A system and method for carbon dioxide capture based on solid amine sorbents

Abstract

This application provides a system and method for carbon dioxide capture based on solid amine adsorbents, belonging to the field of carbon dioxide capture. The system includes multiple adsorption towers, a regeneration gas heater, and a desorption section. When the system operates in adsorption mode, it includes multiple adsorption towers, each comprising a solid amine adsorbent side and a heat exchange side. The solid amine adsorbent side includes a solid amine adsorbent adsorption bed, with flue gas introduced through the inlet of the solid amine adsorbent side and a cooling medium introduced through the inlet of the heat exchange side. When the system operates in desorption mode, it includes multiple adsorption towers, a regeneration gas heater, and a desorption section. A heating medium is introduced through the inlet of the heat exchange side of the multiple adsorption towers, the outlet of the solid amine adsorbent side of the multiple adsorption towers is connected to the adsorbent regeneration gas heater, and the inlet of the solid amine adsorbent side of the multiple adsorption towers is connected to the desorption section. This achieves efficient adsorption of carbon dioxide in flue gas, efficient regeneration of the adsorbent, and a high carbon dioxide recovery rate.

Description

Technical Field

[0001] This application relates to the field of carbon dioxide capture technology, and in particular to a system and method for carbon dioxide capture. Background Technology

[0003] Currently, carbon dioxide emissions in industry mainly come from the combustion of fossil fuels and heavy industries such as steel and cement production. The most mature existing carbon dioxide capture technology is liquid amine absorption, a traditional method currently in operation that utilizes amine scrubbing to absorb CO2 from flue gas from fossil fuel power plants. However, the amine scrubbing method suffers from drawbacks such as corrosion of mechanical parts, release of toxic chemicals and gases, and high regeneration energy requirements, limiting its further adoption. To address the problems of liquid amine absorption technology, solid adsorption technology has been developed. Among these, solid amine capture technology, derived from combining liquid amine absorption and solid adsorption, shows great potential and is gradually gaining attention. Through selective adsorption of the adsorbent, it can achieve efficient separation of carbon dioxide, achieving the goal of low-energy capture. Summary of the Invention

[0004] This application provides a system and method for carbon dioxide capture based on solid amine adsorbents. By innovating the adsorber type, it solves the problem of high heat release during solid adsorption; by innovating the regeneration heating method, it solves the problem of adsorption-regeneration time balance; and by selecting regeneration media at different stages, it solves the problem of carbon dioxide purity and improves product recovery rate.

[0005] In a first aspect, this application provides a carbon dioxide capture system based on a solid amine adsorbent, wherein the system is used for the adsorption and desorption of carbon dioxide, wherein...

[0006] When the system is used for the adsorption of carbon dioxide, the system comprises:

[0007] The plurality of adsorption towers include a solid amine adsorbent side and a heat exchange side. The solid amine adsorbent side includes a solid amine adsorbent adsorption bed. Flue gas is introduced into the inlet of the solid amine adsorbent side, and a cold medium is introduced into the inlet of the heat exchange side. The solid amine adsorbent is used to adsorb carbon dioxide in the flue gas and heat exchange is carried out during the adsorption process to obtain carbon dioxide supported adsorbent and decarbonized flue gas.

[0008] When the system is used for the desorption of carbon dioxide, the system comprises:

[0009] The plurality of adsorption towers, the carbon dioxide regeneration gas heater, and the desorption section are configured such that a heat medium is introduced into the inlet of the heat exchange side of the plurality of adsorption towers, the outlet of the solid amine adsorbent side of the plurality of adsorption towers is connected to the carbon dioxide regeneration gas heater, and the inlet of the solid amine adsorbent side of the plurality of adsorption towers is connected to the desorption section, for heating the carbon dioxide supported adsorbent with carbon dioxide regeneration gas to perform desorption, thereby obtaining solid amine adsorbent and carbon dioxide regeneration gas.

[0010] Optionally, the desorption section includes:

[0011] The first cooling separator is connected to the plurality of adsorption towers and the carbon dioxide regeneration gas heater;

[0012] A vacuum pump, which is connected to the first cooling distributor;

[0013] The second cooling distributor is connected to the vacuum pump and the first cooling distributor.

[0014] Optionally, the system further includes:

[0015] The pretreatment section is connected to the solid amine adsorbent side of the plurality of adsorption towers and is used to pretreat the flue gas.

[0016] Optionally, the preprocessing unit includes:

[0017] A scrubbing tower, wherein flue gas is introduced into the inlet of the scrubbing tower;

[0018] A fine desulfurization adsorption tower, wherein the inlet of the fine desulfurization adsorption tower is connected to the outlet of the washing tower;

[0019] The flue gas cooler has an inlet connected to the outlet of the desulfurization adsorption tower, a flue gas outlet connected to the solid amine adsorbent side of the plurality of adsorption towers, and a condensate outlet connected to the heat exchange side of the plurality of adsorption towers.

[0020] Optionally, the adsorption tower is a tube-and-shell heat exchange adsorption tower.

[0021] Optionally, the multiple adsorption towers are arranged in parallel, and the number of the multiple adsorption towers is ≥3.

[0022] Optionally, the system further includes:

[0023] An air cooler, wherein air is introduced into the air cooler;

[0024] An air separator tank, which is connected to the inlet on the heat exchange side of the air cooler and the plurality of adsorption towers;

[0025] An air heater is connected to the inlet on the heat exchange side of the plurality of adsorption towers.

[0026] Secondly, this application provides a method for carbon dioxide capture based on a solid amine adsorbent, the method comprising:

[0027] Pre-treat the flue gas;

[0028] The carbon dioxide in the pretreated flue gas is adsorbed using a solid amine adsorbent, and heat exchange is carried out during the adsorption process to obtain a carbon dioxide supported adsorbent and decarbonized flue gas.

[0029] The carbon dioxide-supported adsorbent is desorbed using carbon dioxide regeneration gas, and heat is exchanged during the desorption process to heat the carbon dioxide-supported adsorbent, thereby obtaining a solid amine adsorbent and carbon dioxide regeneration gas.

[0030] Optionally, the solid amine adsorbent is an amine-functionalized organic polymer resin.

[0031] Optionally, the temperature of the pretreated flue gas is <30°C; and / or,

[0032] The temperature of the carbon dioxide regeneration gas is >120°C; and / or,

[0033] The desorption pressure is ≤10 kPa.

[0034] The technical solutions provided in this application have the following advantages compared with the prior art:

[0035] This application provides a carbon dioxide capture system based on solid amine adsorbents. The system utilizes the highly efficient adsorption and desorption capabilities of solid amine adsorbents for carbon dioxide, achieving effective separation of carbon dioxide from flue gas through the coordinated operation of multiple adsorption towers, a carbon dioxide regeneration gas heater, and a desorption section. When the system is in adsorption mode, carbon dioxide-containing flue gas enters the adsorption towers through the inlet on the solid amine adsorbent side. These adsorption towers are filled with highly efficient solid amine adsorbents, which have extremely strong selective adsorption capabilities for carbon dioxide. Simultaneously, as the flue gas passes through the solid amine adsorbent adsorption bed, carbon dioxide molecules are adsorbed onto the adsorbent surface, forming a carbon dioxide-supported adsorbent. During this process, the adsorbent releases a large amount of adsorption heat, causing the adsorption bed temperature to rise. To maintain adsorption efficiency, a heat exchange side is introduced, through which a cold medium is introduced to exchange heat with the adsorption bed, removing the heat generated during adsorption and ensuring that the adsorption bed temperature remains within the optimal operating range. When the system is in desorption mode, heated carbon dioxide regeneration gas enters the adsorption tower against the adsorption direction, fully contacting the adsorbent and completely desorbing the carbon dioxide from the adsorbent. The desorbed carbon dioxide regeneration gas is discharged through the inlet on the solid amine adsorbent side and enters the desorption section for further treatment or recovery. Simultaneously, the heat exchange side inlet is changed to allow the introduction of a heat medium to heat the adsorption bed, increasing the temperature of the adsorbent and facilitating the efficient release of carbon dioxide. Therefore, this embodiment employs a novel adsorption tower structure. During adsorption and desorption, the hot and cold media on the heat exchange side are organically integrated with the workflow, achieving cooling and heat removal during adsorption to ensure the adsorption performance of the adsorbent. Simultaneously, it enables simultaneous heating and regeneration of the adsorbent both inside and outside during desorption, ensuring uniform heating and effective regeneration. Attached Figure Description

[0036] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0037] To more clearly illustrate the technical solutions in the embodiments of this application 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.

[0038] Figure 1 A schematic diagram of the structure of a carbon dioxide capture system based on a solid amine adsorbent provided in this application, when operating in the form of adsorption;

[0039] Figure 2 A schematic diagram of the structure of a carbon dioxide capture system based on a solid amine adsorbent provided in this application embodiment when it operates in the form of desorption;

[0040] Figure 3 This is a schematic diagram of the structure of the first tube heat exchange adsorption tower provided in the embodiments of this application;

[0041] Figure 4 This is a schematic diagram of the structure of the second tube heat exchange adsorption tower provided in the embodiments of this application;

[0042] Figure 5 A schematic diagram of the air heat removal structure of the first tube heat exchange adsorption tower provided in the embodiments of this application;

[0043] Figure 6 This is a schematic diagram of the chilled water heat removal structure of the first tube heat exchange adsorption tower provided in the embodiments of this application;

[0044] Figure 7 A schematic flowchart illustrating a method for carbon dioxide capture based on a solid amine adsorbent, provided for an embodiment of this application;

[0045] Figure 8 This is a schematic diagram of the gas flow direction for carbon dioxide adsorption provided in Embodiment 1 of this application;

[0046] Figure 9 This is a schematic diagram of the gas flow direction during the desorption of carbon dioxide provided in Embodiment 1 of this application;

[0047] Figure label:

[0048] 1- Multiple adsorption towers, 11- Solid amine adsorbent side, 12- Heat exchange side, 2- Carbon dioxide regeneration gas heater, 3- Desorption section, 31- First cooling separator, 32- Vacuum pump, 33- Second cooling separator, 4- Pretreatment section, 41- Scrubbing tower, 42- Fine desulfurization adsorption tower, 43- Flue gas cooler, 5- Air cooler, 6- Air separator, 7- Air heater. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0050] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0051] Furthermore, in the description of this application, the terms "comprising," "including," etc., mean "including but not limited to." In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this document, "and / or" describes the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this document, "at least one" means one or more, and "more than" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" or "at least one of a, b, and c" can both represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple. "Parts representation," such as parts by weight or parts by mass, indicates the proportional relationship between components. In the proportional relationships discussed in this article, parameters described by proportion should be understood as the first term of the proportion in the order of description, while the proportion figure should be understood as the second term. For example, if the mass ratio of substance A, substance B, and substance C is 1:2:3, then substances A, B, and C should correspond one-to-one with the proportion figure in the proportion in the order of description, i.e., the mass of substance A : the mass of substance B : the mass of substance C = 1:2:3.

[0052] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0053] Figure 1A schematic diagram of a carbon dioxide capture system based on a solid amine adsorbent provided in this application embodiment;

[0054] like Figure 1 As shown, this application provides a carbon dioxide capture system based on a solid amine adsorbent, wherein the system is used for the adsorption and desorption of carbon dioxide, wherein...

[0055] When the system is used for the adsorption of carbon dioxide, the system comprises:

[0056] The plurality of adsorption towers 1 include a solid amine adsorbent side 11 and a heat exchange side 12. The solid amine adsorbent side 11 includes a solid amine adsorbent adsorption bed 111. Flue gas is introduced into the inlet of the solid amine adsorbent side 11, and a cold medium is introduced into the inlet of the heat exchange side 12. The solid amine adsorbent is used to adsorb carbon dioxide in the flue gas and heat exchange occurs during the adsorption process to obtain carbon dioxide supported adsorbent and decarbonized flue gas.

[0057] When the system is used for the desorption of carbon dioxide, the system comprises:

[0058] The plurality of adsorption towers 1, the carbon dioxide regeneration gas heater 2, and the desorption section 3 are configured such that a heat medium is introduced into the inlet of the heat exchange side 12 of the plurality of adsorption towers 1, the outlet of the solid amine adsorbent side 11 of the plurality of adsorption towers 1 is connected to the carbon dioxide regeneration gas heater 2, and the inlet of the solid amine adsorbent side 11 of the plurality of adsorption towers 1 is connected to the desorption section 3. This configuration is used to desorb the carbon dioxide supported adsorbent using carbon dioxide regeneration gas and to perform heat exchange during the desorption process, thereby heating the carbon dioxide supported adsorbent to obtain solid amine adsorbent and carbon dioxide regeneration gas.

[0059] It should be noted that the solid amine adsorbent side is the area where the flue gas directly contacts the solid amine adsorbent. The flue gas enters through the solid amine adsorbent side inlet, and as it passes through the adsorption bed, carbon dioxide is selectively adsorbed by the adsorbent, generating heat of adsorption. The heat exchange side, located on the other side of the adsorption bed, is used to remove the heat generated during adsorption and to heat the adsorbent during desorption.

[0060] During the adsorption stage, flue gas enters the adsorption tower through the inlet on the solid amine adsorbent side 11. The tower is filled with solid amine adsorbent material, and the flue gas passes through the adsorption bed, where CO2 is selectively and efficiently captured. Simultaneously, a large amount of adsorption heat is generated during CO2 adsorption, and as the bed temperature rises, the adsorption effect of the adsorbent will be affected. To ensure the adsorption effect and improve the adsorption efficiency, in this embodiment, a cooling medium is introduced into the heat exchange side 12 of the adsorption tower to remove the adsorption heat. The cooling medium enters from the inlet of the heat exchange side 12 and exchanges heat with the adsorption bed to reduce the temperature during the adsorption process. After adsorption, a carbon dioxide-supported adsorbent and decarbonized flue gas are obtained. The decarbonized flue gas is discharged from the outlet on the solid amine adsorbent side 11 of the adsorption tower (venting from the top of the tower).

[0061] When the solid amine adsorbent becomes saturated, vacuum heating regeneration is employed to ensure effective regeneration and improve capacity utilization. Therefore, the system switches to desorption mode, and the inlet of heat exchanger 12 is changed to allow the introduction of a heat medium to heat the adsorption bed. Carbon dioxide regeneration gas, heated by carbon dioxide regeneration gas heater 2, is fed into the adsorption tower against the adsorption direction, entering from the outlet 11 on the solid amine adsorbent side of the adsorption tower. It then contacts the carbon dioxide-supported adsorbent, desorbing the carbon dioxide. During desorption, the heated carbon dioxide-supported adsorbent releases carbon dioxide and simultaneously regenerates itself, restoring its adsorption capacity. The desorbed carbon dioxide regeneration gas exits from the inlet 11 on the solid amine adsorbent side of the adsorption tower and enters the desorption section 3 for further processing.

[0062] In some embodiments, the desorption section 3 includes:

[0063] The first cooling distributor 31 is connected to the plurality of adsorption towers 1 and the carbon dioxide regeneration gas heater 2.

[0064] Vacuum pump 32, which is connected to the first cooling distributor 31;

[0065] The second cooling distributor 33 is connected to the vacuum pump 32 and the first cooling distributor 31.

[0066] The first cooling separator 31 is connected to multiple adsorption towers 1 and a carbon dioxide regeneration gas heater 2. It receives the carbon dioxide regeneration gas and desorbed gas desorbed from the adsorption towers and exchanges heat with the new regeneration gas, thus preheating the new carbon dioxide regeneration gas while initially cooling the desorbed carbon dioxide regeneration gas and desorbed gas. The vacuum pump 32 is connected to the first cooling separator 31. After backflushing, it reduces the pressure of the adsorption towers to 10 kPa (or lower) to promote CO2 desorption. The second cooling separator 33 is connected to the vacuum pump 32 and the first cooling separator 31. It further cools and separates the CO2-containing regeneration gas discharged from the vacuum pump 32 to obtain a purer CO2 product gas and supplies new carbon dioxide regeneration gas to the first cooling separator 31.

[0067] The specific desorption process includes:

[0068] Reverse release and vacuum desorption: After the adsorption process is completed, a reverse release operation is performed to discharge the remaining unadsorbed gas in the adsorption tower. After the reverse release is completed, vacuum pump 32 is started to reduce the pressure of the adsorption tower to 10 kPaA, so as to more effectively desorb the CO2 adsorbed on the adsorbent.

[0069] Heating regeneration: The CO2-containing regeneration gas from the vacuum pump 32 outlet is heated to above 120°C using a carbon dioxide regeneration gas heater 2. The heated gas is then fed into the adsorption tower against the adsorption direction, directly contacting the adsorbent to heat the bed and promote CO2 desorption and adsorbent regeneration. Additionally, the heat exchange side 12, used for heat removal during the adsorption process, is circulated with a heat medium such as hot water, hot air, or steam, indirectly heating the bed through a heat exchanger or heat conduction. This combination of direct and indirect heating more effectively increases the bed temperature, shortens the regeneration time, and ensures optimal regeneration results.

[0070] Thermostatic and shut-off heat regeneration valve: When the bed temperature reaches the set value and is maintained for a period of time (the thermostatic stage), the heat regeneration valve is shut off to stop heating.

[0071] Cold blowing cooling: Nitrogen or the adsorbed flue gas is used to cold blow the adsorption tower bed to reduce the bed temperature. The cold blowing process helps to further remove residual CO2 and other impurities in the bed and prepares it for the next round of adsorption.

[0072] Cooling: During or after the cold blowing, a cooling medium for the adsorption process, such as chilled water or air, is introduced into the heat exchange side 12 of the adsorption tower. The bed is cooled by a combination of direct cooling (such as direct contact between the cooling medium and the bed) and indirect cooling (such as through a heat exchanger).

[0073] After cooling, the temperature of the adsorption tower drops to a suitable range for adsorption, making it ready for adsorption to occur again.

[0074] To ensure regeneration efficiency, after the reverse adsorption process, vacuum pump 32 is used to reduce the pressure in the adsorption tower to 10 kPaA to facilitate CO2 desorption. Simultaneously, a heater is used to heat the CO2 product gas from the outlet of vacuum pump 32 to 130°C, and then it is fed into the adsorption tower against the adsorption direction to directly contact the adsorbent and heat the bed for regeneration. Meanwhile, the heat exchange side 12, used for heat removal during the adsorption process, is circulated with hot water, hot air, or steam to indirectly heat the bed. The adsorbent undergoes thermal regeneration using a combination of direct and indirect heating to shorten regeneration time and ensure optimal regeneration efficiency.

[0075] After heating and temperature control are completed, the thermal regeneration valve is shut off, and nitrogen or the adsorbed flue gas is used to cool the adsorption tower bed. Meanwhile, the heat exchange side 12 of the adsorption tower is supplied with the cooling medium used in the adsorption process, such as chilled water or air. A combination of direct and indirect cooling methods is used to cool the bed. After cooling, the adsorption tower is ready for re-adsorption.

[0076] In some embodiments, the system further includes:

[0077] The pretreatment unit 4 is connected to the solid amine adsorbent side 11 of the plurality of adsorption towers 1 and is used to pretreat the flue gas.

[0078] In some embodiments, the preprocessing unit 4 includes:

[0079] Scrubber 41, with flue gas introduced into its inlet;

[0080] Fine desulfurization adsorption tower 42, the inlet of which is connected to the outlet of the washing tower 41;

[0081] The flue gas cooler 43 has its inlet connected to the outlet of the fine desulfurization adsorption tower 42, and its flue gas outlet connected to the solid amine adsorbent side 11 of the plurality of adsorption towers 1.

[0082] The inlet of scrubbing tower 41 is designed to receive and introduce the flue gas to be treated. Its main function is to remove solid particulate matter, such as dust and fly ash, as well as some soluble gases, such as SO2, from the flue gas through spray scrubbing. The inlet of fine desulfurization adsorption tower 42 is connected to the outlet of scrubbing tower 41. This tower is filled with desulfurization adsorbent to further remove residual SO2 from the flue gas, ensuring that the flue gas entering subsequent equipment meets the treatment requirements. The inlet of flue gas cooler 43 is connected to the outlet of fine desulfurization adsorption tower 42. The main function of flue gas cooler 43 is to cool the flue gas using a low-temperature medium (such as chilled water, refrigerant, etc.), thereby separating the condensate. Flue gas cooler 43 has two outlets, one of which is connected to the solid amine adsorbent side 11 of multiple adsorption towers 1, for sending the treated flue gas into the adsorption tower for CO2 capture.

[0083] Figure 3 This is a schematic diagram of the structure of the first tube heat exchange adsorption tower provided in the embodiments of this application; Figure 4 This is a schematic diagram of the structure of the second tube heat exchange adsorption tower provided in the embodiments of this application.

[0084] like Figure 3 and Figure 4 As shown, in some embodiments, the adsorption tower is a tube-and-shell heat exchange adsorption tower.

[0085] This application embodiment employs a novel adsorption tower, similar to a shell-and-tube heat exchanger. The solid amine adsorbent side 11 is filled with adsorbent, and a cooling medium is introduced to the heat exchange side 12 to remove the heat of adsorption. The shell-and-tube heat exchange adsorption tower is a device combining the characteristics of both a shell-and-tube heat exchanger and an adsorption tower. It is primarily used for the adsorption, separation, and purification of gases, while also achieving efficient heat transfer. The core component of the shell-and-tube heat exchange adsorption tower is the tubes, which are typically made of corrosion-resistant and high-temperature-resistant materials, such as stainless steel. The shell is the external frame of the shell-and-tube heat exchange adsorption tower, used to house the tubes and support the entire device. Tube sheets are used to fix the ends of the tubes, ensuring the stability of the tubes within the shell. Baffles are used to guide the flow direction of the fluid within the shell, increasing the contact area between the fluid and the tubes, thereby improving heat and mass transfer efficiency.

[0086] It should be noted that in the first tube-and-shell heat exchange adsorption tower, the solid amine adsorbent side 11 is a tube, and the heat exchange side 12 is a shell, with the solid amine adsorbent filling the tube; in the second tube-and-shell heat exchange adsorption tower, the solid amine adsorbent side 11 is a shell, and the heat exchange side 12 is a tube, with the solid amine adsorbent filling the shell. Figure 3 and Figure 4 In the diagram, A - flue gas inlet / regeneration gas outlet; B - flue gas outlet / regeneration gas inlet; C - cooling medium inlet; D - cooling medium outlet.

[0087] In some embodiments, the plurality of adsorption towers 1 are arranged in parallel with each other, and the number of the plurality of adsorption towers 1 is ≥3.

[0088] Due to the high CO2 content in the flue gas, the adsorption process is short due to limitations in adsorption capacity. Furthermore, the thermal regeneration process is slow due to the influence of the heat transfer coefficient and the limitation of the heating rate. To ensure the continuity of the adsorption and thermal regeneration processes, at least three adsorption towers are required in this embodiment. For example, the number of adsorption towers 1 can be 3, 4, 5, 6, 7, etc.

[0089] In some embodiments, the system further includes:

[0090] Air cooler 5, wherein air is introduced into the air cooler 5;

[0091] Air separator 6, which is connected to the inlet of the heat exchange side 12 of the air cooler 5 and the plurality of adsorption towers 1;

[0092] An air heater 7 is connected to the inlet of the heat exchange side 12 of the plurality of adsorption towers 1.

[0093] In this embodiment, to ensure the adsorption effect, the heat of adsorption generated during the adsorption process needs to be removed to keep the adsorption bed temperature as close to a constant temperature as possible. The adsorption tower is a tube-and-shell heat exchanger type; the adsorbent can be packed inside the tubes (…). Figure 3 ) or outside the pipe ( Figure 4 The specific type is determined based on site conditions, equipment scale, resistance drop requirements, heat removal medium, etc.

[0094] It should be noted that this application provides two adsorption heat removal schemes for different application scenarios. The selectable cooling media are chilled water and gas (air and flue gas are also options). The supply and cutoff of the cooling media in both schemes are automatically switched sequentially. The feed programmable valve opens when the bed is cooled by cold blowing at the end of thermal regeneration and closes when adsorption ends. The following describes the specific implementation schemes for the two heat removal media based on the structure of the first adsorption tower (adsorbent inside the tube, heat removal medium outside the tube):

[0095] Figure 5 This is a schematic diagram of the air heat removal structure of the first tube heat exchange adsorption tower provided in the embodiments of this application.

[0096] like Figure 5As shown, the specific process of air deheating is as follows: After being pressurized by a blower, the air is sent to air cooler 5 to exchange heat with chilled water and cool down to 20°C. Then, after the liquid is separated by air separator 6, it is sent to the outside of the adsorption tower tube to cool the adsorption bed through the deheating feed control valve, and then discharged from the bottom of the tower to the atmosphere. The discharge pipeline is only equipped with a check valve and is not shut off or isolated. After adsorption, the air is sent to the heater along the bypass of the air cooler 5. The heated air enters the outside of the adsorption tower tube through the deheating feed control valve and indirectly exchanges heat with the adsorption bed to provide heat for the thermal regeneration of the adsorbent. After the thermal regeneration isothermal stage is completed, the flow is switched to cold air to cool the adsorbent until the next adsorption process is completed.

[0097] Figure 6 This is a schematic diagram of the chilled water heat removal structure of the first tube heat exchange adsorption tower provided in the embodiments of this application.

[0098] like Figure 6 As shown, the specific process of chilled water heat removal is as follows: Chilled water from the chilled water station is sent to the adsorption tower external cooling adsorption bed via a heat removal feed control valve, and then discharged from the top of the tower via a heat removal discharge valve back to the chilled water return network. After adsorption is completed, the chilled water inlet and outlet control valves are closed, and the hot water inlet and outlet control valves are opened, switching to the hot water system, which indirectly exchanges heat with the adsorption bed to provide heat for the thermal regeneration of the adsorbent. After the thermal regeneration isothermal stage is completed, the system switches back to chilled water to cool the adsorbent until the next adsorption process is completed.

[0099] In summary, the embodiments of this application significantly improve the efficiency of carbon dioxide capture by using novel solid adsorption materials and optimized processes. They are characterized by low energy consumption, simple equipment, and strong adaptability, and can meet the needs of modern industry for efficient carbon capture technology.

[0100] Figure 7 This is a schematic flowchart of a carbon dioxide capture method based on a solid amine adsorbent, provided as an embodiment of this application.

[0101] like Figure 7 As shown, this application provides a method for carbon dioxide capture based on solid amine adsorbents, the method comprising:

[0102] S1. Pre-treat the flue gas;

[0103] Pretreatment removes impurities from the flue gas, providing more favorable conditions for subsequent carbon dioxide adsorption.

[0104] S2. Use a solid amine adsorbent to adsorb carbon dioxide in the pretreated flue gas, and perform heat exchange during the adsorption process to obtain a carbon dioxide supported adsorbent and decarbonized flue gas.

[0105] In some embodiments, the solid amine adsorbent is an amine-functionalized organic polymer resin.

[0106] Amine-functionalized organic polymer resins possess unique polymerization technology and a dense network structure, exhibiting high adsorption capacity for carbon dioxide, good water resistance, low regeneration temperature, good CO2 selectivity, high pollution resistance, and low operating losses. During adsorption, heat exchange equipment is used to exchange heat with the solid amine adsorbent to maintain a stable temperature and improve adsorption efficiency.

[0107] S3. Desorb the carbon dioxide supported adsorbent using carbon dioxide regeneration gas, and perform heat exchange during the desorption process to heat the carbon dioxide supported adsorbent, thereby obtaining solid amine adsorbent and carbon dioxide regeneration gas.

[0108] In some embodiments, the temperature of the pretreated flue gas is <30°C; and / or,

[0109] The temperature of the carbon dioxide regeneration gas is >120°C; and / or,

[0110] The desorption pressure is ≤10 kPa.

[0111] During desorption, heat exchange is also performed to heat the carbon dioxide-supported adsorbent, thereby improving desorption efficiency. The heating temperature needs to be higher than the adsorption temperature to ensure complete desorption of carbon dioxide. The pressure during desorption needs to be controlled at ≤10 kPa to reduce desorption energy consumption and improve desorption efficiency. For example, the temperature of the carbon dioxide regeneration gas can be 121℃, 122℃, 125℃, 128℃, 130℃, 135℃, etc.

[0112] This application's embodiments address the issue of high heat release during solid adsorption by innovating the adsorber type; solve the problem of adsorption-regeneration time balance by innovating the regeneration heating method; and solve the problem of carbon dioxide purity and improve product recovery rate by selecting regeneration media at different stages.

[0113] The main features of the embodiments of this application are as follows:

[0114] 1. Low energy consumption and simple equipment: Through the design of new solid adsorption materials and optimized process flow, the energy consumption in carbon dioxide capture and adsorbent regeneration processes is significantly reduced. The equipment configuration is relatively simple and easy to apply in industrial applications.

[0115] 2. Flexible cooling medium selection: In response to the large amount of adsorption heat generated during the carbon dioxide capture process, this invention provides three cooling medium selection options (gas, chilled water) to adapt to different working conditions and operating conditions, ensuring the efficient operation of the system.

[0116] 3. Strong adaptability of process flow: The process design of this invention has strong adaptability and can adapt to different scales and types of industrial waste gas emission scenarios, meeting the diverse needs of modern industry for carbon emission reduction technology.

[0117] 4. Excellent adsorption performance and high CO2 capture rate: This invention uses a novel high-efficiency adsorbent with high CO2 selectivity, high adsorption capacity, and a CO2 capture rate >90%;

[0118] 5. Good water resistance and low regeneration energy consumption: This invention uses a new type of high-efficiency adsorbent with good water resistance. When flue gas enters the adsorption bed, only free water needs to be separated, which reduces the energy consumption for dehydration and drying; the adsorbent regeneration temperature is low, which reduces the energy consumption for regeneration heating.

[0119] 6. High CO2 recovery rate: The CO2 capture rate is high, and the flue gas in the dead space of the adsorption tower that has not been adsorbed by the adsorption bed is returned to the upstream, resulting in a high overall CO2 recovery rate;

[0120] 7. Novel Adsorption Tower Structure: This invention employs a novel adsorption tower structure, organically integrating the hot and cold media on the heat exchange side with the process flow to achieve cooling and heat removal during the adsorption process, ensuring the adsorption performance of the adsorbent. During the thermal regeneration process, the adsorbent is heated and regenerated simultaneously on both the inner and outer sides, ensuring uniform heating, guaranteeing regeneration efficiency, and shortening regeneration time. Similarly, simultaneous cooling on both the inner and outer sides is used during cooling, shortening the cooling time. This technology enables continuous adsorption and continuous desorption of CO2 products with only three adsorption towers, effectively reducing the number of adsorption towers and investment.

[0121] 8. Simple process and high degree of automation: Compared with the solution adsorption method, this invention significantly shortens the process flow and operates under milder conditions. The entire process is controlled sequentially, enabling unmanned operation.

[0122] 9. Strong Adsorbent Adaptability: The adsorbent exhibits good adaptability to SO2 in flue gas, achieving a removal rate of over 95% after pollution. This invention includes a fine desulfurization tower pre-loaded with the same adsorbent before the CO2 adsorption tower, which can efficiently remove SO2 and regenerate efficiently. The adsorbent has high water resistance, with a capacity loss rate of <2% upon contact with liquid water. Therefore, this invention can adapt to fluctuations in feed or local conditions, exhibiting good adaptability in SO2 and H2O environments.

[0123] 10. Flexible and versatile process with wide applicability: In addition to the strong adaptability of the adsorbent to flue gas, the cooling and heating schemes required by the process are flexible and can be adjusted according to the supply conditions of on-site public works to adapt to different working conditions and operating conditions, ensuring the efficient operation of the system.

[0124] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to industry standards. If there is no corresponding industry standard, then common international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0125] Example 1

[0126] Figure 8 This is a schematic diagram of the gas flow direction for carbon dioxide adsorption provided in Embodiment 1 of this application; Figure 9 This is a schematic diagram of the gas flow direction for carbon dioxide desorption provided in Embodiment 1 of this application.

[0127] like Figure 8 and Figure 9 As shown, a thermal power company is equipped with a solid amine adsorption carbon dioxide capture device. The CO2 content in its flue gas is 12%, and the other main media are nitrogen, oxygen, and saturated water.

[0128] First, the flue gas is sent to the bottom of the scrubbing tower and flows upwards, where it comes into contact with the alkaline solution flowing downwards from the top of the tower to wash away solid particulate impurities, while also removing some SO2. The flue gas at the top of the tower is then pressurized by an induced draft fan and sent to the fine desulfurization adsorption tower 42 for further SO2 removal, and then sent to the CO2 adsorption tower.

[0129] The flue gas from the desulfurization adsorption tower 42 is cooled to 20°C by the flue gas cooler 43, and after the condensed water is separated in the flue gas separator, it is sent to the bottom of the CO2 adsorption tower. In the adsorption bed, CO2 is adsorbed down, and the flue gas after CO2 removal is discharged to the atmosphere from the top of the tower. Three adsorption towers are installed.

[0130] After adsorption in the CO2 adsorption tower is completed, adsorbent regeneration begins. Since the adsorption pressure is close to atmospheric pressure, vacuum regeneration is used to ensure regeneration efficiency. The regeneration process includes several parallel processes: forward release, reverse release, heating, isothermal control, and cooling. After adsorption is complete, the adsorption control valve is shut off. The forward release control valve is opened to vent the flue gas in the upper space of the adsorption tower (stream A). After forward release, the forward release valve is closed, and the reverse release valve is opened for reverse release. The reverse release gas (stream B) is sent to the reverse release gas buffer tank for pressure stabilization before returning to the inlet of the pretreatment unit's induced draft fan. After reverse release, the reverse release valve is closed, and the regeneration gas inlet and outlet control valves are opened for thermal regeneration. A stream of regeneration gas (stream G) is drawn from the CO2 product gas, its flow rate is regulated by a flow control valve, and it is sent to the regeneration gas preheater to exchange heat with the hot regeneration gas from the CO2 adsorption tower. Then, stream H is further heated to 130°C by the regeneration gas electric heater, and stream I enters the CO2 adsorption tower to heat the adsorbent bed, desorbing CO2 from the adsorption bed. The desorbed CO2 and regeneration gas (stream C) are sent out from the bottom of the tower together. After passing through a regeneration gas preheater and a CO2 water cooler for cooling, and then through a CO2 separator for liquid separation, stream D is sent to vacuum pump 32. Vacuum pump 32 maintains the regeneration pressure at 10 kPaA by drawing a vacuum. A water cooler and a water separator are installed at the outlet of vacuum pump 32 to cool and separate the CO2 gas in stream E. Then, part of it is circulated back to the adsorption tower as regeneration gas stream G, and part of it is sent out of the boundary area as product stream F. The isothermal process and the heating process are the same, and the valve positions of the programmable valves remain unchanged. During the heating and isothermal processes, hot water is introduced into the heat exchange side 12 of the adsorption tower to provide heat for the adsorption bed to heat up. After the isothermal process is completed, the adsorbent regeneration ends. The regeneration gas inlet and outlet valves are closed, and the cold blowing gas inlet and outlet valves are opened to start the cooling process. Nitrogen gas (stream J) is used for cooling the adsorption bed, or the flue gas after CO2 removal at the adsorption tower outlet can be used depending on the actual nitrogen supply on site. Nitrogen or cooled flue gas enters the adsorption tower through the cold-blowing feed valve and is then discharged into the atmosphere through the discharge valve. During the cooling process, chilled water is introduced into the heat exchange side 12 of the adsorption tower to cool the adsorption bed. After cooling is completed, the cold-blowing gas inlet and outlet valves are closed, and the adsorption inlet and outlet valves are opened to allow parallel adsorption with the adsorption tower currently undergoing adsorption, thus completing the regeneration process.

[0131] Among them, stream A is for forward venting; stream B is for reverse venting and recovery; streams C, D, and E are for carbon dioxide (regenerated gas + desorbed gas); stream F is for carbon dioxide product gas; streams G and H are for carbon dioxide (regenerated gas) waste heat recovery; stream I is for hot regenerated gas to heat up the adsorbent bed; and stream J is for cold blowing gas to cool down the adsorbent bed.

[0132] Furthermore, one or more technical solutions in the embodiments of this application have at least the following technical effects or advantages:

[0133] In this embodiment, the problems of high energy consumption, complex equipment, and low separation efficiency in the prior art are overcome. Through innovative process flow and cooling scheme, a process for capturing carbon dioxide in flue gas with high adsorption capacity, high heat release, high product purity, and high recovery rate is developed, achieving efficient, economical and environmentally friendly carbon dioxide capture.

[0134] In this embodiment, high-purity carbon dioxide products are obtained by using novel solid adsorption materials, novel adsorption tower structures, and innovative multi-tower vacuum temperature-switching adsorption processes. These products feature high adsorption efficiency, low energy consumption, high recovery rate, good regeneration effect, simple process, simple equipment, highly automated control, and strong adaptability, thus meeting the needs of modern industry for efficient carbon capture technology.

[0135] The proposed cooling or heating schemes in this application aim to improve the adsorption and regeneration efficiency of the carbon dioxide capture process through effective thermal management, thereby meeting the needs of modern industry for efficient and flexible carbon capture processes.

[0136] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A carbon dioxide capture system based on a solid amine adsorbent, the system being used for the adsorption and desorption of carbon dioxide, wherein, When the system is used for the adsorption of carbon dioxide, the system comprises: Multiple adsorption towers (1) include a solid amine adsorbent side (11) and a heat exchange side (12). Flue gas is introduced into the inlet of the solid amine adsorbent side (11), and a cold medium is introduced into the inlet of the heat exchange side (12). The solid amine adsorbent is used to adsorb carbon dioxide in the flue gas, and heat exchange is carried out during the adsorption process to obtain carbon dioxide supported adsorbent and decarbonized flue gas. When the system is used for the desorption of carbon dioxide, the system comprises: The system comprises multiple adsorption towers (1), a regeneration gas heater (2), and a desorption section (3). A heat medium is introduced into the inlet of the heat exchange side (12) of the multiple adsorption towers (1). The outlet of the solid amine adsorbent side (11) of the multiple adsorption towers (1) is connected to the regeneration gas heater (2). The inlet of the solid amine adsorbent side (11) of the multiple adsorption towers (1) is connected to the desorption section (3). The system is used to heat the carbon dioxide supported adsorbent with carbon dioxide hot regeneration gas to perform desorption, thereby obtaining solid amine adsorbent and carbon dioxide regeneration gas.

2. The system according to claim 1, characterized in that, The desorption section includes: The first cooling distributor (31) is connected to the plurality of adsorption towers (1) and the carbon dioxide regeneration gas heater (2); A vacuum pump (32) is connected to the first cooling distributor (31); The second cooling distributor (33) is connected to the vacuum pump (32) and the first cooling distributor (31).

3. The system according to claim 1, characterized in that, The system also includes: The pretreatment section (4) is connected to the solid amine adsorbent side (11) of the plurality of adsorption towers (1) and is used to pretreat the flue gas.

4. The system according to claim 3, characterized in that, The preprocessing unit (4) includes: A scrubbing tower (41) is provided with flue gas at its inlet; Fine desulfurization adsorption tower (42), the inlet of which is connected to the outlet of the washing tower (41); The flue gas cooler (43) has its inlet connected to the outlet of the fine desulfurization adsorption tower (42), and its flue gas outlet is connected to the solid amine adsorbent side (11) of the plurality of adsorption towers (1).

5. The system according to claim 1, characterized in that, The adsorption tower is a tube-and-shell heat exchange adsorption tower.

6. The system according to claim 1, characterized in that, The multiple adsorption towers (1) are arranged in parallel with each other, and the number of the multiple adsorption towers (1) is ≥3.

7. The system according to claim 1, characterized in that, The system also includes: Air cooler (5), which is supplied with air; An air separator (6) is connected to the inlet of the heat exchange side (12) of the air cooler (5) and the plurality of adsorption towers (1); An air heater (7) is connected to the inlet of the heat exchange side (12) of the plurality of adsorption towers (1).

8. A method for carbon dioxide capture based on a solid amine adsorbent, the method comprising: Pre-treat the flue gas; The carbon dioxide in the pretreated flue gas is adsorbed using a solid amine adsorbent, and heat exchange is carried out during the adsorption process to obtain a carbon dioxide supported adsorbent and decarbonized flue gas. The carbon dioxide supported adsorbent is heated with carbon dioxide thermal regeneration gas to perform desorption, yielding a solid amine adsorbent and carbon dioxide regeneration gas.

9. The method according to claim 8, characterized in that, The solid amine adsorbent is an amine-functionalized organic polymer resin.

10. The method according to claim 8, characterized in that, The temperature of the pretreated flue gas is <30°C; and / or, The temperature of the carbon dioxide regeneration gas is >120°C; and / or, The desorption pressure is ≤10 kPa.

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