System for preparing synthesis gas by electrolyzing carbon dioxide as well as operation method and application of system

Abstract

The invention provides a system for preparing synthesis gas through electrolysis of carbon dioxide and an operation method and application of the system. The system comprises an oxygen-enriched combustion boiler, a flue gas treatment unit, a CO2 electrolysis unit, a synthesis gas adjusting unit, an intelligent control center and a carbon authentication module. The electrolytic tank is driven by green electricity, CO2 in oxygen-enriched combustion flue gas is converted into CO and O2, O2 is reused for oxygen-enriched combustion of the boiler, the ratio of CO to H2 in synthesis gas can be dynamically adjusted, and real-time authentication and transaction of carbon emission reduction are achieved through the block chain technology. According to the invention, the problems of low electrolysis efficiency, unstable electrolysis, fixed synthesis gas proportion, high energy consumption and untrusted carbon assets in the prior art are solved, and the technical effects of preparing the synthesis gas by coupling high-carbon-content flue gas after oxygen-enriched combustion of the boiler and green electricity through efficient electrolysis, recycling O2 generated by electrolysis to form a closed loop and reducing the carbon emission of the synthesis gas are achieved.

Description

Technical Field

[0001] The present invention relates to a system for producing synthesis gas by electrolysis of carbon dioxide, and an operation method and application thereof. Background Art

[0002] Carbon dioxide capture, utilization and storage (CCUS) technology is an important means to reduce carbon dioxide emissions in the future.

[0003] In terms of carbon dioxide utilization, electrochemical reduction of carbon dioxide to produce synthesis gas (CO and H2) has found a good outlet for carbon dioxide utilization.

[0004] However, the existing technology of producing synthesis gas by electrolysis of carbon dioxide has problems such as high energy consumption for carbon dioxide capture, low electrolysis efficiency, fixed synthesis gas ratio, intermittent fluctuation of green electricity that easily leads to unstable electrolysis process, and low system integration.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] One of the purposes of the present invention is to provide a system for producing synthesis gas by electrolysis of carbon dioxide, which can solve the problems of low electrolysis efficiency, unstable electrolysis, fixed synthesis gas ratio, high energy consumption and unreliable carbon assets in the prior art.

[0007] A second object of the present invention is to provide an operating method for a system for producing synthesis gas by electrolysis of carbon dioxide, which can efficiently prepare synthesis gas by electrolysis and reuse the O2 produced by electrolysis to form a closed loop. It can not only dynamically adjust the ratio of CO and H2 in the synthesis gas, but also realize real-time authentication and trading of carbon emission reductions through blockchain technology.

[0008] A third object of the present invention is to provide an application of a system for producing synthesis gas by electrolysis of carbon dioxide, which can fully utilize carbon dioxide and help reduce carbon dioxide emissions.

[0009] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are adopted: In a first aspect, a system for producing synthesis gas by electrolysis of carbon dioxide includes an oxyfuel combustion boiler, a flue gas treatment unit, a CO2 electrolysis unit, a synthesis gas conditioning unit, an intelligent control center, and a carbon certification module; The oxygen-enriched combustion boiler is used to generate CO2 flue gas with a concentration of ≥90%; The flue gas treatment unit is used to separate and purify the CO2 flue gas from the oxygen-enriched combustion boiler to obtain CO2 with a purity of ≥99.9%; The CO2 electrolysis unit is used to drive the electrolysis of CO2 from the flue gas treatment unit through green electricity to obtain CO and by-product O2, and at the same time, the by-product O2 is recycled to the oxygen-enriched combustion boiler; The syngas regulating unit is used to supplement H2 in the syngas through water electrolysis, thereby dynamically adjusting the ratio of CO and H2 in the syngas; The intelligent control center is based on the LSTM algorithm and is used to monitor green electricity fluctuations, electrolysis efficiency, and the ratio of CO and H2 in syngas in real time, while optimizing electrolysis parameters and O2 recycling ratio; The carbon certification module is used to monitor data through a sensor network and upload it to the blockchain platform, thereby generating tradable carbon asset certificates.

[0010] Furthermore, the blockchain platform is Hyperledger Fabric; The carbon asset certificate includes a unique hash value and a timestamp.

[0011] Furthermore, the flue gas treatment unit separates and purifies CO2 to a purity of ≥99.9% through multi-stage compression cooling and distillation tower.

[0012] Furthermore, the flue gas treatment unit uses green electricity to drive the compressor, including a multi-stage compressor unit, a pre-cooling device and a distillation tower; The multi-stage compressor unit is used to pressurize the CO2 flue gas to 1.5MPa-3MPa; The pre-cooling device is used to cool the CO2 flue gas to -50°C to -30°C; The distillation tower is used to separate CO2 from N2 and O2, discharge light components from the top of the tower, and output liquid CO2 from the bottom of the tower.

[0013] Furthermore, the electrode structure of the electrolytic cell in the CO2 electrolysis unit adopts a three-dimensional nanoporous nickel foam matrix.

[0014] Furthermore, the pore size of the three-dimensional nanoporous nickel foam matrix is ​​50nm-200nm, and the surface is loaded with Ni-Fe / graphene composite catalyst.

[0015] In a second aspect, a method for operating the system described in any one of the above items comprises the following steps: The oxygen-enriched combustion boiler generates CO2 flue gas with a concentration of ≥90%. The CO2 flue gas is captured and purified by the flue gas treatment unit to obtain purified CO2. The purified CO2 is input into the electrolytic cell in the CO2 electrolysis unit. The electrolytic cell is driven by green electricity to convert CO2 into CO and by-product O2. At the same time, the by-product O2 is recycled to the oxygen-enriched combustion boiler. The synthesis gas regulation unit supplements H2 through water electrolysis and dynamically adjusts the ratio of CO and H2 in the synthesis gas. The intelligent control center optimizes the electrolysis parameters in real time, and the carbon certification module generates blockchain carbon assets.

[0016] Furthermore, the current density of the green electricity driven electrolytic cell is 100 mA / cm 2 -300mA / cm2 , the temperature is 60℃-800℃.

[0017] Furthermore, the ratio of CO and H2 in the syngas is dynamically adjusted to 1:1-2:1.

[0018] A third aspect is an application of any of the above-mentioned systems in carbon resource utilization in high-carbon emission industries.

[0019] Compared with the prior art, the present invention has at least the following beneficial effects: The system for producing synthesis gas by electrolysis of carbon dioxide provided by the present invention includes an oxygen-enriched combustion boiler, a flue gas treatment unit, a CO2 electrolysis unit, a synthesis gas regulation unit, an intelligent control center, and a carbon certification module; specifically, the oxygen-enriched combustion boiler generates high-concentration CO2 flue gas (concentration ≥ 90%), the CO2 flue gas is captured and purified by the flue gas treatment unit, and then input into the electrolytic cell of the CO2 electrolysis unit, and the electrolytic cell is driven by green electricity to convert CO2 into CO and by-product O2, and the by-product O2 is reused in the oxygen-enriched combustion boiler, and the synthesis gas regulation unit utilizes water electrolysis to generate high-concentration CO2 flue gas (concentration ≥ 90%). To supplement the H2 in the synthesis gas, dynamically adjust the ratio of CO and H2 in the synthesis gas, the intelligent control center is used to optimize the electrolysis parameters in real time, and the carbon certification module generates blockchain carbon assets; in short, with the coordinated cooperation of various units, the system of the present invention can solve the problems of low electrolysis efficiency, unstable electrolysis, fixed synthesis gas ratio, high energy consumption and unreliable carbon assets in the existing technology, and achieves the technical effect of efficiently electrolyzing the flue gas with high carbon content after oxygen-enriched combustion in the boiler and coupling it with green electricity to prepare synthesis gas, recycling the O2 produced by electrolysis to form a closed loop, and reducing the carbon emissions of synthesis gas.

[0020] The operating method of the system for producing synthesis gas by electrolysis of carbon dioxide provided by the present invention can efficiently prepare synthesis gas by electrolysis and reuse the O2 produced by electrolysis to form a closed loop. It can not only dynamically adjust the ratio of CO and H2 in the synthesis gas, but also realize real-time authentication and trading of carbon emission reductions through blockchain technology.

[0021] The application of the system for producing synthesis gas by electrolysis of carbon dioxide provided by the present invention is suitable for carbon resource utilization in high-carbon emission industries such as electricity, chemical industry and steel, and can fully utilize carbon dioxide, which is conducive to reducing carbon dioxide emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 A schematic diagram of the system structure for producing synthesis gas by electrolysis of carbon dioxide provided in one embodiment of the present invention. DETAILED DESCRIPTION

[0024] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0025] According to a first aspect of the present invention, there is provided a system for producing synthesis gas by electrolysis of carbon dioxide, comprising an oxyfuel combustion boiler, a flue gas treatment unit, a CO2 electrolysis unit, a synthesis gas conditioning unit, an intelligent control center, and a carbon certification module; Oxygen-enriched combustion boilers are used to generate CO2 flue gas with a concentration of ≥90%; The flue gas treatment unit is used to separate and purify the CO2 flue gas from the oxygen-enriched combustion boiler to obtain CO2 with a purity of ≥99.9%; The CO2 electrolysis unit is used to electrolyze the CO2 from the flue gas treatment unit using green electricity to produce CO and by-product O2, and the by-product O2 is recycled to the oxygen-enriched combustion boiler; The syngas regulating unit is used to supplement the H2 in the syngas through water electrolysis, thereby dynamically adjusting the ratio of CO and H2 in the syngas; The intelligent control center is based on the LSTM algorithm and is used to monitor green power fluctuations, electrolysis efficiency, and the ratio of CO and H2 in syngas in real time, while optimizing electrolysis parameters and O2 recycling ratio. The carbon certification module is used to monitor data through the sensor network and upload it to the blockchain platform to generate tradable carbon asset certificates.

[0026] In the present invention, the oxygen-enriched combustion boiler generates high-concentration CO2 flue gas (concentration ≥ 90%). The CO2 flue gas is captured and purified by the flue gas treatment unit and then input into the electrolyzer of the CO2 electrolysis unit. The electrolyzer is driven by green electricity to convert CO2 into CO and by-product O2. The by-product O2 is reused in the oxygen-enriched combustion boiler. The synthesis gas regulation unit uses water electrolysis to supplement the H2 in the synthesis gas and dynamically adjusts the ratio of CO and H2 in the synthesis gas. The intelligent control center is used to optimize the electrolysis parameters in real time, and the carbon certification module generates blockchain carbon assets.

[0027] In short, with the coordinated cooperation of various units, the system of the present invention can solve the problems of low electrolysis efficiency, unstable electrolysis, fixed synthesis gas ratio, high energy consumption and unreliable carbon assets in the existing technology, and achieves the technical effect of efficiently electrolyzing the high-carbon flue gas after oxygen-enriched combustion in the boiler and coupling it with green electricity to prepare synthesis gas, recycling the O2 produced by electrolysis to form a closed loop, and reducing the carbon emissions of the synthesis gas.

[0028] It should be noted that the carbon emission reduction calculation formula of the carbon certification module is: Emission reduction = CO2 capture + oxygen reuse emission reduction - carbon emissions from electrolysis process; Among them, the emission reduction of oxygen reuse is calculated by reducing boiler fuel consumption.

[0029] In a preferred embodiment, the blockchain platform may be Hyperledger Fabric, and the carbon asset certificate includes a unique hash value and a timestamp.

[0030] In a preferred embodiment, the flue gas treatment unit purifies CO2 to a purity of ≥99.9% through multi-stage compression, cooling and separation in a distillation tower.

[0031] In the present invention, the flue gas treatment unit adopts green electricity to drive the compressor, including a multi-stage compressor unit, a pre-cooling device and a distillation tower; specifically, the multi-stage compressor unit is used to pressurize the CO2 flue gas to 1.5MPa-3MPa, the pre-cooling device is used to cool the CO2 flue gas to -50℃ to -30℃, and the distillation tower is used to separate CO2 from N2 and O2, discharge the light components from the top of the tower, and output liquid CO2 from the bottom of the tower.

[0032] In a preferred embodiment, the electrode structure of the electrolytic cell in the CO2 electrolysis unit can adopt a three-dimensional nanoporous nickel foam matrix, the pore size of which can be 50nm-200nm, and the pore size can be, for example, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 120nm, 140nm, 160nm, 180nm, 200nm, but not limited to this. Its surface can be loaded with Ni-Fe / graphene composite catalyst, which is more conducive to efficient electrolysis, and the electrolysis efficiency can reach more than 85%.

[0033] In the present invention, oxygen-enriched combustion and low-temperature condensation separation technology are used to reduce carbon capture energy consumption and improve CO2 purity. At the same time, the use of high-efficiency electrolyzers can increase the electrolysis efficiency to more than 85%, so it is highly efficient; the synthesis gas ratio can be adapted to scenarios such as methanol synthesis (1:2) and Fischer-Tropsch synthesis (1:1), so it is flexible; in addition, blockchain authenticates carbon assets and supports access to the international carbon trading market, so it is credible.

[0034] A typical system for producing synthesis gas by electrolysis of carbon dioxide, see Figure 1 , including an oxyfuel boiler, a flue gas treatment unit, a CO2 electrolysis unit, a syngas conditioning unit, an intelligent control center, and a carbon certification module; Oxygen-enriched combustion boilers are used to generate CO2 flue gas with a concentration of ≥90%; The flue gas treatment unit (cryogenic distillation) is used to separate and purify CO2 flue gas from the oxy-fuel combustion boiler to obtain CO2 with a purity of ≥99.9%. CO2 is separated through multi-stage compression, cooling and distillation. The CO2 electrolysis unit (high-efficiency electrolyzer) is used to electrolyze CO2 from the flue gas treatment unit using green electricity to produce CO and by-product O2, which is then recycled into the oxygen-enriched combustion boiler. It uses a Ni-Fe / graphene composite catalyst and three-dimensional nanoporous electrodes, achieving an electrolysis efficiency of ≥85%. The syngas regulating unit is used to supplement the H2 in the syngas through water electrolysis, thereby dynamically adjusting the ratio of CO and H2 in the syngas; The intelligent control center is based on the LSTM algorithm and is used to monitor green power fluctuations, electrolysis efficiency, and the ratio of CO and H2 in syngas in real time, while optimizing electrolysis parameters and O2 recycling ratio. The carbon certification module is used to monitor data through the sensor network and upload it to the blockchain platform to generate tradable carbon asset certificates. In summary, the system of the present invention improves the CO2 capture efficiency (≥99.8%) through oxygen-enriched combustion and low-temperature distillation technology, and combines high-efficiency electrolysis (electrolysis efficiency ≥85%) with intelligent regulation to solve the problems of low electrolysis efficiency, unstable electrolysis due to intermittent fluctuations in green electricity, fixed synthesis gas ratio, high energy consumption and unreliable carbon assets in the existing technology.

[0035] According to a second aspect of the present invention, there is provided a method for operating the system described in any one of the above items, comprising the following steps: The oxygen-enriched combustion boiler generates CO2 flue gas with a concentration of ≥90%. The CO2 flue gas is captured and purified by the flue gas treatment unit to obtain purified CO2. The purified CO2 is input into the electrolytic cell in the CO2 electrolysis unit. The electrolytic cell is driven by green electricity to convert CO2 into CO and by-product O2. At the same time, the by-product O2 is recycled to the oxygen-enriched combustion boiler. The synthesis gas regulation unit supplements H2 through water electrolysis and dynamically adjusts the ratio of CO and H2 in the synthesis gas. The intelligent control center optimizes the electrolysis parameters in real time, and the carbon certification module generates blockchain carbon assets.

[0036] The operating method of the system for producing synthesis gas by electrolysis of carbon dioxide provided by the present invention can efficiently prepare synthesis gas by electrolysis and reuse the O2 produced by electrolysis to form a closed loop. It can not only dynamically adjust the ratio of CO and H2 in the synthesis gas, but also realize real-time authentication and trading of carbon emission reductions through blockchain technology.

[0037] In a preferred embodiment, the current density of the green power driven electrolytic cell can be 100 mA / cm 2 -300mA / cm 2 , with a typical but non-limiting current density of, for example, 100 mA / cm 2 , 150mA / cm 2 , 200mA / cm 2 , 250mA / cm 2 、300mA / cm 2 The temperature may be 60°C-800°C, with typical but non-limiting examples being 60°C, 100°C, 200°C, 300°C, 400°C, 500°C, 600°C, 700°C, and 800°C.

[0038] In the present invention, the ratio of CO and H2 in the synthesis gas can be dynamically adjusted to 1:1-2:1.

[0039] According to a third aspect of the present invention, there is provided an application of any of the above-mentioned systems in reducing carbon dioxide emissions in high-carbon emission industries.

[0040] The application of the system for producing synthesis gas by electrolysis of carbon dioxide provided by the present invention is suitable for carbon resource utilization in high-carbon emission industries such as electricity, chemical industry and steel, and can fully utilize carbon dioxide, which is conducive to reducing carbon dioxide emissions.

[0041] The present invention is further described below by way of examples. Unless otherwise specified, the materials in the examples were prepared according to existing methods or directly purchased from the market.

[0042] Example 1 A system for producing synthesis gas by electrolysis of carbon dioxide, comprising an oxyfuel combustion boiler, a flue gas treatment unit, a CO2 electrolysis unit, a synthesis gas conditioning unit, an intelligent control center, and a carbon certification module; Oxygen-enriched combustion boilers are used to generate CO2 flue gas with a concentration of ≥90%; The flue gas treatment unit (cryogenic distillation) is used to separate and purify CO2 flue gas from the oxy-fuel combustion boiler to obtain CO2 with a purity of ≥99.9%. CO2 is separated through multi-stage compression, cooling and distillation. The flue gas treatment unit uses green electricity to drive the compressor, including a multi-stage compressor unit, a pre-cooling device and a distillation tower. The multi-stage compressor unit is used to pressurize the CO2 flue gas to 1.5MPa-3MPa; the pre-cooling device is used to cool the CO2 flue gas to -50℃ to -30℃; the distillation tower is used to separate CO2 from N2 and O2, discharge light components from the top of the tower, and output liquid CO2 from the bottom of the tower. The CO2 electrolysis unit (high-efficiency electrolyzer) is used to electrolyze the CO2 from the flue gas treatment unit using green electricity to produce CO and by-product O2, which is then recycled into the oxy-fuel boiler. The electrode structure of the electrolyzer in the CO2 electrolysis unit adopts a three-dimensional nanoporous nickel foam matrix with a pore size of 50nm-200nm and a Ni-Fe / graphene composite catalyst loaded on the surface, with an electrolysis efficiency of ≥85%; The syngas regulating unit is used to supplement the H2 in the syngas through water electrolysis, thereby dynamically adjusting the ratio of CO and H2 in the syngas; The intelligent control center is based on the LSTM algorithm and is used to monitor green power fluctuations, electrolysis efficiency, and the ratio of CO and H2 in syngas in real time, while optimizing electrolysis parameters and O2 recycling ratio. The carbon certification module is used to monitor data through the sensor network and upload it to the blockchain platform to generate tradable carbon asset certificates. In this embodiment, the oxyfuel combustion boiler is connected to a flue gas treatment unit, which inputs high-purity CO2 into the CO2 electrolysis unit; The input end of the electrolyzer in the CO2 electrolysis unit is connected to high-purity CO2 and green electricity, and the output end is connected to the synthesis gas conditioning unit and oxygen recycling; The intelligent control center connects the sensors of each module through the Industrial Internet of Things (IIoT).

[0043] Comparative Example 1 The only difference between this comparative example and Example 1 is that no flue gas treatment unit is provided; The rest are the same as in Example 1.

[0044] Compared with Example 1, the defect of this comparative example is that it is impossible to separate and purify the CO2 flue gas from the oxygen-enriched combustion boiler, and high-purity CO2 cannot be obtained, which is not conducive to the electrolysis of the subsequent CO2 electrolysis unit.

[0045] Comparative Example 2 The only difference between this comparative example and Example 1 is that the synthesis gas regulating unit is not provided; The rest are the same as in Example 1.

[0046] Compared with Example 1, the drawback of this comparative example is that it is impossible to replenish H2 in the synthesis gas and it is impossible to dynamically adjust the ratio of CO and H2 in the synthesis gas.

[0047] Comparative Example 3 The only difference between this comparative example and Example 1 is that no intelligent control center is provided; The rest are the same as in Example 1.

[0048] Compared with Example 1, the defect of this comparative example is that it is impossible to monitor the green electricity fluctuation in real time and optimize the electrolysis parameters, resulting in unstable electrolysis and poor electrolysis effect.

[0049] Test Example 1 The system for producing synthesis gas by electrolysis of carbon dioxide in Example 1 is applied to methanol synthesis in a stable green electricity scenario: In industrial parks with stable photovoltaic power generation, the system operates at full capacity, capturing CO2 and then electrolyzing it to produce methanol synthesis gas (CO:H2 ratio is 1:2), and the oxygen is recycled for oxygen-enriched combustion in the boiler; enter: 1. Oxygen-enriched combustion boiler: Fuel Type: Natural Gas; Flue gas flow: 1800Nm 3 / h; CO2 concentration: 93% (volume fraction); 2. Flue gas treatment unit: Compression pressure: 2.2MPa; Pre-cooling temperature: -45℃ (using liquid ammonia refrigeration); Distillation tower operating temperature: -25°C (tower top) / -15°C (tower bottom); 3. CO2 electrolysis unit (electrolyzer): Catalyst: Ni-Fe / graphene composite catalyst (Fe loading 10 wt%); Current density: 220 mA / cm 2 ; Working temperature: 80℃ (PEM mode); 4. Green electricity supply: Power: 1.5 MW (photovoltaic power generation, 24-hour energy storage and smoothing); Output: Synthesis gas production: CO 11.5 tons / day, H2 23 tons / day, CO:H2=1:2; Methanol synthesis: Synthesis gas is compressed and fed into the methanol reactor, with a daily output of 10.8 tons (92% conversion rate); Economic benefits: Carbon trading income: 34.5 tons / day × $50 / ton = $1,725 / day (approximately $630,000 / year); Fuel cost savings from oxygen recycling: $1,200 / day.

[0050] Test Example 2 The system for producing synthesis gas by electrolysis of carbon dioxide in Example 1 is applied to dynamic regulation and acetic acid synthesis under green electricity fluctuation scenarios: In areas with fluctuating wind power (nighttime low power of 0.6 MW, daytime peak power of 1.9 MW), the system dynamically adjusts electrolysis parameters to produce acetic acid synthesis gas (CO:H2 = 1:2); enter: 1. Flue gas treatment unit: Compression pressure: 1.8MPa (reduced pressure operation during off-peak period); Pre-cooling temperature: -35℃ (energy-saving mode during off-peak hours); 2. CO2 electrolysis unit (electrolyzer): Switch to SOEC mode (high temperature operation) during off-peak hours; Temperature: 750℃; Current density: 140mA / cm 2 ; Electrolysis efficiency: 76%; Switch to PEM mode during peak hours: Temperature: 70℃; Current density: 260 mA / cm 2 ; Electrolysis efficiency: 84%; 3. Green electricity supply: Average daily power: 1.2 MW (fluctuation range 0.6-1.9 MW); Output: During the low period, the system switches to high-temperature SOEC mode (78% efficiency) and adjusts the syngas ratio to 2:1. Average daily CO2 capture capacity: 15 tons / day; O2 reuse emission reduction: 4.2 tons / day (fuel consumption reduced by 11%); Total emission reduction: 19.2 tons / day; Synthesis gas production: Low period: CO 5.2 tons / day, H2 2.6 tons / day (2:1); Peak hours: CO 7.1 tons / day, H2 7.1 tons / day (1:1); Average daily total production: CO 12.3 tons / day, H2 9.7 tons / day; Acetic acid synthesis: CO:H2=1:2 synthesis gas is used for acetic acid production, with a daily output of 8.5 tons (selectivity 85%); Economical: Carbon trading income: 19.2 tons / day × US$50 = US$960 / day; Dynamic adjustment saves electricity consumption: $200 / day.

[0051] Test Example 3 The system for producing synthesis gas by electrolysis of carbon dioxide in Example 1 is applied to a large-scale steel plant: A large steel plant deployed 10 systems to process blast furnace gas and coke oven flue gas, achieving large-scale CO2 capture and batch trading of carbon assets; enter: 1. Smoke source: Blast furnace gas: CO2 concentration 25% (increased to 90% through oxygen-enriched combustion); Coke oven flue gas: CO2 concentration 18% (increased to 88% through oxygen-enriched combustion); 2. Flue gas treatment unit: Total processing capacity: 25,000Nm 3 / h; Parallel distillation towers: 5, with a single tower processing capacity of 5,000 Nm 3 / h; 3. Green electricity supply: Source: Factory photovoltaic + wind power + energy storage system; Total power: 12 MW (85% utilization); Output: 1. Large-scale capture and electrolysis: Total CO2 capture capacity: 320 tons / day (capture rate 99.7%); Electrolyzer cluster: Single slot power 1.2 MW, total power 12 MW; Average daily CO production: 136 tons / day (86% efficiency); By-product O2 amount: 204 tons / day (purity 99.3%); 2. Synthesis gas utilization: CO:H2=1:2 synthesis gas is used for methanol synthesis in the plant, with a daily output of 125 tons; The remaining CO is used to produce diesel through Fischer-Tropsch synthesis, with a daily output of 38 tons; 3. Carbon asset packaging certification: Calculation of emission reductions: Emission reduction = 320 tons CO2 / day (capture) + 65 tons CO2 / day (O2 reuse) = 385 tons CO2 / day; The blockchain platform packages data from 10 systems and generates Gold Standard certificates (GS#567890) daily, resulting in an annual emission reduction of 140,525 tons; Carbon trading: A long-term agreement was signed at $52 per ton, generating annual revenue of $7.307 million. Economic benefits: Carbon trading income: US$7.307 million / year; Syngas derivatives output value: methanol $45 million / year + diesel $12 million / year; Environmental benefits: It replaces the original coke-to-syngas process, reducing CO2 emissions by 140,525 tons annually.

[0052] In summary, the system of the present invention adopts oxygen-enriched combustion plus low-temperature distillation and green electricity electrolysis coupling technology to improve capture efficiency and reduce energy consumption, while realizing a four-dimensional technical closed loop: intelligent regulation, efficient electrolysis, flexible adjustment of synthesis gas, and deep integration of carbon certification to achieve full-chain management of carbon resources.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A system for producing synthesis gas by electrolysis of carbon dioxide, characterized in that: It includes an oxyfuel boiler, a flue gas treatment unit, a CO2 electrolysis unit, a syngas conditioning unit, an intelligent control center, and a carbon certification module; The oxygen-enriched combustion boiler is used to generate CO2 flue gas with a concentration of ≥90%; The flue gas treatment unit is used to separate and purify CO2 flue gas from the oxy-fuel combustion boiler to obtain CO2 with a purity of ≥99.9%; The CO2 electrolysis unit is used to drive the electrolysis of CO2 from the flue gas treatment unit through green electricity to obtain CO and by-product O2, and at the same time, the by-product O2 is recycled to the oxygen-enriched combustion boiler; The syngas regulating unit is used to supplement H2 in the syngas through water electrolysis, thereby dynamically adjusting the ratio of CO and H2 in the syngas; The intelligent control center is based on the LSTM algorithm and is used to monitor green electricity fluctuations, electrolysis efficiency, and the ratio of CO and H2 in syngas in real time, while optimizing electrolysis parameters and O2 recycling ratio; The carbon certification module is used to monitor data through a sensor network and upload it to the blockchain platform, thereby generating tradable carbon asset certificates.

2. The system according to claim 1, wherein: The blockchain platform is Hyperledger Fabric; The carbon asset certificate includes a unique hash value and a timestamp.

3. The system according to claim 1 or 2, characterized in that The flue gas treatment unit purifies CO to a purity of ≥99.9% through multi-stage compression cooling and distillation tower separation.

4. The system according to claim 3, characterized in that The flue gas treatment unit uses green electricity to drive the compressor, including a multi-stage compressor unit, a pre-cooling device and a distillation tower; The multi-stage compressor unit is used to pressurize the CO2 flue gas to 1.5MPa-3MPa; The pre-cooling device is used to cool the CO2 flue gas to -50°C to -30°C; The distillation tower is used to separate CO2 from N2 and O2, discharge light components from the top of the tower, and output liquid CO2 from the bottom of the tower.

5. The system according to claim 1 or 2, characterized in that The electrode structure of the electrolytic cell in the CO2 electrolysis unit adopts a three-dimensional nanoporous nickel foam matrix.

6. The system according to claim 5, characterized in that The pore size of the three-dimensional nanoporous nickel foam matrix is ​​50nm-200nm, and the surface is loaded with a Ni-Fe / graphene composite catalyst.

7. A method for operating the system according to any one of claims 1 to 6, characterized in that: The following steps are involved: The oxygen-enriched combustion boiler generates CO2 flue gas with a concentration of ≥90%. The CO2 flue gas is captured and purified by the flue gas treatment unit to obtain purified CO2. The purified CO2 is input into the electrolyzer in the CO2 electrolysis unit. The electrolyzer is driven by green electricity to convert CO2 into CO and by-product O2. At the same time, the by-product O2 is recycled to the oxygen-enriched combustion boiler. The synthesis gas regulation unit supplements H2 through water electrolysis and dynamically adjusts the ratio of CO and H2 in the synthesis gas. The intelligent control center optimizes the electrolysis parameters in real time, and the carbon certification module generates blockchain carbon assets.

8. The operating method according to claim 7, characterized in that: The current density of the green electricity driven electrolytic cell is 100 mA / cm 2 -300mA / cm 2 , the temperature is 60℃-800℃.

9. The operating method according to claim 7, characterized in that: The ratio of CO and H2 in the dynamic adjustment synthesis gas is 1:1-2:

1.

10. Application of the system according to any one of claims 1 to 6 in carbon resource utilization in high carbon emission industries.

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