Solid adsorption cycle carbon capture device and method

Abstract

The present invention discloses a solid adsorption cycle carbon capture device and method, the device performs carbon capture through an alkali metal-based solid absorbent, and the device at least comprises: a fluidized reactor having a hydration reaction zone and an adsorption reaction zone which are relatively isolated; a hydration bed layer is arranged at the bottom of the hydration reaction area, and water vapor introduced from the bottom of the hydration bed layer is subjected to fluidized hydration reaction; an adsorption bed layer is arranged at the bottom of the adsorption reaction area, and a fluidized adsorption reaction is carried out through carbon-containing gas introduced from the bottom of the adsorption bed layer; the hydration bed layer is communicated with the adsorption bed layer through a vertical pipe; and a hydrated adsorbent particle dense-phase region is arranged in the vertical pipe and is used for isolating the hydration reaction region from the adsorption reaction region. According to the scheme of partition reaction, the contradiction that the reaction rates between hydration and carbonation are not matched is fundamentally solved, the performance of the adsorbent can be exerted to the maximum extent, and the treatment efficiency of carbon capture is effectively improved; the hydration reaction and the adsorption reaction can be subjected to process reinforcement through the fluidized reactor, so that the efficiency of the hydration reaction and the adsorption reaction is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of carbon capture technology, and in particular to a solid adsorption circulating carbon capture device and method. Background Technology

[0002] Carbon capture technology is a key measure for achieving low-carbon utilization of fossil energy. Amine-based CO2 absorption technology has been widely used in the chemical industry, especially in coal-fired power plants. However, it has significant drawbacks, including large equipment size, the need for large amounts of solvent, the corrosiveness and easy degradation of amine solvents, the necessity of washing and eliminating solvent emissions from the recovery tower, large steam requirements, expired solvent disposal issues, and high energy and capital expenditure. Compared with traditional solvent absorption processes, solid adsorbents offer advantages such as ease of handling, no solvent loss, low energy consumption, less environmental pollution, relatively simple processes, and lower operating costs.

[0003] In recent years, the dry CO2 removal technology using alkali metal-based adsorbents has attracted widespread attention in the industry due to its advantages such as low raw material cost, low reaction energy consumption, high recycling efficiency, no equipment corrosion, and no secondary pollution. Alkali metal-based adsorbents mainly consist of sodium carbonate and potassium carbonate, which directly adsorb CO2 through a chemical reaction. The resulting bicarbonate is decomposed by heating in a regeneration reactor, and the generated gas is condensed to remove moisture, yielding high-purity CO2. The carbonate can then be recycled. This method combines the process characteristics of both chemical absorption and physical adsorption, effectively solving the equipment corrosion problems and high energy consumption of absorbent regeneration in chemical absorption, while overcoming the shortcomings of low adsorbent adsorption capacity and low CO2 selectivity in physical adsorption. Therefore, it has broad application prospects.

[0004] For example, PCT patent application WO2022235664A3 discloses a method for removing CO2 from a CCh-containing gas containing water vapor, comprising: (a) contacting the CO2-containing gas containing water vapor with an alkali metal carbonate adsorbent, the contact conditions being such that (i) the water vapor in the CO2-containing gas reacts with the alkali metal carbonate to form the corresponding alkali metal carbonate hydrate, and (ii) the corresponding alkali metal carbonate hydrate reacts with CO2 in the CO2-containing gas containing water vapor to form the corresponding alkali metal sesquicarbonate; and (b) reacting the alkali metal sesquicarbonate under conditions that effectively recover CO2 and regenerate the alkali metal carbonate hydrate adsorbent therefrom. A system for carrying out this method is also disclosed, suitable for direct air capture (DAC) of CO2, and for the treatment of CO2-containing flue gas from power plants and other oxidation and combustion sources. However, the different reaction rates of carbonates (such as potassium carbonate) with water during hydration and the different reaction rates of potassium carbonate with CO2 and H2O during carbonation lead to a mismatch in reaction rates, which reduces the performance and treatment efficiency of solid adsorbents.

[0005] Therefore, there is an urgent need for a solid adsorption circulating carbon capture device and method that can maximize the performance of the adsorbent and effectively improve the carbon capture efficiency.

[0006] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0007] The purpose of this invention is to provide a solid adsorption circulating carbon capture device and method. By using a partitioned reaction scheme, the mismatch between the reaction rates of hydration and carbonation is fundamentally resolved, which can maximize the performance of the adsorbent and effectively improve the carbon capture efficiency.

[0008] Another objective of this invention is to provide a solid adsorption circulating carbon capture device and method, which can enhance the hydration and adsorption processes through a fluidized bed reactor, thereby effectively improving the efficiency of the hydration and adsorption reactions.

[0009] To achieve the above objectives, according to a first aspect of the present invention, the present invention provides a solid adsorption circulating carbon capture device, which captures carbon using an alkali metal-based solid absorbent, comprising at least: a fluidized bed reactor having a relatively isolated hydration reaction zone and an adsorption reaction zone; the bottom of the hydration reaction zone is a hydration bed, through which a fluidized hydration reaction is carried out by water vapor introduced at the bottom of the hydration bed; the bottom of the adsorption reaction zone is an adsorption bed, through which a carbon-containing gas is introduced at the bottom of the adsorption bed, through which a fluidized adsorption reaction is carried out; the hydration bed and the adsorption bed are connected by a riser; the riser contains a dense phase region of hydrated adsorbent particles, used for isolation between the hydration reaction zone and the adsorption reaction zone.

[0010] Furthermore, in the above technical solution, the riser can also be used to dissipate heat from the hydrated adsorbent particles to the reaction temperature required for the adsorption process.

[0011] Furthermore, in the above technical solution, the device of the present invention further includes: a regeneration unit, which is disposed outside the fluidized reactor and connected to the adsorption reaction zone through a regeneration inclined tube, for regenerating the adsorbent by high-temperature decomposition and discharging CO2 gas; and a heat extraction unit, which is connected to the regeneration unit through a regeneration inclined tube, for exchanging heat between the regenerated high-temperature adsorbent and liquid water, so that the cooled adsorbent particles are driven back to the hydration reaction zone by air through the riser, and the water vapor generated by the heat exchange is introduced into the bottom of the hydration bed.

[0012] Furthermore, in the above technical solution, the regeneration unit can be a moving bed reactor; the heat extraction unit can be an external heat extractor.

[0013] Furthermore, in the above technical solution, the active component of the alkali metal-based solid absorbent is preferably K2CO3.

[0014] Furthermore, in the above technical solution, the top of the hydration reaction zone may be provided with: a first cyclone separator, used to receive the regenerated adsorbent particles and separate them from the air, and the separated adsorbent particles are added to the hydration bed; a second cyclone separator, used to receive the fluidized adsorbent particles in the hydration reaction zone and separate them from the water vapor, and the separated adsorbent particles fall into the hydration bed; the air separated by the first cyclone separator and the water vapor separated by the second cyclone separator are combined and discharged.

[0015] Furthermore, in the above technical solution, the top of the adsorption reaction zone may be equipped with a third cyclone separator, which is used to receive the adsorbent particles after the adsorption reaction and separate them from the decarbonized gas after the reaction; the separated adsorbent particles enter the regeneration unit through the waiting inclined tube, and the decarbonized gas is discharged.

[0016] According to a second aspect of the present invention, the present invention provides a solid adsorption cycle carbon capture method, using the aforementioned apparatus, comprising at least the following steps: A. Hydration process: using water vapor as fluidizing air, the active component of the alkali metal-based solid adsorbent undergoes a hydration reaction with water to generate hydrates for CO2 adsorption; B. forming a dense phase region of adsorbent particles through a riser at the bottom of the hydration bed, thereby isolating the hydration reaction zone and the adsorption reaction zone, and simultaneously cooling the adsorbent particles transported to the adsorption reaction zone to the temperature required for the adsorption reaction; C. Adsorption process: using carbon-containing gas as fluidizing air, CO2 is captured through the adsorption reaction between the carbon-containing gas and the hydrated adsorbent particles.

[0017] Furthermore, in the above technical solution, the method also includes the following steps: D. Regeneration process: the adsorbent particles after adsorbing CO2 are decomposed by a high-temperature regeneration reaction to obtain regenerated adsorbent particles; E. Heat extraction process: the regenerated high-temperature adsorbent particles are exchanged with liquid water, so that the adsorbent particles are cooled and refluxed and hydrated. The water vapor formed by the heat exchange is used as the fluidizing air for the hydration process.

[0018] Furthermore, in the above technical solution, the active component of the alkali metal-based solid adsorbent is preferably potassium carbonate, and the auxiliary agent can be one or more of transition metals and rare earth metals; the adsorbent is formed into microspheres for fluidized beds, and the average particle size of the microspheres can be 40-120 μm.

[0019] Furthermore, in the above technical solution, the preferred reaction operating conditions for the hydration process are: reaction pressure of 0.1–2.0 MPa, reaction temperature of 60–150 °C, water vapor velocity of 0.001–0.1 m / s, and water vapor content of 1–35%.

[0020] Furthermore, in the above technical solution, the adsorption process is a carbonation reaction process, and the preferred reaction operating conditions are: reaction pressure of 0.1 to 2.0 MPa, reaction temperature of 40 to 100°C, carbon-containing gas flow rate of 0.001 to 0.1 m / s, and CO2 content in the carbon-containing gas of 1 to 40%.

[0021] Furthermore, in the above technical solution, the preferred reaction operating conditions for the regeneration process are: a reaction pressure of 0.1–2.0 MPa and a reaction temperature of 100–200 °C.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1) By employing a partitioned and relatively isolated fluidized bed reactor, this invention integrates the hydration process and the adsorption process in the same reactor. This not only helps to ensure the continuity of the reaction and creates better conditions for recycling, but also fundamentally solves the contradiction of the mismatch between the reaction rates of the hydration process and the carbonation process (i.e., the adsorption process). This can maximize the performance of the adsorbent and effectively improve the carbon capture efficiency.

[0024] 2) In this invention, the active components can undergo complete reaction in two fluidized reaction zones, which can maximize the performance of the adsorbent; the fluidized reactor can enhance the process of hydration reaction and adsorption reaction. By integrating the advantages of uniform temperature distribution and sufficient gas-solid contact of fluidized reaction, the efficiency of hydration reaction and adsorption reaction can be maximized.

[0025] 3) The hydration bed and the adsorption bed of the present invention are connected by a riser, so that the inside of the riser is the dense phase region of the hydrated adsorbent particles. The riser serves as a particle transport channel between the hydration reaction zone and the adsorption reaction zone, which not only achieves relative isolation between the two zones, but also allows for a certain degree of heat dissipation during particle transport due to its length. This reduces the temperature of the hydrated adsorbent particles from the hydration reaction temperature to the temperature required for the adsorption reaction, thereby creating more favorable conditions for the carbonation adsorption process in the adsorption reaction zone.

[0026] 4) The heat extraction unit of the present invention is connected to the regeneration unit, which can preheat and vaporize the water with the high-temperature adsorbent after the regeneration reaction. While effectively utilizing the high-temperature waste heat, it can also reduce the temperature of the adsorbent to the temperature range of the hydration reaction, which plays a key role in the heat balance of the overall process.

[0027] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, and to make the above and other objects, technical features and advantages of the present invention easier to understand, one or more preferred embodiments are listed below and described in detail with reference to the accompanying drawings. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structural connection of the solid adsorption circulating carbon capture device of the present invention.

[0029] Explanation of key figure labels:

[0030] 100-Fluidized reactor, 1-Hydration reaction zone, 11-Riser, 2-Adsorption reaction zone, 3-Regeneration unit, 4-Heat extraction unit, 5-Riser, 6-First cyclone separator, 7-Second cyclone separator, 8-Third cyclone separator, 9-Waiting inclined tube, 10-Regeneration inclined tube. Detailed Implementation

[0031] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0032] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0033] In this document, for ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” “above,” “upper,” etc., are used to describe the relationship of one element or feature to another element or feature in the accompanying drawings. It should be understood that spatial relative terms are intended to encompass different orientations of an object in use or operation, in addition to those depicted in the figures. For example, if an object in the figure is flipped, an element described as “below” or “under” another element or feature would be oriented “above” that element or feature. Thus, the exemplary term “below” can encompass both the downward and upward orientations. An object may also have other orientations (rotated 90 degrees or other orientations), and the spatial relative terms used herein should be interpreted accordingly.

[0034] In this document, the terms "first," "second," etc., are used to distinguish two different elements or parts, and are not used to define specific positions or relative relationships. In other words, in some embodiments, the terms "first," "second," etc., can also be used interchangeably.

[0035] This invention is based on the principle of hydration adsorption and uses alkali metal-based solid adsorbents to capture carbon dioxide. The process mainly includes four steps: hydration, adsorption, regeneration, and heat extraction. The main reactions that occur (taking potassium carbonate as the active component as an example) are as follows:

[0036] (1) The reaction during hydration: K2CO3 + 1.5H2O = K2CO3·1.5H2O

[0037] (2) The reaction of the adsorption process: K2CO3·1.5H2O+CO2=2KHCO3+0.5H2O.

[0038] (3) Regeneration process reaction: 2KHCO3=K2CO3+CO2+H2O.

[0039] Based on the above reaction principle, such as Figure 1 As shown, this invention provides a solid adsorption circulating carbon capture device that captures carbon using an alkali metal-based solid absorbent similar to potassium carbonate. The device includes at least a fluidized bed reactor 100, which has a relatively isolated hydration reaction zone 1 and an adsorption reaction zone 2. The bottom of the hydration reaction zone 1 is a hydration bed, through which water vapor is introduced to carry out a fluidized hydration reaction. The bottom of the adsorption reaction zone 2 is an adsorption bed, through which carbon-containing gas is introduced to carry out a fluidized adsorption reaction. The hydration bed and the adsorption bed are connected by a riser 11. The riser 11 contains a dense phase region of the hydrated adsorbent particles, serving as an isolation between the hydration reaction zone and the adsorption reaction zone. The riser 11 can also be used to dissipate heat from the hydrated adsorbent particles to the reaction temperature required for the adsorption process.

[0040] This invention integrates the hydration and adsorption processes into a single fluidized bed reactor by employing a partitioned and relatively isolated system. This not only improves reaction continuity and creates better conditions for cyclic treatment, but also fundamentally resolves the mismatch in reaction rates between the hydration and carbonation processes (i.e., adsorption). This maximizes the performance of the adsorbent and effectively improves carbon capture efficiency. Specifically, the adsorbent first undergoes a hydration reaction with water in the hydration reaction zone 1 of the integrated reactor 100 to generate K₂CO₃·1.5H₂O hydrate. Then, the K₂CO₃·1.5H₂O hydrate undergoes a carbonation reaction with CO₂ in the adsorption reaction zone 2 of the reactor 100 to generate KHCO₃, achieving efficient CO₂ removal. Furthermore, in both fluidized reaction zones, the active components can react completely, maximizing the adsorbent's performance. Additionally, the fluidized bed reactor can enhance the hydration and adsorption processes by integrating the fluidized bed reaction temperature... The uniform distribution and sufficient gas-solid contact maximize the efficiency of hydration and adsorption reactions. Furthermore, the hydration bed and adsorption bed are connected by a riser, making the riser a dense phase region of the hydrated adsorbent particles. The riser serves as a particle transport channel between the hydration reaction zone and the adsorption reaction zone, achieving relative isolation between the two zones. Moreover, the riser's length allows for some heat dissipation during particle transport, lowering the temperature of the hydrated adsorbent particles from the hydration reaction temperature to the temperature required for the adsorption reaction. This creates more favorable conditions for the carbonation adsorption process in the adsorption reaction zone.

[0041] Further as Figure 1 As shown, the solid adsorption circulating carbon capture device of the present invention further includes a regeneration unit 3 and a heat extraction unit 4. The regeneration unit 3 is located outside the fluidized bed reactor 100 and is connected to the adsorption reaction zone 2 via a regeneration inclined tube 9. It is used to regenerate the adsorbent through high-temperature decomposition and discharge CO2 gas. The heat extraction unit 4 is connected to the regeneration unit 3 via a regeneration inclined tube 10 and is used to exchange heat between the regenerated high-temperature adsorbent and liquid water (using an external water source). This allows the cooled adsorbent particles to flow back to the hydration reaction zone 1 via air driven by the riser tube 5, and the water vapor generated during heat exchange is introduced into the bottom of the hydration bed. The regeneration unit 3 preferably uses a moving bed reactor; the heat extraction unit 4 preferably uses an external heat extractor.

[0042] The regeneration unit 3 of this invention can decompose the adsorbent particles after CO2 adsorption from the adsorption reaction zone through a high-temperature regeneration reaction (2KHCO3=K2CO3+CO2+H2O) to obtain K2CO3 and CO2. Specifically, the adsorbent particles after CO2 adsorption enter the regeneration unit 3 from the pre-regeneration inclined tube 9 for high-temperature decomposition. The resulting CO2 gas is discharged from the top of the regeneration unit 3, and the regenerated adsorbent particles enter the heat extraction unit 4 from the regeneration inclined tube 10. The heat extraction unit 4 of this invention can heat and vaporize external liquid water through heat exchange with the regenerated high-temperature adsorbent, thereby achieving efficient heat utilization (i.e., heating the liquid water into water vapor, which serves as the fluidizing air for the hydration reaction, while simultaneously cooling the adsorbent particles to the required hydration reaction temperature). The specific process is as follows: the regenerated adsorbent particles enter the heat extraction unit 4, where they use their own heat to heat the liquid water to vaporization and introduce it into the hydration bed. External air is introduced from the bottom of the riser pipe 5 and drives the regenerated and cooled adsorbent particles into the hydration reaction zone 1 for hydration reaction. The heat extraction unit 4, by using an external heat exchanger, can preheat and vaporize the water with the high-temperature adsorbent after the regeneration reaction. While effectively utilizing the high-temperature waste heat, it also lowers the temperature of the adsorbent to the temperature range of the hydration reaction, playing a crucial role in the heat balance of the overall process.

[0043] To better facilitate gas-solid separation within the hydration reaction zone 1, a first cyclone separator 6 and a second cyclone separator 7 can be installed at the top of the hydration reaction zone. The first cyclone separator 6 receives the regenerated adsorbent particles and separates them from the air; the separated adsorbent particles can then be added back to the hydration bed. The second cyclone separator 7 receives the fluidized adsorbent particles within the hydration reaction zone 1 and separates them from the water vapor; the separated adsorbent particles can then fall back into the hydration bed. The air separated by the first cyclone separator 6 and the water vapor separated by the second cyclone separator 7 can be combined and discharged.

[0044] To better facilitate gas-solid separation within the adsorption reaction zone 2, a third cyclone separator 8 can be installed at the top of the adsorption reaction zone. This third cyclone separator 8 is used to receive the adsorbent particles after the adsorption reaction and separate them from the decarbonized gas after the reaction. The separated adsorbent particles enter the regeneration unit 3 through the inclined tube 9, while the decarbonized gas is discharged.

[0045] refer to Figure 1 This invention also provides a solid adsorption circulating carbon capture method using the aforementioned apparatus. The active component of the alkali metal-based solid adsorbent is preferably potassium carbonate, and the auxiliary agent can be one or more transition metals or rare earth metals. The adsorbent is molded into microspheres specifically for fluidized beds, with an average particle size preferably of 40–120 μm. The method includes the following steps:

[0046] Step S101, Hydration Process: Water vapor is used as fluidizing air, and the active component of the alkali metal-based solid adsorbent undergoes a hydration reaction with water to generate hydrates for CO2 adsorption. Specifically, the hydration process involves the active component K2CO3 of the adsorbent reacting with water to generate a hydrate with high CO2 adsorption activity, K2CO3·1.5H2O (K2CO3+1.5H2O=K2CO3·1.5H2O). The specific process is as follows: Air is used as a power source, entering from the bottom of the riser 5 and carrying the regenerated adsorbent upwards. After separation by the first cyclone separator 6, the adsorbent enters the hydration bed and undergoes a hydration reaction with the water vapor, converting the active component on the adsorbent into hydrates. The solid particles obtained from the second cyclone separator 7 at the top of the bed return to the hydration bed, while the gas is discharged. The hydrated adsorbent at the bottom of the hydration bed enters the adsorption bed through the riser 11. The preferred operating conditions for the hydration process are: reaction pressure of 0.1–2.0 MPa, reaction temperature of 60–150 °C, water vapor velocity of 0.001–0.1 m / s, and water vapor content of 1–35%.

[0047] In step S102, a dense phase region of adsorbent particles is formed by the riser 11 at the bottom of the hydration bed. While isolating the hydration reaction zone 1 and the adsorption reaction zone 2, the adsorbent particles transported to the adsorption reaction zone 2 can be cooled to the temperature required for the adsorption reaction (that is, the temperature is reduced from the hydration reaction temperature of 60-150°C in step S101 to the adsorption reaction temperature of 40-100°C in step S103).

[0048] Step S103, Adsorption Process: Carbon-containing gas is used as fluidizing air, and CO2 is captured through the adsorption reaction between the carbon-containing gas and the hydrated adsorbent particles (K2CO3·1.5H2O+CO2=2KHCO3+0.5H2O). Specifically, adsorbent particles transported from the hydration reaction zone 1 enter the adsorption bed; carbon-containing flue gas is used as fluidizing air, entering the adsorption reaction zone 2 from the bottom of the bed, reacting with the fluidized adsorbent. After the reaction, the material is separated in the top third cyclone separator 8, and the adsorbent is regenerated through the regeneration inclined tube 9, resulting in decarbonized gas discharged from the reactor. The adsorption process is a carbonation reaction process, and the preferred reaction operating conditions are: reaction pressure 0.1~2.0MPa, reaction temperature 40~100℃; carbon-containing gas flow rate 0.001~0.1m / s, and CO2 content in the carbon-containing gas 1~40%.

[0049] Step S104, regeneration process: The adsorbent particles after adsorbing CO2 are decomposed through a high-temperature regeneration reaction to obtain regenerated adsorbent particles. The preferred reaction conditions for the regeneration process are: reaction pressure of 0.1–2.0 MPa and reaction temperature of 100–200 °C.

[0050] Step S105, heat extraction process: The regenerated high-temperature adsorbent particles and liquid water are exchanged for heat, so that the adsorbent particles are cooled and refluxed and undergo a hydration process. The water vapor generated by the heat exchange is used as the fluidizing air for the hydration process.

[0051] The method of the present invention can achieve the same technical effect as the device, and will not be described in detail here.

[0052] Example 1

[0053] In this embodiment, potassium carbonate-loaded microspheres were used as the adsorbent, and experiments were conducted in a fluidized bed reactor 100.

[0054] Flue gas with a CO2 volume fraction of 12% was used as the gas feedstock and entered from the bottom of the adsorption reaction zone 2 for CO2 adsorption. The operating conditions were: 0.1 MPa, 65℃, and gas linear velocity of 0.01 m / s. The decarbonized gas after CO2 adsorption was discharged from the third cyclone separator 8. The CO2 volume fraction in the decarbonized gas was 0.32%, and the decarbonization efficiency was 97.3%.

[0055] After adsorption saturation, the adsorbent enters the regeneration unit 3 from the bottom of the third cyclone separator 8 through the regeneration inclined tube 9. The regeneration unit adopts a downward moving bed and is regenerated at 0.1 MPa and 120℃. The desorbed CO2 is discharged from the top of the regeneration unit with a purity of 99.2%.

[0056] After regeneration, the adsorbent enters the heat exchange unit 4 through the regeneration inclined tube 10 to exchange heat with liquid water, vaporizing the water. Then, the adsorbent enters the bottom of the riser tube 5, where it is lifted upwards by air at a linear velocity of 7.5 m / s and transported to the first cyclone separator 6. The air exits from the top, and the adsorbent enters the hydration reaction zone 1 from the bottom of the first cyclone separator 6. Under conditions of 0.1 MPa and 70°C, it undergoes a hydration reaction with a water vapor medium at a linear velocity of 0.008 m / s, where the volume fraction of water vapor is 8.2%. After the hydration reaction, a hydrated adsorbent is obtained. This hydrated adsorbent then enters the adsorption reaction zone 2 through the bed riser 11 for recycling and adsorbing CO2.

[0057] The foregoing description of specific exemplary embodiments of the present invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. Any simple modifications, equivalent changes, and alterations made to the foregoing exemplary embodiments should fall within the scope of protection of the present invention.

Claims

1. A solid adsorption circulating carbon capture device, characterized in that, Carbon capture using alkali metal-based solid absorbents includes: A fluidized bed reactor has a relatively isolated hydration reaction zone and an adsorption reaction zone. The bottom of the hydration reaction zone is a hydration bed, through which water vapor is introduced to carry out the fluidized hydration reaction. The bottom of the adsorption reaction zone is an adsorption bed, through which carbon-containing gas is introduced to carry out the fluidized adsorption reaction. The hydration bed and the adsorption bed are connected by a riser. The riser contains a dense phase region of hydrated adsorbent particles, which serves to isolate the hydration reaction zone and the adsorption reaction zone.

2. The solid adsorption circulating carbon capture device according to claim 1, characterized in that, The riser is also used to dissipate heat from the hydrated adsorbent particles to the reaction temperature required for the adsorption process.

3. The solid adsorption circulating carbon capture device according to claim 1, characterized in that, The device further includes: The regeneration unit is located outside the fluidized reactor and is connected to the adsorption reaction zone through a regeneration inclined tube. It is used to regenerate the adsorbent by high-temperature decomposition and discharge CO2 gas. The heat extraction unit is connected to the regeneration unit through the regeneration inclined tube. It is used to exchange heat between the regenerated high-temperature adsorbent and liquid water, so that the cooled adsorbent particles are driven back to the hydration reaction zone by the air in the riser tube, and the water vapor generated by the heat exchange is introduced into the bottom of the hydration bed.

4. The solid adsorption circulating carbon capture device according to claim 3, characterized in that, The regeneration unit is a moving bed reactor; the heat extraction unit is an external heat extractor.

5. The solid adsorption circulating carbon capture device according to claim 1, characterized in that, The active component of the alkali metal-based solid absorbent is K2CO3.

6. The solid adsorption circulating carbon capture device according to claim 1, characterized in that, The top of the hydration reaction zone is equipped with: The first cyclone separator is used to receive the regenerated adsorbent particles and separate them from the air. The regenerated adsorbent particles are then added to the hydrated bed. The second cyclone separator is used to receive the fluidized adsorbent particles in the hydration reaction zone and separate them from the water vapor. The separated adsorbent particles fall into the hydration bed. The air separated by the first cyclone separator and the water vapor separated by the second cyclone separator are combined and discharged.

7. The solid adsorption circulating carbon capture device according to claim 3, characterized in that, The top of the adsorption reaction zone is provided with: The third cyclone separator is used to receive the adsorbent particles after the adsorption reaction and separate them from the decarbonized gas after the reaction; the separated adsorbent particles enter the regeneration unit through the waiting inclined tube, and the decarbonized gas is discharged.

8. A solid adsorption circulating carbon capture method, characterized in that, Using the apparatus as described in any one of claims 1 to 7, the method includes the following steps: A. Hydration process: Water vapor is used as fluidizing air, and the active components of the alkali metal-based solid adsorbent react with water to generate hydrates for adsorbing CO2. B. A dense phase zone of adsorbent particles is formed by the riser at the bottom of the hydration bed. While isolating the hydration reaction zone and the adsorption reaction zone, the adsorbent particles transported to the adsorption reaction zone are cooled to the temperature required for the adsorption reaction. C. Adsorption process: Carbon-containing gas is used as fluidizing air, and CO2 is captured through the adsorption reaction between the carbon-containing gas and the hydrated adsorbent particles.

9. The solid adsorption circulating carbon capture method according to claim 8, characterized in that, The method further includes the following steps: D. Regeneration process: The adsorbent particles after adsorbing CO2 are decomposed by a high-temperature regeneration reaction to obtain regenerated adsorbent particles. E. Heat extraction process: The regenerated high-temperature adsorbent particles and liquid water are exchanged for heat, so that the adsorbent particles are cooled and refluxed for hydration. The water vapor generated by the heat exchange is used as the fluidizing air for the hydration process.

10. The solid adsorption and recycling carbon capture method according to claim 9, characterized in that, The active component of the alkali metal-based solid adsorbent is potassium carbonate, and the auxiliary agent is one or more of transition metals and rare earth metals; the adsorbent is shaped into microspheres for fluidized beds, with an average particle size of 40-120 μm.

11. The solid adsorption circulating carbon capture method according to claim 10, characterized in that, The reaction operating conditions for the hydration process are as follows: reaction pressure of 0.1–2.0 MPa, reaction temperature of 60–150 °C, water vapor velocity of 0.001–0.1 m / s, and water vapor content of 1–35%.

12. The solid adsorption circulating carbon capture method according to claim 10, characterized in that, The adsorption process is a carbonation reaction process, and the reaction operating conditions are: reaction pressure of 0.1 to 2.0 MPa, reaction temperature of 40 to 100 °C; carbon-containing gas flow rate of 0.001 to 0.1 m / s, and CO2 content in the carbon-containing gas of 1 to 40%.

13. The solid adsorption circulating carbon capture method according to claim 10, characterized in that, The reaction operating conditions for the regeneration process are: reaction pressure of 0.1–2.0 MPa and reaction temperature of 100–200 °C.

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