A method and system for carbon dioxide zero emission capture from a float glass furnace

Abstract

The application discloses a kind of float glass melting furnace carbon dioxide zero emission capture method and system, belong to industrial flue gas carbon capture technical field.The method includes: float glass melting furnace flue gas is passed into absorption tower, and sodium hydroxide absorption liquid countercurrent contact, obtain purified gas and carbon sodium-containing rich liquid;The rich liquid is reacted with calcium hydroxide slurry, and sodium hydroxide is regenerated and calcium carbonate precipitate is generated;Regenerated liquid is returned to absorption tower and recycled;After calcium carbonate precipitate is separated, dehydrated and dried, calcium carbonate product is obtained.The system includes absorption module, regeneration module, circulation module and solid-liquid separation and product processing module.The application realizes the continuous capture of carbon dioxide, absorption liquid recycling and calcium carbonate resource utilization, with the advantages of high absorption efficiency, low regeneration energy consumption and low operating cost.

Description

Technical Field

[0001] This invention relates to the fields of green and low-carbon development, energy conservation and emission reduction, specifically to a method and system for zero-emission capture of carbon dioxide from float glass melting furnaces. Background Technology

[0002] In the production of float glass, the melting furnace consumes a large amount of fossil fuels, and the decomposition of carbonates in the raw materials also produces a large amount of carbon dioxide (CO2), making it a major carbon emitter in the building materials industry.

[0003] Currently, common industrial CO2 capture methods include ammonia absorption, amine absorption, phase change absorption, carbonate absorption, and membrane separation. However, these methods have many limitations when applied to glass melting furnace flue gas: ammonia absorption carries the risk of ammonia escape and secondary pollution; amine absorbents are costly, easily degraded, and require significant energy for regeneration; phase change absorption technology is still immature, with challenges in solvent development and system control; the hot potassium carbonate method is energy-intensive and only suitable for high-concentration CO2 flue gas; and membrane separation is limited by the performance and stability of membrane materials and remains in the laboratory stage.

[0004] Therefore, developing a carbon dioxide capture and resource utilization technology suitable for float glass melting furnaces that is highly efficient, low-energy, low-cost, and free from secondary pollution has become a key issue that the industry urgently needs to address. Summary of the Invention

[0005] The purpose of this invention is to provide a system and method for zero carbon dioxide emissions from float glass melting furnaces, in order to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, embodiments of the present invention provide a method for zero-emission capture and resource utilization of carbon dioxide in float glass melting furnace flue gas, comprising the following steps: S1. The flue gas from the float glass melting furnace is introduced into the absorption module, and the flue gas is brought into countercurrent contact with the sodium hydroxide absorption liquid in the absorption tower to absorb the carbon dioxide in the flue gas, thereby obtaining purified gas and a rich liquid containing sodium carbonate. S2. The sodium carbonate-containing rich solution is introduced into the regeneration module, and calcium hydroxide slurry is added to the regeneration module to cause the sodium carbonate-containing rich solution and calcium hydroxide slurry to undergo a causticization reaction to generate sodium hydroxide regeneration solution and calcium carbonate precipitate. S3. The sodium hydroxide regenerated solution is returned to the absorption module and recycled as an absorption solution to form a closed-loop sodium-alkali cycle. S4. The calcium carbonate precipitate is transported to the solid-liquid separation and product processing module. After separation, dehydration and drying, calcium carbonate product is obtained. The calcium carbonate product is either reused as a raw material for glass production or output as an industrial product. Among them, by combining sodium hydroxide absorption with calcium hydroxide regeneration, continuous capture of carbon dioxide in float glass melting furnace flue gas, recycling and regeneration of absorbent liquid, and solid resource utilization are achieved.

[0007] Preferably, the absorption tower is a packed absorption tower or a plate absorption tower, and adopts a countercurrent absorption method, with flue gas entering from the bottom of the tower and sodium hydroxide absorbent entering from the top of the tower.

[0008] Preferably, the pH value of the sodium hydroxide absorbent solution is greater than or equal to 12 to maintain the ability to absorb carbon dioxide.

[0009] Preferably, in step S2, the regeneration module operates under stirring conditions and controls the pH value of the regeneration reaction system to be 9-13, so as to improve the regeneration efficiency of sodium hydroxide and inhibit precipitation accumulation.

[0010] Preferably, the calcium hydroxide slurry is prepared by reacting calcium oxide with water and then transported to the regeneration module.

[0011] Preferably, the solid-liquid separation and product processing in step S4 includes sedimentation, concentration, dehydration and drying processes performed sequentially, and the separated liquid phase is returned to the absorption module or circulation pipeline for continued use.

[0012] In a second aspect, embodiments of the present invention provide a zero-emission carbon dioxide capture and resource recovery system for float glass melting furnace flue gas for implementing the method described in any one of the first aspects, characterized in that it comprises: The absorption module is used to bring the flue gas from the float glass melting furnace into contact with sodium hydroxide absorbent and absorb carbon dioxide, outputting purified gas and a rich solution containing sodium carbonate. The regeneration module, connected to the absorption module, is used to cause the sodium carbonate-containing rich solution and calcium hydroxide slurry to undergo a causticization reaction, and output sodium hydroxide regenerated solution and calcium carbonate precipitate. A circulation module, connected to the regeneration module and the absorption module, is used to return the sodium hydroxide regenerated solution to the absorption module for recycling. The solid-liquid separation and product processing module is connected to the regeneration module and is used to separate, dehydrate and dry the calcium carbonate precipitate. The absorption module, regeneration module, circulation module, and solid-liquid separation and product processing module are connected in sequence through pipelines to form a closed-loop circulation system, so as to realize carbon dioxide capture, absorption liquid regeneration and product resource utilization.

[0013] Preferably, the absorption module includes an absorption tower, which is provided with a flue gas inlet, a sodium hydroxide absorbent inlet, a purified gas outlet, and a rich liquid outlet. The tower is equipped with a sprayer and a liquid redistributor.

[0014] Preferably, the regeneration module includes a regeneration reaction device and a calcium hydroxide preparation device. The regeneration reaction device is provided with a rich liquid inlet, a calcium hydroxide slurry inlet, a sodium hydroxide regeneration liquid outlet, and a calcium carbonate precipitate outlet. The regeneration reaction device is also provided with a stirring device and a pH control device.

[0015] Preferably, the solid-liquid separation and product processing module includes a settling tank, a concentration device, a dehydrator, and a drying device; the circulation module is equipped with a sodium hydroxide replenishment device; and the system is also equipped with a flow control device, a pressure control device, and a temperature control device.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. Combining high efficiency and economy: The high alkalinity and high solubility of NaOH enable rapid and efficient absorption of CO2, while the cost of continuous operation is significantly reduced by regenerating NaOH with inexpensive CaO.

[0017] 2. Zero emissions and resource utilization: The gaseous CO2 is converted into stable and widely used calcium carbonate products, realizing permanent carbon fixation and turning waste into treasure. The whole process has no harmful by-product emissions.

[0018] 3. Low energy consumption and mild conditions: The absorption and regeneration processes are carried out under normal pressure and near-normal temperature conditions, eliminating the need for high-temperature and high-pressure regeneration. The system energy consumption is significantly lower than that of traditional technologies such as the amine method.

[0019] 4. High system integration and strong applicability: The system is modularly designed and can be flexibly adapted to the transformation of existing glass melting furnaces; the by-product calcium carbonate can be directly recycled for glass production, forming an in-plant material cycle and further reducing raw material costs.

[0020] 5. Environmentally friendly: There are no secondary pollution problems such as ammonia escape and solvent degradation. The exhaust gas is clean after treatment, which helps glass factories to achieve close proximity to cities and industrial parks. Attached Figure Description

[0021] Figure 1 This is a flowchart of a method according to an embodiment of the present invention; Figure 2 This is a system framework diagram of an embodiment of the present invention; Figure 3 This is a schematic diagram of the CO2 capture process provided in the embodiments of the present invention; Figure 4 This is a system block diagram of an embodiment of the present invention. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Please see Figure 1 , Figure 2 , Figure 3 This invention provides a technical solution: a method for zero-emission capture and resource utilization of carbon dioxide from float glass melting furnace flue gas, comprising the following steps: S1. The flue gas from the float glass melting furnace is introduced into the absorption module, and the flue gas is brought into countercurrent contact with the sodium hydroxide absorption liquid in the absorption tower to absorb the carbon dioxide in the flue gas, thereby obtaining purified gas and a rich liquid containing sodium carbonate. S2. The sodium carbonate-containing rich solution is introduced into the regeneration module, and calcium hydroxide slurry is added to the regeneration module to cause the sodium carbonate-containing rich solution and calcium hydroxide slurry to undergo a causticization reaction to generate sodium hydroxide regeneration solution and calcium carbonate precipitate. S3. The sodium hydroxide regenerated solution is returned to the absorption module and recycled as an absorption solution to form a closed-loop sodium-alkali cycle. S4. The calcium carbonate precipitate is transported to the solid-liquid separation and product processing module. After separation, dehydration and drying, calcium carbonate product is obtained. The calcium carbonate product is either reused as a raw material for glass production or output as an industrial product. Among them, by combining sodium hydroxide absorption with calcium hydroxide regeneration, continuous capture of carbon dioxide in float glass melting furnace flue gas, recycling and regeneration of absorbent liquid, and solid resource utilization are achieved.

[0024] In a preferred embodiment of the present invention, the absorption tower is a packed absorption tower or a plate absorption tower, and a countercurrent absorption method is adopted, with flue gas entering from the bottom of the tower and sodium hydroxide absorbent entering from the top of the tower.

[0025] In a preferred embodiment of the present invention, the pH value of the sodium hydroxide absorbent is greater than or equal to 12 in order to maintain the ability to absorb carbon dioxide.

[0026] In a preferred embodiment of the present invention, in step S2, the regeneration module operates under stirring conditions and controls the pH value of the regeneration reaction system to be 9-13, so as to improve the regeneration efficiency of sodium hydroxide and inhibit precipitation accumulation.

[0027] In a preferred embodiment of the present invention, the calcium hydroxide slurry is prepared by reacting calcium oxide with water and then transported to the regeneration module.

[0028] In a preferred embodiment of the present invention, the solid-liquid separation and product processing in step S4 includes sedimentation, concentration, dehydration and drying processes performed sequentially, and the separated liquid phase is returned to the absorption module or circulation pipeline for continued use.

[0029] In addition, please see Figure 4 The present invention also provides a zero-emission carbon dioxide capture and resource recovery system for float glass melting furnace flue gas for implementing any of the above-described methods, comprising: Absorption module 10 is used to contact the flue gas from the float glass melting furnace with sodium hydroxide absorbent and absorb carbon dioxide, and output purified gas and sodium carbonate-rich liquid. The regeneration module 20 is connected to the absorption module and is used to cause the sodium carbonate-containing rich solution and calcium hydroxide slurry to undergo a causticization reaction, and output sodium hydroxide regenerated solution and calcium carbonate precipitate. The circulation module 30 is connected to the regeneration module and the absorption module, and is used to return the sodium hydroxide regenerated solution to the absorption module for recycling. The solid-liquid separation and product processing module 40 is connected to the regeneration module and is used to separate, dehydrate and dry the calcium carbonate precipitate. The absorption module, regeneration module, circulation module, and solid-liquid separation and product processing module are connected in sequence through pipelines to form a closed-loop circulation system, so as to realize carbon dioxide capture, absorption liquid regeneration and product resource utilization.

[0030] In this embodiment, the absorption module includes an absorption tower, which is provided with a flue gas inlet, a sodium hydroxide absorbent inlet, a purified gas outlet, and a rich liquid outlet. The tower is equipped with a sprayer and a liquid redistributor.

[0031] Furthermore, the absorption module is used to complete step S1, that is, to absorb carbon dioxide in the flue gas of the float glass melting furnace.

[0032] The absorption module includes an absorption tower, which can be a packed absorption tower or a plate absorption tower, preferably a packed absorption tower. The absorption tower has a flue gas inlet, a sodium hydroxide absorbent inlet, a purified gas outlet, and a rich liquid outlet. To improve the uniformity of absorbent distribution within the tower, a sprayer and a liquid redistributor are installed inside the absorption tower; when using a packed absorption tower, alkali-resistant packing, such as Pall ring packing, can be selected.

[0033] During operation, the float glass melting furnace flue gas enters the absorption tower from the bottom, while the sodium hydroxide absorbent enters from the top, and the two react countercurrently within the tower. Carbon dioxide in the flue gas reacts with the sodium hydroxide absorbent to form a rich solution containing sodium carbonate, which is discharged from the bottom of the absorption tower; the purified gas is discharged from the top. The pH of the sodium hydroxide absorbent is preferably controlled to be greater than or equal to 12 to ensure absorption capacity.

[0034] In this embodiment, the absorption reaction can be represented as: 2NaOH + CO2 → Na2CO3 + H2O The above absorption process achieves efficient transfer of carbon dioxide from the flue gas to the liquid phase.

[0035] Furthermore, the recycling module is used to complete step S3, that is, to return the regenerated sodium hydroxide solution to the absorption module for recycling.

[0036] The circulation module connects the regeneration module and the absorption module through pipelines, and is used to transport sodium hydroxide regenerated liquid to the top of the absorption tower, so that it can continue to participate in the next round of carbon dioxide absorption process as absorbent, thus forming a closed-loop sodium-alkali circulation system.

[0037] To compensate for the reduction of sodium hydroxide caused by entrainment, sewage discharge or other losses during system operation, the circulation module can also be equipped with a sodium hydroxide replenishment device to quantitatively replenish fresh sodium hydroxide solution, so as to maintain the system's absorption capacity and the stability of the circulating liquid concentration.

[0038] Furthermore, the solid-liquid separation and product processing module is used to complete step S4, namely, to separate, dehydrate and dry the calcium carbonate precipitate.

[0039] The solid-liquid separation and product processing module is connected to the regeneration module and includes a settling tank, a concentration device, a dewatering machine, and a drying device. The calcium carbonate-containing precipitate slurry output from the regeneration reaction device first enters the settling tank for preliminary settling, then enters the concentration device for concentration, followed by dewatering through the dewatering machine, and finally drying through the drying device to obtain the calcium carbonate product. The dewatering machine can be a filter press or a vacuum belt dewatering machine.

[0040] In this embodiment, the liquid phase obtained from solid-liquid separation can be returned to the absorption module or circulation pipeline for continued use, thereby reducing system liquid loss and improving overall utilization. The resulting calcium carbonate product can be directly reused as a raw material in the float glass production process, or output as an industrial-grade calcium carbonate product.

[0041] Furthermore, in this embodiment, to ensure stable system operation, the system is also equipped with a flow control device, a pressure control device, and a temperature control device, which are used to monitor and adjust the operating parameters of the absorption module, regeneration module, circulation module, and solid-liquid separation and product processing module.

[0042] The flow control device is used to control the flow rate of flue gas, sodium hydroxide absorbent, calcium hydroxide slurry, and regenerated liquid; the pressure control device is used to control the operating pressure of the absorption tower and related pipelines; and the temperature control device is used to control the operating temperature of each reaction and processing unit, thereby improving the stability and continuity of the system operation.

[0043] In this embodiment, the regeneration module includes a regeneration reaction device and a calcium hydroxide preparation device. The regeneration reaction device is provided with a rich liquid inlet, a calcium hydroxide slurry inlet, a sodium hydroxide regeneration liquid outlet, and a calcium carbonate precipitation outlet. The regeneration reaction device is also provided with a stirring device and a pH control device.

[0044] Furthermore, the regeneration module is used to complete step S2, which involves a causticization reaction between the sodium carbonate-rich solution and the calcium hydroxide slurry to generate a sodium hydroxide regenerated solution and a calcium carbonate precipitate.

[0045] The regeneration module includes a regeneration reaction device and a calcium hydroxide preparation device. The calcium hydroxide preparation device is used to react calcium oxide with water to prepare calcium hydroxide slurry. The prepared calcium hydroxide slurry is then transported to the regeneration reaction device. The regeneration reaction device is equipped with a rich solution inlet, a calcium hydroxide slurry inlet, a sodium hydroxide regeneration solution outlet, and a calcium carbonate precipitation outlet. The device is internally equipped with a stirring device and a pH control device.

[0046] During operation, the sodium carbonate-rich solution output from the absorption module enters the regeneration reaction device, and calcium hydroxide slurry is added simultaneously. A causticizing reaction is then carried out under stirring conditions. Preferably, the pH of the regeneration reaction system is controlled between 9 and 13 to balance regeneration efficiency and precipitation effect, while preventing localized accumulation of precipitate within the equipment.

[0047] This regeneration reaction can be represented as: Na2CO3 + Ca(OH)2 → 2NaOH + CaCO3↓ After the reaction, sodium hydroxide regeneration solution and calcium carbonate precipitate slurry are obtained.

[0048] In this embodiment, the solid-liquid separation and product processing module includes a settling tank, a concentration device, a dehydrator, and a drying device. The circulation module is equipped with a sodium hydroxide replenishment device, and the system is also equipped with a flow control device, a pressure control device, and a temperature control device.

[0049] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for zero carbon dioxide emissions from a float glass melting furnace, characterized in that, Includes the following steps: S1. The flue gas from the float glass melting furnace is introduced into the absorption module, and the flue gas is brought into countercurrent contact with the sodium hydroxide absorption liquid in the absorption tower to absorb the carbon dioxide in the flue gas, thereby obtaining purified gas and a rich liquid containing sodium carbonate. S2. The sodium carbonate-containing rich solution is introduced into the regeneration module, and calcium hydroxide slurry is added to the regeneration module to cause the sodium carbonate-containing rich solution and calcium hydroxide slurry to undergo a causticization reaction to generate sodium hydroxide regeneration solution and calcium carbonate precipitate. S3. The sodium hydroxide regenerated solution is returned to the absorption module and recycled as an absorption solution to form a closed-loop sodium-alkali cycle. S4. The calcium carbonate precipitate is transported to the solid-liquid separation and product processing module. After separation, dehydration and drying, calcium carbonate product is obtained. The calcium carbonate product is either reused as a raw material for glass production or output as an industrial product. Among them, by combining sodium hydroxide absorption with calcium hydroxide regeneration, continuous capture of carbon dioxide in float glass melting furnace flue gas, recycling and regeneration of absorbent liquid, and solid resource utilization are achieved.

2. The method according to claim 1, characterized in that: The absorption tower is a packed absorption tower or a plate absorption tower, which adopts a countercurrent absorption method. The flue gas enters from the bottom of the tower, and the sodium hydroxide absorbent enters from the top of the tower.

3. The method according to claim 1, characterized in that: The pH value of the sodium hydroxide absorbent solution is greater than or equal to 12 to maintain its ability to absorb carbon dioxide.

4. The method according to claim 1, characterized in that: In step S2, the regeneration module operates under stirring conditions and controls the pH value of the regeneration reaction system to be 9-13 in order to improve the regeneration efficiency of sodium hydroxide and inhibit precipitation accumulation.

5. The method according to claim 1, characterized in that: The calcium hydroxide slurry is prepared by reacting calcium oxide with water and then transported to the regeneration module.

6. The method according to claim 1, characterized in that: The solid-liquid separation and product processing in step S4 includes sedimentation, concentration, dehydration and drying processes performed sequentially, and the separated liquid phase is returned to the absorption module or circulation pipeline for continued use.

7. A zero-carbon dioxide emission system for a float glass melting furnace for implementing the method according to any one of claims 1 to 6, characterized in that, include: The absorption module is used to bring the flue gas from the float glass melting furnace into contact with sodium hydroxide absorbent and absorb carbon dioxide, outputting purified gas and a rich solution containing sodium carbonate. The regeneration module, connected to the absorption module, is used to cause the sodium carbonate-containing rich solution and calcium hydroxide slurry to undergo a causticization reaction, and output sodium hydroxide regenerated solution and calcium carbonate precipitate. A circulation module, connected to the regeneration module and the absorption module, is used to return the sodium hydroxide regenerated solution to the absorption module for recycling. The solid-liquid separation and product processing module is connected to the regeneration module and is used to separate, dehydrate and dry the calcium carbonate precipitate. The absorption module, regeneration module, circulation module, and solid-liquid separation and product processing module are connected in sequence through pipelines to form a closed-loop circulation system, so as to realize carbon dioxide capture, absorption liquid regeneration and product resource utilization.

8. The system according to claim 7, characterized in that: The absorption module includes an absorption tower, which has a flue gas inlet, a sodium hydroxide absorbent inlet, a purified gas outlet, and a rich liquid outlet. The tower is equipped with a sprayer and a liquid redistributor.

9. The system according to claim 7, characterized in that: The regeneration module includes a regeneration reaction device and a calcium hydroxide preparation device. The regeneration reaction device is equipped with a rich liquid inlet, a calcium hydroxide slurry inlet, a sodium hydroxide regeneration liquid outlet, and a calcium carbonate precipitation outlet. The regeneration reaction device is also equipped with a stirring device and a pH control device.

10. The system according to claim 7, characterized in that: The solid-liquid separation and product processing module includes a settling tank, a concentration device, a dehydrator, and a drying device. The circulation module is equipped with a sodium hydroxide replenishment device, and the system is also equipped with a flow control device, a pressure control device, and a temperature control device.

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