System and method for renewable energy driven carbon dioxide hydrogenation

Abstract

The application discloses a method for carbon dioxide hydrogenation driven by renewable energy, which comprises the following steps: a renewable energy power generation device generates power by using renewable energy; the generated electric energy is stored and used by a renewable energy storage device; carbon dioxide collected by a carbon dioxide collecting device and hydrogen obtained by electrolyzing water are introduced into a raw material buffer tank, mixed and then introduced into a micro-reactor hydrogenation device to perform carbon dioxide hydrogenation reaction; reaction products are separated by a three-phase separator to obtain product water as raw material for electrolyzing water; liquid products are introduced into a liquid hydrocarbon separation system to separate C5 + gasoline products; gas products are introduced into a gas separation system to separate unreacted carbon dioxide and hydrogen, lean dry gas, low-carbon olefins and liquefied gas; the unreacted carbon dioxide and hydrogen are recycled to the system.

Description

Technical Field

[0001] This invention relates to the field of clean energy utilization and carbon capture and utilization, specifically to a system and method for renewable energy-driven carbon dioxide hydrogenation. Background Technology

[0002] Fossil fuels (coal, oil, and natural gas) have provided enormous economic benefits to human society. However, in recent decades, the large-scale combustion of fossil fuels has led to a continuous increase in CO2 emissions, causing serious environmental problems such as global warming. Therefore, researching CO2 capture and catalytic conversion technologies to utilize CO2 resources is an effective way to solve the greenhouse effect, replace fossil fuels, and generate chemicals with higher economic value. This is of great significance to the sustainable development of the world's energy and ecological environment.

[0003] Renewable energy sources include solar, wind, and tidal energy—clean, green, and low-carbon energy sources that are naturally renewable and inexhaustible. These energy sources do not face resource depletion issues and do not pose a threat to the environment, making them an inevitable choice for sustainable development strategies. Using CO2 as a carbon source and clean energy as an energy source not only reduces CO2 emissions but also fully utilizes renewable energy to convert CO2 into high-value-added chemical products, which has significant strategic importance.

[0004] Chinese patent document CN104437504A discloses a catalyst for the efficient conversion of CO2 to low-carbon olefins, the catalyst having the structural formula A-(B(C x Fe y )O z )-Fe / S, where x+y=2, z=3.2~4.2, A is an alkali metal or alkaline earth metal element, B is a divalent ion of a transition metal element, C is a trivalent ion of a transition metal element, and S is the support. A-(B(C) x Fe y )O z Fe is the active ingredient. This paper provides an Fe-based catalyst and its preparation method for the efficient conversion of CO2 to olefins. When the catalyst is used in the CO2 hydrogenation reaction, the main products are low-carbon olefins (propylene, ethylene, and butene), with a CO2 conversion rate exceeding 60%. However, the selectivity for low-carbon olefins in this process remains low, generating large amounts of methane and other long-chain alkanes, resulting in low hydrogen utilization. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a system and method for renewable energy-driven carbon dioxide hydrogenation, which uses captured carbon dioxide as a carbon source and water electrolysis to produce hydrogen as a hydrogen source. This can effectively alleviate environmental problems such as the greenhouse effect, and the energy of the entire device comes entirely from non-fossil energy sources, achieving zero carbon emissions for the entire system.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A renewable energy-driven carbon dioxide hydrogenation system includes a renewable energy driving device, a carbon dioxide capture device, a water electrolysis hydrogen production device, a feed buffer tank, a microreactor hydrogenation device, and a product separation device.

[0008] The renewable energy drive device includes a renewable energy power generation device and a renewable energy storage device;

[0009] The product separation device includes a three-phase separator, a liquid hydrocarbon separation system, and a gas separation system.

[0010] Preferably, the microreactor hydrogenation device comprises n groups of microreactors, where n ≥ 2; each group of microreactors is connected in parallel or in series.

[0011] Preferably, the microreactor hydrogenation device comprises n groups of microreactors, where n is 2 to 20; each group of microreactors is connected in parallel.

[0012] Preferably, each group of microreactors contains m microreactors, where m ≥ 2; each microreactor is connected in parallel or in series.

[0013] Preferably, each group of microreactors contains m microreactors, where m is 2 to 6; and each microreactor is connected in series.

[0014] The present invention also claims a method for hydrogenating carbon dioxide driven by the renewable energy source, comprising: using electricity provided by the renewable energy source to drive hydrogen and carbon dioxide to undergo a hydrogenation reaction in the presence of a carbon dioxide hydrogenation catalyst, and then separating the hydrogen to obtain low-carbon olefins and gasoline.

[0015] Preferably, the method for renewable energy-driven carbon dioxide hydrogenation includes the following steps:

[0016] The renewable energy power generation device generates electricity using renewable energy sources, which is then stored and used through a renewable energy storage device. Carbon dioxide captured by the carbon dioxide capture device and hydrogen produced by the water electrolysis hydrogen production device are fed into a raw material buffer tank, mixed, and then fed into a microreactor hydrogenation device for carbon dioxide hydrogenation reaction. The reaction products are separated in a three-phase separator, and the separated product water is used as a raw material for water electrolysis. The liquid products enter a liquid hydrocarbon separation system to separate C5+ gasoline products. The gaseous products enter a gas separation system to separate unreacted carbon dioxide and hydrogen, lean dry gas, low-carbon olefins, and liquefied petroleum gas. The unreacted carbon dioxide and hydrogen are returned to the system for recycling.

[0017] Preferably, in the carbon dioxide hydrogenation reaction, the volume ratio of carbon dioxide to hydrogen is 1:20 to 20:1, and the reaction pressure is 0 to 10 MPa.

[0018] Preferably, in the carbon dioxide hydrogenation reaction, the volume ratio of carbon dioxide to hydrogen is 1:2 to 1:9, and the reaction pressure is 2 to 8 MPa.

[0019] Preferably, in the carbon dioxide hydrogenation reaction, the residence time of the carbon dioxide and hydrogen mixture is 0.1 to 10000 s.

[0020] Preferably, the carbon dioxide hydrogenation catalyst comprises 10-80 wt% nano-metal oxide and 20-90 wt% modified ZSM-5 molecular sieve. The nano-metal oxide and modified ZSM-5 molecular sieve are treated with a silane coupling agent and then calcined to obtain the carbon dioxide hydrogenation catalyst.

[0021] Preferably, the carbon dioxide hydrogenation catalyst comprises 20-50 wt% nano-metal oxide and 50-80 wt% modified ZSM-5 molecular sieve. The nano-metal oxide and modified ZSM-5 molecular sieve are treated with a silane coupling agent and then calcined to obtain the carbon dioxide hydrogenation catalyst.

[0022] Preferably, the nano-metal oxide comprises component A and component B, wherein component A is selected from any three of iron oxide, cobalt oxide, molybdenum oxide, nickel oxide, and copper oxide, and component B is selected from any one of zirconium oxide, potassium oxide, and calcium oxide.

[0023] Preferably, component A includes component 1, component 2, and component 3, wherein component 1, component 2, and component 3 are any three selected from iron oxide, cobalt oxide, molybdenum oxide, nickel oxide, and copper oxide, and each accounts for 1 to 80% of the weight percentage of the nano-metal oxide.

[0024] Preferably, component A includes component 1, component 2, and component 3, wherein component 1, component 2, and component 3 are any three selected from iron oxide, cobalt oxide, molybdenum oxide, nickel oxide, and copper oxide, and each accounts for 10-70% of the weight percentage of the nano-metal oxide.

[0025] Preferably, component B accounts for 1 to 10% of the weight of the nano-metal oxide.

[0026] Preferably, component B accounts for 1 to 5% of the weight of the nano-metal oxide.

[0027] Preferably, the modified ZSM-5 molecular sieve includes component a, component b, and ZSM-5 molecular sieve, wherein component a is selected from either lanthanum oxide or cerium oxide, and component b is selected from either potassium oxide or magnesium oxide.

[0028] Preferably, component a accounts for 0.1-5% of the weight of the modified ZSM-5 molecular sieve, and component b accounts for 0.1-3% of the weight of the modified ZSM-5 molecular sieve.

[0029] Preferably, component a accounts for 0.5 to 3% of the weight of the modified ZSM-5 molecular sieve, and component b accounts for 0.1 to 1.5% of the weight of the modified ZSM-5 molecular sieve.

[0030] Preferably, the silane coupling agent is KH560 and / or KH570.

[0031] Preferably, the preparation method of the carbon dioxide hydrogenation catalyst includes the following steps:

[0032] (1) Dissolve the first metal salt in deionized water, then add sucrose and polyethylene glycol, stir to obtain a sol, dry and calcine the sol to obtain nano metal oxides;

[0033] (2) Dissolve the second metal salt in deionized water to obtain a second metal salt solution, age the ZSM-5 molecular sieve, then impregnate the ZSM-5 molecular sieve with the second metal salt solution, let it stand, dry it, and calcine it to obtain the modified ZSM-5 molecular sieve.

[0034] (3) Disperse nano-metal oxides and modified ZSM-5 molecular sieves in deionized water, add ethanol and silane coupling agent, stir thoroughly to obtain slurry, spray dry the slurry to form a shape, then dry and calcine to obtain carbon dioxide hydrogenation catalyst.

[0035] Preferably, in step (1), the first metal salt is one or more of the nitrates of Fe, Co, Mo, Ni, Cu, Zr, K, and Ca, and the weight ratio of the first metal salt to deionized water is 15-40:100; in step (2), the second metal salt is one or more of the nitrates of La, Ce, K, and Mg, and the weight ratio of the second metal salt to deionized water is 10-30:100.

[0036] Preferably, in step (1), the stirring conditions are stirring at 40-95℃ for 5-15 hours, the drying conditions are drying at 110-120℃ for 10-15 hours, and the calcination conditions are calcination at 400-600℃ for 5-15 hours.

[0037] Preferably, in step (1), the polyethylene glycol is PEG2000 and / or PEG4000; sucrose and polyethylene glycol account for 0.01-5% and 0.01-10% of the weight of the sol, respectively.

[0038] Preferably, in step (1), sucrose and polyethylene glycol account for 0.1-3% and 0.1-5% of the weight of the sol, respectively.

[0039] Preferably, in step (2), the aging conditions are aging at 550-700℃ for 2-5 hours, the standing time is 10-15 hours, the drying conditions are drying at 100-120℃ for 8-15 hours, and the calcination conditions are calcination at 500-600℃ for 10-15 hours; the ZSM-5 molecular sieve has a particle size of <800nm ​​and a silicon-aluminum ratio of 80-300.

[0040] Preferably, in step (2), the ZSM-5 molecular sieve has a particle size of <800nm ​​and a silicon-to-aluminum ratio of 100 to 200.

[0041] Preferably, in step (3), ethanol and silane coupling agent account for 0.5-3% and 1-5% of the weight of the slurry, respectively.

[0042] Preferably, in step (3), the solid content of the slurry is 25-35 wt%.

[0043] Preferably, in step (3), the furnace temperature during spray drying is 300-450℃, the outlet temperature of the drying tower is 130-250℃, and the spray pressure of the drying tower is 2.0-4.0MPa; the particle size of the catalyst after spray drying is 15-35μm; the drying conditions after catalyst formation are 100-130℃ for 4-7h, and the calcination conditions are 400-600℃ for 5-10h.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] 1) The present invention provides a renewable energy-driven carbon dioxide hydrogenation system and method, including a renewable energy driving device, a carbon dioxide capture device, an electrolytic water hydrogen production device, a microreactor hydrogenation device, and a product separation device; all the energy required by the entire system comes from the renewable energy driving device, which can improve the stability and continuity of the carbon dioxide hydrogenation reaction and enable the entire system to have zero emissions; the system uses carbon dioxide and hydrogen to produce olefins, which can not only address environmental issues such as the greenhouse effect, but also convert CO2 into high-value-added chemical products, thereby improving economic benefits.

[0046] 2) This invention provides a renewable energy-driven carbon dioxide hydrogenation system and method, which utilizes a microreactor hydrogenation device to produce olefins and gasoline. The microreactor has a large specific surface area and high mass and heat transfer efficiency, which can effectively improve the conversion rate and product selectivity of the reaction. The intense heat of reaction generated can be removed in time, and the reaction temperature deviation can be controlled within ±2℃, resulting in high reaction precision and production safety. By combining microreactor groups, different hydrogenation products can be obtained by adjusting the catalyst and production conditions as needed. It is also possible to start / stop some of the microreactor groups according to changes in production scale without affecting continuous production, resulting in high production efficiency and flexible operation.

[0047] 3) This invention provides a renewable energy-driven carbon dioxide hydrogenation system and method, and provides a carbon dioxide hydrogenation catalyst with a carbon dioxide conversion rate exceeding 40% and excellent selectivity for low-carbon olefins. The combination and selection of nano-metal oxides can effectively improve hydrogenation activity and increase the conversion rate of carbon dioxide hydrogenation. Modified metal salts modify ZSM-5 molecular sieves to give them good hydrothermal stability and coke-holding capacity, increasing the selectivity and lifespan of the catalyst. Ethanol and KH560 modify the nano-metal oxide ZSM-5 molecular sieves to effectively increase the mechanical strength of the catalyst, reduce the formation of by-products, and improve the conversion rate and selectivity of the target product. Attached Figure Description

[0048] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some schematic diagrams of certain embodiments of the present invention, and therefore should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0049] Figure 1 This is a schematic diagram of a renewable energy-driven carbon dioxide hydrogenation system provided by the present invention.

[0050] In the diagram, 1. Renewable energy power generation device; 2. Renewable energy storage device; 3. Carbon dioxide capture device; 4. Electrolytic water hydrogen production device; 5. Raw material buffer tank; 6. First group of microreactors; 7. nth group of microreactors (n≥2); 8. First microreactor of the first group; 9. Circulating carbon dioxide and hydrogen; 10. mth microreactor of the first group (m≥2); 11. Three-phase separator; 12. Product water; 13. Liquid hydrocarbon separation system; 14. Gas separation system; 15. Unreacted carbon dioxide and hydrogen; 16. Other gaseous hydrocarbons. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. Of course, the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0052] The terms "first," "second," etc., are used only for descriptive distinction and should not be interpreted as indicating or implying relative importance. Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," not that the structure must be perfectly horizontal, but can be slightly tilted.

[0053] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0054] Unless otherwise specified, all chemical reagents and materials in this invention are purchased from the market or synthesized from raw materials purchased from the market.

[0055] The microreactor used in the examples is a non-standard device; any microreactor that meets the reaction conditions can be used.

[0056] like Figure 1 As shown, the present invention provides a renewable energy-driven carbon dioxide hydrogenation system, including a renewable energy driving device, a carbon dioxide capture device 3, an electrolysis water hydrogen production device 4, a raw material buffer tank 5, a microreactor hydrogenation device, and a product separation device.

[0057] The renewable energy drive device includes a renewable energy power generation device 1 and a renewable energy storage device 2;

[0058] The product separation device includes a three-phase separator 11, a liquid hydrocarbon separation system 13, and a gas separation system 14.

[0059] Specifically, the microreactor hydrogenation device comprises n groups of microreactors, n≥2, preferably 2 to 20, which can be 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20; the connection method of each group of microreactors is either parallel or series, preferably parallel.

[0060] Specifically, each group of microreactors contains m microreactors, where m ≥ 2, preferably 2 to 6, and can be 2, 3, 4, 5, or 6; each microreactor is connected in parallel or in series, preferably in series.

[0061] The present invention also claims a method for hydrogenating carbon dioxide driven by the aforementioned renewable energy source, comprising the following steps:

[0062] The renewable energy power generation device 1 generates electricity using renewable energy, and the generated electricity is stored and used through the renewable energy storage device 2. All the energy required by the entire system comes directly or indirectly from this device.

[0063] Carbon dioxide captured by carbon dioxide capture device 3 and hydrogen obtained by water electrolysis hydrogen production device 4 are fed into raw material buffer tank 5. After mixing, they are divided into n streams and fed into n groups of microreactors for carbon dioxide hydrogenation reaction. Each group of microreactors contains m microreactors. The inlet raw material of the m-th microreactor is the outlet product of the (m-1)-th microreactor.

[0064] The reaction products enter the three-phase separator 11 for separation, and the separated product water 12 is used as the raw material for water electrolysis; the liquid products enter the liquid hydrocarbon separation system 13 to separate C5+ gasoline products; the gaseous products enter the gas separation system 14 to separate unreacted carbon dioxide and hydrogen 15, lean dry gas, low carbon olefins, and liquefied gas; the unreacted carbon dioxide and hydrogen are returned to the system for recycling.

[0065] Specifically, the renewable energy power generation device utilizes one or more of solar power, wind power, and tidal power.

[0066] Specifically, the renewable energy storage device is one or more of battery storage, pumped hydro storage, molten salt thermal storage, and hydrogen storage. Since renewable energy power generation may be intermittent and unstable, the renewable energy storage device is used for energy storage and stabilization after renewable energy power generation, so as to provide a continuous and stable energy supply for the entire carbon dioxide hydrogenation system.

[0067] Specifically, the carbon dioxide capture uses one or more of the following methods: chemical absorption, physical absorption, or adsorption; the source of the carbon dioxide replenishment can be carbon dioxide in the air or carbon dioxide in the exhaust gas from the combustion of fossil fuels in refineries, power plants, etc.

[0068] Specifically, the hydrogen production by water electrolysis uses one or more of the following: alkaline water electrolysis, proton exchange membrane water electrolysis, and high-temperature solid oxide water electrolysis; the hydrogen obtained by water electrolysis can be used as a hydrogen feedstock for subsequent carbon dioxide hydrogenation, or it can be used to store electrical energy.

[0069] Specifically, the renewable energy power generation device and renewable energy storage system provide the necessary electrical energy for carbon dioxide capture, water electrolysis hydrogen production, carbon dioxide hydrogenation device and product separation device, and the entire system is directly or indirectly driven by renewable electrical energy.

[0070] Specifically, in the hydrogenation reaction of carbon dioxide, the volume ratio of carbon dioxide to hydrogen is 1:20 to 20:1, and can be 20:1, 19:1, 18:1, 17:1, 16:1, 15:1, 14:1, 13:1, 12:1, 11:1, 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, 2:1, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1... The ratios are 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19, 1:20, and more preferably 1:2 to 1:9; the reaction pressure is 0 to 10 MPa, and can be 0 MPa, 1 MPa, 2 MPa, 3 MPa, 4 MPa, 5 MPa, 6 MPa, 7 MPa, 8 MPa, 9 MPa, 10 MPa, and more preferably 2 to 8 MPa.

[0071] Specifically, in the carbon dioxide hydrogenation reaction, the residence time of the carbon dioxide and hydrogen mixture is 0.1 to 10000 s, which can be 0.1s, 0.2s, 0.3s, 0.4s, 0.5s, 0.6s, 0.7s, 0.8s, 0.9s, 1s, 2s, 3s, 4s, 5s, 6s, 7s, 8s, 9s, 10s, 20s, 30s, 40s, 50s, 60s, 70s, 80s, 90s, 100s, 200s, 300s, 400s, 500s, 600s, 700s, 800s, 900s, 1000s, 2000s, 3000s, 4000s, 5000s, 6000s, 7000s, 8000s, 9000s, and 10000s.

[0072] Specifically, in the carbon dioxide hydrogenation reaction, the carbon dioxide hydrogenation catalyst includes 10-80 wt% nano-metal oxide and 20-90 wt% modified ZSM-5 molecular sieve. The nano-metal oxide and modified ZSM-5 molecular sieve are treated with a silane coupling agent and then calcined to obtain the carbon dioxide hydrogenation catalyst.

[0073] The nano-metal oxide can account for 10 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, or 80 wt% of the nano-metal oxide, preferably 20 to 50 wt%.

[0074] The modified ZSM-5 molecular sieve can account for 20wt%, 30wt%, 40wt%, 50wt%, 60wt%, 70wt%, 80wt%, or 90wt% of the nano-metal oxide, preferably 50-80wt%.

[0075] Specifically, the nano-metal oxide includes component A and component B. Component A is selected from any three of iron oxide, cobalt oxide, molybdenum oxide, nickel oxide, and copper oxide, and component B is selected from any one of zirconium oxide, potassium oxide, and calcium oxide.

[0076] More specifically, component A includes component 1, component 2, and component 3. Component 1, component 2, and component 3 are any three selected from iron oxide, cobalt oxide, molybdenum oxide, nickel oxide, and copper oxide, and each accounts for 1 to 80% of the weight percentage of the nano-metal oxide. The weight percentages can be 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or 80%, with a more preferred weight percentage of 10% to 70%.

[0077] More specifically, component B accounts for 1 to 10% of the weight of the nano-metal oxide, and can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%, with a more preferred percentage being 1 to 5%.

[0078] Specifically, the modified ZSM-5 molecular sieve includes component a, component b, and ZSM-5 molecular sieve. Component a is selected from either lanthanum oxide or cerium oxide, and component b is selected from either potassium oxide or magnesium oxide.

[0079] More specifically, component a accounts for 0.1% to 5% of the weight of the modified ZSM-5 molecular sieve, and can be 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5%, with a more preferred percentage being 0.5% to 3%.

[0080] More specifically, component b accounts for 0.1% to 3% of the weight of the modified ZSM-5 molecular sieve, and can be 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, or 3%, with a more preferred percentage being 0.1% to 1.5%.

[0081] Preferably, the silane coupling agent is KH560 and / or KH570.

[0082] The method for preparing the catalyst includes the following steps:

[0083] (1) Dissolve the first metal salt in deionized water, then add sucrose and polyethylene glycol, stir to obtain a sol, dry and calcine the sol to obtain nano metal oxides;

[0084] Specifically, in step (1), the first metal salt is one or more of the nitrates of Fe, Co, Mo, Ni, Cu, Zr, K, and Ca, and the weight ratio of the first metal salt to deionized water is 15 to 40:100, which can be 15:100, 20:100, 25:100, 30:100, 35:100, or 40:100.

[0085] Specifically, in step (1), the stirring conditions are 40-95℃ for 5-15 hours, the drying conditions are 110-120℃ for 10-15 hours, and the calcination conditions are 400-600℃ for 5-15 hours.

[0086] Specifically, in step (1), the polyethylene glycol is PEG2000 and / or PEG4000;

[0087] Optionally, in step (1), the sucrose is 0.01% to 5% of the weight of the sol, and can be 0.01%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5%, preferably 0.1% to 3%.

[0088] Optionally, in step (1), the polyethylene glycol is 0.01% to 10% of the weight of the sol, and can be 0.01%, 0.05%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%, preferably 0.1% to 5%.

[0089] (2) Dissolve the second metal salt in deionized water to obtain a second metal salt solution, age the ZSM-5 molecular sieve, then impregnate the ZSM-5 molecular sieve with the modified solution, let it stand, dry it, and calcine it to obtain the modified ZSM-5 molecular sieve.

[0090] Specifically, in step (2), the second metal salt is one or more of the nitrates of La, Ce, K, and Mg, and the weight ratio of the second metal salt to deionized water is 10 to 30:100, which can be 10:100, 15:100, 20:100, 25:100, or 30:100.

[0091] Specifically, in step (2), the aging conditions are aging at 550-700℃ for 2-5 hours, the standing time is 10-15 hours, the drying conditions are drying at 100-120℃ for 8-15 hours, and the calcination conditions are calcination at 500-600℃ for 10-15 hours.

[0092] Specifically, in step (2), the ZSM-5 molecular sieve has a particle size of <800nm ​​and a silicon-to-aluminum ratio of 80 to 300, which can be 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, or 300, with a preferred ratio of 100 to 200.

[0093] (3) Disperse nano-metal oxides and modified ZSM-5 molecular sieves in deionized water, add ethanol and silane coupling agent, stir thoroughly to obtain slurry, spray dry the slurry to form a shape, then dry and calcine to obtain carbon dioxide hydrogenation catalyst.

[0094] Specifically, in step (3), ethanol accounts for 0.5% to 3% of the weight of the slurry, and can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.5%, 2%, 2.5%, or 3%.

[0095] Specifically, in step (3), the silane coupling agent accounts for 1 to 5% of the slurry weight, which can be 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5%.

[0096] More specifically, in step (3), the solid content of the slurry is 25-35 wt%, which can be 25 wt%, 26 wt%, 27 wt%, 28 wt%, 29 wt%, 30 wt%, 31 wt%, 32 wt%, 33 wt%, 34 wt%, or 35 wt%.

[0097] Specifically, in step (3), the furnace temperature during spray drying is 300-450℃, the outlet temperature of the drying tower is 130-250℃, and the spray pressure of the drying tower is 2.0-4.0MPa; the particle size of the catalyst after spray drying is 15-35μm; the drying conditions after catalyst formation are 100-130℃ for 4-7h, and the calcination conditions are 400-600℃ for 5-10h.

[0098] The present invention will be further described below through specific embodiments.

[0099] Example 1

[0100] A method for preparing a carbon dioxide hydrogenation catalyst includes the following steps:

[0101] (1) Dissolve 5 kg Fe(NO3)3·9H2O, 0.2 kg Cu(NO3)2·3H2O, 3.2 kg Ni(NO3)2·6H2O, and 0.04 kg Zr(NO3)4·5H2O in 20 kg of deionized water. After stirring evenly, add 0.05 kg sucrose and 0.2 kg PEG2000. Stir at 80 °C for 8 h to obtain a sol. Dry the sol at 120 °C for 10 h and then calcine at 480 °C for 8 h to obtain nano-metal oxides.

[0102] (2) Dissolve 92g La(NO3)3·6H2O and 4g KNO3 in 500g deionized water to obtain a modified solution. Age 1kg of nano ZSM-5 molecular sieve at 550℃ for 2h, then impregnate ZSM-5 molecular sieve with the modified solution, let stand for 12h, dry at 110℃ for 8h, and then calcine at 550℃ for 12h to obtain modified ZSM-5 molecular sieve.

[0103] (3) Disperse nano-metal oxides and modified ZSM-5 molecular sieves in 7 kg of deionized water, then add 100 g of ethanol and 300 g of silane coupling agent KH560, stir thoroughly to obtain a slurry, send the slurry into a spray drying tower, and spray dry to form a shaped catalyst under the conditions of furnace temperature 400℃, outlet temperature 150℃ and spray pressure 3.0 MPa. Then dry the shaped catalyst at 130℃ for 7 h and calcine it at 500℃ for 10 h to obtain a carbon dioxide hydrogenation catalyst.

[0104] Example 2

[0105] A renewable energy-driven system for hydrogenating carbon dioxide:

[0106] It includes a renewable energy drive unit, a carbon dioxide capture unit 3, an electrolysis water hydrogen production unit 4, a raw material buffer tank 5, a microreactor hydrogenation unit, and a product separation unit; the renewable energy drive unit includes a renewable energy power generation unit 1 and a renewable energy storage unit 2; the product separation unit includes a three-phase separator 11, a liquid hydrocarbon separation system 13, and a gas separation system 14.

[0107] The microreactor hydrogenation device comprises three groups of microreactors, and each group of microreactors is connected in parallel.

[0108] Each group of microreactors contains three microreactors, and each microreactor is connected in series.

[0109] A method for hydrogenation of carbon dioxide driven by renewable energy includes the following steps:

[0110] The system generates electricity using a solar power plant, which is then stored and used in batteries. All energy required by the entire system comes directly or indirectly from this source. Carbon dioxide is captured using a chemical absorption method. The captured carbon dioxide and hydrogen produced by the alkaline water electrolysis hydrogen production unit enter a feed buffer tank. The volume ratio of raw carbon dioxide to raw hydrogen is 1:4. The feed in the buffer tank is divided into three streams, which are then fed into the first microreactor of three microreactor groups. The reaction temperature of each microreactor group is 400℃, the reaction pressure is 3MPa, and the residence time of the feed in each microreactor is 0.5s. The products from the three microreactor groups enter a three-phase separator for separation. The separated product water is used as the feed for water electrolysis. The liquid hydrocarbon is C5+ gasoline and does not require further separation. The gaseous products enter a gas separation system to separate unreacted carbon dioxide and hydrogen, lean dry gas, low-carbon olefins, and liquefied petroleum gas (LPG). The unreacted carbon dioxide and hydrogen are divided into six streams and fed into the second and third microreactors of the three microreactor groups to continue the reaction. The composition of the carbon dioxide hydrogenation product is shown in Table 1.

[0111] Table 1. Composition of the product from Example 2: Hydrogenation of Carbon Dioxide to Low-Carbon Olefins

[0112] <![CDATA[CO2 conversion rate / %]]> 41.1 <![CDATA[C1+C2 0 / m%]]> 15.6 <![CDATA[C2 ＝ +C3 ＝ / m%]]> 66.7 C5+ liquid / m% 9.9 C5+ Aromatics in Liquid / m% 94.6

[0113] Example 3

[0114] A renewable energy-driven system for hydrogenating carbon dioxide:

[0115] The system includes a renewable energy drive unit, a carbon dioxide capture unit 3, a water electrolysis hydrogen production unit 4, a raw material buffer tank 5, a microreactor hydrogenation unit, and a product separation unit. The renewable energy drive unit includes a renewable energy power generation unit 1 and a renewable energy storage unit 2. The product separation unit includes a three-phase separator 11, a liquid hydrocarbon separation system 13, and a gas separation system 14. The microreactor hydrogenation unit comprises two sets of microreactors, each set connected in parallel. Each set of microreactors contains six microreactors, each connected in series.

[0116] A method for hydrogenation of carbon dioxide driven by renewable energy includes the following steps:

[0117] The system generates electricity using wind power generation devices, which is then stored and utilized through molten salt thermal energy storage. All energy required by the entire system comes directly or indirectly from this source. Carbon dioxide is captured using a physical absorption method. The captured carbon dioxide and hydrogen produced by an alkaline water electrolysis hydrogen production unit enter a feed buffer tank. The volume ratio of feed carbon dioxide to feed hydrogen is 1:8. The feed in the buffer tank is divided into two streams, which enter the first microreactor of two sets of microreactors. The reaction temperature of each set of microreactors is 390℃, the reaction pressure is 7MPa, and the residence time of the feed in each microreactor is 10s. The products from the two sets of microreactors enter a three-phase separator for separation. The separated product water is used as feed for water electrolysis. The liquid hydrocarbons are C5+ gasoline products, which enter a liquid hydrocarbon separation system to separate small amounts of C5+ non-aromatic gasoline, benzene, toluene, and xylene. The gaseous products enter a gas separation system to separate unreacted carbon dioxide and hydrogen, lean dry gas, low-carbon olefins, and liquefied petroleum gas (LPG). The unreacted carbon dioxide and hydrogen are divided into eight streams, which enter the second, third, fourth, and fifth microreactors of the two sets of microreactors to continue the reaction. The composition of the carbon dioxide hydrogenation product is shown in Table 2.

[0118] Table 2 Composition of the product from Example 3: Hydrogenation of carbon dioxide to olefins

[0119] <![CDATA[CO2 conversion rate / %]]> 42.4 <![CDATA[C1+C2 0 / m%]]> 14.3 <![CDATA[C2 ＝ +C3 ＝ / m%]]> 61.4 C5+ liquid / m% 15.1 C5+ liquid benzene / m% 18.3 C5+ liquid toluene / m% 44.6 Xylene in C5+ liquid / m% 29.2 C5+ liquid C9+ aromatics / m% 7.9

[0120] Example 4

[0121] A renewable energy-driven system for hydrogenating carbon dioxide:

[0122] The system includes a renewable energy drive unit, a carbon dioxide capture unit 3, a water electrolysis hydrogen production unit 4, a raw material buffer tank 5, a microreactor hydrogenation unit, and a product separation unit. The renewable energy drive unit includes a renewable energy power generation unit 1 and a renewable energy storage unit 2. The product separation unit includes a three-phase separator 11, a liquid hydrocarbon separation system 13, and a gas separation system 14. The microreactor hydrogenation unit comprises seven groups of microreactors, each group connected in parallel. Each group of microreactors contains two microreactors, each connected in series.

[0123] A method for hydrogenation of carbon dioxide driven by renewable energy includes the following steps:

[0124] The system generates electricity using a tidal power plant, which is then stored and utilized through pumped-storage hydroelectricity. All energy required by the entire system comes directly or indirectly from this source. Carbon dioxide is captured using an adsorption method. The captured carbon dioxide and hydrogen produced by a proton exchange membrane water electrolysis hydrogen production unit enter a feed buffer tank. The volume ratio of feed carbon dioxide to feed hydrogen is 1:5. The feed in the buffer tank is divided into seven streams, each entering one of the first microreactors in one of seven microreactor groups. Each microreactor group contains two microreactors for carbon dioxide hydrogenation to produce low-carbon olefins. The reaction temperature in each microreactor group is 340℃, the reaction pressure is 3.5MPa, and the residence time of the feed in each microreactor is 1s. The reaction products enter a three-phase separator for separation. The separated product water is used as feedstock for water electrolysis. The liquid hydrocarbons are C5+ gasoline products. The gaseous products enter a gas separation system to separate unreacted carbon dioxide and hydrogen, lean dry gas, low-carbon olefins, and liquefied petroleum gas (LPG). The unreacted carbon dioxide and hydrogen are evenly distributed into the microreactors to continue the reaction. The composition of the carbon dioxide hydrogenation to olefins product is shown in Table 3.

[0125] Table 3. Composition of the product from Example 4: Hydrogenation of carbon dioxide to produce low-carbon olefins.

[0126] <![CDATA[CO2 conversion rate / %]]> 40.9 <![CDATA[C1+C2 0 / m%]]> 15.5 <![CDATA[C2 ＝ +C3 ＝ / m%]]> 70.2 C5+ liquid / m% 7.2 C5+ Aromatics in Liquid / m% 97.2

[0127] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for generating low-carbon olefins using a carbon dioxide hydrogenation system driven by renewable energy, characterized in that, The carbon dioxide hydrogenation system driven by renewable energy includes a renewable energy drive unit, a carbon dioxide capture unit (3), a water electrolysis hydrogen production unit (4), a raw material buffer tank (5), a microreactor hydrogenation unit, and a product separation unit; The renewable energy drive device includes a renewable energy power generation device (1) and a renewable energy storage device (2). The product separation device includes a three-phase separator (11), a liquid hydrocarbon separation system (13), and a gas separation system (14). The method for generating low-carbon olefins using a renewable energy-driven carbon dioxide hydrogenation system is as follows: using electricity provided by a renewable energy-driven device to drive hydrogen and carbon dioxide to undergo a hydrogenation reaction under the action of a carbon dioxide hydrogenation catalyst, and then separating to obtain low-carbon olefins and gasoline. The carbon dioxide hydrogenation catalyst comprises 10-80 wt% nano-metal oxide and 20-90 wt% modified ZSM-5 molecular sieve. The nano-metal oxide and modified ZSM-5 molecular sieve are treated with a silane coupling agent and then calcined to obtain the carbon dioxide hydrogenation catalyst. The nano-metal oxide comprises component A and component B. Component A is selected from any three of iron oxide, cobalt oxide, molybdenum oxide, nickel oxide, and copper oxide, and component B is selected from any one of zirconium oxide, potassium oxide, and calcium oxide. Component B accounts for 1-10% of the weight of the nano-metal oxide. The modified ZSM-5 molecular sieve comprises component a, component b, and ZSM-5 molecular sieve. Component a is selected from either lanthanum oxide or cerium oxide, and component b is selected from either potassium oxide or magnesium oxide. Component a accounts for 0.1-5% of the weight of the modified ZSM-5 molecular sieve, and component b accounts for 0.1-3% of the weight of the modified ZSM-5 molecular sieve. The silane coupling agent is KH560 and / or KH570.

2. The method according to claim 1, characterized in that, The microreactor hydrogenation device comprises n groups of microreactors, where n ≥ 2; each group of microreactors is connected in parallel or in series.

3. The method according to claim 2, characterized in that, Each group of microreactors contains m microreactors, where m ≥ 2; each microreactor is connected in parallel or in series.

4. The method according to claim 1, characterized in that, In the hydrogenation reaction, the volume ratio of carbon dioxide to hydrogen is 1:20 to 20:1, and the reaction pressure is 0 to 10 MPa.

5. The method according to claim 1, characterized in that, In the hydrogenation reaction, the residence time of the carbon dioxide and hydrogen mixture is 0.1~10000s.

6. The method according to claim 1, characterized in that, The preparation method of the carbon dioxide hydrogenation catalyst includes the following steps: (1) Dissolve the first metal salt in deionized water, then add sucrose and polyethylene glycol, stir to obtain a sol, dry and calcine the sol to obtain nano metal oxides; (2) Dissolve the second metal salt in deionized water to obtain a second metal salt solution, age the ZSM-5 molecular sieve, then impregnate the ZSM-5 molecular sieve with the second metal salt solution, let it stand, dry it, and calcine it to obtain the modified ZSM-5 molecular sieve. (3) Disperse nano-metal oxides and modified ZSM-5 molecular sieves in deionized water, add ethanol and silane coupling agent, stir thoroughly to obtain slurry, spray dry the slurry to form a shape, then dry and calcine to obtain carbon dioxide hydrogenation catalyst.

7. The method according to claim 6, characterized in that, In step (1), the first metal salt is one or more of the nitrates of Fe, Co, Mo, Ni, Cu, Zr, K, and Ca, and the weight ratio of the first metal salt to deionized water is 15~40:100; in step (2), the second metal salt is one or more of the nitrates of La, Ce, K, and Mg, and the weight ratio of the second metal salt to deionized water is 10~30:

100.

8. The method according to claim 6, characterized in that, In step (1), the stirring conditions are 40~95℃ for 5~15h, the drying conditions are 110~120℃ for 10~15h, the calcination conditions are 400~600℃ for 5~15h, the polyethylene glycol is PEG2000 and / or PEG4000, and the sucrose and polyethylene glycol account for 0.01~5% and 0.01~10% of the weight of the sol, respectively; in step (2), the aging conditions are 550~700℃ for 2~5h, the standing time is 10~15h, the drying conditions are 100~120℃ for 8~15h, and the calcination conditions are 500~600℃ for 10~15h; the ZSM-5 molecular sieve has a particle size of <800nm ​​and a silicon-aluminum ratio of 80~300.

9. The method according to claim 6, characterized in that, In step (3), ethanol and silane coupling agent account for 0.5-3% and 1-5% of the weight of the slurry, respectively; the solid content of the slurry is 25-35 wt%.

10. The method according to claim 6, characterized in that, In step (3), the furnace temperature during spray drying is 300~450℃, the outlet temperature of the drying tower is 130~250℃, and the spray pressure of the drying tower is 2.0~4.0MPa; the particle size of the catalyst after spray drying is 15~35μm. After the catalyst is formed, the drying conditions are 100~130℃ for 4~7h, and the calcination conditions are 400~600℃ for 5~10h.

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