbon dioxide hydrogenation catalyst at a rate of 224 mL per minute. The reaction was carried out for 1 hour, and the cycle was repeated 3 times. 0.11 g of ethanol was collected. After 3 cycles, the ethanol conversion rate was 24.0%.

[0101] Example 4: Two-step method for producing hydrogen from water via thermochemical splitting and hydrogenation of carbon dioxide to produce ethanol.

[0102] Preparation of metal oxide catalysts for water splitting to produce hydrogen: A 0.25 mol / L magnesium oxide, 0.25 mol / L ferric oxide, 0.25 mol / L nickel oxide, and 0.25 mol / L cobalt oxide in a 0.8 mol / L ratio were prepared by ball milling. 10 g of the metal oxides were mixed with 1 g of nano-copper powder (10 nm particle size), along with a binder and a pore-forming agent. After ball milling and dispersion, the mixture was coated inside a first quartz glass tube and sintered at a maximum temperature of 800°C. The sintered catalyst was then cooled for later use.

[0103] Preparation of a composite metal oxide catalyst for ethanol production: An oxide mixture of 0.2 mol zirconium dioxide and 0.8 mol cerium dioxide was prepared via a sol-gel method. 10 g of the metal oxide was then mixed with 1 g of nano-copper powder, 0.5 g of palladium powder, and 0.5 g of silver powder, and 6 times the volume of Na was added. + The amount of beta zeolite, along with binder and pore-forming agent, is dispersed by ball milling, coated inside a second quartz glass tube, sintered at a maximum temperature of 800 degrees Celsius, and then cooled.

[0104] The first quartz glass tube was heated using a solar concentrator while high-purity, oxygen-free nitrogen was introduced. Once the temperature reached 600 degrees Celsius, microwave heating at 2450 MHz was initiated, raising the temperature to 550-900 degrees Celsius. The heating power was 10 kW / kg of catalyst (10 W / g power). After 30 minutes of reaction, nitrogen was introduced for another 5 minutes. Nitrogen was then stopped, the gas was evacuated, and water vapor was introduced. After removing the water vapor from the outlet gas, it was introduced into the quartz tube for the hydrogenation of carbon dioxide to ethanol, while simultaneously introducing a mixture of 2 parts carbon dioxide and 6 parts hydrogen. The catalyst in the second quartz glass tube was irradiated using a solar concentrator for 30 minutes, followed by 100 kHz high-frequency inductive heating for 5 minutes, raising the temperature to 200 degrees Celsius. The ethanol was collected after condensation in a condenser, and the ethanol yield was determined.

[0105] Analysis showed that the hydrogen production rate was 2.5 ml per gram of catalyst per hour. After removing water vapor, the hydrogen was mixed with carbon dioxide and fed into a reactor coated with a carbon dioxide hydrogenation catalyst at a rate of 224 ml per minute. The reaction was carried out for 1 hour, and the cycle was repeated 3 times. 0.16 grams of ethanol were collected. After 3 cycles, the ethanol conversion rate was 36.4%.

[0106] Throughout this specification, references to "an example," "an embodiment," or "an embodiment" indicate that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment. Therefore, the appearance of "an example," "an embodiment," or "an embodiment" in various places throughout this specification does not necessarily refer to the same embodiment. Furthermore, a particular feature, structure, or characteristic may be combined in any manner in one or more embodiments.

[0107] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A metal oxide catalyst for hydrogen production by water splitting, characterized in that, The structural formula of the metal oxide catalyst is: M1+(M2O)a(M3O)b, wherein M1 is selected from at least one of gold, silver, copper, palladium, and platinum; M2O represents the oxide of metal M2, which is selected from at least one of calcium, magnesium, strontium, titanium, molybdenum, tungsten, zirconium, gadolinium, samarium, bismuth, and erbium; M3O represents the oxide of metal M3, which is selected from at least one of iron, cobalt, nickel, cerium, manganese, indium, and tin; a = 0.0-0.5 mol, b = 0.6-0.80 mol. Preferably, the metal M1 in the metal oxide catalyst exists in the form of nanoparticles with a particle size of 2-100 nm. Preferably, the amount of metal M1 is 1%-20% of the sum of the mass of M2O and M3O in the metal oxide catalyst.

2. A composite metal oxide catalyst for the production of ethanol, characterized in that, The composite metal oxide catalyst has the following structural formula: Cu+M4+(M5O)c(M6O)d(M7O)e+Na+-beta zeolite, wherein... M4 is selected from at least one of gold, silver, palladium, and platinum; M5O represents an oxide of metal M5, where M5 is selected from at least one of calcium, magnesium, and strontium. M6O represents an oxide of metal M6, where M6 is selected from at least one of titanium, molybdenum, tungsten, zirconium, gadolinium, samarium, and bismuth. M7O represents the oxide of metal M7, where M7 is selected from at least one of iron, cobalt, nickel, cerium, manganese, indium, and tin. c represents the sum of the moles of M6O and M7O, d = 0.01-0.5 mol, e = 0.5-0.8 mol. Preferably, the amount of Na+-beta zeolite used is 1-6 times the total volume of the metal and oxide.

3. A two-step method for producing ethanol, characterized in that, Includes the following steps: Step S1: Under normal pressure, the reaction of splitting water to produce hydrogen is carried out under the action of the metal oxide catalyst described in claim 1, and the reaction temperature range is 500℃-1300℃; Step S2: Under the action of the composite metal oxide catalyst described in claim 2, the hydrogen prepared in step S1 is reacted with carbon dioxide to produce ethanol. The reaction pressure is 1-10 standard atmospheres and the reaction temperature is 100-200℃.

4. The two-step method for producing ethanol according to claim 3, characterized in that, Step S1 includes: S11: The metal oxide catalyst of claim 1 decomposes at 500℃-1300℃ to obtain an intermediate and oxygen, and the oxygen is discharged by purging with inert gas. S12: The intermediate reacts with water to obtain the metal oxide catalyst and hydrogen.

5. The two-step method for producing ethanol according to claim 3 or 4, characterized in that, In step S1 or step S11, the reaction temperature is controlled within the range of 500℃-1300℃ under at least one heating condition selected from light energy heating, microwave heating, high frequency inductive heating, and low temperature plasma heating. Preferably, the heating power is greater than or equal to 10KW / kg catalyst.

6. The two-step method for producing ethanol according to any one of claims 3-5, characterized in that, In step S2, the desired reaction temperature is controlled under at least one of the following heating conditions: light energy heating, microwave heating, high-frequency inductive heating, and low-temperature plasma heating. Preferably, the heating power is greater than or equal to 10KW / kg catalyst.

7. The two-step method for producing ethanol according to any one of claims 3-6, characterized in that, The process also includes step S3: purging the reaction products containing ethanol and carbon dioxide with inert gas, condensing the reaction products containing ethanol, carbon dioxide, and inert gas to obtain high-purity ethanol and a mixture containing carbon dioxide and hydrogen, which is then returned to step S2 for recycling.

8. An apparatus for producing ethanol in a two-step process, characterized in that, include: The system comprises a first reaction vessel, a first heating mechanism, and a condensation mechanism. The first reaction vessel has a hydrogen inlet, a carbon dioxide inlet, and a first mixed gas outlet. The first heating mechanism is used to heat the first reaction vessel. The condensation mechanism includes a condensation inlet, a condensation outlet, and a condensate outlet. The condensation inlet of the condensation mechanism is connected to the first mixed gas outlet of the first reaction vessel, and the condensation outlet is connected to the carbon dioxide inlet of the first reaction vessel. The second reaction vessel and the second heating mechanism are provided. The second reaction vessel has an inert gas inlet, a water vapor inlet, an oxygen outlet, and a hydrogen outlet. The hydrogen outlet is connected to the hydrogen inlet of the first reaction vessel.

9. The apparatus for two-step ethanol production according to claim 8, characterized in that, The first heating mechanism employs at least one of the following heating methods: light energy heating, microwave heating, high-frequency inductive heating, and low-temperature plasma heating. Preferably, the first reaction vessel is made of a high-temperature resistant and highly transparent material, and the internal pressure of the first reaction vessel is 1-10 standard atmospheres.

10. The apparatus for two-step ethanol production according to claim 8, characterized in that, The second heating mechanism employs at least one of the following heating methods: light energy heating, microwave heating, high-frequency inductive heating, and low-temperature plasma heating. Preferably, the second heating mechanism is made of a high-temperature resistant and highly transparent material.

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