A system and method for separating and reusing flue gas components

Abstract

This invention relates to the field of industrial exhaust gas purification and gas utilization technology, specifically to a system and method for separating and reusing flue gas components. The system includes a flue gas treatment skid-mounted module, a flue gas recovery skid-mounted module, and a solid product generation skid-mounted module. The flue gas treatment skid-mounted module includes a denitrification unit, a dust removal unit, a desulfurization tower, and a CO2 capture unit connected in sequence. The flue gas recovery skid-mounted module includes an air separation unit and a CO2 regeneration unit. The solid product generation skid-mounted module includes a carbonization reactor and an oxidation reactor. This invention achieves the capture, purification, and high-value utilization of CO2 from industrial flue gas to prepare nano-calcium carbonate through integrated skid-mounted modules, resulting in high gas utilization efficiency, excellent application effects, and high product economics.

Description

Technical Field

[0001] This invention relates to the field of industrial exhaust gas purification and gas utilization technology, specifically to a system and method for separating and reusing flue gas components. Background Technology

[0002] Flue gas contains nitrogen, carbon dioxide, oxygen, water vapor, and small amounts of nitrogen and sulfur compounds. Among these, carbon dioxide, besides being a major greenhouse gas, is also a key raw material for the production of inorganic materials such as calcium carbonate and carbon nanotubes. Therefore, carbon dioxide in flue gas must not only be removed but also utilized. Sulfides and nitrogen oxides emitted into the atmosphere will generate sulfuric acid and nitric acid, which can easily cause environmental hazards such as acid rain, disrupt the ecological balance, and cause soil acidification. Sulfide oxides and calcium-containing compounds can be further oxidized to produce gypsum. In addition, nitrogen, the main component of flue gas, is usually directly emitted into the air in current industrial research without being utilized, which is a waste of resources.

[0003] Calcium carbonate is an inexpensive powder filler with good thermal stability, and can be used in industries such as plastics, rubber, papermaking, coatings, and inks. Calcium hydroxide and calcium carbonate are gradually replacing sodium carbonate as desulfurizing agents. Through further oxidation, calcium sulfate (gypsum) can be prepared, which has advantages such as low cost and low environmental pollution.

[0004] The carbon dioxide regenerated after flue gas treatment has high purity. Besides being processed into dry ice and stored underground, it can also be mineralized into carbonates and other samples with high economic value, representing an efficient carbon neutralization strategy. Invention patent application CN114432853A describes an integrated device and method for energy storage, desulfurization, and carbon capture, as well as its application. However, this method does not recover and reuse components such as nitrogen and oxygen. Calcium hydroxide is used as a direct carbon capture agent to capture CO2, resulting in low-value products and limiting the application potential of this technology. Summary of the Invention

[0005] To address the shortcomings of existing technologies in flue gas treatment, such as the lack of recovery and reuse of components like nitrogen and oxygen, this invention provides a system and method for separating and reusing flue gas components. This system integrates components into a skid-mounted module to achieve the capture, purification, and high-value utilization of CO2 from industrial flue gas to prepare nano-calcium carbonate. It boasts high gas utilization efficiency, excellent application results, and high product economics.

[0006] In a first aspect, the present invention provides a system for separating and reusing flue gas components, including a flue gas treatment skid module, a flue gas recovery skid module, and a solid product generation skid module.

[0007] The flue gas treatment skid-mounted module includes a denitrification device, a dust removal device, a desulfurization tower, and a CO2 capture device connected in sequence.

[0008] The flue gas recovery skid-mounted module includes an air separation unit and a CO2 regeneration unit. The residual gas outlet of the CO2 capture unit is connected to the air separation unit, which is also connected to an O2 storage tank and an N2 storage tank. The carbon dioxide outlet of the CO2 capture unit is connected to the CO2 regeneration unit, which is connected to the CO2 storage tank.

[0009] The solid product generation skid-mounted module includes a carbonation reactor and an oxidation reactor. The CO2 and N2 storage tanks are connected to the reaction gas inlet of the carbonation reactor. The product outlet of the carbonation reactor is connected to the calcium carbonate storage tank. The solid outlet of the CO2 capture device is connected to the calcium carbonate storage tank. The reaction gas inlet of the oxidation reactor is connected to the O2 storage tank. The reactant inlet of the oxidation reactor is connected to the solid outlet of the desulfurization tower. The product outlet of the oxidation reactor is connected to the calcium sulfate storage tank.

[0010] Furthermore, a solid-liquid separation device, a washing device, and a drying device are connected in sequence between the carbonation kettle and the calcium carbonate storage tank.

[0011] Furthermore, the CO2 storage tank and N2 storage tank are connected to the carbonization reactor via a buffer tank.

[0012] Furthermore, the reactant inlet of the carbonization reactor is connected to the digestion reactor, which in turn is connected to the calcium oxide storage tank; even further, the calcium oxide storage tank can be used to dry the flue gas discharged after passing through the CO2 capture device.

[0013] Secondly, the present invention provides a method for separating and reusing flue gas components using the above-described system, comprising the following steps:

[0014] (1) Flue gas containing 100-500 ppm nitrogen oxides reacts with a reducing agent under the action of a denitrification catalyst to remove nitrogen oxides from the flue gas;

[0015] (2) Then, after electrostatic dust removal, the flue gas containing 100-500ppm sulfur oxides enters the desulfurization tower to obtain flue gas containing 10%-40% carbon dioxide by volume.

[0016] (3) Capture carbon dioxide in the flue gas after desulfurization to obtain treated flue gas;

[0017] (4) The flue gas processed in step (3) is passed through an air separation unit to obtain pure oxygen and nitrogen, and the corresponding gases are stored in O2 storage tank and N2 storage tank respectively;

[0018] (5) The calcium sulfite and calcium sulfate solids obtained from the desulfurization tower react with the oxygen in the O2 storage tank in the oxidation reactor to obtain calcium sulfate product;

[0019] (6) Heat the carbon dioxide saturated solution obtained by capture to regenerate carbon dioxide. Store the regenerated high-purity carbon dioxide in a CO2 storage tank. The carbon dioxide in the CO2 storage tank and the nitrogen in the N2 storage tank react with the digested calcium oxide raw material in a carbonation reactor to obtain calcium carbonate slurry. After separation, washing and drying, obtain nano calcium carbonate and store it in a calcium carbonate storage tank. Alternatively, pass the carbon dioxide saturated solution obtained by capture into calcium hydroxide to obtain calcium carbonate slurry. After separation, washing and drying, obtain nano calcium carbonate and store it in a calcium carbonate storage tank. Alternatively, store the calcium carbonate obtained by capture directly in a calcium carbonate storage tank.

[0020] Furthermore, the denitrification catalyst is a supported catalyst, and the support for the supported catalyst is one of TiO2, Al2O3, SiO2, and activated carbon. The active component of the supported catalyst is one or more of V2O5, Pt-Rh, Pt, Fe2O3, CuO, and MgO. Preferably, the supported catalyst also includes an additive, which is at least one of WO3 and MoO3. The reducing agent is one of liquid ammonia, ammonia water, and urea.

[0021] Furthermore, calcium oxide, calcium hydroxide, and / or the nano-calcium carbonate obtained in step (6) are used as desulfurizing agents in the desulfurization tower.

[0022] Furthermore, carbon dioxide is captured using a chemical absorption method. The absorbed carbon dioxide-saturated liquid is regenerated by heating. The flue gas discharged after passing through the CO2 capture device is dried with calcium oxide. The calcium oxide absorbs water and then digests to obtain calcium hydroxide, which is used for carbonation to produce nano-calcium carbonate. Alternatively, the absorbed carbon dioxide-saturated liquid is passed into a calcium hydroxide regenerator to obtain calcium carbonate slurry. After filtration, washing, and drying, calcium carbonate is obtained and stored in a calcium carbonate storage tank.

[0023] Furthermore, carbon dioxide is captured by adsorption. The adsorbent is a mixture of calcium oxide and calcium hydroxide in a molar ratio of 1:0.2-1:5. After adsorption saturation, the calcium carbonate slurry is separated, washed, and dried to obtain calcium carbonate, which is then stored in a calcium carbonate storage tank.

[0024] Furthermore, during the carbonation reaction to produce calcium carbonate, the volume concentration of carbon dioxide in the mixture of carbon dioxide and nitrogen is 25%-100%.

[0025] The beneficial effects of this invention are as follows:

[0026] This invention achieves the removal of low-concentration nitrogen oxides and the utilization of sulfur oxides, and utilizes various components such as carbon dioxide, nitrogen, oxygen and water vapor. It not only achieves the separation and recovery of flue gas, but also obtains high-value chemicals such as nano-calcium carbonate.

[0027] The flue gas treatment skid module, flue gas recovery skid module, and solid product generation skid module of the present invention are both independent and interconnected. Each module is installed centrally, allowing for flexible expansion and relocation. Different combinations of these modules can be used to operate according to different flue gas environments, product requirements, and market development trends.

[0028] This invention achieves high-value utilization of resources while reducing environmental pollution and mitigating the greenhouse effect, and prepares products with high economic value such as nano-calcium carbonate, calcium carbonate, and gypsum. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the connection relationship of the system for separating and reusing flue gas according to Embodiment 1 of the present invention.

[0031] Figure 2 This is a SEM image of the nano-calcium carbonate prepared in Example 2 of this invention.

[0032] Figure 3 This is a SEM image of the nano-calcium carbonate prepared in Example 4 of this invention.

[0033] Figure 4 This is a SEM image of the nano-calcium carbonate prepared in Example 5 of this invention.

[0034] In the diagram, 1-Denitrification unit, 2-Dust removal unit, 3-Desulfurization tower, 4-CO2 capture unit, 5-Air separation unit, 6-CO2 regeneration unit, 7-O2 storage tank, 8-N2 storage tank, 9-CO2 storage tank, 10-Carbonization kettle, 11-Oxidation kettle, 12-Buffer tank, 13-Calcium oxide storage tank, 14-Digestion kettle, 15-Calcium carbonate storage tank, 16-Calcium sulfate storage tank. Detailed Implementation

[0035] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0036] Example 1

[0037] A system for separating and reusing flue gas components includes a flue gas treatment skid module, a flue gas recovery skid module, and a solid product generation skid module.

[0038] The flue gas treatment skid-mounted module includes a denitrification device 1, a dust removal device 2, a desulfurization tower 3, and a CO2 capture device 4 connected in sequence.

[0039] The flue gas recovery skid-mounted module includes an air separation unit 5 and a CO2 regeneration unit 6. The residual gas outlet of the CO2 capture unit 4 is connected to the air separation unit 5. The air separation unit 5 is also connected to the O2 storage tank 7 and the N2 storage tank 8 respectively. The carbon dioxide outlet of the CO2 capture unit 4 is connected to the CO2 regeneration unit 6. The CO2 regeneration unit 6 is connected to the CO2 storage tank 9.

[0040] The solid product generation skid-mounted module includes a carbonization reactor 10 and an oxidation reactor 11. A CO2 storage tank 9 and an N2 storage tank 8 are connected to the reaction gas inlet of the carbonization reactor 10 via a buffer tank 12. A calcium oxide storage tank 13 is connected to the reactant inlet of the carbonization reactor 10 via a digestion tank 14. The calcium oxide in the calcium oxide storage tank 13 also serves as a desiccant to absorb moisture carried by the flue gas passing through the CO2 capture device 4. The product outlet of the carbonization reactor 10 is sequentially connected to a solid-liquid separation device (not shown in the figure), a washing device (not shown in the figure), a drying device (not shown in the figure), and a calcium carbonate storage tank 15. The solid-liquid separation device can be one or a combination of a hydrocyclone separator, a filter press, or a vacuum filter. The solid outlet of the CO2 capture device 4 is connected to the calcium carbonate storage tank 15. The reaction gas inlet of the oxidation reactor 11 is connected to the O2 storage tank 7. The reactant inlet of the oxidation reactor 11 is connected to the solid outlet of the desulfurization tower 3. The product outlet of the oxidation reactor 11 is connected to the calcium sulfate storage tank 16.

[0041] The specific steps for separating and reusing flue gas using the above system are as follows:

[0042] (1) Flue gas containing 100-500 ppm nitrogen oxides reacts with a reducing agent under the action of a denitrification catalyst to remove nitrogen oxides from the flue gas. The denitrification catalyst is a supported catalyst. The support of the supported catalyst is one of TiO2, Al2O3, SiO2, and activated carbon. The active component of the supported catalyst is one or more of V2O5, Pt-Rh, Pt, Fe2O3, CuO, and MgO. The auxiliary agent of the supported catalyst is at least one of WO3 and MoO3. The reducing agent is one of liquid ammonia, ammonia water, and urea.

[0043] (2) Then, after electrostatic dust removal, the flue gas containing 100-500ppm sulfur oxides enters the desulfurization tower 3. Calcium oxide, calcium hydroxide and / or the nano calcium carbonate obtained in step (7) are used as desulfurizing agents, and one of liquid ammonia, ammonia water and urea is used as a reducing agent to desulfurize, and flue gas containing 10%-40% carbon dioxide by volume is obtained.

[0044] (3) Capture carbon dioxide in the flue gas after desulfurization to obtain treated flue gas;

[0045] Carbon dioxide can be captured by chemical absorption. The absorbed carbon dioxide saturated liquid is regenerated by heating. The flue gas discharged after passing through CO2 capture device 4 is dried with calcium oxide. The calcium oxide absorbs water and then digests to obtain calcium hydroxide, which is used for carbonation to produce nano-calcium carbonate. Alternatively, the absorbed carbon dioxide saturated liquid is passed into calcium hydroxide regener to obtain calcium carbonate slurry. After filtration, washing and drying, calcium carbonate is obtained and stored in calcium carbonate storage tank 15.

[0046] Carbon dioxide capture can also be achieved through adsorption, where the adsorbent is a mixture of calcium oxide and calcium hydroxide in a molar ratio of 1:0.2-1:5. After adsorption saturation, the adsorbent is directly stored in calcium carbonate storage tank 15.

[0047] (4) The flue gas processed in step (3) is passed through the air separation unit 5 to obtain pure oxygen and nitrogen, and the corresponding gases are stored in O2 storage tank 7 and N2 storage tank 8 respectively;

[0048] (5) The calcium sulfite and calcium sulfate solids obtained from desulfurization in desulfurization tower 3 react with oxygen in O2 storage tank 7 in oxidation reactor 11 to obtain calcium sulfate product;

[0049] (6) The carbon dioxide saturated solution obtained by heating is used to regenerate carbon dioxide. The regenerated high-purity carbon dioxide is stored in CO2 storage tank 9. The carbon dioxide in CO2 storage tank 9, the nitrogen in N2 storage tank 8 and the digested calcium oxide raw material are reacted in carbonation kettle 10. The volume concentration of carbon dioxide in the mixed gas of carbon dioxide and nitrogen is 25%-100%, and calcium carbonate slurry is obtained. After separation, washing and drying, nano calcium carbonate is obtained and stored in calcium carbonate storage tank 15; or the carbon dioxide saturated solution obtained by heating is passed into calcium hydroxide to obtain calcium carbonate slurry. After separation, washing and drying, calcium carbonate is obtained and stored in calcium carbonate storage tank 15; or the calcium carbonate slurry obtained by heating is separated, washed and dried to obtain calcium carbonate and stored in calcium carbonate storage tank 15.

[0050] Example 2

[0051] A method for separating and reusing flue gas, using the apparatus of Example 1, comprises the following steps:

[0052] (1) Flue gas containing 200 ppm nitrogen oxides reacts with liquid ammonia under the action of a denitrification catalyst to remove nitrogen oxides from the flue gas. The denitrification catalyst is a supported catalyst, the support of the supported catalyst is TiO2, and the active component of the supported catalyst is V2O5.

[0053] (2) Then, after electrostatic dust removal, the flue gas containing 150 ppm sulfur oxides enters the desulfurization tower. The nano-calcium carbonate obtained in step (6) is used as a desulfurizing agent to desulfurize the flue gas containing 25% carbon dioxide by volume.

[0054] (3) Carbon dioxide in the flue gas after desulfurization is captured by chemical absorption method to obtain the treated flue gas. The flue gas discharged after passing through the CO2 capture device is dried with calcium oxide to obtain O2 / N2 mixed gas with a volume concentration of 13% oxygen. After the calcium oxide absorbs water, it is digested to obtain calcium hydroxide, which is used for carbonization to produce nano calcium carbonate.

[0055] (4) The O2 / N2 mixture after step (3) is processed by an air separation unit to obtain pure oxygen and nitrogen, and the corresponding gases are stored in O2 storage tank and N2 storage tank respectively;

[0056] (5) The calcium sulfite and calcium sulfate solids obtained from the desulfurization tower are separated at the bottom and reacted with oxygen in the O2 storage tank in the oxidation kettle to obtain calcium sulfate product with a purity of 95%, which can be sold as a product.

[0057] (6) The carbon dioxide saturated solution obtained by heating and capturing is used to regenerate carbon dioxide. The regenerated high-purity carbon dioxide with a volume concentration of 99.9% is stored in a CO2 storage tank. The carbon dioxide in the CO2 storage tank and the nitrogen in the N2 storage tank are mixed to obtain a CO2 / N2 mixture with a CO2 volume concentration of 30%. This mixture is reacted with the digested calcium oxide raw material in a carbonation reactor to obtain a calcium carbonate slurry. The slurry is then separated by a hydrocyclone separator, washed with water, and dried at 90°C to obtain nano-calcium carbonate with a particle size of 50-70 nm (e.g., ...). Figure 2 (as shown), and stored in calcium carbonate storage tanks for sale as a desulfurizing agent or final product.

[0058] Example 3

[0059] A method for separating and reusing flue gas, using the apparatus of Example 1, comprises the following steps:

[0060] (1) Flue gas containing 300 ppm nitrogen oxides reacts with urea under the action of a denitrification catalyst to remove nitrogen oxides from the flue gas. The denitrification catalyst is a supported catalyst, the support of the supported catalyst is activated carbon, the active component of the supported catalyst is V2O5, and the auxiliary agent of the supported catalyst is WO3.

[0061] (2) Then, after electrostatic dust removal, the flue gas containing 200 ppm sulfur oxides enters the desulfurization tower, and calcium oxide is used as the desulfurizing agent to obtain flue gas containing 23% carbon dioxide by volume.

[0062] (3) The carbon dioxide in the flue gas after desulfurization is captured by chemical absorption method to obtain the treated flue gas. The flue gas discharged after passing through the CO2 capture device is dried with calcium oxide to obtain O2 / N2 mixed gas with a volume concentration of 15% oxygen. After the calcium oxide absorbs water, it is digested to obtain calcium hydroxide, which is used for carbonization to produce nano calcium carbonate.

[0063] (4) The O2 / N2 mixture after step (3) is processed by an air separation unit to obtain pure oxygen and nitrogen, and the corresponding gases are stored in O2 storage tank and N2 storage tank respectively;

[0064] (5) The calcium sulfite and calcium sulfate solids obtained from the desulfurization tower are separated at the bottom and reacted with oxygen in the O2 storage tank in the oxidation reactor to obtain calcium sulfate product with a purity of 98%, which can be sold as a product.

[0065] (6) The carbon dioxide saturated solution obtained by heating and capturing is used to regenerate carbon dioxide. The regenerated high-purity carbon dioxide with a volume concentration of 99.8% is stored in a CO2 storage tank. The carbon dioxide in the CO2 storage tank and the nitrogen in the N2 storage tank are mixed to obtain a CO2 / N2 mixed gas with a CO2 volume concentration of 25%. This mixed gas is reacted with the digested calcium oxide raw material in a carbonation kettle to obtain calcium carbonate slurry. The slurry is separated by a hydrocyclone separator, washed with water, and dried at 80°C to obtain nano-calcium carbonate with a particle size of 55-80nm. The nano-calcium carbonate is stored in a calcium carbonate storage tank and sold as a desulfurizing agent or product.

[0066] Example 4

[0067] A method for separating and reusing flue gas, using the apparatus of Example 1, comprises the following steps:

[0068] (1) Flue gas containing 200 ppm nitrogen oxides reacts with liquid ammonia under the action of a denitrification catalyst to remove nitrogen oxides from the flue gas. The denitrification catalyst is a supported catalyst, the support of the supported catalyst is activated carbon, and the active component of the supported catalyst is Pt-Rh.

[0069] (2) Then, after electrostatic dust removal, the flue gas containing 150 ppm sulfur oxides enters the desulfurization tower, and calcium oxide is used as the desulfurizing agent to obtain flue gas containing 20% ​​carbon dioxide by volume.

[0070] (3) The carbon dioxide in the flue gas after desulfurization is captured by chemical absorption method to obtain the treated flue gas. The flue gas discharged after passing through the CO2 capture device is dried with calcium oxide to obtain O2 / N2 mixed gas with a volume concentration of 15% oxygen. After the calcium oxide absorbs water, it is digested to obtain calcium hydroxide, which is used for carbonization to produce nano calcium carbonate.

[0071] (4) The O2 / N2 mixture after step (3) is processed by an air separation unit to obtain pure oxygen and nitrogen, and the corresponding gases are stored in O2 storage tank and N2 storage tank respectively;

[0072] (5) The calcium sulfite and calcium sulfate solids obtained from the desulfurization tower are separated at the bottom and reacted with oxygen in the O2 storage tank in the oxidation reactor to obtain calcium sulfate product with a purity of 98%, which can be sold as a product.

[0073] (6) The carbon dioxide saturated solution obtained by collection is used as a regenerator to obtain calcium carbonate slurry. After separation by a filter press, washing with water, and drying at 80℃, a calcium carbonate sample with a particle size of 1 μm is obtained (e.g., Figure 3 (as shown), and stored in calcium carbonate storage tanks for sale as a product.

[0074] Example 5

[0075] A method for separating and reusing flue gas, using the apparatus of Example 1, comprises the following steps:

[0076] (1) Flue gas containing 200 ppm nitrogen oxides reacts with liquid ammonia under the action of a denitrification catalyst to remove nitrogen oxides from the flue gas. The denitrification catalyst is a supported catalyst, the support of the supported catalyst is Al2O3, and the active component of the supported catalyst is V2O5.

[0077] (2) Then, after electrostatic dust removal, the flue gas containing 200 ppm sulfur oxides enters the desulfurization tower, and calcium hydroxide is used as the desulfurizing agent to obtain flue gas containing 15% carbon dioxide by volume.

[0078] (3) Carbon dioxide in the flue gas after desulfurization is captured by adsorption method. The adsorbent is a mixture of calcium oxide and calcium hydroxide with a molar ratio of 1:1. The treated flue gas is obtained. The flue gas discharged after passing through the CO2 capture device is dried with calcium oxide to obtain O2 / N2 mixed gas with a volume concentration of 15% oxygen. After calcium oxide absorbs water, it is digested to obtain calcium hydroxide, which is used for carbonization to produce nano calcium carbonate.

[0079] (4) The O2 / N2 mixture after step (3) is processed by an air separation unit to obtain pure oxygen and nitrogen, and the corresponding gases are stored in O2 storage tank and N2 storage tank respectively;

[0080] (5) The calcium sulfite and calcium sulfate solids obtained from the desulfurization tower are separated at the bottom and reacted with oxygen in the O2 storage tank in the oxidation reactor to obtain calcium sulfate product with a purity of 50%, which can be sold as a product.

[0081] (6) The calcium carbonate slurry was collected, separated by a hydrocyclone, washed with water, and dried at 90℃ to obtain calcium carbonate samples with a particle size of 0.5-2 μm (e.g., Figure 4(as shown), and stored in calcium carbonate storage tanks for sale as a product.

[0082] Example 6

[0083] A method for separating and reusing flue gas, using the apparatus of Example 1, comprises the following steps:

[0084] (1) Flue gas containing 200 ppm nitrogen oxides reacts with liquid ammonia under the action of a denitrification catalyst to remove nitrogen oxides from the flue gas. The denitrification catalyst is a supported catalyst, the support of the supported catalyst is V2O5, the active component of the supported catalyst is V2O5, and the auxiliary agent of the supported catalyst is WO3.

[0085] (2) Then, after electrostatic dust removal, the flue gas containing 150 ppm sulfur oxides enters the desulfurization tower, and calcium hydroxide is used as the desulfurizing agent to obtain flue gas containing 15% carbon dioxide by volume.

[0086] (3) The carbon dioxide in the flue gas after desulfurization is captured by chemical absorption method, and the treated flue gas is directly discharged into the atmosphere;

[0087] (4) The calcium sulfite and calcium sulfate solids obtained from the desulfurization tower are separated at the bottom to obtain calcium sulfate product with a purity of 50%, which can be sold as a product.

[0088] (6) Heat the saturated carbon dioxide solution obtained by capture to regenerate carbon dioxide, and store the regenerated high-purity carbon dioxide with a volume concentration of 99.5% in a CO2 storage tank.

[0089] Although the present invention has been described in detail with reference to the accompanying drawings and preferred embodiments, the present invention is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the present invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the present invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should also be covered within the protection scope of the present invention.

Claims

1. A system for separating and reusing flue gas components, characterized in that, This includes a flue gas treatment skid-mounted module, a flue gas recovery skid-mounted module, and a solid product generation skid-mounted module; The flue gas treatment skid-mounted module includes a denitrification device, a dust removal device, a desulfurization tower, and a CO2 capture device connected in sequence. The flue gas recovery skid-mounted module includes an air separation unit and a CO2 regeneration unit. The residual gas outlet of the CO2 capture unit is connected to the air separation unit, which is also connected to an O2 storage tank and an N2 storage tank. The carbon dioxide outlet of the CO2 capture unit is connected to the CO2 regeneration unit, which is connected to the CO2 storage tank. The solid product generation skid-mounted module includes a carbonation reactor and an oxidation reactor. The CO2 and N2 storage tanks are connected to the reaction gas inlet of the carbonation reactor. The product outlet of the carbonation reactor is connected to the calcium carbonate storage tank. The solid outlet of the CO2 capture device is connected to the calcium carbonate storage tank. The reaction gas inlet of the oxidation reactor is connected to the O2 storage tank. The reactant inlet of the oxidation reactor is connected to the solid outlet of the desulfurization tower. The product outlet of the oxidation reactor is connected to the calcium sulfate storage tank.

2. The system as described in claim 1, characterized in that, A solid-liquid separation device, a washing device, and a drying device are also connected in sequence between the carbonation kettle and the calcium carbonate storage tank.

3. The system as described in claim 1, characterized in that, The CO2 and N2 storage tanks are connected to the carbonization reactor via a buffer tank.

4. The system as described in claim 1, characterized in that, The reactant inlet of the carbonization reactor is connected to the digestion reactor, which in turn is connected to the calcium oxide storage tank.

5. A method for separating and reusing flue gas components using the system described in any one of claims 1-4, characterized in that, Includes the following steps: (1) Flue gas containing 100-500 ppm nitrogen oxides reacts with a reducing agent under the action of a denitrification catalyst to remove nitrogen oxides from the flue gas; (2) Then, after electrostatic dust removal, the flue gas containing 100-500ppm sulfur oxides enters the desulfurization tower to obtain flue gas containing 10%-40% carbon dioxide by volume. (3) Capture carbon dioxide in the flue gas after desulfurization to obtain treated flue gas; (4) The flue gas processed in step (3) is passed through an air separation unit to obtain pure oxygen and nitrogen, and the corresponding gases are stored in O2 storage tank and N2 storage tank respectively; (5) The calcium sulfite and calcium sulfate solids obtained from the desulfurization tower react with the oxygen in the O2 storage tank in the oxidation reactor to obtain calcium sulfate product; (6) Heat the carbon dioxide saturated solution obtained by capture to regenerate carbon dioxide. Store the regenerated high-purity carbon dioxide in a CO2 storage tank. The carbon dioxide in the CO2 storage tank and the nitrogen in the N2 storage tank react with the digested calcium oxide raw material in a carbonation reactor to obtain calcium carbonate slurry. After separation, washing and drying, obtain nano calcium carbonate and store it in a calcium carbonate storage tank. Alternatively, pass the carbon dioxide saturated solution obtained by capture into calcium hydroxide to obtain calcium carbonate slurry. After separation, washing and drying, obtain nano calcium carbonate and store it in a calcium carbonate storage tank. Alternatively, store the calcium carbonate obtained by capture directly in a calcium carbonate storage tank.

6. The method as described in claim 5, characterized in that, The denitrification catalyst is a supported catalyst. The support for the supported catalyst is one of TiO2, Al2O3, SiO2, or activated carbon. The active component of the supported catalyst is one or more of V2O5, Pt-Rh, Pt, Fe2O3, CuO, or MgO. The reducing agent is one of liquid ammonia, ammonia water, or urea.

7. The method as described in claim 5, characterized in that, Calcium oxide, calcium hydroxide, and / or the nano-calcium carbonate obtained in step (6) are used as desulfurizing agents in the desulfurization tower.

8. The method as described in claim 5, characterized in that, Carbon dioxide is captured using a chemical absorption method. The absorbed carbon dioxide-saturated liquid is regenerated by heating. The flue gas discharged after passing through the CO2 capture device is dried with calcium oxide. The calcium oxide absorbs water and is then digested to obtain calcium hydroxide, which is used for carbonation to produce nano-calcium carbonate. Alternatively, the absorbed carbon dioxide-saturated liquid is passed into a calcium hydroxide regenerator to obtain calcium carbonate slurry. After filtration, washing, and drying, calcium carbonate is obtained and stored in a calcium carbonate storage tank.

9. The method as described in claim 5, characterized in that, Carbon dioxide is captured by adsorption. The adsorbent is a mixture of calcium oxide and calcium hydroxide in a molar ratio of 1:0.2-1:

5. After the calcium carbonate slurry is saturated with adsorption, it is separated, washed and dried to obtain calcium carbonate, which is then stored in a calcium carbonate storage tank.

10. The method as described in claim 5, characterized in that, When producing calcium carbonate through carbonation, the volume concentration of carbon dioxide in the mixture of carbon dioxide and nitrogen is 25%-100%.

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