Preparation method of bifunctional material and application of bifunctional material in separation and quality separation of blast furnace gas carbon resources
By preparing a calcium-based dual-functional material with both CO2 capture and hydrogenation conversion properties, the problem of CO2 utilization in blast furnace gas is solved, and CO2 capture and conversion with low cost and low energy consumption is achieved, coke consumption is reduced, the material's reaction activity and circulation stability is improved, and the carbon emissions of blast furnace smelting are reduced.
Patent Information
- Application Number
- CN202510283437.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-11
- Publication Date
- 2025-07-25
AI Technical Summary
The prior art is difficult to effectively utilize CO2 in blast furnace gas, resulting in high carbon emissions of tonnes of iron and coke consumption, and existing dual-functional materials have low activity and poor circulation stability during CO2 capture and hydrogenation conversion.
A calcium-based bifunctional material with CO2 capture and hydrogenation conversion properties was prepared. Calcium, nickel, iron, magnesium and cerium materials were prepared by gradient calcining method, which was used for decarbonization and conversion of blast furnace gas, and was coupled to blast furnace for gas-based reduction.
It has achieved low-cost, low-energy consumption of CO2 capture and conversion, reduced coke consumption, reduced carbon emissions of blast furnace smelting by more than 10%, reduced iron cost by 10-30 yuan/ton, and improved material reactive activity and cycle stability.
Smart Images
Figure CN120361904A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of metallurgical energy conservation and emission reduction, and particularly relates to a preparation method of a bifunctional material and its application in the separation and fractionation of carbon resources in blast furnace gas. Background Art
[0002] Industrial emissions are one of the main sources of CO2 emissions. In 2022, the carbon emissions of the iron and steel industry in China were approximately 1.798 billion tons, accounting for about 15% of the total national carbon emissions. The iron and steel industry has currently become one of the industries with the largest carbon emissions and the most difficult to achieve the carbon neutrality goal. The blast furnace process in the iron and steel production process is the largest source of carbon emissions, accounting for about 70% of the total CO2 emissions. Achieving CO2 emissions reduction in the blast furnace is the key to realizing CO2 emissions reduction in the entire iron and steel industry.
[0003] The CO2 emissions from the blast furnace mainly exist in the form of blast furnace gas, which is mainly composed of N2 (49%), CO2 (21%), CO (25%), H2 (3%) and a small amount of CH4, O2, H2O, H2S / COS, etc. Due to its large volume and containing a certain amount of CO component, blast furnace gas is a good fuel and reducing agent. Using blast furnace gas for gas-based direct reduction of iron ore pellets to reduce the coke consumption is a feasible route to reduce carbon emissions in the blast furnace process. However, the CO2 content in blast furnace gas reaches more than 20%. On the one hand, the thermodynamic equilibrium limits the deep reduction of iron oxides in iron ore to sponge iron. On the other hand, the reduction reaction of carbon with CO2 further causes excessive consumption of coke. The above reasons make it difficult for blast furnace gas to be directly recycled to the blast furnace for utilization and unable to exert the gas-based reduction benefit of CO.
[0004] Patent CN2022100482456 reported a low-carbon ironmaking method for blast furnace gas carbon cycle, in which the blast furnace top gas is pressurized after removing CO2 and then sprayed into the blast furnace, without considering the reuse of CO2. Patents CN2023101677545, CN202310316050X, and CN2023104327577, etc., focus on capturing the CO2 component in blast furnace gas by using different technical solutions or processes. They not only do not consider the utilization of decarbonized gas but also do not take into account the reuse of CO2. Although the above inventions pay attention to the carbon emissions problem in the blast furnace process, they cannot continue to reduce the demand for coke and pulverized coal in the blast furnace, and the carbon emissions per ton of iron are still very high. There is an urgent need for a technological breakthrough.
[0005] Blast furnace gas is an important by-product of the blast furnace metallurgical process. It also contains about 25% CO, so it is a good fuel and reducing agent. Using blast furnace gas for gas-based direct reduction of iron ore pellets, thereby reducing the use of coke, is a feasible route to reduce carbon emissions from blast furnace metallurgy. However, blast furnace gas also contains about 20% CO2. The presence of CO2 not only limits the deep reduction of iron oxides in iron ore to sponge iron, but also the reduction reaction of coke and CO2 further causes excessive consumption of coke.
[0006] It is an effective method to separate and fractionate carbon resources in blast furnace gas using dual-functional materials that have both CO2 capture performance and hydrogenation catalytic conversion performance. The development and preparation of dual-functional materials is the key to whether this method can be industrialized. Summary of the invention
[0007] The purpose of the present invention is to solve the problems that the existing blast furnace gas is difficult to directly utilize, the carbon emissions per ton of iron are high, and the coke consumption is large. A method for preparing a dual-functional material and its application in the separation and fractionation of carbon resources in blast furnace gas are provided. This method breaks through the problems of low activity and poor cycle stability of the dual-functional materials used in the synergistic process of CO2 capture and hydrogenation conversion.
[0008] To achieve the above purpose, the technical solution adopted by the present invention is as follows:
[0009] A preparation method of a dual-functional material, the method comprising: fully complexing a calcium source and other metal sources under the action of a complexing agent to obtain a gel system, and gradient calcining the gel system to obtain the dual-functional material; the other metal sources can provide iron, nickel, cerium and magnesium metals.
[0010] Furthermore, the method is specifically as follows:
[0011] Step 1, weighing precursor salts of nickel, iron, magnesium, cerium and a calcium source and dissolving them in deionized water to prepare a mixed solution, wherein the molar ratio of calcium element to water in the mixed solution is 1:40-1000;
[0012] Step 2: Add a complexing agent to the mixed metal ion salt solution and let it stand for 10 minutes. The molar ratio of calcium element to complexing agent is 1:1-5.
[0013] Step 3, stirring the gel system obtained in step 2 at 60-80° C. for 2-3 hours, and drying at 130-180° C. for 6-9 hours after being fully mixed;
[0014] Step 4: Grind the product obtained in step 3 and calcine it at 200-400°C for 2h, then heat it to 650-850°C and calcine it for 3h. After sieving through a 60-120 mesh sieve, a dual-functional material that meets the requirements and has both CO2 adsorption performance and hydrogenation catalytic conversion performance is obtained.
[0015] Further, in step one, the calcium source is at least one of calcium carbonate, calcium nitrate, calcium hydroxide, calcium chloride, organic acid calcium salts (such as calcium acetate, calcium gluconate, etc.); the other metal source is at least one of the corresponding metal oxides, carbonates, nitrates, organic acid salts, and halide salts; in step two, the complexing agent is one of citric acid, tartaric acid, ethylenediaminetetraacetic acid, and stearic acid.
[0016] Further, in step one, the precursor salt of nickel is one of nickel nitrate, nickel acetate, and nickel chloride, the precursor salt of iron is one of iron nitrate, iron acetate, and iron chloride, the precursor salt of magnesium is one of magnesium nitrate, magnesium acetate, and magnesium chloride, and the precursor of cerium is one of cerium nitrate, cerium acetate, and cerium chloride.
[0017] Further, in step one, the molar ratio of calcium, nickel, iron, magnesium, and cerium is 1:0.04 - 0.2:0.04 - 0.2:0.25:0.1.
[0018] Further, in step four, the atmosphere in the calcination stage is an oxygen-containing atmosphere, preferably air.
[0019] Further, in step four, the temperature in the first stage is 250 - 350 °C, preferably 300 °C, and the temperature in the second stage is 750 - 800 °C, more preferably 800 °C.
[0020] Application of a bifunctional material prepared by the above preparation method in the separation and fractionation of carbon resources from blast furnace gas, and the application is as follows:
[0021] Step one: Heat-treat the bifunctional material in a hydrogen-containing atmosphere to fully activate the catalyst.
[0022] Step two: Use the heat-treated bifunctional material to capture carbon dioxide in blast furnace gas, and then convert the captured carbon dioxide into CO products in a hydrogen-containing atmosphere. The content of each gas component in the blast furnace gas is N2 (49%), CO2 (21%), CO (25%), H2 (3%), and a small amount of CH4, O2, H2O, H2S / COS.
[0023] Further, the specific steps of step two are as follows:
[0024] (1) Blast furnace gas is introduced into a decarbonization reactor, and CO2 in the blast furnace gas reacts with the calcium-based bifunctional material to undergo a carbonation reaction.
[0025] (2) The calcium-based bifunctional material after the reaction in the decarbonization reactor enters a conversion reactor and undergoes an in-situ conversion reaction of CO2 with hydrogen to convert the adsorbed CO2 into CO. The reacted bifunctional material returns to the decarbonization reactor to achieve recycling.
[0026] (3) The decarbonized coal gas from the decarbonization reactor and the CO / H2 product gas from the reforming reactor are mixed in a mixer and then coupled and blown into the blast furnace to give full play to the synergistic effect of the gas-based reducing agent and achieve low-carbon metal smelting.
[0027] Further, in step one, the hydrogen concentration in the hydrogen-containing gas is 5% - 100% vol, the hydrogen heat treatment temperature is 550 - 650 °C, and the treatment time is 0.5 h - 2 h; in step two, the temperature in the carbon dioxide capture stage is 600 - 750 °C; the temperature in the hydrogenation reforming stage is 550 - 750 °C, further preferably 650 - 700 °C, the time is 10 - 30 min, and the hydrogen concentration is 5% - 100%, further preferably 50% - 100%; the flow rates of the blast furnace gas and H2 gas in the decarbonization reactor and the reforming reactor are 3 - 5 m / s, the bed pressure drop is 5 - 15 kPa, the reactor temperature is 600 - 700 °C, and the pressure is 120 - 200 kPa.
[0028] Before use, the composite catalyst needs to be reduced with H2 at 650 °C for 1 h, and the reaction temperatures of both the decarbonization reactor and the reforming reactor are 650 °C.
[0029] The beneficial effects of the present invention compared with the prior art are as follows:
[0030] (1) Decarbonization with low cost and low energy consumption, the cost ≤ 150 yuan / tCO2, the energy consumption < 1.8 GJ / tCO2. Compared with the domestic decarbonization technology of the same level, both the cost and energy consumption are reduced by half.
[0031] (2) Coupled injection gives full play to the coordinated effect of the gas-based reducing agent, reduces the consumption of coke, and reduces the excessive dependence of blast furnace smelting on coke. Compared with the domestic blast furnace ironmaking of the same level, it can reduce carbon by more than 10%, and the molten iron cost is reduced by 10 - 30 yuan / ton.
[0032] (3) A composite catalyst with both catalytic and adsorption properties is provided, which solves the problems of low reaction activity and poor cycle stability of the bifunctional materials used in the existing CO2 capture and hydrogenation reforming synergy process. Description of the Drawings
[0033] Figure 1 It is a method for separating and grading the carbon resources of blast furnace gas provided by the present invention.
[0034] Among them, 1 - blast furnace; 2 - blower; 3 - decarbonization reactor; 4 - regeneration reactor; 5 - electrolytic water hydrogen production device; 6 - mixer; 7 - condenser; 8 - liquid tank;
[0035] Figure 2 It is a comparison chart of the material properties of different nickel-cerium ratios. Detailed Embodiments
[0036] The present invention will be further described below in conjunction with embodiments. The examples given are only used to explain the present invention and are not intended to limit the scope of the present invention. It should be understood that the present invention is not limited to the specific embodiments described below, and those skilled in the art can make various modifications or alterations within the scope of the claims.
[0037] Example 1:
[0038] A bifunctional material for separating and fractionating carbon resources from blast furnace gas is prepared by using the present invention, which includes the following steps:
[0039] (1) Weigh 2 g of calcium carbonate, 0.808 g of iron nitrate, 0.58 g of nickel nitrate, 1.3 g of magnesium nitrate, and 1.3 g of cerium nitrate, and dissolve them in 200 ml of deionized water to form a mixed solution (calcium:nickel:iron:magnesium:cerium = 1:0.1:0.1:0.25:0.1);
[0040] (2) Add 13.8 g of citric acid monohydrate to the mixed solution, let it stand for 10 min, and fully complex;
[0041] (3) Stir the obtained gel at 80 °C for 2 h, and then dry it at 180 °C for 6 h;
[0042] (4) Grind the solid obtained in step (3), calcine it at 300 °C for 2 h, then raise the temperature to 800 °C and calcine it for 3 h. After screening through a 60-120 mesh sieve, a bifunctional material with both CO2 adsorption performance and hydrogenation catalytic conversion performance is obtained.
[0043] Physical property data of the bifunctional material prepared in Example 1:
[0044] Specific surface area: 17.68 m 2 / g; pore volume: 0.14 cm 3 / g; pore diameter: 37.3 nm.
[0045] Performance test of the bifunctional material:
[0046] A fixed-bed experimental bench is used to simulate and explore the carbon dioxide capture and conversion performance of the bifunctional material. Carbon dioxide-nitrogen and hydrogen-nitrogen mixed gases are used as the reaction gases in the experimental process, and the concentrations of carbon dioxide and hydrogen are 17.6% and 30% respectively. An online multi-component infrared analyzer is used to analyze the composition of the tail gas, and data such as the carbon dioxide capture amount and carbon monoxide production are calculated. The specific experimental steps are as follows: Take a certain amount of the bifunctional material and place it in a fixed-bed reactor. Heat-treat it at 30% H2 / N2 and 650 °C for 1 h. Keep the temperature unchanged, introduce the carbon dioxide-nitrogen mixed gas for carbon dioxide capture, and after the capture is completed, switch to a hydrogen atmosphere to convert the captured carbon dioxide into carbon monoxide products.
[0047] Experimental results: The CO production rate was 7.3 mmol / g in the first cycle and 8 mmol / g after 15 cycles.
[0048] Example 2:
[0049] Compared with Example 1, the only difference is that the molar ratio of nickel to cerium in the bifunctional material is changed (the molar ratio of nickel to cerium in Example 1 is 5:5). The experimental groups are as follows:
[0050] Group A: nickel-cerium ratio is 0:10
[0051] Group B: nickel-cerium ratio is 2:8
[0052] Group C: nickel-cerium ratio is 8:2
[0053] Group D: nickel-cerium ratio is 10:0
[0054] The experimental results of the CO production rate for each group are as follows:
[0055] Group Number of cycles Average value Minimum value Maximum value Example 1 15 8.07 7.26 8.33 A 15 6.47 5.64 6.99 B 15 7.24 6.54 7.28 C 15 7.69 6.58 8.15 D 15 7.81 6.55 8.66
[0056] Example 3:
[0057] Compared with Example 1, the difference is that the calcium source is changed to calcium nitrate, and only calcium nitrate, nickel nitrate, magnesium nitrate and cerium nitrate are added (where calcium:nickel:magnesium:cerium = 1:0.1:0.2:0.2)
[0058] Experimental results: The CO production rate is 8.09 mmol / g.
[0059] Example 4:
[0060] Compared with Example 3, the only difference is that the calcium source is changed to calcium carbonate.
[0061] Experimental results: The CO production rate is 8.7 mmol / g.
[0062] Example 5:
[0063] Considering the influence of the actual gas components in blast furnace gas, especially water vapor, on the performance of the bifunctional material, in this example, based on Example 1, the reaction gas in the carbon dioxide capture process is changed to a carbon dioxide-water vapor-nitrogen mixture (10% H2O / N2, 17.6% CO2 / N2), and other conditions and steps remain unchanged.
[0064] Experimental results: The CO production rate is 6.76 mmol / g.
Claims
1. A preparation method of a bifunctional material, characterized in that: The method comprises: fully complexing a calcium source and other metal sources under the action of a complexing agent to obtain a gel system, and gradient calcining the gel system to obtain a dual-functional material; The other metal sources can provide iron, nickel, cerium and magnesium metals.
2. The preparation method of a bifunctional material according to claim 1, characterized in that: The method is specifically as follows: Step 1, weighing precursor salts of nickel, iron, magnesium, cerium and a calcium source and dissolving them in deionized water to prepare a mixed solution, wherein the molar ratio of calcium element to water in the mixed solution is 1:40-1000; Step 2: Add the complexing agent to the mixed solution and let it stand for 10 minutes. The molar ratio of calcium element to complexing agent is 1:1-5. Step 3, stirring the gel system obtained in step 2 at 60-80° C. for 2-3 hours, and drying at 130-180° C. for 6-9 hours after being fully mixed; Step 4: Grind the product obtained in step 3 and calcine it at 200-400° C. for 2 h, then heat it to 650-850° C. and calcine it for 3 h, and sieve it through a 60-120 mesh sieve to obtain a dual-functional material.
3. The preparation method of a bifunctional material according to claim 1 or 2, characterized in that: In step 1, the calcium source is at least one of calcium carbonate, calcium nitrate, calcium hydroxide, calcium chloride, and organic acid calcium (such as calcium acetate, calcium gluconate, etc.); the other metal sources are at least one of corresponding metal oxides, carbonates, nitrates, organic acid salts, and halide salts; in step 2, the complexing agent is one of citric acid, tartaric acid, ethylenediaminetetraacetic acid, and stearic acid.
4. The preparation method of a bifunctional material according to claim 1 or 2, characterized in that: In step 1, the precursor salt of nickel is one of nickel nitrate, nickel acetate, and nickel chloride, the precursor salt of iron is one of ferric nitrate, ferric acetate, and ferric chloride, the precursor salt of magnesium is one of magnesium nitrate, magnesium acetate, and magnesium chloride, and the precursor of cerium is one of cerium nitrate, cerium acetate, and cerium chloride.
5. The preparation method of a bifunctional material according to claim 1 or 2, characterized in that: In step 1, the molar ratio of calcium, nickel, iron, magnesium and cerium is 1:0.04-0.2:0.04-0.2:0.25:0.
1.
6. The preparation method of a bifunctional material according to claim 1 or 2, characterized in that: In step 4, the atmosphere during the calcination stage is an oxygen-containing atmosphere.
7. The preparation method of a bifunctional material according to claim 1 or 2, characterized in that: In step 4, the temperature of the first stage is 250-350°C, and the temperature of the second stage is 750-800°C.
8. Use of the bifunctional material prepared by the preparation method according to any one of claims 1 to 7 in the separation and fractionation of carbon resources in blast furnace gas, characterized in that: The application is: Step 1: heat-treating the bifunctional material in a hydrogen atmosphere to fully activate the catalyst; Step 2: Use the heat-treated dual-functional material to capture carbon dioxide in blast furnace gas, and then convert the captured carbon dioxide into CO products in a hydrogen-containing atmosphere.
9. The application according to claim 8, wherein: The step 2 is specifically as follows: (1) Blast furnace gas is introduced into a decarbonization reactor, and CO2 in the blast furnace gas reacts with the calcium-based bifunctional material to undergo a carbonation reaction; (2) The calcium-based bifunctional material after the reaction in the decarbonization reactor enters the conversion reactor and undergoes an in-situ CO2 conversion reaction with hydrogen to convert the adsorbed CO2 into CO.
10. The application according to claim 8, wherein: In Step 1, the hydrogen concentration in the hydrogen-containing gas is 5% - 100% vol, the hydrogen heat treatment temperature is 550 - 650 °C, and the treatment time is 0.5 h - 2 h; in Step 2, the temperature in the carbon dioxide capture stage is 600 - 750 °C; the temperature in the hydrogenation conversion stage is 550 - 750 °C, the time is 10 - 30 min, and the hydrogen concentration is 5% - 100%; the flow rates of blast furnace gas and H2 gas in the decarbonization reactor and the conversion reactor are 3 - 5 m / s, the bed pressure drop is 5 - 15 kPa, the reactor temperature is 600 - 700 °C, and the pressure is 120 - 200 kPa.