Four-bed vacuum temperature swing adsorption process and device for CO2 separation from power plant flue gas

Abstract

This invention discloses a four-bed vacuum temperature-switching adsorption process and apparatus for CO2 separation from power plant flue gas, relating to the field of carbon dioxide adsorption technology. The process includes the following steps: S1: Four adsorption beds are set on a four-bed adsorption ring. The four-bed adsorption ring is rotated, causing the four adsorption beds to circulate sequentially in a vacuum low-temperature adsorption station, a waiting station, a heating separation station, and a cooling station on the vacuum temperature-switching adsorption mechanism; S2: Power plant flue gas is introduced into the vacuum low-temperature adsorption station, which creates a vacuum low-temperature environment for the adsorption beds. Simultaneously, while the four-bed adsorption ring rotates, the adsorption beds in the cooling station are pre-cooled. All four adsorption beds on the four-bed adsorption ring can cyclically perform adsorption, desorption, and regeneration operations. The entire adsorption process reuses both the high-temperature and low-temperature states of the power plant flue gas, significantly reducing the energy consumption for CO2 separation from power plant flue gas.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide adsorption technology, specifically to a four-bed vacuum temperature-switching adsorption process and apparatus for CO2 separation in power plant flue gas. Background Technology

[0002] Vacuum temperature swing adsorption (VSA) is a process of adsorption at low or room temperature followed by desorption by heating. In addition to adsorption and desorption, the entire VSA operation also includes auxiliary steps such as drying and cooling the desorbed adsorbent. VSA is used for dehumidification of gases and air at normal pressure, and for the recovery of solvent vapors from the air. Since power plant flue gas contains a large amount of carbon dioxide, which does not meet the standards for direct emission, vacuum temperature swing adsorption can be used to adsorb carbon dioxide from the power plant flue gas.

[0003] Existing carbon dioxide vacuum temperature-switching adsorption processes, such as the carbon dioxide adsorption system disclosed in patent publication number CN118526923A and the low-pressure, low-energy-consumption flue gas carbon dioxide recovery system and recovery process disclosed in patent publication number CN117101335A, have long processes and require a lot of equipment, resulting in high carbon dioxide adsorption costs and making them unsuitable for use. Summary of the Invention

[0004] In order to overcome the above-mentioned technical problems, the purpose of this invention is to provide a four-bed vacuum temperature-switching adsorption process and device for CO2 separation in power plant flue gas, so as to solve the problem that in the prior art, the carbon dioxide vacuum temperature-switching adsorption process is long, requires a lot of equipment, and manufacturers have to invest a lot before deployment, resulting in high carbon dioxide treatment costs.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] The first aspect of this invention is to provide a four-bed vacuum temperature-switching adsorption process for CO2 separation in power plant flue gas, comprising the following steps:

[0007] S1: Four adsorption beds are set on the four-bed adsorption ring. The four-bed adsorption ring is rotated so that the four adsorption beds circulate sequentially in the vacuum low temperature adsorption station, waiting station, heating separation station and cooling station on the vacuum temperature-changing adsorption mechanism.

[0008] S2: The vacuum low-temperature adsorption station creates a vacuum low-temperature environment for the adsorption bed, and at the same time, when the four adsorption rings rotate, the adsorption bed in the cooling station is pre-cooled.

[0009] S3: The adsorption bed in the vacuum low-temperature adsorption station is transferred to the waiting station, where the adsorption bed is preheated.

[0010] S4: The adsorption bed in the waiting station is transferred to the heating and separation station, where the adsorption bed is heated and decompressed.

[0011] S5: The adsorption bed in the heating and separation station is transferred to the cooling station, where the adsorption bed is cooled down.

[0012] S5: Repeat S1 to S6 until the power plant flue gas is completely adsorbed.

[0013] As a further aspect of the present invention: step S1 includes the following steps:

[0014] S1.1: The power plant flue gas is pressurized using a compressor and transported to a high-pressure pipeline. The high-pressure pipeline passes through a waiting station and exchanges heat with the adsorption bed therein. The high-pressure power plant flue gas is automatically cooled to room temperature in the high-pressure pipeline.

[0015] S2.2: High-voltage power plant flue gas passes through a high-pressure pipeline to a waiting station, where it undergoes heat exchange with the adsorption bed.

[0016] S2.3: The high-voltage power plant flue gas after waiting for the work station is automatically cooled to room temperature in the high-voltage pipeline;

[0017] S2.4: Use a vacuum pump to evacuate the low-temperature gas in the vacuum low-temperature adsorption station to create a negative pressure environment within the vacuum low-temperature adsorption station;

[0018] S2.5: The vacuum pump delivers the cryogenic gas drawn from the vacuum cryogenic adsorption station to the cooling station;

[0019] S2.6: A throttling valve is used to transport the high-pressure power plant flue gas in the high-pressure pipeline to the vacuum low-temperature adsorption station. The high-pressure power plant flue gas is rapidly depressurized and absorbs heat in the vacuum low-temperature adsorption station, so that the environment in the vacuum low-temperature adsorption station forms a low-temperature negative pressure.

[0020] S2.7: The pressure value of the environment in the vacuum cryogenic adsorption station is controlled by the throttle valve. When the pressure value of the environment in the vacuum cryogenic adsorption station reaches the preset pressure threshold, the high-voltage power plant flue gas is stopped from being introduced into the vacuum cryogenic adsorption station.

[0021] As a further aspect of the present invention: when the adsorption bed in the four-bed adsorption ring enters the vacuum low-temperature adsorption station from the cooling station, the vacuum low-temperature adsorption station reduces the pressure of the adsorption bed in the cooling station, thereby further cooling the adsorption bed in the cooling station.

[0022] As a further aspect of the present invention: step S4 includes the following steps:

[0023] S4.1: Transfer the adsorption bed in the four-bed adsorption ring corresponding to the waiting station to the heating separation station;

[0024] S4.2: The adsorption bed in the four-bed adsorption ring is heated to 60 to 100 degrees Celsius by the heating equipment in the heating separation station, so that the carbon dioxide in the adsorption bed is desorbed;

[0025] S4.3: Use a vacuum pump to draw out the desorbed carbon dioxide in the heating and separation station, and pump the carbon dioxide into a gas cylinder for storage.

[0026] As a further aspect of the present invention: step S5 includes the following steps:

[0027] S5.1: Transfer the adsorption bed in the corresponding four-bed adsorption ring after heating and decompression in the heating and separation station to the cooling station;

[0028] S5.2: The adsorption bed and vacuum pump in the cooling station exchange heat with the low-temperature gas drawn from the vacuum low-temperature adsorption station to reduce the temperature of the adsorption bed.

[0029] S5.3: The cooling station directly discharges the low-temperature gas after heat exchange.

[0030] A second aspect of the present invention is to provide a four-bed vacuum temperature-switching adsorption device for CO2 separation in power plant flue gas, the four-bed vacuum temperature-switching adsorption device using the four-bed vacuum temperature-switching adsorption process for CO2 separation in power plant flue gas as described in any one of claims 1-5, characterized in that it includes a vacuum temperature-switching adsorption mechanism and four-bed adsorption rings.

[0031] The four-bed adsorption ring is equipped with four adsorption beds, and the adsorption beds can be changed inside the vacuum temperature-changing adsorption mechanism by rotating the four-bed adsorption ring.

[0032] As a further aspect of the present invention: the vacuum temperature-changing adsorption mechanism is provided with a vacuum low-temperature adsorption station, a waiting station, a heating separation station and a cooling station, which are arranged in a ring shape, and the four adsorption rings are matched with the vacuum low-temperature adsorption station, the waiting station, the heating separation station and the cooling station.

[0033] As a further aspect of the present invention: a driving mechanism is installed at the center of the top surface of the vacuum temperature-changing adsorption mechanism. The driving mechanism is used to transmit power to the four adsorption rings, so that the four adsorption rings rotate in the vacuum low-temperature adsorption station, the waiting station, the heating separation station, and the cooling station.

[0034] As a further aspect of the present invention: the four-bed adsorption ring includes an adsorption shell, and four isolation plates are uniformly arranged inside the adsorption shell. The four isolation plates divide the inner cavity of the adsorption shell into four adsorption beds of the same volume, and several parallel adsorption inner plates are uniformly arranged inside the adsorption beds.

[0035] As a further aspect of the present invention, the adsorption inner plate is activated carbon, molecular sieve, or metal-organic framework.

[0036] The beneficial effects of this invention are:

[0037] 1. In this invention, all four adsorption beds on the four-bed adsorption ring can cycle through adsorption, desorption, and regeneration operations. The entire adsorption process reuses the high-temperature and low-temperature states of power plant flue gas, significantly reducing the energy consumption for CO2 separation in power plant flue gas, which in turn reduces the processing cost of CO2 separation in power plant flue gas. It is suitable for widespread use in the treatment of power plant flue gas, ensuring that the treated power plant flue gas meets emission standards. The heating separation station can collect high-concentration carbon dioxide gas through a negative pressure pump, which reduces carbon emissions and also obtains high-concentration carbon dioxide products, achieving the results of cost reduction and efficiency improvement.

[0038] 2. In this invention, the α-adsorption bed entering the heating and separation station will undergo heating and separation operations within the heating and separation station. Since the power plant flue gas was compressed and heated under the operation of the compressor, the high-temperature and high-pressure power plant flue gas can be used to exchange heat with the α-adsorption bed within the heating and separation station. On the one hand, the α-adsorption bed can be heated to promote the desorption of carbon dioxide on the α-adsorption bed. On the other hand, the temperature of the high-temperature and high-pressure power plant flue gas can be reduced, so that the high-temperature and high-pressure power plant flue gas enters the vacuum low-temperature adsorption station at a lower temperature, ensuring the adsorption effect of the adsorption bed on carbon dioxide in the vacuum low-temperature adsorption station.

[0039] 3. In this invention, when the adsorption bed a enters the cooling station, the stability of the adsorption bed a is at a high level, and there is still residual carbon dioxide gas in the adsorption bed a. At this time, the low-temperature gas drawn from the vacuum low-temperature adsorption station can carry away the residual carbon dioxide gas on the one hand, and reduce the temperature of the adsorption bed a on the other hand, so as to ensure that the adsorption bed a is at a low temperature when it re-enters the vacuum low-temperature adsorption station, which is conducive to the re-adsorption of carbon dioxide. Attached Figure Description

[0040] The invention will now be further described with reference to the accompanying drawings.

[0041] Figure 1 This is a flowchart of the four-bed vacuum temperature-switching adsorption process for CO2 separation in power plant flue gas according to the present invention.

[0042] Figure 2 This is a flowchart of step 3 in the four-bed vacuum temperature-switching adsorption process for CO2 separation in power plant flue gas of the present invention.

[0043] Figure 3 This is a flowchart of step 5 in the four-bed vacuum temperature-switching adsorption process for CO2 separation in power plant flue gas of the present invention.

[0044] Figure 4 This is a flowchart of step 6 in the four-bed vacuum temperature-switching adsorption process for CO2 separation in power plant flue gas of the present invention.

[0045] Figure 5 This is a schematic diagram of the structure of the four-bed vacuum temperature-switching adsorption device for CO2 separation in power plant flue gas according to the present invention;

[0046] Figure 6 This is a top view of the four-bed vacuum temperature-switching adsorption device for CO2 separation in power plant flue gas according to the present invention;

[0047] Figure 7 This is a schematic diagram of the vacuum temperature-changing adsorption mechanism in this invention;

[0048] Figure 8 This is a schematic diagram of the four-bed adsorption ring structure in this invention.

[0049] In the diagram: 1. Vacuum temperature-changing adsorption mechanism; 11. Vacuum low-temperature adsorption station; 111. Inlet pipe; 12. Waiting station; 13. Heating and separation station; 131. Carbon dioxide collection pipe; 14. Cooling station; 15. Drive mechanism; 16. Rectangular trough; 2. Four-bed adsorption ring; 21. Adsorption shell; 22. Isolation plate; 23. Inner adsorption plate. Detailed Implementation

[0050] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0051] Example 1

[0052] like Figures 1-8 As shown, this invention discloses a four-bed vacuum temperature-switching adsorption process for CO2 separation in power plant flue gas, comprising the following steps:

[0053] S1: Four adsorption beds are set on the four-bed adsorption ring 2. The four adsorption beds can be labeled a, b, c, and d in sequence. The specific design can be adapted by those skilled in the art based on the four-bed adsorption ring 2. The four adsorption beds a, b, c, and d have the same volume. The four adsorption beds a, b, c, and d correspond to the vacuum low-temperature adsorption station 11, the waiting station 12, the heating separation station 13, and the cooling station 14 on the vacuum temperature-changing adsorption mechanism 1, respectively. It should be noted that the four-bed adsorption ring 2 is circular in shape. The four adsorption beds a, b, c, and d are equidistantly distributed on the four-bed adsorption ring 2 and occupy the same volume. The volumes of the vacuum low-temperature adsorption station 11, the waiting station 12, the heating separation station 13, and the cooling station 14 should also be the same. When the four adsorption beds a, b, c, and d enter the vacuum low-temperature adsorption station 11, the waiting station 12, the heating separation station 13, and the cooling station 14 in sequence, When in position 13 and cooling position 14, the four adsorption beds a, b, c and d will isolate the vacuum low temperature adsorption position 11, waiting position 12, heating separation position 13 and cooling position 14, so that the vacuum low temperature adsorption position 11, waiting position 12, heating separation position 13 and cooling position 14 are not connected to each other. In this way, when the adsorption beds inside the vacuum temperature variable adsorption mechanism 1 need to be replaced, it is only necessary to rotate the four-bed adsorption ring 2. For example, when adsorption bed a completes the adsorption operation of carbon dioxide in the vacuum temperature variable adsorption mechanism 1, adsorption bed a can be removed from the vacuum low temperature adsorption position 11 by rotating the four-bed adsorption ring 2, while adsorption bed d enters the vacuum low temperature adsorption position 11 at the same time. This ensures that the vacuum low temperature adsorption position 11 can continuously adsorb carbon dioxide in the power plant flue gas, thereby improving the efficiency of carbon dioxide separation in the vacuum temperature variable adsorption mechanism 1.

[0054] The adsorption bed a on the four-bed adsorption ring 2 first enters the vacuum low-temperature adsorption station 11. The adsorption beds b, c, and d then sequentially enter the waiting station 12, the heating separation station 13, and the cooling station 14. It should be noted that since the four adsorption beds a, b, c, and d on the four-bed adsorption ring 2 are integrated together, and the vacuum low-temperature adsorption station 11, the waiting station 12, the heating separation station 13, and the cooling station 14 on the vacuum temperature-changing adsorption mechanism 1 correspond to the four adsorption beds on the four-bed adsorption ring 2, when the vacuum temperature-changing adsorption mechanism 1 works with the four-bed adsorption ring 2 to perform four-bed vacuum temperature-changing adsorption of carbon dioxide in power plant flue gas, simply rotating the four-bed adsorption ring 2 is enough to simultaneously complete the rotation of the adsorption beds at the four stations on the vacuum temperature-changing adsorption mechanism 1. This significantly reduces the adsorption process of carbon dioxide in power plant flue gas, simplifies the workload of on-site technicians, and indirectly reduces the labor cost of carbon dioxide adsorption in power plant flue gas.

[0055] S2: Power plant flue gas is added to the vacuum low-temperature adsorption station 11. The adsorption bed a adsorbs carbon dioxide from the power plant flue gas in a vacuum low-temperature environment. When the carbon dioxide in the vacuum low-temperature adsorption station 11 reaches the saturated vapor pressure, the adsorption bed a stops adsorption. It should be noted that step S3 also includes the following steps:

[0056] S2.1: The power plant flue gas is pressurized using a compressor, and the high-pressure power plant flue gas is transported to a high-pressure pipeline. It should be noted that the working principle of the compressor is to compress the gas mechanically, thereby increasing the gas pressure. When the power plant flue gas is transported to the compressor through the pipeline, the compressor can compress the power plant flue gas to a high-pressure state. The pressure is selected by those skilled in the art based on the specific power plant flue gas. A large amount of heat is generated during the compression process of the power plant flue gas. At this time, the high-pressure pipeline can be transported to the heating and separation station 13 to transfer the heat to the heating and separation station 13, maximizing the utilization of heat and saving energy. The distribution and position of the high-pressure pipeline in the heating and separation station 13 are selected by those skilled in the art based on the space in the heating and separation station 13, ensuring that it does not affect the rotation of the four-bed adsorption ring 2 in the heating and separation station 3.

[0057] S2.2: High-voltage power plant flue gas passes through a high-pressure pipeline to a waiting station, where it exchanges heat with the adsorption bed. It should be noted that after the high-voltage power plant flue gas is pressurized by the compressor, high-temperature flue gas forms in the high-pressure pipeline. The high-pressure pipeline is a metal pipe that facilitates heat exchange. The high-pressure pipeline is positioned in waiting station 12. It is important to ensure that the high-pressure pipeline in waiting station 12 does not interfere with the rotation of the adsorption bed within waiting station 12. Thus, when the adsorption bed enters waiting station 12, the high-pressure pipeline can heat the adsorption bed in waiting station 12, allowing the adsorption bed to exchange heat. The adsorption bed in station 12 is heated to above 50 degrees Celsius. The specific temperature is determined by those skilled in the art based on the residence time of the adsorption bed in station 12. This reduces the energy consumption required for the heating and separation station 13. It should also be noted that when the high-pressure pipeline heats the adsorption bed in station 12, the increased temperature of the adsorption bed will cause the carbon dioxide in the adsorption bed to desorb. This will increase the gas pressure in station 12, and carbon dioxide will also fill station 12. This will further promote the heat exchange between the high-pressure pipeline and station 12, and improve the heat exchange effect of the high-pressure pipeline.

[0058] S2.3: The high-voltage power plant flue gas is automatically cooled to room temperature in the high-voltage pipeline. The high-voltage pipeline can be cooled by air or water. It should be noted that since the cooling station 14 will discharge low-temperature gas, the high-voltage pipeline can be heat-exchanged with the low-temperature gas discharged from the cooling station 14 to improve the cooling efficiency of the power plant flue gas in the high-voltage pipeline.

[0059] S2.4: Use a vacuum pump to evacuate the low-temperature gas in the vacuum low-temperature adsorption station 11, so that the environment inside the vacuum low-temperature adsorption station 11 is negative pressure. It should be noted that the specifications of the vacuum pump shall be adapted to the vacuum degree required by the person skilled in the art according to the vacuum degree required by the vacuum low-temperature adsorption station 11, so as to ensure that the vacuum pump can maintain or reduce the pressure inside the vacuum low-temperature adsorption station 11 at its rated power. The installation position of the vacuum pump shall be adapted to the vacuum low-temperature adsorption station 11 according to the person skilled in the art. It should be noted that the input pipe of the vacuum pump is connected to the inner cavity of the vacuum low-temperature adsorption station 11. After the vacuum pump is turned on, the vacuum pump can evacuate the low-temperature gas in the vacuum low-temperature adsorption station 11 through the input pipe, and at the same time reduce the environmental pressure inside the vacuum low-temperature adsorption station 11, so that the environmental pressure inside the vacuum low-temperature adsorption station 11 is within the preset pressure range.

[0060] S2.5: The vacuum pump delivers the low-temperature gas drawn from the vacuum low-temperature adsorption station 11 to the cooling station 14. The adsorption bed in the cooling station is pre-cooled to initially reduce the temperature of the adsorption bed. It should be noted that the output pipe of the vacuum pump is connected to the internal environment of the cooling station 14. The placement of the output pipe in the internal environment of the cooling station 14 shall be adapted by those skilled in the art according to the internal environment of the cooling station 14, so as not to affect the rotation of the four adsorption rings 2 in the cooling station 14.

[0061] S2.6: A throttling valve is used to transport the high-pressure power plant flue gas in the high-pressure pipeline to the vacuum low-temperature adsorption station 11. The high-pressure power plant flue gas rapidly depressurizes and absorbs heat in the vacuum low-temperature adsorption station 11, creating a low-temperature negative pressure environment within the vacuum low-temperature adsorption station 11. It should be noted that when the high-pressure flue gas flows through the throttling valve, the valve opening affects the gas flow rate and pressure. During the throttling process, the gas pressure drops rapidly, causing its temperature to drop accordingly. According to thermodynamic principles, the gas absorbs heat during throttling, causing the surrounding environment temperature to drop. This process is the key to achieving pressure and temperature reduction of the high-pressure power plant flue gas. Therefore, after the high-pressure power plant flue gas enters the vacuum low-temperature adsorption station 11 through the throttling valve, it will form low-pressure low-temperature power plant flue gas, which means that a low-temperature negative pressure environment is created within the vacuum low-temperature adsorption station 11.

[0062] S2.7: The pressure value of the environment inside the vacuum low-temperature adsorption station 11 is controlled by a throttle valve. When the pressure value of the environment inside the vacuum low-temperature adsorption station 11 reaches the preset pressure threshold, the high-pressure power plant flue gas is stopped from being introduced into the vacuum low-temperature adsorption station 11. It should be noted that those skilled in the art set the pressure threshold and low temperature range for the vacuum low-temperature adsorption station 11. For example, the environment of the vacuum low-temperature adsorption station 11 can be -20 degrees Celsius to -10 degrees Celsius, and the pressure can be 0.05 to 0.1 atmospheres. This is just one example of the vacuum low-temperature adsorption station 11. The specific environmental pressure and stability settings of the vacuum low-temperature adsorption station 11 are adaptively selected by those skilled in the art based on the adsorption of carbon dioxide to ensure that the power plant flue gas meets the emission standards.

[0063] The adsorption of carbon dioxide is determined by the separation efficiency of carbon dioxide. The formula for calculating the separation efficiency of carbon dioxide in vacuum cryogenic adsorption station 11 is as follows:

[0064]

[0065] Where η is the separation efficiency, q m Where K is the maximum adsorption capacity, C is the equilibrium constant, and K is the maximum adsorption capacity. e For equilibrium concentration, n is the adsorption heterogeneity index, E a Let R be the activation energy, T be the gas constant, T be the Fahrenheit temperature, and mCO2 be the mass of adsorbed CO2. in To determine the quality of the power plant flue gas entering the vacuum cryogenic adsorption station, m out Let Q be the mass of the power plant flue gas discharged from the vacuum cryogenic adsorption station, Q be the heat, m be the mass of the adsorption zone of the four-bed adsorption ring, and C be the mass of the flue gas discharged from the vacuum cryogenic adsorption station. p P represents the specific heat capacity of the adsorption zone in the four-bed adsorption ring, ΔT represents the change in flue gas temperature in the power plant, and P represents the specific heat capacity of the adsorption zone in the four-bed adsorption ring. in P is the pressure of the power plant flue gas before it enters the vacuum cryogenic adsorption station. ref T represents the initial pressure within the vacuum cryogenic adsorption station, where α is the pressure coefficient. max The maximum adsorption temperature of the vacuum cryogenic adsorption station is given by β, which is the temperature coefficient. Note that η is the separation efficiency, representing the overall efficiency of carbon dioxide separation and reflecting the system's performance. m The maximum adsorption capacity is the maximum amount of carbon dioxide that the four-bed adsorption ring 2 can adsorb, indicating the effectiveness of the four-bed adsorption ring 2. K is the equilibrium constant, describing the strength of the interaction between the four-bed adsorption ring 2 and carbon dioxide, and affecting the driving force of the adsorption process. The equilibrium constant K can be determined by the static adsorption test method, specifically:

[0066] Prepare several CO2 solutions (or gas mixtures) of known concentration and introduce them into the four-bed adsorption ring 2; keep the system stationary at a preset temperature until equilibrium is reached, and then analyze the CO2 concentration on the adsorbent and the CO2 concentration in the liquid or gas phase at equilibrium. According to the Langmuir adsorption model, the equilibrium constant can be calculated using the following formula:

[0067]

[0068] Where q e C represents the CO2 concentration on the adsorbent. e To balance the concentration, that is, the concentration of carbon dioxide in the adsorption zone on the four-bed adsorption ring 2;

[0069] n is the adsorption heterogeneity index. It should be noted that n can be determined using a static adsorption test method, specifically:

[0070] Prepare several CO2 solutions (or gas mixtures) of known concentrations and introduce them into the four-bed adsorption ring 2; keep the system static at a preset temperature until equilibrium is reached; record q at equilibrium. e and C e ;

[0071] Fit the data to the Freundlich model:

[0072]

[0073] After linearizing the above formula, take its logarithm:

[0074]

[0075] The slope and intercept are obtained through linear regression analysis, and then n is calculated.

[0076] The pressure coefficient α is determined by those skilled in the art using static adsorption experiments or dynamic adsorption experiments, and the temperature coefficient β is determined by those skilled in the art using isothermal adsorption experiments or thermogravimetric analysis. The pressure and temperature inside the vacuum low-temperature adsorption station 11 and the temperature of the heating separation station 13 are controlled by the carbon dioxide separation efficiency to ensure that the carbon dioxide separation efficiency is within the set range.

[0077] S3: Rotate the four-bed adsorption ring 2 to move adsorption bed a to the waiting station 12. Adsorption beds b, c, and d sequentially enter the heating separation station 13, cooling station 14, and vacuum low-temperature adsorption station 11. Adsorption bed d repeats step S3. It should be noted that when adsorption bed a is saturated with carbon dioxide in the vacuum low-temperature adsorption station 11, it indicates that adsorption bed a has completed adsorption. At this point, the four-bed adsorption ring 2 can be rotated to... Figure 1 and Figure 2For example, when the four-bed adsorption ring 2 rotates counterclockwise, adsorption bed a on the four-bed adsorption ring 2 enters the waiting station 12. Then, adsorption beds b, c and d on the four-bed adsorption ring 2 enter the heating separation station 13, the cooling station 14 and the vacuum low temperature adsorption station 11 in sequence. Since adsorption bed d was previously in the cooling station 14, adsorption bed d must be ready to adsorb carbon dioxide. Therefore, after adsorption bed d enters the vacuum low temperature adsorption station 11, it can adsorb and separate carbon dioxide from the power plant flue gas in the vacuum low temperature adsorption station 11, so that the vacuum low temperature adsorption station 11 can continue to process the power plant flue gas and ensure the processing efficiency of the vacuum low temperature adsorption station 11.

[0078] S4: Rotate the four-bed adsorption ring 2 again, so that adsorption bed a enters the heating separation station 13, and adsorption beds b, c and d enter the cooling station 14, the vacuum low-temperature adsorption station 11 and the waiting station 12 in sequence. Adsorption bed a undergoes heating and decompression operation in the heating separation station 13 to separate carbon dioxide from the four-bed adsorption ring 2. Adsorption bed c repeats step S3, and also includes the following steps:

[0079] S4.1: Transfer the adsorption bed in the four-bed adsorption ring 2 corresponding to the waiting station 12 to the heating separation station 13;

[0080] S4.2: The adsorption bed in the four-bed adsorption ring 2 is heated to 60 to 100 degrees Celsius by the heating equipment in the heating separation station 13, so that the carbon dioxide in the adsorption bed is desorbed;

[0081] S4.3: Use a vacuum pump to draw out the desorbed carbon dioxide in the heating separation station 13 and pump the carbon dioxide into a gas cylinder for storage.

[0082] It should be noted that the condition for rotating the four-bed adsorption ring 2 again is that the d adsorption bed is saturated with carbon dioxide in the vacuum low-temperature adsorption station 11. Then the d adsorption bed will enter the waiting station 12, while the c adsorption bed in the cooling station 14 will enter the vacuum low-temperature adsorption station 11 to repeat the carbon dioxide adsorption and separation operation. The a adsorption bed that enters the heating separation station 13 will undergo heating and separation operation in the heating separation station 13. Since the power plant flue gas was compressed and heated by the compressor, the high-temperature and high-pressure power plant flue gas can be used to exchange heat with the a adsorption bed in the heating separation station 13. On the one hand, the a adsorption bed can be heated to promote the desorption of carbon dioxide on the a adsorption bed. On the other hand, the temperature of the high-temperature and high-pressure power plant flue gas can be reduced so that the high-temperature and high-pressure power plant flue gas enters the vacuum low-temperature adsorption station 11 at a lower temperature, ensuring the adsorption effect of the adsorption bed on carbon dioxide in the vacuum low-temperature adsorption station 11.

[0083] S5: Continue rotating the four-bed adsorption ring 2, so that adsorption bed a enters the cooling station 14. Adsorption beds b, c, and d sequentially enter the vacuum low-temperature adsorption station 11, the waiting station 12, and the heating separation station 13. Adsorption bed a absorbs the remaining power plant flue gas for heat exchange in the cooling station 14 and the vacuum low-temperature adsorption station 11. Adsorption bed b repeats step S3. Adsorption bed d undergoes heating separation in the heating separation station 13. The following steps are also included:

[0084] S5.1: Transfer the adsorption bed in the corresponding four-bed adsorption ring 2 after heating and decompression in the heating and separation station 13 to the cooling station 14;

[0085] S5.2: The adsorption bed and vacuum pump in the cooling station 14 exchange heat with the low-temperature gas drawn from the vacuum low-temperature adsorption station 11 to reduce the temperature of the adsorption bed.

[0086] S5.3: Cooling station 14 directly discharges the low-temperature gas after heat exchange;

[0087] It should be noted that when the adsorption bed α enters the cooling station 14, the temperature inside the adsorption bed α is relatively high, and there is still residual carbon dioxide gas in the adsorption bed α. At this time, the low-temperature gas drawn from the vacuum low-temperature adsorption station 11 can carry away the residual carbon dioxide gas on the one hand, and on the other hand, it can lower the temperature of the adsorption bed α, ensuring that the adsorption bed α is at a lower temperature when it re-enters the vacuum low-temperature adsorption station 11, which is conducive to the re-adsorption of carbon dioxide.

[0088] S6: Finally, rotate the four-bed adsorption ring 2 so that adsorption bed a on the four-bed adsorption ring 2 re-enters the vacuum low-temperature adsorption station 11. Adsorption beds b, c and d enter the waiting station 12, the heating separation station 13 and the cooling station 14 in sequence. It should be noted that when adsorption bed a on the four-bed adsorption ring 2 re-enters the vacuum low-temperature adsorption station 11, the pressure of the environment around adsorption bed a will suddenly drop when adsorption bed a on the four-bed adsorption ring 2 is connected to the vacuum low-temperature adsorption station 11 due to the low air pressure inside the vacuum low-temperature adsorption station 11. This will cause the temperature of adsorption bed a on the four-bed adsorption ring 2 to drop again, which is the re-cooling operation of adsorption bed a. This allows adsorption bed a to go through two processes of pre-cooling and re-cooling. Therefore, the cooling of adsorption bed a is in two stages, and the temperature drop is gradual, which helps to protect the physical properties of activated carbon in adsorption bed a and ensures the re-adsorption performance of adsorption bed a.

[0089] Repeat steps S1 to S6 until the power plant flue gas is completely adsorbed. Since the four adsorption beds a, b, c, and d on the four-bed adsorption ring 2 correspond to the vacuum low-temperature adsorption station 11, waiting station 12, heating separation station 13, and cooling station 14 on the vacuum temperature-changing adsorption mechanism 1, the four adsorption beds a, b, c, and d on the four-bed adsorption ring 2 can all perform adsorption, desorption, and regeneration operations in a cyclical manner. The entire adsorption process reuses the high-temperature and low-temperature states of the power plant flue gas, significantly reducing the energy consumption for CO2 separation in the power plant flue gas, which means reducing the treatment cost of CO2 separation in the power plant flue gas. It is suitable for widespread use in the treatment of power plant flue gas, ensuring that the power plant flue gas meets emission standards after treatment. The heating separation station 13 can collect high-concentration carbon dioxide gas through a negative pressure pump, which reduces carbon emissions and also obtains high-concentration carbon dioxide products, resulting in cost reduction and efficiency improvement.

[0090] Example 2

[0091] like Figures 1-8 As shown, this invention discloses a four-bed vacuum temperature-switching adsorption device for CO2 separation in power plant flue gas. This four-bed vacuum temperature-switching adsorption device uses the above-mentioned four-bed vacuum temperature-switching adsorption process for CO2 separation in power plant flue gas, including a vacuum temperature-switching adsorption mechanism 1 and a four-bed adsorption ring 2. It should be noted that both the vacuum temperature-switching adsorption mechanism 1 and the four-bed adsorption ring 2 are annular. In order to reduce the frictional force when the four-bed adsorption ring 2 rotates on the vacuum temperature-switching adsorption mechanism 1, a pulley can also be installed on the bottom surface of the four-bed adsorption ring 2 to reduce the frictional force when the four-bed adsorption ring 2 rotates.

[0092] The four-bed adsorption ring 2 is equipped with four adsorption beds a, b, c and d. The four-bed adsorption ring 2 can change the adsorption beds inside the vacuum temperature-changing adsorption mechanism 1 by rotating. Since both the vacuum temperature-changing adsorption mechanism 1 and the four-bed adsorption ring 2 are annular and the four adsorption beds a, b, c and d are adapted to the vacuum temperature-changing adsorption mechanism 1, the four-bed adsorption ring 2 can rotate freely on the vacuum temperature-changing adsorption mechanism 1.

[0093] The vacuum temperature-switching adsorption mechanism 1 is equipped with a vacuum low-temperature adsorption station 11, a waiting station 12, a heating separation station 13, and a cooling station 14. The vacuum low-temperature adsorption station 11, the waiting station 12, the heating separation station 13, and the cooling station 14 are arranged in a ring. The four adsorption rings 2 are matched with the vacuum low-temperature adsorption station 11, the waiting station 12, the heating separation station 13, and the cooling station 14. It should be noted that the vacuum low-temperature adsorption station 11, the waiting station 12, the heating separation station 13, and the cooling station 14 occupy the same space size on the vacuum temperature-switching adsorption mechanism 1. In this way, when adsorption bed a is matched with the vacuum low-temperature adsorption station 11, the three adsorption beds b, c, and d can be matched with the waiting station 12, the heating separation station 13, and the cooling station 14.

[0094] A drive mechanism 15 is installed at the center of the top surface of the vacuum temperature-controlled adsorption mechanism 1. The drive mechanism 15 is used to transmit power to the four-bed adsorption rings 2, causing the four-bed adsorption rings 2 to rotate within the vacuum low-temperature adsorption station 11, the waiting station 12, the heating separation station 13, and the cooling station 14. It should be noted that the drive mechanism 15 includes a drive motor and a planetary reducer. The drive motor's output shaft is connected to the input end of the planetary reducer, and the output end of the planetary reducer meshes with the inner surface of the four-bed adsorption rings 2 through gears. When the drive motor is turned on, the output shaft of the drive motor can transmit power to the four-bed adsorption rings 2 through the planetary reducer. The output end of the planetary reducer then transmits power to the four-bed adsorption ring 2 through gears, enabling the four-bed adsorption ring 2 to rotate between the vacuum low-temperature adsorption station 11, the waiting station 12, the heating separation station 13, and the cooling station 14. The model and specifications of the drive motor and planetary reducer are selected by those skilled in the art based on the specifications of the vacuum variable temperature adsorption mechanism 1 and the four-bed adsorption ring 2, ensuring that the drive motor and planetary reducer can drive the four-bed adsorption ring 2. It should also be noted that the transmission between the drive motor and planetary reducer and the four-bed adsorption ring 2 needs to be sealed.

[0095] The vacuum cryogenic adsorption station 11 and the cooling station 14 are connected by a pipeline. A set of vacuum pumps can be installed in the middle of the pipeline, with the output end of the vacuum pump corresponding to the cooling station 14 and the input end corresponding to the vacuum cryogenic adsorption station 11. Figure 1 The top surfaces of the medium vacuum cryogenic adsorption station 1, waiting station 12, and cooling station 14 are all equipped with sealing plates. Figure 1 To make it clear, no appendix was included. Figure 1 As shown, rectangular grooves 16 are provided at the joints between the vacuum low-temperature adsorption station 11, the waiting station 12, the heating separation station 13, and the cooling station 14. The rectangular grooves 16 fit into the four-bed adsorption rings 2. An air inlet pipe 111 is connected to one side of the vacuum low-temperature adsorption station 11. A throttle valve is installed inside the air inlet pipe 111. The power plant flue gas enters the inner cavity of the vacuum low-temperature adsorption station 11 through the air inlet pipe 111. A carbon dioxide collection pipe 131 is fixedly connected to the center of the top surface of the heating separation station 13. The carbon dioxide collection pipe 131 is connected to a gas cylinder through a negative pressure pump to ensure that the carbon dioxide gas in the carbon dioxide collection pipe 131 can be drawn into the gas cylinder by the negative pressure pump for collection. The gas cylinder can also be replaced by those skilled in the art according to the specific site conditions to ensure that the carbon dioxide can be collected normally.

[0096] like Figure 8As shown, the four-bed adsorption ring 2 includes an adsorption shell 21. Four isolation plates 22 are uniformly arranged inside the adsorption shell 21. The four isolation plates 22 divide the inner cavity of the adsorption shell 21 into four adsorption beds of the same volume. Several parallel adsorption inner plates 23 are uniformly arranged inside the adsorption beds. It should be noted that several U-shaped heat exchange pipes can be distributed inside the adsorption inner plates 23. These heat exchange pipes are used to connect to high-temperature and high-pressure power plant flue gas. The adsorption inner plates 23 can also be heated by electric auxiliary heating to ensure that the carbon dioxide adsorbed on the adsorption inner plates 23 can be heated to 60 degrees Celsius to 100 degrees Celsius.

[0097] The adsorption inner plate 23 is made of activated carbon, molecular sieve, or metal-organic framework. It should be noted that the adsorption inner plate 23 made of activated carbon can provide good adsorption capacity for carbon dioxide. The adsorption inner plate 23 can be set in a vertical state, a horizontal state, or a strip shape. The main purpose is to increase the contact area with the power plant flue gas in the vacuum low-temperature adsorption station 11 and improve the adsorption efficiency of carbon dioxide. The specifications and types of activated carbon, molecular sieve, or metal-organic framework are all adapted to the specific carbon dioxide adsorption situation and the composition of the power plant flue gas by those skilled in the art.

[0098] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A four-bed vacuum temperature-switching adsorption process for CO2 separation in power plant flue gas, characterized in that, Includes the following steps: S1: Four adsorption beds are set on the four-bed adsorption ring. The four-bed adsorption ring is rotated so that the four adsorption beds circulate sequentially in the vacuum low temperature adsorption station, waiting station, heating separation station and cooling station on the vacuum temperature-changing adsorption mechanism. S2: Power plant flue gas is introduced into the vacuum low-temperature adsorption station, which creates a vacuum low-temperature environment for the adsorption bed. At the same time, the adsorption bed in the cooling station is pre-cooled when the four adsorption rings rotate. S2.1: The power plant flue gas is pressurized using a compressor and transported to a high-pressure pipeline. The high-pressure pipeline passes through a waiting station and exchanges heat with the adsorption bed therein. The high-pressure power plant flue gas is automatically cooled to room temperature in the high-pressure pipeline. S2.2: High-voltage power plant flue gas passes through a high-pressure pipeline to a waiting station, where it undergoes heat exchange with the adsorption bed. S2.3: The high-voltage power plant flue gas after waiting for the work station is automatically cooled to room temperature in the high-voltage pipeline; S2.4: Use a vacuum pump to evacuate the low-temperature gas in the vacuum low-temperature adsorption station to create a negative pressure environment within the vacuum low-temperature adsorption station; S2.5: The vacuum pump transports the low-temperature gas drawn from the vacuum low-temperature adsorption station to the cooling station to pre-cool the adsorption bed in the cooling station. S2.6: A throttling valve is used to transport the high-pressure power plant flue gas in the high-pressure pipeline to the vacuum low-temperature adsorption station. The high-pressure power plant flue gas is rapidly depressurized and absorbs heat in the vacuum low-temperature adsorption station, so that the environment in the vacuum low-temperature adsorption station forms a low-temperature negative pressure. S2.7: The pressure value of the environment in the vacuum low-temperature adsorption station is controlled by the throttle valve. When the pressure value of the environment in the vacuum low-temperature adsorption station reaches the preset pressure threshold, the high-voltage power plant flue gas is stopped from being introduced into the vacuum low-temperature adsorption station. S3: The adsorption bed in the vacuum low-temperature adsorption station is transferred to the waiting station, where the adsorption bed is preheated. S4: The adsorption bed in the waiting station is transferred to the heating and separation station, where the adsorption bed is heated and decompressed. S5: The adsorption bed in the heating and separation station is transferred to the cooling station, where the adsorption bed is cooled down. S6: Repeat S1 to S6 until the power plant flue gas is completely adsorbed.

2. The four-bed vacuum temperature-switching adsorption process for CO2 separation in power plant flue gas according to claim 1, characterized in that, When the adsorption bed in the four-bed adsorption ring enters the vacuum low-temperature adsorption station from the cooling station, the vacuum low-temperature adsorption station reduces the pressure of the adsorption bed in the cooling station and further cools the adsorption bed in the cooling station.

3. The four-bed vacuum temperature-switching adsorption process for CO2 separation in power plant flue gas according to claim 1, characterized in that, S4 includes the following steps: S4.1: Transfer the adsorption bed in the four-bed adsorption ring corresponding to the waiting station to the heating separation station; S4.2: The adsorption bed in the four-bed adsorption ring is heated to 60 to 100 degrees Celsius by the heating equipment in the heating separation station, so that the carbon dioxide in the adsorption bed is desorbed; S4.3: Use a vacuum pump to draw out the desorbed carbon dioxide in the heating and separation station, and pump the carbon dioxide into a gas cylinder for storage.

4. The four-bed vacuum temperature-switching adsorption process for CO2 separation in power plant flue gas according to claim 2, characterized in that, S5 includes the following steps: S5.1: Transfer the adsorption bed in the corresponding four-bed adsorption ring after heating and decompression in the heating and separation station to the cooling station; S5.2: The adsorption bed and vacuum pump in the cooling station exchange heat with the low-temperature gas drawn from the vacuum low-temperature adsorption station to reduce the temperature of the adsorption bed. S5.3: The cooling station directly discharges the low-temperature gas after heat exchange.

5. A four-bed vacuum temperature-switching adsorption device for CO2 separation in power plant flue gas, employing the four-bed vacuum temperature-switching adsorption process for CO2 separation in power plant flue gas as described in any one of claims 1-4, characterized in that, Includes a vacuum temperature-controlled adsorption mechanism and a four-bed adsorption ring; The four-bed adsorption ring is equipped with four adsorption beds, a, b, c, and d. The four-bed adsorption ring can be rotated to change the adsorption beds inside the vacuum temperature-changing adsorption mechanism.

6. The four-bed vacuum temperature-switching adsorption device for CO2 separation in power plant flue gas according to claim 5, characterized in that, The vacuum temperature-changing adsorption mechanism is equipped with a vacuum low-temperature adsorption station, a waiting station, a heating separation station, and a cooling station. The vacuum low-temperature adsorption station, the waiting station, the heating separation station, and the cooling station are arranged in a ring. The four adsorption rings are matched with the vacuum low-temperature adsorption station, the waiting station, the heating separation station, and the cooling station.

7. The four-bed vacuum temperature-switching adsorption device for CO2 separation in power plant flue gas according to claim 6, characterized in that, A drive mechanism is installed at the center of the top surface of the vacuum temperature-changing adsorption mechanism. The drive mechanism is used to transmit power to the four adsorption rings, so that the four adsorption rings rotate in the vacuum low temperature adsorption station, the waiting station, the heating separation station, and the cooling station.

8. The four-bed vacuum temperature-switching adsorption device for CO2 separation in power plant flue gas according to claim 6, characterized in that, The four-bed adsorption ring includes an adsorption shell, and four partition plates are uniformly arranged inside the adsorption shell. The four partition plates divide the inner cavity of the adsorption shell into four adsorption beds of the same volume. Several parallel adsorption inner plates are uniformly arranged inside the adsorption beds.

9. The four-bed vacuum temperature-switching adsorption device for CO2 separation in power plant flue gas according to claim 8, characterized in that, The adsorption inner plate is made of activated carbon, molecular sieve, or metal-organic framework.

Images