Solid adsorption circulating carbon capture device and method

Abstract

The 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 adsorption reactor which is used as an adsorption reaction zone and has an adsorption bed layer at the bottom, and performs a fluidized adsorption reaction through carbon-containing gas introduced from the bottom of the adsorption bed layer; the lifting pipe is arranged in the fluidized adsorption reactor and serves as a hydration reaction zone; the upper end of the lifting pipe is higher than the adsorption bed layer, and the lower end of the lifting pipe penetrates out of the fluidized adsorption reactor and mixed gas of air and water vapor is introduced as fluidizing air for hydration reaction; and the regeneration unit is connected between the fluidized adsorption reactor and the riser and is used for carrying out regeneration treatment on the adsorbent particles subjected to carbon capture and recycling the adsorbent particles. According to the invention, the riser is arranged in the fluidized reactor, so that the performance of the adsorbent can be exerted to the maximum extent, and the treatment efficiency of carbon capture and efficient utilization of energy are effectively improved; the hydration reaction and the adsorption reaction can be respectively subjected to process strengthening, so that the efficiency of the hydration reaction and the adsorption reaction is effectively improved.

Description

A solid adsorption circulating carbon capture device and method 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 the hydration reaction of carbonates (such as potassium carbonate) with water and the carbonation reaction of potassium carbonate with CO2 and H2O lead to a mismatch in reaction rates, which reduces the performance and treatment efficiency of the solid adsorbent, and the energy in the entire process cannot be used efficiently.

[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 processing efficiency of carbon capture and the efficient utilization of energy.

[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 embedding the riser in a fluidized reactor, relatively independent hydration reaction zones and adsorption reaction zones are constructed within the same reactor, fundamentally solving the contradiction of the mismatch between hydration and carbonation reaction rates. This maximizes the performance of the adsorbent and effectively improves the carbon capture efficiency and energy utilization.

[0008] Another objective of this invention is to provide a solid adsorption circulating carbon capture device and method, which can enhance the hydration reaction and adsorption reaction respectively through a fluidized bed reactor with built-in riser, thereby effectively improving the efficiency of the hydration reaction and adsorption reaction.

[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 adsorption reactor, which serves as an adsorption reaction zone and has an adsorption bed at the bottom, wherein a carbon-containing gas is introduced through the bottom of the adsorption bed to carry out a fluidized bed adsorption reaction; a riser, which is built into the fluidized bed adsorption reactor and serves as a hydration reaction zone; the upper end of the riser is higher than the adsorption bed, and the lower end extends out of the fluidized bed adsorption reactor and is introduced with a mixture of air and water vapor as fluidizing air for the hydration reaction; and a regeneration unit, which is connected between the fluidized bed adsorption reactor and the riser, for regenerating the adsorbent particles after carbon capture and recycling them.

[0010] Furthermore, in the above technical solution, the upper end of the riser is provided with two outlet branches; the first outlet branch can be used to provide hydrated adsorbent particles to the fluidized adsorption reactor; the second outlet branch can be used to return the insufficiently hydrated adsorbent particles to the riser for further hydration, and to cool the high-temperature adsorbent particles from the regeneration unit to the temperature range required for the hydration reaction.

[0011] Furthermore, in the above technical solution, solenoid valves for adjusting flow distribution can be installed at the two outlet branches; correspondingly, a thermometer is installed at the part of the riser pipe that penetrates the fluidized adsorption reactor, and the opening degree of the solenoid valve can be adjusted based on the temperature data of the thermometer, thereby controlling the flow distribution of the two outlet branches for temperature regulation.

[0012] Furthermore, in the above technical solution, the second outlet branch can be connected to the lower part of the riser pipe through an adsorbent circulation inclined tube.

[0013] Furthermore, in the above technical solution, the regeneration unit is preferably a moving bed reactor, which is used to regenerate the adsorbent by high-temperature decomposition and discharge CO2 gas.

[0014] Furthermore, in the above technical solution, the upper part of the regeneration unit can be connected to the fluidized adsorption reactor through the waiting inclined tube, and the lower part can be connected to the lower end of the riser through the regeneration inclined tube.

[0015] Furthermore, in the above technical solution, the active component of the alkali metal-based solid absorbent is preferably K2CO3.

[0016] Furthermore, in the above technical solution, the device may also include: a first cyclone separator, which is connected at the first outlet branch for gas-solid separation, wherein the separated hydrated adsorbent particles are added to the adsorption bed, and the separated air and water vapor mixture is discharged or recycled; and a second cyclone separator, which is connected at the second outlet branch for gas-solid separation, wherein the separated hydrated adsorbent particles are returned to the riser through the adsorbent circulation inclined tube, and the separated air and water vapor mixture is discharged or recycled.

[0017] Furthermore, in the above technical solution, the top of the fluidized adsorption reactor 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 fall into the adsorption bed, and the decarbonized gas is discharged.

[0018] To achieve the above objectives, according to a second aspect of the present invention, a solid adsorption cyclic carbon capture method is provided, using the aforementioned apparatus, comprising at least the following steps: A. Hydration process: A mixture of water vapor and air is used as fluidizing air, and in a riser built into a fluidized bed adsorption reactor, the active component of an alkali metal-based solid adsorbent undergoes a hydration reaction with water to generate hydrates for CO2 adsorption; B. Adsorption process: Carbon-containing gas is used as fluidizing air, and in a fluidized bed adsorption reactor, CO2 is captured through an adsorption reaction between the carbon-containing gas and the hydrated adsorbent particles; C. Regeneration process: The adsorbent particles after carbon capture are regenerated and recycled.

[0019] Furthermore, in the above technical solution, the method may also include the following steps: returning a portion of the insufficiently hydrated adsorbent particles to the bottom of the riser, and during the circulating hydration, using this portion of adsorbent particles to exchange heat with the adsorbent particles decomposed at high temperature from the regeneration unit, thereby reducing the temperature of the adsorbent particles to the temperature range required for the hydration reaction zone.

[0020] Furthermore, in the above technical solution, the adsorbent particles that flow back to the bottom of the riser can be adjusted to regulate the actual temperature of the hydration reaction zone inside the riser through flow distribution control.

[0021] 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 is preferably 40-120 μm.

[0022] 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, gas flow rate of 0.1–20 m / s, and water vapor content in the gas of 1–35%.

[0023] 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%.

[0024] 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.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1) By embedding the riser in the fluidized adsorption reactor as the hydration reaction zone, the present 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 treatment efficiency of carbon capture.

[0027] 2) In this invention, the active components can undergo complete reaction in two fluidized reaction zones, which can maximize the performance of the adsorbent. In addition, the fluidized riser and fluidized adsorption reactor can respectively enhance the hydration reaction and the adsorption reaction. By integrating the advantages of uniform temperature distribution and sufficient gas-solid contact in the fluidized reaction, the efficiency of the hydration reaction and the adsorption reaction can be maximized.

[0028] 3) The present invention uses a circulating hydration method to allow a portion of the circulating adsorbent particles to merge and exchange heat with the adsorbent particles from the regeneration unit, thereby cooling the high-temperature adsorbent particles from the regeneration unit to the temperature range required for the hydration reaction, without the need for additional cooling measures.

[0029] 4) The present invention can adjust the opening degree of the solenoid valves set at the two outlet branches of the riser based on the temperature data of the thermometer, thereby controlling the flow distribution of the two outlet branches and automatically adjusting the temperature of the hydration reaction zone in the riser.

[0030] 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

[0031] Figure 1 is a schematic diagram of the structural connection of the solid adsorption circulating carbon capture device of the present invention.

[0032] Explanation of key figure labels:

[0033] 1-Fluidized adsorption reactor, 2-Prepared inclined tube, 3-Regeneration unit, 4-Regeneration inclined tube, 5-Riser, 50-Solenoid distribution valve, 51-First outlet branch, 52-Second outlet branch, 6-Adsorbent circulation inclined tube, 7-First cyclone separator, 8-Second cyclone separator, 9-Third cyclone separator, 10-Thermometer. Detailed Implementation

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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 three steps: hydration, adsorption, and regeneration. The main reactions (taking potassium carbonate as an example of the active component) are as follows:

[0039] (1) The reaction during hydration: K2CO3 + 1.5H2O = K2CO3·1.5H2O

[0040] (2) The reaction of the adsorption process: K2CO3·1.5H2O+CO2=2KHCO3+0.5H2O.

[0041] (3) Regeneration process reaction: 2KHCO3=K2CO3+CO2+H2O.

[0042] Based on the above reaction principle, as shown in Figure 1, this invention provides a solid adsorption circulating carbon capture device that captures carbon using an alkali metal-based solid absorbent. It includes at least a fluidized bed adsorption reactor 1, a riser 5, and a regeneration unit 3. The fluidized bed adsorption reactor 1 serves as the adsorption reaction zone and has an adsorption bed at the bottom. The adsorption reaction is carried out by a carbon-containing gas introduced from the bottom of the adsorption bed. The riser 5 is built into the fluidized bed adsorption reactor 1 and serves as the hydration reaction zone. The upper end of the riser 5 is higher than the adsorption bed, and the lower end extends out of the fluidized bed adsorption reactor 1, through which a mixture of air and water vapor is introduced as the fluidizing air for the hydration reaction. The regeneration unit 3 is connected between the fluidized bed adsorption reactor 1 and the riser 5, and is used to regenerate the adsorbent particles after carbon capture and recycle them.

[0043] This invention integrates the hydration and adsorption processes in the same reactor by embedding the riser inside the fluidized bed adsorption reactor as the hydration reaction zone. 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 and carbonation processes (i.e., the adsorption process). This can maximize the performance of the adsorbent and effectively improve the treatment efficiency of carbon capture. Specifically, the adsorbent first undergoes a hydration reaction with water in the riser 5 (i.e., the hydration reaction zone) to generate K2CO3·1.5H2O hydrate. Then, the K2CO3·1.5H2O hydrate undergoes a carbonation reaction with CO2 in the fluidized bed adsorption reactor 1 (i.e., the adsorption reaction zone) to generate KHCO3, achieving the goal of efficiently removing CO2. Secondly, in both fluidized reaction zones, the active components can undergo complete reactions, maximizing the performance of the adsorbent. In addition, the fluidized riser and fluidized bed adsorption reactor can respectively enhance the hydration and adsorption reactions. By integrating the advantages of uniform temperature distribution and sufficient gas-solid contact in the fluidized bed reaction, the efficiency of the hydration and adsorption reactions can be maximized.

[0044] As further shown in Figure 1, the regeneration unit 3 preferably adopts a moving bed reactor, which is set outside the fluidized bed adsorption reactor 1 and connected to the adsorption bed of the fluidized bed adsorption reactor 1 through the regeneration inclined tube 2. It is used to regenerate the adsorbent by high-temperature decomposition and discharge CO2 gas. The lower part of the regeneration unit 3 is connected to the lower end of the riser 5 through the regeneration inclined tube 4.

[0045] As shown in Figure 1, the upper end of the riser 5 has two outlet branches. The first outlet branch 51 is used to provide hydrated adsorbent particles to the fluidized adsorption reactor 1. The second outlet branch 52 is used to return insufficiently hydrated adsorbent particles to the riser 5 for further hydration (using the riser as the hydration reaction zone, a single hydration will be insufficient, therefore this invention adopts a circulating hydration method). Through circulating hydration, the circulating adsorbent particles can exchange heat with the adsorbent particles from the regeneration unit 3, that is, the high-temperature adsorbent particles from the regeneration unit 3 are cooled to the temperature range required for the hydration reaction, without the need for additional cooling measures. The second outlet branch 52 can be connected to the lower part of the riser 5 through the adsorbent circulation inclined pipe 6 to achieve the merging of the two streams of adsorbent particles. Furthermore, preferably but not limitingly, the two outlet branches are provided with solenoid valves 50 for adjusting the flow distribution. Correspondingly, the riser pipe 5 is provided with a thermometer 10 at the penetration point of the fluidized adsorption reactor 1. The present invention can adjust the opening degree of the solenoid valves 50 based on the temperature data of the thermometer, thereby controlling the flow distribution of the two outlet branches and adjusting the temperature of the hydration reaction zone in the riser pipe 5.

[0046] The regeneration unit 3 of this invention can decompose the adsorbent particles after CO2 adsorption from the fluidized bed adsorption reactor 1 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 2 for high-temperature decomposition. The resulting CO2 gas is discharged from the top of the regeneration unit 3. The regenerated adsorbent particles enter the lower part of the riser tube 5 from the regeneration inclined tube 4, and after heat exchange with the adsorbent particles from the adsorbent circulation inclined tube 6, undergo a hydration reaction in the hydration reaction zone of the riser tube 5.

[0047] As shown in Figure 1, to better achieve gas-solid separation at the top of the hydration reaction zone within the riser 5, a first cyclone separator 7 and a second cyclone separator 8 are respectively installed at the first outlet branch 51 and the second outlet branch 52. The hydrated adsorbent particles separated by the first cyclone separator 7 are added to the adsorption bed, while the separated air-water vapor mixture is discharged. The hydrated adsorbent particles separated by the second cyclone separator 8 are returned to the riser 5 through the adsorbent circulation inclined tube 6, while the separated air-water vapor mixture is discharged.

[0048] As shown in Figure 1, the fluidized bed adsorption reactor 1 is equipped with a third cyclone separator 9 at the top, which can be used to receive the adsorbent particles after the adsorption reaction and separate them from the decarbonized gas after the reaction; the separated adsorbent particles fall into the adsorption bed, and the decarbonized gas is discharged.

[0049] Referring 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:

[0050] Step S101, Hydration Process: A mixture of water vapor and air is used as the fluidizing air (the water vapor is water vapor formed by heating externally supplied liquid water through high-temperature particles generated in the regeneration unit). In the riser 5 built into the fluidized bed adsorption reactor 1, 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 the initial fluidizing air, carrying a certain amount of water into the bottom of the riser 5, lifting the regenerated adsorbent upwards. When the regenerated adsorbent comes into contact with the air, it heats the water to complete vaporization (i.e., forming water vapor) using its own heat. Simultaneously, as the regenerated adsorbent moves upwards, it undergoes a hydration reaction with the water vapor, converting the active component on the adsorbent into hydrates. The preferred operating conditions for the hydration process are: reaction pressure of 0.1–2.0 MPa, reaction temperature of 60–150 °C, gas flow rate of 0.1–20 m / s, and water vapor content in the gas of 1–35%. Further, after the hydration reaction, a portion of the insufficiently hydrated adsorbent particles can be returned to the bottom of the riser 5. During the circulating hydration, these adsorbent particles exchange heat with the high-temperature decomposed adsorbent particles from the regeneration unit, lowering the adsorbent particle temperature to the required temperature range for the hydration reaction zone. That is, the hydrated adsorbent particles circulating from the adsorbent circulation inclined tube 6 return to the riser 5 to continue participating in the hydration reaction. Simultaneously, the circulating adsorbent particles cool the regenerated adsorbent particles coming from the bottom of the riser 5 to a certain extent, ensuring they meet the temperature requirements for the hydration reaction. Preferably, but not limitingly, the actual temperature of the hydration reaction zone within the riser 5 can be adjusted by controlling the flow rate of the adsorbent particles returned to the bottom of the riser 5.

[0051] Step S102, Adsorption Process: Carbon-containing gas is used as fluidizing air in the fluidized bed adsorption reactor 1. 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, the material after hydration is divided into two parts from the outlet of riser 5. One part is separated in the first cyclone separator 7 via the first outlet branch 51, and the adsorbent particles enter the adsorption bed for CO2 adsorption. The other part is separated in the second cyclone separator 8 via the second outlet branch 52 and then undergoes the aforementioned circulating hydration. The adsorption process in this step is a carbonation reaction process. The preferred reaction operating conditions are: reaction pressure of 0.1–2.0 MPa, reaction temperature of 40–100℃, carbon-containing gas flow rate of 0.001–0.1 m / s, and CO2 content in the carbon-containing gas of 1–40%.

[0052] Step S103, Regeneration Process: The adsorbent particles after adsorbing CO2 are decomposed through a high-temperature regeneration reaction to obtain regenerated adsorbent particles for recycling. The preferred reaction conditions for the regeneration process are: reaction pressure of 0.1–2.0 MPa and reaction temperature of 100–200 °C.

[0053] The method of the present invention can achieve the same technical effect as the device, and will not be described in detail here.

[0054] Example 1

[0055] In this embodiment, a special microsphere loaded with potassium carbonate was used as the adsorbent, and an experiment was conducted within the device described above in this invention:

[0056] Flue gas with a CO2 volume fraction of 15% was used as the gas feedstock and entered the fluidized bed adsorption reactor 1 from the bottom of the reactor for carbonation reaction to remove CO2. The operating conditions were: 0.1 MPa, 62℃, and gas linear velocity of 0.008 m / s. The decarbonized gas after CO2 adsorption was discharged from the third cyclone separator 9. The CO2 volume fraction in the decarbonized gas was 0.46%, and the decarbonization efficiency was 96.9%.

[0057] After the carbonation reaction, the adsorbent enters the regeneration unit 3 from the bottom of the fluidized bed adsorption reactor 1 through the regeneration inclined tube 2. The regeneration unit adopts a downward moving bed and is regenerated at 0.1 MPa and 122 °C. The desorbed CO2 is discharged from the top of the moving bed with a purity of 99.5%.

[0058] After regeneration, the adsorbent enters the riser 5 through the regeneration inclined tube 4 for hydration reaction. Fluidizing air with a water vapor content of 9.2% enters from the bottom of the riser 5 at a linear velocity of 8.4 m / s, lifting and transporting the regenerated adsorbent and the adsorbent from the adsorbent circulation inclined tube 6 upwards. The reaction conditions are controlled at 0.1 MPa and the outlet temperature of the riser 5 is 65℃.

[0059] After hydration, a portion of the adsorbent enters the first cyclone separator 7 at the outlet of riser 5 for gas-solid separation. The adsorbent then enters the fluidized bed adsorption reactor 1 to participate in the adsorption reaction. The gas phase exits from the top of the first cyclone separator 7 and returns to the steam inlet of riser 5, where it mixes with fresh steam and is recycled. The other portion of the adsorbent enters the second cyclone separator 8 for gas-solid separation. It then enters riser 5 through the adsorbent circulation inclined pipe 6 and mixes with the regenerated adsorbent to continue participating in the hydration reaction. The gas phase exits from the top of the second cyclone separator 8, merges with the gas phase at the top of the first cyclone separator 7, and returns to the steam inlet of riser 5, where it mixes with fresh steam and is recycled.

[0060] 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 adsorption reactor, which serves as the adsorption reaction zone and has an adsorption bed at the bottom, through which a carbon-containing gas is introduced to carry out the fluidized bed adsorption reaction; a riser, which is built into the fluidized bed adsorption reactor and serves as the hydration reaction zone; the upper end of the riser is higher than the adsorption bed, and the lower end extends out of the fluidized bed adsorption reactor and is supplied with a mixture of air and water vapor as the fluidizing air for the hydration reaction; and a regeneration unit, which is connected between the fluidized bed adsorption reactor and the riser, for regenerating the adsorbent particles after carbon capture and recycling them.

2. The solid adsorption circulating carbon capture device according to claim 1, characterized in that, The riser has two outlet branches at its upper end; the first outlet branch is used to provide hydrated adsorbent particles to the fluidized adsorption reactor; the second outlet branch is used to return insufficiently hydrated adsorbent particles to the riser for further hydration, and to cool the high-temperature adsorbent particles from the regeneration unit to the temperature range required for the hydration reaction.

3. The solid adsorption circulating carbon capture device according to claim 2, characterized in that, The two outlet branches are equipped with solenoid valves for adjusting the flow distribution; correspondingly, the riser is equipped with a thermometer at the penetration point of the fluidized adsorption reactor. The opening degree of the solenoid valve is adjusted based on the temperature data of the thermometer, thereby controlling the flow distribution of the two outlet branches for temperature regulation.

4. The solid adsorption circulating carbon capture device according to claim 3, characterized in that, The second outlet branch is connected to the lower part of the riser pipe through an adsorbent circulation inclined tube.

5. The solid adsorption circulating carbon capture device according to claim 1, characterized in that, The regeneration unit is a moving bed reactor, used to regenerate the adsorbent through high-temperature decomposition and discharge CO2 gas.

6. The solid adsorption circulating carbon capture device according to claim 5, characterized in that, The upper part of the regeneration unit is connected to the fluidized adsorption reactor through a pre-regeneration inclined tube, and the lower part is connected to the lower end of the riser through a regeneration inclined tube.

7. 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.

8. The solid adsorption circulating carbon capture device according to claim 4, characterized in that, The device further includes: a first cyclone separator connected to the first outlet branch for gas-solid separation, wherein the separated hydrated adsorbent particles are fed into the adsorption bed, and the separated air and water vapor mixture is discharged or recycled; and a second cyclone separator connected to the second outlet branch for gas-solid separation, wherein the separated hydrated adsorbent particles are returned to the riser through the adsorbent circulation inclined tube, and the separated air and water vapor mixture is discharged or recycled.

9. The solid adsorption circulating carbon capture device according to claim 3, characterized in that, The fluidized bed adsorption reactor is equipped with a third cyclone separator at the top, 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 fall into the adsorption bed and the decarbonized gas is discharged.

10. A solid adsorption circulating carbon capture method, characterized in that, The apparatus according to any one of claims 1 to 9 comprises the following steps: A. Hydration process: A mixture of water vapor and air is used as fluidizing air, and in the riser built into the fluidized bed adsorption reactor, the active component of the alkali metal-based solid adsorbent undergoes a hydration reaction with water to generate hydrates for CO2 adsorption; B. Adsorption process: Carbon-containing gas is used as fluidizing air, and in the fluidized bed adsorption reactor, CO2 is captured through an adsorption reaction between the carbon-containing gas and the hydrated adsorbent particles; C. Regeneration process: The adsorbent particles after carbon capture are regenerated and recycled.

11. The solid adsorption circulating carbon capture method according to claim 10, characterized in that, The method further includes the following steps: returning a portion of the insufficiently hydrated adsorbent particles to the bottom of the riser tube, and during the circulating hydration, using this portion of adsorbent particles to exchange heat with the adsorbent particles decomposed at high temperature from the regeneration unit, thereby reducing the temperature of the adsorbent particles to the temperature range required for the hydration reaction zone.

12. The solid adsorption circulating carbon capture method according to claim 11, characterized in that, The adsorbent particles that flow back to the bottom of the riser are used to regulate the actual temperature of the hydration reaction zone inside the riser through flow distribution control.

13. The solid adsorption circulating carbon capture method according to claim 10, 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.

14. 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 is 0.1–2.0 MPa, reaction temperature is 60–150 °C, gas flow rate is 0.1–20 m / s, and water vapor content in the gas is 1–35%.

15. 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%.

16. 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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