Carbon dioxide concentration self-adaptive adsorption and desorption control system

Abstract

The invention discloses a carbon dioxide concentration self-adaptive adsorption and desorption device and a method using the device, the device comprises two adsorption towers, a gas supply machine, a heating gas supply assembly and a controller assembly, the top of each tower body is provided with an adsorption gas inlet pipe, a desorption gas inlet pipe, a pressure release valve and a corresponding electric valve, the adsorption gas inlet pipe is connected with the gas supply machine, and the desorption gas inlet pipe is connected with the gas supply machine. The desorption gas inlet pipe is connected with the heating gas supply assembly, a supporting net is arranged in the tower body, and a water absorption carrier layer, a molecular sieve layer and an inert breathable particulate matter layer are laid above the supporting net from bottom to top. Temperature measuring assemblies are arranged at the upper, middle and lower positions of the molecular sieve layer. An adsorption exhaust pipe, a desorption exhaust pipe, a corresponding electric valve and a carbon dioxide concentration sensor are arranged at the bottom of the tower body. The adsorption exhaust pipe is connected with the heating air supply assembly through a scavenging branch pipe. According to the method disclosed by the invention, self-adaptive adsorption and desorption can be realized by using the device, and the energy required by regeneration is reduced under the condition of preventing carbon dioxide penetration, so that the production energy consumption is reduced and the system safety is improved.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide separation technology, specifically to a carbon dioxide concentration adaptive adsorption and desorption control system. Background Technology

[0002] Before air enters the distillation column after being compressed and cooled, carbon dioxide and water vapor must be removed; otherwise, they will freeze at low temperatures, clogging equipment and pipes. Traditional "pure molecular sieve purification systems" are used to adsorb these impurities. Traditional purification adsorption and desorption systems often switch periodically, leading to energy waste due to "regeneration before the adsorbent is saturated" or premature saturation of the molecular sieve, causing carbon dioxide to permeate the purification system.

[0003] Therefore, the adsorption tower and control system are upgraded to enable them to stop desorption when regeneration and desorption are complete and the system is close to saturation, thus preventing carbon dioxide penetration, reducing the energy required for regeneration, thereby reducing production energy consumption and improving system safety. Summary of the Invention

[0004] The purpose of this invention is to provide an adaptive adsorption and desorption control system for carbon dioxide concentration to solve the problems described in the background art.

[0005] The technical solution of this invention is implemented as follows:

[0006] An adaptive carbon dioxide adsorption and desorption device includes two adsorption towers, a gas supply unit, a heating and gas supply assembly, and a controller assembly. Each adsorption tower includes a tower body, with an adsorption inlet pipe, a desorption inlet pipe, and a pressure relief valve connected to the top of the tower body. The adsorption inlet pipe is equipped with an adsorption inlet valve, and the desorption inlet pipe is equipped with a desorption inlet valve and an inlet temperature sensor. The adsorption inlet pipe is connected to the gas supply unit, and the desorption inlet pipe is connected to the heating and gas supply assembly. A support mesh is fixed inside the tower body, separating the upper and lower parts of the tower body. A water-absorbing adsorption carrier layer is laid above the support mesh, a molecular sieve layer is laid above the water-absorbing adsorption carrier, and an inert, permeable particulate matter layer is laid above the molecular sieve layer. At least three sets of temperature measuring components are also fixed to the inner wall of the tower body. The components are respectively located at the upper, middle, and lower ends of the molecular sieve layer. A gas diversion component is fixed in the tower body above the inert and permeable particles. The tower body below the support net is connected to an adsorption exhaust pipe and a desorption exhaust pipe. An adsorption exhaust valve and a carbon dioxide concentration sensor are installed on the adsorption exhaust pipe, and a desorption exhaust valve and a carbon dioxide concentration sensor are installed on the desorption exhaust pipe. A scavenging branch pipe is also connected to the adsorption exhaust pipe downstream of the adsorption exhaust valve. A scavenging valve is also installed on the scavenging branch pipe. The scavenging pipe is connected to the heating gas supply component. The gas supply machine, heating gas supply component, adsorption inlet valve, adsorption exhaust valve, desorption inlet valve, desorption exhaust valve, carbon dioxide concentration sensor, inlet temperature sensor, scavenging valve, and temperature measuring component are all electrically connected to the controller component.

[0007] A further technical solution is that the temperature measuring component includes an intermediate tube, with adapters detachably installed inside the pipe openings at both ends of the intermediate tube, multiple vent holes opened on the pipe wall of the intermediate tube, and connecting pipes detachably installed outside the pipe openings at both ends of the intermediate tube. The connecting pipes are sealed and pass through the side wall of the tower body. A connector is detachably installed inside the adapter, and a temperature measuring probe is installed in the connector. The temperature measuring probe is electrically connected to the controller component.

[0008] A further technical solution is that the water-absorbing adsorption carrier layer is composed of activated alumina balls, the molecular sieve layer is composed of 13X molecular sieves, and the inert and breathable particulate matter layer is composed of inert alumina balls.

[0009] A further technical solution is that the gas diversion component is a diversion plate, with multiple air holes opened between the upper and lower end faces of the diversion plate, and the edge of the diversion plate is fixedly connected to the side wall of the tower body.

[0010] A further technical solution is that the support net includes a stainless steel mesh frame, with a stainless steel mesh laid on the upper surface of the mesh frame. The mesh diameter of the stainless steel mesh is smaller than the diameter of the activated alumina balls. A support part is fixedly provided at the bottom of the mesh frame. The edge of the mesh frame is fixedly connected to the side wall of the tower body, and the bottom of the support part is fixedly connected to the bottom of the tower body.

[0011] A further technical solution is that the air supply unit is an air compressor, and the heating air supply assembly includes a blower and an air heater. The scavenging branch pipe is connected to the air inlet of the blower, the air outlet of the blower is connected to the air inlet of the air heater, the air outlet of the air heater is connected to the desorption air inlet pipe, and the air compressor, blower and air heater are all electrically connected to the controller assembly.

[0012] A method using a carbon dioxide concentration adaptive adsorption and desorption device defines one adsorption tower as tower A and another adsorption tower as tower B. Accordingly,

[0013] The temperatures measured by the temperature probes located at the upper middle part of the molecular sieve layers in towers A and B are T_top_A and T_top_B, respectively.

[0014] The temperatures measured by the temperature probes located at the midpoints of the molecular sieve layers in towers A and B are T_mid_A and T_mid_B, respectively.

[0015] The temperatures measured by the temperature probes located at the lower middle end of the sub-sieve layers in towers A and B are T_bot_A and T_bot_B, respectively.

[0016] The carbon dioxide concentrations measured by the carbon dioxide concentration sensors located at the adsorption exhaust pipes of tower A and tower B are C_out_A and C_out_B, respectively.

[0017] The carbon dioxide concentrations measured by the carbon dioxide concentration sensors located at the desorption exhaust pipes of towers A and B are C_desorb_A and C_desorb_B, respectively.

[0018] The inlet temperature sensors located at the desorption inlet pipes of tower A and tower B measure the temperatures T_in_A and T_in_B, respectively.

[0019] The execution steps of this method are as follows:

[0020] S1. Open the adsorption inlet valve and adsorption outlet valve of tower A, and start the air compressor to allow compressed air to pass through tower A from top to bottom. At this time, water vapor and carbon dioxide in the air are captured by the 13X molecular sieve, and clean and dry air flows out from the adsorption outlet pipe.

[0021] S2. The controller component monitors T_top_A, T_mid_A and T_bot_A in real time. The controller component calculates and analyzes the rise rate of T_mid_A in real time. When either of the following two conditions is triggered, step S3 is executed: Condition 1 is when T_top_A reaches the preset value and T_mid_A reaches the preset value within 5 to 10 minutes, step S3 is executed; Condition 2 is when C_out_A exceeds the preset value, step S3 is executed.

[0022] S3. The controller component controls the adsorption inlet valve and adsorption exhaust valve of tower B to linearly open to the fully open state within 10 to 120 seconds, and then controls the adsorption inlet valve and adsorption exhaust valve of tower A to linearly close to the fully closed state within 10 to 120 seconds.

[0023] S4. First, open the desorption exhaust valve of tower A, then open the scavenging valve of tower B and the desorption intake valve of tower A. Then start the blower so that some dry, carbon dioxide-free regenerated gas from the adsorption exhaust pipe of tower B enters tower A from top to bottom. Then start the air heater to heat the regenerated gas to the set temperature.

[0024] S5. Continuously monitor the values ​​of C_desorb_A and T_top_A. When both reach the preset values ​​at the same time, it is determined that the heating desorption is complete and the air heater is turned off.

[0025] S6. When T_mid_A-T_in_A≤10℃, cooling is considered complete. The blower, the scavenging valve of tower B, the desorption inlet valve of tower A, and the desorption exhaust valve of tower A are closed in sequence, and tower A enters standby state.

[0026] S7. The controller component monitors T_top_B, T_mid_B and T_bot_B in real time. The controller component calculates and analyzes the rise rate of T_mid_B in real time. When either of the following two conditions is triggered, step S8 is executed: Condition 1 is when T_top_B reaches the preset value and T_mid_B reaches the preset value within 5 to 10 minutes, step S8 is executed; Condition 2 is when C_out_B exceeds the preset value, step S8 is executed.

[0027] S8. The controller component controls the adsorption inlet valve and adsorption exhaust valve of tower A to linearly open to the fully open state within 10 to 120 seconds, and then controls the adsorption inlet valve and adsorption exhaust valve of tower B to linearly close to the fully closed state within 10 to 120 seconds.

[0028] S9. First, open the desorption exhaust valve of tower B, then open the scavenging valve of tower A and the desorption intake valve of tower B, then start the blower so that some dry, carbon dioxide-free regenerated gas from the adsorption exhaust pipe of tower A enters tower B from top to bottom, and then start the air heater to heat the regenerated gas to the set temperature.

[0029] S10. Continuously monitor the values ​​of C_desorb_B and T_top_B. When both reach the preset values ​​at the same time, it is determined that the heating desorption is complete and the air heater is turned off.

[0030] S11. When T_mid_B-T_in_B≤10℃, cooling is determined to be complete. The blower, the scavenging valve of tower A, the desorption inlet valve of tower B, and the desorption exhaust valve of tower B are closed in sequence, and tower B enters standby state.

[0031] S12. Repeat steps S2 to S11.

[0032] A further technical solution is that, in step S2, the method for calculating and setting the rise rate of T_mid_A is as follows: the controller component reads the value of T_mid_A at a fixed period, the current value of T_mid_A is set as a variable value T_current_A stored in the storage area, and the T_current_A recorded in the previous period is stored in T_previous_A in the storage area. A preset calculation program is used, which is calculated as (T_current_A - T_previous_A) / scan period time. The calculation program is executed once in each reading period to obtain the real-time rise rate. In step S7, the method for calculating and setting the rise rate of T_mid_B is as follows: the controller component reads the value of T_mid_B at a fixed period, the current value of T_mid_B is set as a variable value T_current_B stored in the storage area, and the T_current_B recorded in the previous period is stored in T_previous_B in the storage area. A preset calculation program is used, which is calculated as (T_current_B - T_previous_B) / scan period time. The calculation program is executed once in each reading period to obtain the real-time rise rate.

[0033] A further technical solution is that, in condition two, step S3 is executed when C_out_A exceeds 10~15ppm, and in step S7, in condition two, step S8 is executed when C_out_B exceeds 10~15ppm.

[0034] A further technical solution is that, in step S4, the regeneration gas is heated to a set temperature of 175~185℃; in step S5, when C_desorb_A is less than 400ppm and lasts for more than 60 seconds, and T_top_A is at 175~185℃ and lasts for more than 300 seconds, the heating desorption is determined to be complete, and the air heater is turned off; in step S9, the regeneration gas is heated to a set temperature of 175~185℃; in step S10, when C_desorb_B is less than 400ppm and lasts for more than 60 seconds, and T_top_B is at 175~185℃ and lasts for more than 300 seconds, the heating desorption is determined to be complete, and the air heater is turned off.

[0035] The beneficial effects of this invention are as follows:

[0036] This system combines "bed temperature trend prediction" with "real-time monitoring of outlet concentration" to achieve an adaptive shift from hysteresis control to proactive control in adsorption and desorption. By using "concentration target achievement" and "temperature stability" as dual criteria, the system ensures the stability of both the adsorption and desorption processes. While ensuring that carbon dioxide cannot easily penetrate the adsorbent, it efficiently utilizes the adsorbent capacity and significantly reduces regeneration energy consumption, thereby lowering production energy consumption and improving system safety. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the overall structure of the device;

[0038] Figure 2 This is a cross-sectional schematic diagram of the temperature sensing component;

[0039] Figure 3 This is a top view of the supporting net.

[0040] In the diagram, 1. Adsorption inlet valve, 2. Adsorption inlet pipe, 3. Desorption inlet valve, 4. Desorption inlet pipe, 5. Tower body, 6. Diverter plate, 7. Inert alumina balls, 8. Molecular sieve, 9. Activated alumina balls, 10. Temperature measuring component, 11. Carbon dioxide concentration sensor, 12. Adsorption exhaust valve, 13. Adsorption exhaust pipe, 14. Desorption exhaust valve, 15. Desorption exhaust pipe, 16. Support mesh, 17. Support section, 18. Pressure relief valve, 19. Connecting pipe, 20. Intermediate pipe, 21. Vent hole, 22. Adapter, 23. Connector, 24. Temperature probe, 25. Air compressor, 26. Blower, 27. Air heater, 28. Scavenging branch pipe, 29. Scavenging valve, 30. Inlet temperature sensor. Detailed Implementation

[0041] To better understand the technical content of this invention, specific embodiments are provided below, and the invention will be further described in conjunction with the accompanying drawings.

[0042] See Figures 1 to 3 A carbon dioxide concentration adaptive adsorption and desorption control system includes a carbon dioxide concentration adaptive adsorption and desorption device and a method of using the device.

[0043] The carbon dioxide concentration adaptive adsorption and desorption device consists of two adsorption towers. The adsorption towers have a flat bottom, cylindrical body, and conical top structure.

[0044] It also includes an air supply unit, which mainly uses an air compressor 25. You can directly purchase a cabinet-type air compressor 25 with particulate matter filtration currently available on the market.

[0045] It also includes a heating and air supply assembly, which includes a blower 26 and an air heater 27. The blower 26 can be a commercially available air compressor 25 with an air inlet and an air outlet. The air heater 27 can be a commercially available long-tube air heater 27. The air outlet of the blower 26 is connected to the air inlet of the air heater 27.

[0046] It also includes controller components, which include a PLC controller, signal converters, control panels, and display panels. The PLC controller can be a mid-to-high-end PLC such as Siemens S7-1200 / 1500 or Rockwell CompactLogix series. The connection between the PLC controller and the signal converters, control panels, and display panels is a standard technique in existing technology, and the connection methods will not be described in detail here.

[0047] The adsorption tower includes a tower body 5, with an adsorption inlet pipe 2, a desorption inlet pipe 4, and a pressure relief valve 18 connected to the top of the tower body 5. The adsorption inlet pipe 2 is equipped with an adsorption inlet valve 1, which is an electrically operated valve. The desorption inlet pipe 4 is equipped with a desorption inlet valve 3 and an inlet temperature sensor 30, which is also an electrically operated valve. The adsorption inlet pipe 2 is connected to an air supply unit, and the outlet of the air heater 27 is connected to the desorption inlet pipe 4.

[0048] The tower body 5 is internally equipped with a support mesh 16 that separates the upper and lower parts of the tower body 5. Specifically, the support mesh 16 includes a stainless steel mesh frame, with a stainless steel mesh laid on the upper surface of the mesh frame, and a support part 17 fixed at the bottom of the mesh frame. The edge of the mesh frame is fixedly connected to the side wall of the tower body 5, and the bottom of the support part 17 is fixedly connected to the bottom of the tower body 5.

[0049] A water-absorbing carrier layer is laid on top of the support net 16. Preferably, the water-absorbing carrier layer is composed of activated alumina balls 9, and the mesh diameter of the stainless steel mesh is smaller than the diameter of the activated alumina balls 9.

[0050] A layer of molecular sieve 8 is laid on top of the water-absorbing adsorption carrier. Preferably, the molecular sieve 8 is composed of 13X molecular sieve 8.

[0051] An inert, breathable particulate layer is laid on top of the molecular sieve layer 8. Preferably, the inert, breathable particulate layer is composed of inert alumina balls 7.

[0052] The inner wall of the tower body 5 is also fixed with three sets of temperature measuring components 10, which are respectively located at the upper middle, middle and lower middle ends of the molecular sieve 8 layers.

[0053] Specifically, the temperature measuring component 10 includes a stainless steel intermediate tube 20. The inner walls of both ends of the intermediate tube 20 are threaded. An adapter 22 is installed inside each end of the intermediate tube 20. The outer wall of the adapter 22 is threaded, and the inner wall of the adapter 22 is also threaded. The adapter 22 is screwed into the inner threads of the inner walls of the ends of the intermediate tube 20 via its external threads. Multiple vent holes 21 are formed on the wall of the intermediate tube 20, with the diameter of the vent holes 21 being smaller than the diameter of the molecular sieve 8. The outer walls of both ends of the intermediate tube 20 are threaded. A connecting pipe 19 is detachably connected to the outer walls of both ends of the intermediate tube 20. The inner wall of the connecting pipe 19 is threaded, and the connecting pipe 19 is screwed into the external threads at the ends of the intermediate tube 20 via its internal threads. The connecting pipe 19 passes through the side wall of the tower body 5 and is sealed by welding. A connector 23 is also detachably connected inside the adapter 22, and a temperature measuring probe 24 is installed in the connector 23. The connector 23 is a conventional connector 23, and the temperature probe 24 is a PT100 temperature probe 24. The temperature probe 24 passes through the middle of the connector 23. The connector 23 is a threaded connector 23, which is screwed onto the internal thread of the adapter 22. The temperature probe 24 extends into the intermediate tube 20 to measure the temperature. During installation, a commonly used installation sleeve is required. This installation sleeve is a long, straight, round tube with open ends. One end has an internal hexagonal groove. The wire of the temperature probe 24 is inserted through the internal hexagonal groove and pulled out from the other open end. The end of the connector 23 with the hexagonal nut is pressed into the internal hexagonal groove. The sleeve is inserted along the connecting tube 19 until the connector 23 contacts the adapter 22. Then, the sleeve is rotated to screw the connector 23 into the adapter 22. It should be noted that sealing rings should be provided on the abutting and limiting surfaces when the intermediate pipe 20 is connected to the connecting pipe 19, the abutting and limiting surfaces when the adapter 22 is connected to the intermediate pipe 20, and the abutting and limiting surfaces when the connector 23 is connected to the adapter 22. This is a conventional connection technique and will not be explained further here.

[0054] A gas diversion component is fixed inside the tower body 5 above the inert and breathable particles. The gas diversion component is a diversion plate 6. Multiple air holes are opened between the upper and lower end faces of the diversion plate 6. The edge of the diversion plate 6 is fixedly connected to the side wall of the tower body 5.

[0055] The tower body 5 below the support net 16 is connected to an adsorption exhaust pipe 13 and a desorption exhaust pipe 15. The adsorption exhaust pipe 13 is equipped with an adsorption exhaust valve 12 and a carbon dioxide concentration sensor 11. The adsorption exhaust valve 12 is an electric valve. The desorption exhaust pipe 15 is equipped with a desorption exhaust valve 14 and a carbon dioxide concentration sensor 11. The desorption exhaust valve 14 is an electric valve.

[0056] Downstream of the adsorption exhaust valve 12, the adsorption exhaust pipe 13 is also connected to a scavenging branch pipe 28, which is equipped with a scavenging valve 29. The scavenging valve 29 is an electric valve, and the scavenging branch pipe 28 is connected to the air inlet of the blower 26.

[0057] Air compressor 25, air heater 27, blower 26, adsorption inlet valve 1, adsorption exhaust valve 12, desorption inlet valve 3, desorption exhaust valve 14, carbon dioxide concentration sensor 11, inlet air temperature sensor 30, scavenging valve 29 and temperature probe 24 are all electrically connected to the controller assembly.

[0058] The method of applying this device is as follows: designate one adsorption tower as tower A and the other adsorption tower as tower B, and accordingly,

[0059] The temperatures measured by the temperature probe 24, located at the upper middle part of the 8 layers of molecular sieves in towers A and B, are T_top_A and T_top_B, respectively.

[0060] The temperatures measured by the temperature probe 24 located in the middle of the 8th layer of the molecular sieve in tower A and tower B are T_mid_A and T_mid_B, respectively.

[0061] The temperatures measured by the temperature probe 24 located at the lower middle end of the sub-sieve layer in towers A and B are T_bot_A and T_bot_B, respectively.

[0062] The carbon dioxide concentrations measured by the carbon dioxide concentration sensor 11 located at the adsorption exhaust pipe 13 of tower A and tower B are C_out_A and C_out_B, respectively.

[0063] The carbon dioxide concentrations measured by the carbon dioxide concentration sensor 11 located at the desorption exhaust pipe 15 of tower A and tower B are C_desorb_A and C_desorb_B, respectively.

[0064] The temperatures measured by the inlet temperature sensor 30, located at the desorption inlet pipe 4 of tower A and tower B, are T_in_A and T_in_B, respectively.

[0065] The execution steps of this method are as follows:

[0066] S1. Open the adsorption inlet valve 1 and adsorption outlet valve 12 of tower A, and start the air compressor 25 so that compressed air passes through tower A from top to bottom. At this time, water vapor and carbon dioxide in the air are captured by 13X molecular sieve 8, and clean and dry air flows out from the adsorption outlet pipe 13.

[0067] S2. The controller component monitors T_top_A, T_mid_A and T_bot_A in real time. The controller component calculates and analyzes the rise rate of T_mid_A in real time. When either of the following two conditions is triggered, step S3 is executed: Condition 1 is when T_top_A reaches the preset value and T_mid_A reaches the preset value within 5 to 10 minutes, step S3 is executed; Condition 2 is when C_out_A exceeds the preset value, step S3 is executed.

[0068] S3. The controller component controls the adsorption inlet valve 1 and adsorption exhaust valve 12 of tower B to linearly open to the fully open state within 10 to 120 seconds, and then controls the adsorption inlet valve 1 and adsorption exhaust valve 12 of tower A to linearly close to the fully closed state within 10 to 120 seconds.

[0069] S4. First, open the desorption exhaust valve 14 of tower A, then open the scavenging valve 29 of tower B and the desorption inlet valve 3 of tower A, then start the blower 26 so that some dry carbon dioxide-free regenerated gas at the adsorption exhaust pipe 13 of tower B enters tower A from top to bottom, and then start the air heater 27 to heat the regenerated gas to the set temperature.

[0070] S5. Continuously monitor the values ​​of C_desorb_A and T_top_A. When both reach the preset values ​​at the same time, it is determined that the heating desorption is complete and the air heater 27 is turned off.

[0071] S6. When T_mid_A-T_in_A≤10℃, cooling is determined to be complete. Then, blower 26, scavenging valve 29 of tower B, desorption inlet valve 3 of tower A, and desorption exhaust valve 14 of tower A are closed in sequence, and tower A enters standby state.

[0072] S7. The controller component monitors T_top_B, T_mid_B and T_bot_B in real time. The controller component calculates and analyzes the rise rate of T_mid_B in real time. When either of the following two conditions is triggered, step S8 is executed: Condition 1 is when T_top_B reaches the preset value and T_mid_B reaches the preset value within 5 to 10 minutes, step S8 is executed; Condition 2 is when C_out_B exceeds the preset value, step S8 is executed.

[0073] S8. The controller assembly controls the adsorption inlet valve 1 and adsorption exhaust valve 12 of tower A to linearly open to the fully open state within 10 to 120 seconds, and then controls the adsorption inlet valve 1 and adsorption exhaust valve 12 of tower B to linearly close to the fully closed state within 10 to 120 seconds.

[0074] S9. First, open the desorption exhaust valve 14 of tower B, then open the scavenging valve 29 of tower A and the desorption inlet valve 3 of tower B, then start the blower 26 so that some dry carbon dioxide-free regenerated gas at the adsorption exhaust pipe 13 of tower A enters tower B from top to bottom, and then start the air heater 27 to heat the regenerated gas to the set temperature.

[0075] S10. Continuously monitor the values ​​of C_desorb_B and T_top_B. When both reach the preset values ​​at the same time, it is determined that the heating desorption is complete and the air heater 27 is turned off.

[0076] S11. When T_mid_B-T_in_B≤10℃, cooling is determined to be complete. Then, blower 26, scavenging valve 29 of tower A, desorption inlet valve 3 of tower B, and desorption exhaust valve 14 of tower B are closed in sequence, and tower B enters standby state.

[0077] S12. Repeat steps S2 to S11.

[0078] Preferably, in step S2, the method for calculating the rise rate of T_mid_A is as follows: the controller component reads the value of T_mid_A every 10 seconds; the current value of T_mid_A is set and stored in a variable value T_current_A in the storage area; the T_current_A recorded in the previous cycle is stored in T_previous_A in the storage area; a preset calculation program (T_current_A - T_previous_A) / 10 is used, and the calculation program is executed once in each reading cycle to obtain the real-time rise rate. In step S7, the method for calculating the rise rate of T_mid_B is as follows: the controller component reads the value of T_mid_B every 10 seconds; the current value of T_mid_B is set and stored in a variable value T_current_B in the storage area; the T_current_B recorded in the previous cycle is stored in T_previous_B in the storage area; a preset calculation program (T_current_B - T_previous_B) / 10 is used, and the calculation program is executed once in each reading cycle to obtain the real-time rise rate.

[0079] Example: If the current temperature T_current_A is 31.0°C, the previous temperature T_previous_A was 30.8°C, and the scan period is 10 seconds, the heating rate = (31.0 - 30.8) / 10 = 0.02°C / s.

[0080] Preferably, in step S2, condition two is to execute step S3 when C_out_A exceeds 10ppm, and in step S7, condition two is to execute step S8 when C_out_B exceeds 10ppm.

[0081] Preferably, in step S4, the regeneration gas is heated to a set temperature of 175~185℃; in step S5, when C_desorb_A is less than 400ppm and lasts for more than 60 seconds, and T_top_A is at 180~185℃ and lasts for more than 300 seconds, the heating desorption is determined to be complete, and the air heater 27 is turned off. In step S9, the regeneration gas is heated to a set temperature of 175~185℃; in step S10, when C_desorb_B is less than 400ppm and lasts for more than 60 seconds, and T_top_B is at 180~185℃ and lasts for more than 300 seconds, the heating desorption is determined to be complete, and the air heater 27 is turned off.

[0082] It should be noted that in steps S2 and S7, the "preset value" in condition one, which states that T_top_A / T_top_B reaches the preset value and T_mid_A / T_top_B reaches the preset value within 5 to 10 minutes, needs to be specified based on the actual situation and is not a general value. For example, if the air temperature entering through the adsorption inlet pipe 2 is 30°C (this temperature can be obtained from the air compressor 25 without the need for an additional temperature sensor, although an additional temperature sensor can be installed if necessary), then the preset value of T_top_A will vary depending on the manufacturing process of the molecular sieve 8, the material and process of the tower body 5, and the gas convection conditions of the on-site environment. The preset value may be 10 to 20°C higher than the adsorption inlet temperature. This requires engineers and process personnel to set it after on-site debugging, and it is a value that can be obtained through a limited number of debugging sessions.

[0083] Working principle of this invention:

[0084] When using this device, first power on the controller assembly and all actuators. By default, column A is selected to enter adsorption mode, and column B enters standby or desorption-post-standby state. Open the adsorption inlet valve 1 and adsorption exhaust valve 12 of column A. The air compressor 25 supplies compressed air, which flows from top to bottom through column A. At this time, water vapor and carbon dioxide in the air are captured by the 13X molecular sieve 8, and the clean and dry air flows from the adsorption exhaust pipe 13 of column A to the subsequent distillation column.

[0085] By setting up the flow divider 6, the compressed air can be evenly diffused downwards, avoiding erosion of the lower bed. By setting up an inert and permeable particulate layer, and using inert alumina balls 7, the gas can be further evenly distributed and the bed can be protected, preventing high-speed airflow from directly impacting the molecular sieve 8. It can also prevent the molecular sieve 8 from jumping up and down and rubbing against each other when the pressure fluctuates, thus preventing dust from being generated.

[0086] It is worth noting that the 8-layer molecular sieve is a continuous, deep bed, and cannot be configured as a multi-layered structure.

[0087] By setting up a water-absorbing adsorption carrier layer and using activated alumina balls 9 as fillers, moisture can be removed even further.

[0088] Throughout the adsorption process, the controller continuously records the carbon dioxide concentration C_out_A and bed temperatures T_top_A, T_mid_A, and T_bot_A at the outlet of tower A. During the adsorption phase, the principle of heat of adsorption is used for prediction. When gas molecules are adsorbed onto the surface of molecular sieve 8, they release heat, i.e., the heat of adsorption. Therefore, the temperature in the molecular sieve 8 layer region where intense adsorption is occurring will be significantly higher than other regions, forming a temperature peak moving from top to bottom. After adsorption begins, the temperature at the upper end of molecular sieve 8 layer starts to rise, and this temperature peak moves downwards along with the adsorption. Therefore, when the temperature in the middle of molecular sieve 8 layer begins to show a significant and sustained upward trend, it proves that adsorption has gradually shifted to the middle of molecular sieve 8 layer. At this point, the time it takes for adsorption to shift downwards from the molecular sieve 8 layer can be predicted by calculating the rate of temperature rise. This avoids over-adsorption in the adsorption tower, leaving a certain margin during each adsorption cycle.

[0089] Throughout the desorption process, relying solely on monitoring the carbon dioxide concentration at the desorption exhaust pipe 15 to determine desorption completion carries risks. In some cases, the molecular sieve 8 layers may develop micro-cracks or channels due to long-term use or airflow impact, or certain areas may form dead zones due to uneven packing density. During desorption, most of the hot purge gas preferentially passes through the channels with the lowest resistance, rapidly regenerating the adsorbent in these channels and quickly reducing the discharged carbon dioxide concentration. However, the molecular sieve 8 in dead zones or areas not fully penetrated by the airflow may still retain a large amount of carbon dioxide. If the system prematurely terminates heating based on the decrease in concentration at the desorption exhaust pipe 15, these unregenerated molecular sieves 8 will become a source of contamination at the start of the next adsorption cycle, causing premature carbon dioxide penetration at the outlet and rendering adsorption ineffective. Furthermore, if the carbon dioxide concentration sensor 11 malfunctions or its reading drifts, it may continuously provide an erroneous low concentration value, leading the system to mistakenly believe that desorption is complete. After multiple cycles, this accumulation will cause the adsorption tower to completely fail, resulting in a production accident. When temperature-assisted judgment is set, even if the carbon dioxide concentration at the outlet decreases, as long as a large number of molecular sieves 8 continue to undergo desorption reactions inside the bed (which is an endothermic process), the temperature of the entire bed, especially the temperature at the top, which is the most difficult to heat, cannot reach and stabilize within the set regeneration temperature range. The temperature curve will get stuck at a certain point and fail to rise. If the carbon dioxide concentration sensor 11 malfunctions, the temperature criterion can serve as an independent safety backup. Only when the bed is uniformly heated to the regeneration temperature and remains stable is the physical energy condition for complete regeneration physically ensured. Through the dual criteria of temperature and concentration, good adaptive adsorption and adaptive desorption effects are achieved.

[0090] By placing the temperature probe 24 into the bed using an intermediate pipe 20 and a connecting pipe 19, the exposed temperature probe 24 is prevented from being directly inserted into the adsorbent particles, thus avoiding wear and failure. This method is simple, effective, and easy to install and remove. Placing two temperature probes 24 at the same height ensures that in most cases, if one probe fails, the other can continue operating. The PLC programming is also relatively simple: the logic is as follows: first, the value of temperature probe 24 numbered 1 in the same layer is used and stabilized. If the value of temperature probe 24 numbered 1 fluctuates beyond a preset range or is lost within a certain time, then the value of temperature probe 24 numbered 2 is activated. These are standard techniques in automation settings and will not be elaborated further here.

[0091] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A carbon dioxide concentration adaptive adsorption and desorption device, comprising two adsorption towers, a gas supply unit, a heating and gas supply assembly, and a controller assembly, characterized in that: The adsorption tower includes a tower body. The top of the tower body is connected to an adsorption inlet pipe, a desorption inlet pipe, and a pressure relief valve. The adsorption inlet pipe is equipped with an adsorption inlet valve, and the desorption inlet pipe is equipped with a desorption inlet valve and an inlet temperature sensor. The adsorption inlet pipe is connected to a gas supply unit, and the desorption inlet pipe is connected to a heating gas supply assembly. A support mesh is fixed inside the tower body, separating the upper and lower parts of the tower. A water-absorbing adsorption carrier layer is laid above the support mesh, followed by a molecular sieve layer, and then an inert, permeable particulate matter layer. At least three sets of temperature measuring components are also fixed to the inner wall of the tower body, located at the upper middle, middle, and lower middle ends of the molecular sieve layer. A gas diversion component is fixedly installed inside the tower body above the inert, permeable particulate matter. The tower body below the support net is connected to an adsorption exhaust pipe and a desorption exhaust pipe. The adsorption exhaust pipe is equipped with an adsorption exhaust valve and a carbon dioxide concentration sensor, and the desorption exhaust pipe is equipped with a desorption exhaust valve and a carbon dioxide concentration sensor. A scavenging branch pipe is also connected to the adsorption exhaust pipe downstream of the adsorption exhaust valve. The scavenging branch pipe is also equipped with a scavenging valve. The scavenging pipe is connected to the heating gas supply component. The gas supply unit, heating gas supply component, adsorption inlet valve, adsorption exhaust valve, desorption inlet valve, desorption exhaust valve, carbon dioxide concentration sensor, inlet temperature sensor, scavenging valve, and temperature measuring component are all electrically connected to the controller component.

2. The carbon dioxide concentration adaptive adsorption and desorption device according to claim 1, characterized in that: The temperature measuring component includes an intermediate tube, with adapters detachably installed inside the openings at both ends of the intermediate tube. Multiple vent holes are provided on the wall of the intermediate tube. Connecting pipes are detachably installed outside the openings at both ends of the intermediate tube. The connecting pipes are sealed and pass through the side wall of the tower body. A connector is detachably installed inside the adapter, and a temperature measuring probe is installed in the connector. The temperature measuring probe is electrically connected to the controller component.

3. The carbon dioxide concentration adaptive adsorption and desorption device according to claim 2, characterized in that: The water-absorbing and adsorbing carrier layer is composed of activated alumina balls, the molecular sieve layer is composed of 13X molecular sieves, and the inert and breathable particulate matter layer is composed of inert alumina balls.

4. The carbon dioxide concentration adaptive adsorption and desorption device according to claim 3, characterized in that: The gas diversion component is a diversion plate, with multiple air holes opened between the upper and lower end faces of the diversion plate, and the edge of the diversion plate is fixedly connected to the side wall of the tower body.

5. The carbon dioxide concentration adaptive adsorption and desorption device according to claim 4, characterized in that: The support mesh includes a stainless steel mesh frame with a stainless steel mesh covering the upper surface of the mesh frame. The mesh opening diameter of the stainless steel mesh is smaller than the diameter of the activated alumina balls. A support part is fixed at the bottom of the mesh frame. The edge of the mesh frame is fixedly connected to the side wall of the tower body, and the bottom of the support part is fixedly connected to the bottom of the tower body.

6. The carbon dioxide concentration adaptive adsorption and desorption device according to claim 5, characterized in that: The air supply unit is an air compressor, and the heating air supply assembly includes a blower and an air heater. The scavenging branch pipe is connected to the air inlet of the blower, the air outlet of the blower is connected to the air inlet of the air heater, and the air outlet of the air heater is connected to the desorption air inlet pipe. The air compressor, blower, and air heater are all electrically connected to the controller assembly.

7. A method using the carbon dioxide concentration adaptive adsorption and desorption device as described in claim 5, characterized in that: Let one adsorption tower be tower A, and the other adsorption tower be tower B. Accordingly, The temperatures measured by the temperature probes located at the upper middle part of the molecular sieve layers in towers A and B are T_top_A and T_top_B, respectively. The temperatures measured by the temperature probes located at the midpoints of the molecular sieve layers in towers A and B are T_mid_A and T_mid_B, respectively. The temperatures measured by the temperature probes located at the lower middle end of the sub-sieve layers in towers A and B are T_bot_A and T_bot_B, respectively. The carbon dioxide concentrations measured by the carbon dioxide concentration sensors located at the adsorption exhaust pipes of tower A and tower B are C_out_A and C_out_B, respectively. The carbon dioxide concentrations measured by the carbon dioxide concentration sensors located at the desorption exhaust pipes of towers A and B are C_desorb_A and C_desorb_B, respectively. The inlet temperature sensors located at the desorption inlet pipes of tower A and tower B measure the temperatures T_in_A and T_in_B, respectively. The execution steps of this method are as follows: S1. Open the adsorption inlet valve and adsorption outlet valve of tower A, and start the air compressor to allow compressed air to pass through tower A from top to bottom. At this time, water vapor and carbon dioxide in the air are captured by the 13X molecular sieve, and clean and dry air flows out from the adsorption outlet pipe. S2. The controller component monitors T_top_A, T_mid_A and T_bot_A in real time. The controller component calculates and analyzes the rise rate of T_mid_A in real time. When either of the following two conditions is triggered, step S3 is executed: Condition 1 is when T_top_A reaches the preset value and T_mid_A reaches the preset value within 5 to 10 minutes, step S3 is executed; Condition 2 is when C_out_A exceeds the preset value, step S3 is executed. S3. The controller component controls the adsorption inlet valve and adsorption exhaust valve of tower B to linearly open to the fully open state within 10 to 120 seconds, and then controls the adsorption inlet valve and adsorption exhaust valve of tower A to linearly close to the fully closed state within 10 to 120 seconds. S4. First, open the desorption exhaust valve of tower A, then open the scavenging valve of tower B and the desorption intake valve of tower A. Then start the blower so that some dry, carbon dioxide-free regenerated gas from the adsorption exhaust pipe of tower B enters tower A from top to bottom. Then start the air heater to heat the regenerated gas to the set temperature. S5. Continuously monitor the values ​​of C_desorb_A and T_top_A. When both reach the preset values ​​at the same time, it is determined that the heating desorption is complete and the air heater is turned off. S6. When T_mid_A-T_in_A≤10℃, cooling is considered complete. The blower, the scavenging valve of tower B, the desorption inlet valve of tower A, and the desorption exhaust valve of tower A are closed in sequence, and tower A enters standby state. S7. The controller component monitors T_top_B, T_mid_B and T_bot_B in real time. The controller component calculates and analyzes the rise rate of T_mid_B in real time. When either of the following two conditions is triggered, step S8 is executed: Condition 1 is when T_top_B reaches the preset value and T_mid_B reaches the preset value within 5 to 10 minutes, step S8 is executed; Condition 2 is when C_out_B exceeds the preset value, step S8 is executed. S8. The controller component controls the adsorption inlet valve and adsorption exhaust valve of tower A to linearly open to the fully open state within 10 to 120 seconds, and then controls the adsorption inlet valve and adsorption exhaust valve of tower B to linearly close to the fully closed state within 10 to 120 seconds. S9. First, open the desorption exhaust valve of tower B, then open the scavenging valve of tower A and the desorption intake valve of tower B, then start the blower so that some dry, carbon dioxide-free regenerated gas from the adsorption exhaust pipe of tower A enters tower B from top to bottom, and then start the air heater to heat the regenerated gas to the set temperature. S10. Continuously monitor the values ​​of C_desorb_B and T_top_B. When both reach the preset values ​​at the same time, it is determined that the heating desorption is complete and the air heater is turned off. S11. When T_mid_B-T_in_B≤10℃, cooling is determined to be complete. The blower, the scavenging valve of tower A, the desorption inlet valve of tower B, and the desorption exhaust valve of tower B are closed in sequence, and tower B enters standby state. S12. Repeat steps S2 to S11.

8. A method for using the carbon dioxide concentration adaptive adsorption and desorption device as described in claim 5 according to claim 7, characterized in that: In step S2, the method for calculating the rise rate of T_mid_A is as follows: the controller component reads the value of T_mid_A at a fixed period. The current value of T_mid_A is set into a variable value T_current_A stored in the storage area. The T_current_A recorded in the previous period is stored in T_previous_A in the storage area. A preset calculation program is used, which is calculated as (T_current_A - T_previous_A) / scan period time. The calculation program is executed once in each reading period to obtain the real-time rise rate. In step S7, the method for calculating the rise rate of T_mid_B is as follows: the controller component reads the value of T_mid_B at a fixed period. The current value of T_mid_B is set into a variable value T_current_B stored in the storage area. The T_current_B recorded in the previous period is stored in T_previous_B in the storage area. A preset calculation program is used, which is calculated as (T_current_B - T_previous_B) / scan period time. The calculation program is executed once in each reading period to obtain the real-time rise rate.

9. A method for using the carbon dioxide concentration adaptive adsorption and desorption device as described in claim 5 according to claim 8, characterized in that: Condition 2 is to execute step S3 when C_out_A exceeds 10~15ppm. In step S7, condition 2 is to execute step S8 when C_out_B exceeds 10~15ppm.

10. A method for using the carbon dioxide concentration adaptive adsorption and desorption device as described in claim 5 according to claim 9, characterized in that: In step S4, the regeneration gas is heated to a set temperature of 175~185℃. In step S5, when C_desorb_A is less than 400ppm and lasts for more than 60 seconds, and T_top_A is at 175~185℃ and lasts for more than 300 seconds, the heating desorption is determined to be complete, and the air heater is turned off. In step S9, the regeneration gas is heated to a set temperature of 175~185℃. In step S10, when C_desorb_B is less than 400ppm and lasts for more than 60 seconds, and T_top_B is at 175~185℃ and lasts for more than 300 seconds, the heating desorption is determined to be complete, and the air heater is turned off.

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