Method and device for removing carbon dioxide in flue gas by high gravity and mineralization

Abstract

The present application relates to the technical field of carbon dioxide removal from flue gas, and is a method and device for removing carbon dioxide from flue gas by supergravity mineralization, the former comprising: preparing a calcium-containing mineralization solution; reacting the calcium-containing mineralization solution with flue gas containing CO2 to remove CO2 from the flue gas, obtaining a suspension containing calcium carbonate and purified gas; and separating and filtering the suspension containing calcium carbonate to obtain superfine calcium carbonate; and the latter comprising a solid-liquid separator, a supergravity mineralization reactor, a liquid-solid separator, a filter and a heat exchanger. The present application uses an efficient reaction device to make CO2 in flue gas react with raw materials containing alkaline or alkaline earth metal oxides to generate carbonates, thereby being solidified and sealed for use, without the need for a capture and purification process, directly converting CO2 in flue gas into green carbon sequestration calcium carbonate, which can achieve efficient separation of carbon dioxide from flue gas in power plants, and can also achieve resource recycling and efficient utilization of CO2 and carbon, achieving the goal of emission reduction.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide removal technology in flue gas, and is a method and apparatus for removing carbon dioxide from flue gas using ultragravity mineralization. Background Technology

[0002] In recent years, with rapid industrial development and the consumption of large quantities of fossil fuels, the massive emissions of carbon dioxide have led to increasingly severe global climate change problems. Due to inadequate carbon dioxide recovery measures, less than 1% of carbon dioxide emissions can be recovered and reused annually, making carbon dioxide capture and recycling a focus of widespread attention both domestically and internationally.

[0003] Currently, carbon dioxide emissions from flue gas from coal-fired power plants in my country account for more than half of the total carbon dioxide emissions. Therefore, effectively removing and reusing carbon dioxide from flue gas is one of the key pathways for carbon emission reduction. Organic amine materials are often used to capture carbon dioxide from flue gas, which is relatively expensive, requires complex capture equipment, and demands high temperatures and pressures. The organic amine chemical absorption method absorbs carbon dioxide from flue gas at low temperatures (40℃), then the solution is heated (above 100℃), causing the carbon dioxide to desorb from the chemical solvent, resulting in the collection of high-concentration carbon dioxide. This method has advantages such as fast absorption speed, high absorption capacity, and high purity of recovered carbon dioxide. However, the commercial application of MDEA (N-methyldiethanolamine) for carbon removal faces significant limitations, mainly due to the following reasons: firstly, the operating energy consumption is too high, and the energy consumption for absorbent regeneration is also very large; secondly, MDEA absorbent suffers from oxidation and degradation during operation, leading to excessive absorbent loss. Furthermore, existing power plant flue gas carbon dioxide capture devices mostly use power plant steam extraction and waste heat from flue gas as regeneration heat sources, which reduces the power plant's power generation efficiency.

[0004] Chinese patent document CN108246090A discloses a wet decarburization process using steel slag slurry. This process involves grinding steelmaking slag (containing a large amount of CaO) and adding water to create a slurry, which absorbs carbon dioxide from flue gas. This achieves the recycling of waste materials such as steel slag and reduces carbon dioxide emissions, representing a wet decarburization technology. However, its reaction efficiency is low, meaning the reaction cannot reach equilibrium in a short time, resulting in high production costs.

[0005] Therefore, reducing the energy consumption of carbon dioxide in flue gas and improving the economic efficiency of the process are urgent problems to be solved in flue gas carbon dioxide capture. Summary of the Invention

[0006] This invention provides a method and apparatus for removing carbon dioxide mineralization from flue gas using supergravity, which overcomes the shortcomings of the prior art and can effectively solve the problems of complex carbon dioxide removal processes, high energy consumption, and high costs in existing power plant flue gas.

[0007] One of the technical solutions of this invention is achieved through the following measures: a method for removing carbon dioxide from flue gas using ultragravity mineralization, comprising the following steps: The first step is to prepare a calcium-containing mineralization solution; The second step involves reacting the calcium-containing mineralized liquid with the CO2-containing flue gas to remove the CO2 from the flue gas, resulting in a calcium carbonate suspension and purified gas. The third step is to separate and filter the calcium carbonate suspension to obtain ultrafine calcium carbonate.

[0008] The following are further optimizations and / or improvements to one of the above-mentioned technical solutions: In the first step above, the specific preparation steps of the calcium-containing mineralizing solution are carried out according to the following method: S1, grinding the calcium carbide slag or steel slag containing CaO to obtain solid powder; S2, after adjusting the pH of the ammonium chloride solution to 5.8 to 6.5, the solid powder is mixed with the ammonium chloride solution to obtain the first mixture; S3, adjust the pH of the first mixture to 8 to 9, raise the temperature to 80°C to 90°C, stir the reaction, and obtain a solid-liquid mixture; S4. The solid-liquid mixture is separated to obtain the supernatant, which is the calcium-containing mineralized solution.

[0009] In step S1 above, the calcium carbide slag containing CaO is ground to obtain solid powder, wherein the CaO content in the calcium carbide slag is ≥70%, and the particle size of the obtained solid powder is 100 mesh to 200 mesh; or / and, in step S2, the concentration of ammonium chloride solution is 0.5 mol / L to 1 mol / L; or / and, in step S3, the stirring time is 0.5 h to 2 h.

[0010] In step S1 above, the particle size of the solid powder obtained is 200 mesh.

[0011] In the second step above, the molar ratio of calcium-containing mineralized liquid to CO2-containing flue gas is 1 to 1.2:1.

[0012] In the second step above, the molar ratio of calcium-containing mineralized solution to CO2-containing flue gas is 1.2:1.

[0013] In the second step above, the reaction conditions between the calcium-containing mineralized solution and the CO2-containing flue gas include: a reaction pressure of 0.4 MPa to 1.0 MPa, a reaction temperature of 30°C to 60°C, and a residence time of the CO2-containing flue gas in the calcium-containing mineralized solution of 15 s to 100 s.

[0014] In the second step above, the reaction conditions between the calcium-containing mineralized solution and the CO2-containing flue gas include: a reaction pressure of 0.7 MPa to 0.8 MPa, a reaction temperature of 45°C to 50°C, and a residence time of the CO2-containing flue gas in the calcium-containing mineralized solution of 30 to 60 seconds.

[0015] The second technical solution of the present invention is achieved through the following measures: an apparatus for implementing a method of removing carbon dioxide from flue gas using centrifugal force, comprising a solid-liquid separator, a centrifugal mineralization reactor, a liquid-solid separator, a filter, and a heat exchanger. The solid-liquid separator has a feed inlet at its top, a solvent inlet pipeline is fixedly connected to the upper liquid inlet of the solid-liquid separator, a calcium-containing mineralization liquid pipeline is fixedly connected between the middle liquid outlet of the solid-liquid separator and the lower liquid inlet of the centrifugal mineralization reactor, and a CO2-containing gas inlet pipeline is fixedly connected to the heat exchanger. A flue gas pipeline is fixedly connected to the heat exchanger outlet and the bottom inlet of the supergravity mineralization reactor. A reaction liquid pipeline is fixedly connected to the bottom outlet of the supergravity mineralization reactor and the top inlet of the liquid-solid separator. A suspension pipeline is fixedly connected to the bottom outlet of the liquid-solid separator and the inlet of the filter. A product output pipeline is fixedly connected to the outlet of the filter. A purified gas output pipeline is fixedly connected to the top outlet of the supergravity mineralization reactor. A coarse sand discharge pipeline is fixedly connected to the bottom outlet of the solid-liquid separator.

[0016] The following are further optimizations and / or improvements to the second technical solution of the above invention: A regeneration circulating solvent pipeline is fixedly connected between the liquid outlet in the middle of the above-mentioned liquid-solid separator and the solvent inlet pipeline.

[0017] This invention employs a highly efficient reaction device that allows CO2 in flue gas to react with raw materials containing alkaline or alkaline earth metal oxides to generate carbonates, which are then solidified, sealed, and utilized without the need for a capture and purification process. This directly converts CO2 in flue gas into green carbon-fixing calcium carbonate, achieving both efficient separation of carbon dioxide from power plant flue gas and efficient recycling of CO2 and carbon, thus achieving emission reduction goals. Attached Figure Description

[0018] Appendix Figure 1 This is a schematic diagram of the process flow of Embodiment 9 of the present invention.

[0019] The codes in the attached diagram are as follows: 1 is a solid-liquid separator, 2 is a high-gravity mineralization reactor, 3 is a liquid-solid separator, 4 is a filter, 5 is a heat exchanger, 6 is a solvent inlet pipeline, 7 is a calcium-containing mineralization liquid pipeline, 8 is a CO2-containing flue gas pipeline, 9 is an air inlet pipeline, 10 is a reaction liquid pipeline, 11 is a suspension pipeline, 12 is a product output pipeline, 13 is a purified gas output pipeline, 14 is a coarse sand discharge pipeline, and 15 is a regeneration circulating solvent pipeline. Detailed Implementation

[0020] This invention is not limited to the following embodiments; specific implementation methods can be determined based on the technical solution of this invention and actual circumstances. Unless otherwise specified, all chemical reagents and chemical products mentioned in this invention are well-known and commonly used chemical reagents and chemical products in the prior art.

[0021] The present invention will be further described below with reference to embodiments: Example 1: The method for removing carbon dioxide from flue gas using ultragravity mineralization is carried out according to the following steps: The first step is to prepare a calcium-containing mineralization solution; The second step involves reacting the calcium-containing mineralized liquid with the CO2-containing flue gas to remove the CO2 from the flue gas, resulting in a calcium carbonate suspension and purified gas. The third step is to separate and filter the calcium carbonate suspension to obtain ultrafine calcium carbonate.

[0022] This invention utilizes hazardous waste carbide slag and steel slag, selectively extracting calcium as a mineralizing solution to capture carbon dioxide in flue gas without concentration, generating high-value-added ultrafine calcium carbonate. The entire process is green and environmentally friendly, with excellent application prospects. It achieves the mineralization and solidification of carbon dioxide into carbon-fixed calcium carbonate (CaCO3) without the need for capture and purification processes, directly converting CO2 in flue gas into the green mineralized product calcium carbonate (CaCO3). The mineralized product calcium carbonate represents the most thermodynamically stable state of carbon dioxide, achieving long-term, continuous, and stable carbon fixation. The mineralized product calcium carbonate has economic value and can be widely used in industries such as construction, plastics, papermaking, and coatings, with a huge market capacity. It realizes the resource recycling of CO2, achieving both efficient separation of carbon dioxide from power plant flue gas and efficient carbon utilization to achieve emission reduction goals.

[0023] Example 2: As an optimization of the above example, in the first step, the specific preparation steps of the calcium-containing mineralization solution are carried out according to the following method: S1, grinding the calcium carbide slag or steel slag containing CaO to obtain solid powder; S2, after adjusting the pH of the ammonium chloride solution to 5.8 to 6.5 (weakly acidic), the solid powder is mixed with the ammonium chloride solution to obtain the first mixture; S3, adjust the pH of the first mixture to 8 to 9, raise the temperature to 80°C to 90°C, stir the reaction, and obtain a solid-liquid mixture; S4. The solid-liquid mixture is separated to obtain the supernatant, which is the calcium-containing mineralized solution.

[0024] If necessary, by adjusting the pH value of the first mixture, the selectivity of calcium can reach 97%, thus avoiding the extraction of Fe ions into the mineralization solution.

[0025] Example 3: As an optimization of the above example, in step S1, the carbide slag containing CaO is ground to obtain solid powder, wherein the CaO content in the carbide slag is ≥70%, and the particle size of the obtained solid powder is 100 mesh to 200 mesh; in step S2, the concentration of ammonium chloride solution is 0.5 mol / L to 1 mol / L; in step S3, the stirring time is 0.5 h to 2 h.

[0026] Example 4: As an optimization of the above example, in step S1, the particle size of the obtained solid powder is 200 mesh.

[0027] Example 5: As an optimization of the above example, in the second step, the molar ratio of calcium-containing mineralized liquid to CO2-containing flue gas is 1 to 1.2:1.

[0028] Example 6: As an optimization of the above example, in the second step, the molar ratio of calcium-containing mineralized liquid to CO2-containing flue gas is 1.2:1.

[0029] Example 7: As an optimization of the above example, in the second step, the reaction conditions of the calcium-containing mineralized liquid and the CO2-containing flue gas include: a reaction pressure of 0.4 MPa to 1.0 MPa, a reaction temperature of 30°C to 60°C, and a residence time of the CO2-containing flue gas in the calcium-containing mineralized liquid of 15 s to 100 s.

[0030] The implementation of Embodiment 7 of the present invention can achieve a CO2 removal rate of over 90% in flue gas.

[0031] Example 8: As an optimization of the above example, in the second step, the reaction conditions between the calcium-containing mineralized liquid and the CO2-containing flue gas include: a reaction pressure of 0.7 MPa to 0.8 MPa, a reaction temperature of 45°C to 50°C, and a residence time of the CO2-containing flue gas in the calcium-containing mineralized liquid of 30 s to 60 s.

[0032] The implementation of Embodiment 8 of the present invention can achieve a CO2 removal rate of over 95% in flue gas.

[0033] Example 9: As attached Figure 1As shown, the apparatus for implementing the carbon dioxide mineralization method for removing carbon dioxide from flue gas using centrifugal force includes a solid-liquid separator 1, a centrifugal mineralization reactor 2, a liquid-solid separator 3, a filter 4, and a heat exchanger 5. The solid-liquid separator 1 has a feed inlet at its top, and a solvent inlet line 6 is fixedly connected to the upper inlet of the solid-liquid separator 1. A calcium-containing mineralization liquid line 7 is fixedly connected between the middle outlet of the solid-liquid separator 1 and the lower inlet of the centrifugal mineralization reactor 2. The inlet of the heat exchanger 5 is fixedly connected to a CO2-containing flue gas line 8, and the outlet of the heat exchanger 5 is connected to the centrifugal mineralization reactor 2. An air inlet pipeline 9 is fixedly connected between the bottom air inlet of gravity mineralization reactor 2 and the top air inlet of liquid-solid separator 3. A reaction liquid pipeline 10 is fixedly connected between the bottom liquid outlet of liquid-solid separator 3 and the inlet of filter 4. A suspension pipeline 11 is fixedly connected between the bottom outlet of liquid-solid separator 3 and the inlet of filter 4. A product output pipeline 12 is fixedly connected between the outlet of filter 4 and the top air outlet of gravity mineralization reactor 2. A purified gas output pipeline 13 is fixedly connected between the top air outlet of solid-liquid separator 2 and the bottom outlet of solid-liquid separator 1. A coarse sand discharge pipeline 14 is fixedly connected between the bottom outlet of solid-liquid separator 1.

[0034] Example 10: As an optimization of the above embodiments, as shown in the appendix Figure 1 As shown, a regeneration circulating solvent pipeline 15 is fixedly connected between the liquid outlet in the middle of the liquid-solid separator 3 and the solvent inlet pipeline 6.

[0035] As needed, the regenerated solvent is returned to the regeneration circulation solvent line 15 for reuse, saving production costs.

[0036] Unless otherwise specified, all equipment and devices used in this invention are existing and commonly known in the art.

[0037] Depending on the needs, the pipelines and equipment of the apparatus for implementing the carbon dioxide mineralization method for removing carbon dioxide from flue gas by supergravity may also be equipped with conventional valves, thermometers and pressure gauges known and commonly used in the art, as required by production.

[0038] Example 11: The method for removing carbon dioxide from flue gas using ultragravity mineralization is carried out according to the following steps: The first step is to prepare a calcium-containing mineralizing solution: S1, made from carbide slag with 71% CaO, is ground into a 100-mesh powder to obtain a solid powder. S2, using a 0.8 mol / L ammonium chloride solution, adjusts the pH of the solution to 5.8, and mixes it with the solid powder to obtain the first mixture. S3, adjust the pH of the first mixture to 8.3, raise the temperature to 80℃, and stir for 2 hours to obtain a solid-liquid mixture. S4. The solid-liquid mixture is subjected to solid-liquid separation to obtain the supernatant, which is the calcium-containing mineral solution, in which the calcium extraction rate is 90%. The second step involves reacting calcium-containing mineralized liquid with CO2-containing flue gas at a molar ratio of 1.2:1 in a high-gravity reactor to remove CO2 from the flue gas, resulting in a calcium carbonate suspension and purified gas. The reaction pressure is 0.6 MPa, the reaction temperature is 50°C, and the residence time is 60 s. The third step is to separate and filter the calcium carbonate suspension to obtain ultrafine calcium carbonate (i.e., nano-sized light calcium carbonate).

[0039] In Example 11 of this invention, the CO2 content in the flue gas before the reaction was 12%, and the CO2 content in the purified flue gas exiting the supergravity reactor after the reaction was 0.5%, with a CO2 conversion rate (recovery rate) of 95.8%.

[0040] The obtained product, nano-grade light calcium carbonate, has a purity of 98.5%, meeting the industrial precipitated calcium carbonate quality standard HG / T2226-2010.

[0041] Example 12: The method for removing carbon dioxide from flue gas using ultragravity mineralization is carried out according to the following steps: The first step is to prepare a calcium-containing mineralizing solution: S1, made from carbide slag with 75% CaO, is ground into a 200-mesh powder to obtain a solid powder. S2, using a 1.0 mol / L ammonium chloride solution, adjusts the pH of the solution to 5.8, and mixes it with the solid powder to obtain the first mixture. S3, adjust the pH of the first mixture to 8.8, raise the temperature to 80℃, and stir for 2 hours to obtain a solid-liquid mixture. S4. The solid-liquid mixture is subjected to solid-liquid separation to obtain the supernatant, which is the calcium-containing mineral solution, in which the calcium extraction rate is 72%. The second step involves reacting calcium-containing mineralized liquid with CO2-containing flue gas at a molar ratio of 1.2:1 in a high-gravity reactor to remove CO2 from the flue gas, resulting in a calcium carbonate suspension and purified gas. The reaction pressure is 0.6 MPa, the reaction temperature is 60°C, and the residence time is 60 s. The third step is to separate and filter the calcium carbonate suspension to obtain ultrafine calcium carbonate (i.e., nano-sized light calcium carbonate).

[0042] In Example 11 of this invention, the CO2 content in the flue gas before the reaction was 12.5%, and the CO2 content in the purified flue gas exiting the supergravity reactor after the reaction was 0.3%, with a CO2 conversion rate (recovery rate) of 97.6%.

[0043] The obtained product, nano-grade light calcium carbonate, has a purity of 99%, meeting the industrial precipitated calcium carbonate quality standard HG / T2226-2010.

[0044] Example 13: The method for removing carbon dioxide from flue gas using ultragravity mineralization is carried out according to the following steps: The first step is to prepare a calcium-containing mineralizing solution: S1, using carbide slag, CaO: 80%, ground into 100-mesh powder, yields a solid powder. S2, using a 0.5 mol / L ammonium chloride solution, adjust the pH of the solution to 6.0, and mix it with the solid powder to obtain the first mixture. S3, adjust the pH of the first mixture to 8.3, raise the temperature to 80℃, and stir for 2 hours to obtain a solid-liquid mixture. S4. The solid-liquid mixture is subjected to solid-liquid separation to obtain the supernatant, which is the calcium-containing mineral solution, in which the calcium extraction rate is 91%. The second step involves reacting calcium-containing mineralized liquid with CO2-containing flue gas at a molar ratio of 1.1:1 in a high-gravity reactor to remove CO2 from the flue gas, resulting in a calcium carbonate suspension and purified gas. The reaction pressure is 0.6 MPa, the reaction temperature is 50°C, and the residence time is 45 s. The third step is to separate and filter the calcium carbonate suspension to obtain ultrafine calcium carbonate (i.e., nano-sized light calcium carbonate).

[0045] In Example 13 of this invention, the CO2 content in the flue gas before the reaction was 11.9%, and the CO2 content in the purified flue gas exiting the supergravity reactor after the reaction was 0.5%, with a CO2 conversion rate (recovery rate) of 95.7%.

[0046] The obtained product, nano-grade light calcium carbonate, has a purity of 98%, meeting the industrial precipitated calcium carbonate quality standard HG / T2226-2010.

[0047] Example 14: The method for removing carbon dioxide from flue gas using ultragravity mineralization is carried out according to the following steps: The first step is to prepare a calcium-containing mineralizing solution: S1, using steel slag, CaO: 35%, ground into 150-mesh powder, yields a solid powder. S2, using a 1.0 mol / L ammonium chloride solution, adjusts the pH of the solution to 5.6, and mixes it with the solid powder to obtain the first mixture. S3, adjust the pH of the first mixture to 8.8, raise the temperature to 80℃, and stir for 2 hours to obtain a solid-liquid mixture. S4. The solid-liquid mixture is subjected to solid-liquid separation to obtain the supernatant, which is the calcium-containing mineral solution, in which the calcium extraction rate is 90%. The second step involves reacting calcium-containing mineralized liquid with CO2-containing flue gas at a molar ratio of 1.2:1 in a high-gravity reactor to remove CO2 from the flue gas, resulting in a calcium carbonate suspension and purified gas. The reaction pressure is 0.6 MPa, the reaction temperature is 60°C, and the residence time is 60 s. The third step is to separate and filter the calcium carbonate suspension to obtain ultrafine calcium carbonate (i.e., nano-sized light calcium carbonate).

[0048] In Example 14 of this invention, the CO2 content in the flue gas before the reaction was 11.5%, and the CO2 content in the purified flue gas exiting the supergravity reactor after the reaction was 0.4%, with a CO2 conversion rate (recovery rate) of 96.5%.

[0049] The obtained product, nano-grade light calcium carbonate, has a purity of 98.5%, meeting the industrial precipitated calcium carbonate quality standard HG / T2226-2010.

[0050] Example 15: The method for removing carbon dioxide from flue gas using ultragravity mineralization is carried out according to the following steps: The first step is to prepare a calcium-containing mineralizing solution: S1, using carbide slag, CaO: 70%, ground into 100-mesh powder, yields a solid powder. S2, using a 1.0 mol / L ammonium chloride solution, adjusts the pH of the solution to 5.8, and mixes it with the solid powder to obtain the first mixture. S3, adjust the pH of the first mixture to 8.5, raise the temperature to 80℃, and stir for 2 hours to obtain a solid-liquid mixture. S4. The solid-liquid mixture is subjected to solid-liquid separation to obtain the supernatant, which is the calcium-containing mineral solution, in which the calcium extraction rate is 90%. The second step involves reacting calcium-containing mineralized liquid with CO2-containing flue gas at a molar ratio of 1.1:1 in a high-gravity reactor to remove CO2 from the flue gas, resulting in a calcium carbonate suspension and purified gas. The reaction pressure is 0.6 MPa, the reaction temperature is 40°C, and the residence time is 60 s. The third step is to separate and filter the calcium carbonate suspension to obtain ultrafine calcium carbonate (i.e., nano-sized light calcium carbonate).

[0051] In Example 15 of this invention, the CO2 content in the flue gas before the reaction was 11.5%, and the CO2 content in the purified flue gas exiting the supergravity reactor after the reaction was 0.3%, with a CO2 conversion rate (recovery rate) of 97.4%.

[0052] The obtained product, nano-grade light calcium carbonate, has a purity of 98%, meeting the industrial precipitated calcium carbonate quality standard HG / T2226-2010.

[0053] Example 16: The method for removing carbon dioxide from flue gas using ultragravity mineralization is carried out according to the following steps: The first step is to prepare a calcium-containing mineralizing solution: S1, using carbide slag, CaO: 70%, ground into 200-mesh powder, yields a solid powder. S2, using a 1.0 mol / L ammonium chloride solution, adjusts the pH of the solution to 5.8, and mixes it with the solid powder to obtain the first mixture. S3, adjust the pH of the first mixture to 8.5, raise the temperature to 80℃, and stir for 2 hours to obtain a solid-liquid mixture. S4. The solid-liquid mixture is subjected to solid-liquid separation to obtain the supernatant, which is the calcium-containing mineral solution, in which the calcium extraction rate is 91%. The second step involves reacting calcium-containing mineralized liquid with CO2-containing flue gas at a molar ratio of 1.2:1 in a high-gravity reactor to remove CO2 from the flue gas, resulting in a calcium carbonate suspension and purified gas. The reaction pressure is 0.6 MPa, the reaction temperature is 60°C, and the residence time is 60 s. The third step is to separate and filter the calcium carbonate suspension to obtain ultrafine calcium carbonate (i.e., nano-sized light calcium carbonate).

[0054] In Example 16 of this invention, the CO2 content in the flue gas before the reaction was 12.5%, and the CO2 content in the purified flue gas exiting the hypergravity reactor after the reaction was 0.2%, with a CO2 conversion rate (recovery rate) of 98.4%.

[0055] The obtained product, nano-grade light calcium carbonate, has a purity of 99%, meeting the industrial precipitated calcium carbonate quality standard HG / T2226-2010.

[0056] In summary, this invention employs a highly efficient reaction device that allows CO2 in flue gas to react with raw materials containing alkaline or alkaline earth metal oxides to generate carbonates, which are then solidified, sealed, and utilized without the need for a capture and purification process. This directly converts CO2 in flue gas into green carbon-fixing calcium carbonate, achieving both efficient separation of carbon dioxide from power plant flue gas and efficient recycling of CO2 and carbon, thus achieving emission reduction goals.

[0057] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. A method for removing carbon dioxide from flue gas using ultragravity mineralization, characterized in that... Follow these steps: The first step is to prepare a calcium-containing mineralization solution; The second step involves reacting the calcium-containing mineralized liquid with the CO2-containing flue gas to remove the CO2 from the flue gas, resulting in a calcium carbonate suspension and purified gas. The third step is to separate and filter the calcium carbonate suspension to obtain ultrafine calcium carbonate.

2. The method for removing carbon dioxide from flue gas using ultragravity mineralization according to claim 1, characterized in that... In the first step, the specific preparation steps of the calcium-containing mineralization solution are carried out according to the following method: S1, grinding the calcium carbide slag or steel slag containing CaO to obtain solid powder; S2, after adjusting the pH of the ammonium chloride solution to 5.8 to 6.5, the solid powder is mixed with the ammonium chloride solution to obtain the first mixture; S3, adjust the pH of the first mixture to 8 to 9, raise the temperature to 80°C to 90°C, stir the reaction, and obtain a solid-liquid mixture; S4. The solid-liquid mixture is separated to obtain the supernatant, which is the calcium-containing mineralized solution.

3. The method for removing carbon dioxide from flue gas using ultragravity mineralization according to claim 2, characterized in that... In step S1, the carbide slag containing CaO is ground to obtain solid powder, wherein the CaO content in the carbide slag is ≥70%, and the particle size of the obtained solid powder is 100 mesh to 200 mesh; or / and, in step S2, the concentration of ammonium chloride solution is 0.5 mol / L to 1 mol / L; or / and, in step S3, the stirring time is 0.5 h to 2 h.

4. The method for removing carbon dioxide from flue gas using ultragravity mineralization according to claim 3, characterized in that... In step S1, the particle size of the obtained solid powder is 200 mesh.

5. The method for removing carbon dioxide from flue gas using ultragravity mineralization according to any one of claims 1 to 4, characterized in that... In the second step, the molar ratio of calcium-containing mineralized liquid to CO2-containing flue gas is 1 to 1.2:

1.

6. The method for removing carbon dioxide from flue gas using ultragravity mineralization according to claim 5, characterized in that... In the second step, the molar ratio of calcium-containing mineralized liquid to CO2-containing flue gas is 1.2:

1.

7. The method for removing carbon dioxide from flue gas using ultragravity mineralization according to any one of claims 1 to 6, characterized in that... In the second step, the reaction conditions between the calcium-containing mineralized solution and the CO2-containing flue gas include: a reaction pressure of 0.4 MPa to 1.0 MPa, a reaction temperature of 30°C to 60°C, and a residence time of the CO2-containing flue gas in the calcium-containing mineralized solution of 15 s to 100 s.

8. The method and apparatus for removing carbon dioxide from flue gas using ultragravity mineralization according to claim 7, characterized in that... In the second step, the reaction conditions between the calcium-containing mineralized solution and the CO2-containing flue gas include: a reaction pressure of 0.7 MPa to 0.8 MPa, a reaction temperature of 45°C to 50°C, and a residence time of the CO2-containing flue gas in the calcium-containing mineralized solution of 30 to 60 seconds.

9. An apparatus for implementing the supergravity method for removing carbon dioxide from flue gas using mineralization, according to any one of claims 1 to 8, characterized in that... The system includes a solid-liquid separator, a high-gravity mineralization reactor, a liquid-solid separator, a filter, and a heat exchanger. The solid-liquid separator has a feed inlet at the top, and a solvent inlet pipeline is fixedly connected to the upper inlet. A calcium-containing mineralization liquid pipeline is fixedly connected between the middle outlet of the solid-liquid separator and the lower inlet of the high-gravity mineralization reactor. A CO2-containing flue gas pipeline is fixedly connected to the heat exchanger inlet. An air inlet pipeline is fixedly connected between the heat exchanger outlet and the bottom inlet of the high-gravity mineralization reactor. A reaction liquid pipeline is fixedly connected between the lower outlet of the high-gravity mineralization reactor and the upper inlet of the liquid-solid separator. A suspension pipeline is fixedly connected between the bottom outlet of the liquid-solid separator and the feed inlet of the filter. A product output pipeline is fixedly connected to the filter outlet. A purified gas output pipeline is fixedly connected to the top outlet of the high-gravity mineralization reactor. A coarse sand discharge pipeline is fixedly connected to the bottom outlet of the solid-liquid separator.

10. The apparatus according to claim 9, characterized in that... A regeneration and circulating solvent pipeline is fixedly connected between the liquid outlet in the middle of the liquid-solid separator and the solvent inlet pipeline.

Images