Heat pump-driven regenerative direct air capture system

Abstract

A heat pump-driven regenerative direct air capture (DAC) system, comprising: a heat pump subsystem mainly formed by a heat pump condenser (21) and a heat pump evaporator (20) and a DAC subsystem mainly formed by a first adsorption bed (5), a second adsorption bed (6), and a first condenser (16) used for condensing produced gas. The heat pump condenser (21) is separately connected to heat exchange channels of the first adsorption bed (5) and the second adsorption bed (6) by means of a liquid inlet pipeline provided with a ninth switching valve (30) and a liquid return pipeline provided with a tenth switching valve (31) to form an internal heat source circulation pipeline. The heat pump evaporator (20) is connected to a medium pipeline of the first condenser (16) by means of a pipeline to form a condensation circulation pipeline.

Description

A heat pump driven regenerative direct air carbon capture system Technical Field

[0001] The present invention relates to the technical field of direct air carbon capture, and in particular to a heat pump driven heat recovery type direct air carbon capture system. Background Art

[0002] With economic development and industrial progress, the use of fossil fuels has increased, and CO2 concentrations in the air have subsequently risen sharply, severely impacting the ecological environment and human health. In recent years, a negative emissions technology—direct air capture (DAC)—has become a research hotspot. Due to its ability to capture CO2 directly from the atmosphere, its unrestricted use of time and space, its flexible deployment, and its low land and water resource utilization, DAC is considered an essential solution for maintaining a suitable atmospheric environment, protecting human health, and contributing to my country's low-carbon research and industry development.

[0003] The main challenge with current DAC technology is its high capture energy consumption. For one thing, DAC desorption energy consumption is typically 6-8 GJ / t or even higher, far exceeding the 2-4 GJ / t energy consumption of flue gas capture. Furthermore, competitive adsorption exists between H2O and CO2 in the air. In practical applications, CO2 storage or industrial utilization often require high concentrations of the CO2 product gas. This means that the condensation energy required to separate and purify the CO2 from the H2O-CO2 mixed gas is high. Therefore, developing a high-efficiency, low-energy DAC system for high-concentration gas production is crucial.

[0004] A heat pump is a technology that efficiently converts low-grade thermal energy into high-grade heat. Coupling the cooling and heating capacity of the heat pump system's hot and cold ends to the regeneration and condensation energy consumption of the aforementioned DAC system is expected to provide a promising solution for developing low-energy DAC systems. Patent document CN115077130B discloses a dual-source heat pump air-to-carbon capture system. The evaporator of a high-temperature heating heat pump subsystem is used to recover low-grade waste heat and is connected in parallel with the adsorption bed in the continuous direct CO2 capture subsystem, forming a dual heat source supply for the system. Two refrigerant fluids are fed into the jet pump in the high-temperature heating heat pump subsystem. The refrigerant fluid exiting the jet pump enters the desorption bed in the continuous direct CO2 capture subsystem, providing the heat required for desorption. This system uses the low-grade waste heat from the heat pump evaporator and the adsorption heat from the DAC adsorption bed to generate a high-grade heat source for the DAC regeneration process, effectively improving the performance of the heat pump system and reducing the DAC's regeneration energy consumption. However, the current technology has the following problems: 1) The large condensation energy consumption in the DAC subsystem is not taken into account; 2) Although the performance of the heat pump subsystem has been greatly improved, its coupling with the DAC subsystem is limited to the hot end of the heat pump, and the in-depth coupling between the cold end of the heat pump and the DAC system is not fully considered; due to the large condensation energy consumption in the DAC, the overall efficiency of the heat pump-DAC system is low; 3) The thermodynamic cycle optimization of the heat pump-DAC system is not fully considered, such as the utilization of sensible heat waste heat of the desorption bed in the DAC subsystem, the latent heat recovery of the adsorption bed treated gas outlet, and the use of natural cooling sources, which are very important and necessary for the deep energy integration of the DAC system, the reduction of capture energy consumption, and the improvement of the overall system performance.

[0005] Summary of the Invention

[0006] In response to the above-mentioned problems in the prior art, the present invention provides a heat pump-driven heat recovery type direct air carbon capture system. The system fully utilizes the cooling and heat of the hot and cold ends of the heat pump, and applies them to the condensation of H2O in the produced gas and the internal heat desorption process of the desorption bed, respectively, thereby improving the thermodynamic utilization efficiency of the heat pump subsystem and effectively reducing the comprehensive energy consumption of the capture and separation purification of the DAC subsystem. On this basis, when the latent heat cooling capacity of the adsorption bed treatment gas outlet or the cooling capacity of the cooling tower is used to provide an internal cooling source for the DAC subsystem, the system also introduces a passive heat recovery and series heat recovery scheme between the adsorption bed and the desorption bed, which is conducive to extending the effective adsorption / desorption time and reducing the desorption energy input, greatly improving the comprehensive energy utilization efficiency and overall benefits of the system.

[0007] A heat pump driven regenerative direct air carbon capture system, comprising: a heat pump subsystem mainly composed of a heat pump condenser and a heat pump evaporator; and a DAC subsystem mainly composed of a first adsorption bed, a second adsorption bed, and a first condenser for condensing product gas;

[0008] The heat pump condenser is connected to the heat exchange channels of the first adsorption bed and the second adsorption bed respectively through the liquid inlet pipeline with the ninth switching valve and the liquid return pipeline with the tenth switching valve to form an internal heat source circulation pipeline;

[0009] The heat pump evaporator is connected to the medium pipeline of the first condenser through a pipeline to form a condensation circulation pipeline.

[0010] The heat exchange channel can be a heating coil disposed on the first adsorption bed and the second adsorption bed. The present invention provides desorption heat or an internal cooling source for adsorption to the first adsorption bed and the second adsorption bed through the heat exchange channel; and provides condensation cooling to the produced gas through the condensation circulation pipeline.

[0011] In one embodiment, the internal heat source circulation circuit further includes a hot water tank and a hot water pump, which are disposed on the liquid inlet line between the outlet of the heat pump condenser and the ninth switching valve. The hot water tank is used for steady-state hot water control, and the hot water pump is used to provide circulation power. Hot water generated by the heat pump condenser sequentially passes through the hot water tank, the hot water pump, and the liquid inlet line into the desorbing adsorption bed. After releasing heat, it circulates back through the return line to the heat pump condenser for further heating.

[0012] In one embodiment, the condensing circulation system further includes a cold water tank and a cold water pump, which are located in the pipeline between the outlet of the heat pump evaporator and the inlet of the medium pipeline of the first condenser. The cold water tank and cold water pump function similarly to the hot water tank and hot water pump. The cold water medium generated by the heat pump evaporator passes through the cold water tank, the cold water pump, and the liquid inlet pipeline, ultimately entering the medium pipeline of the first condenser. After absorbing heat, it circulates back through the liquid return pipeline to the heat pump evaporator for cooling.

[0013] Preferably, the ninth and tenth switching valves are three-way switching valves. When the first adsorption bed / the second adsorption bed is in a desorption state, the passages corresponding to the ninth and tenth switching valves are open, respectively connecting the heat pump condenser to the first adsorption bed / the second adsorption bed in the desorption state, thereby providing heat required for desorption.

[0014] During actual connection, the air inlets of the first and second adsorption beds are connected to the first air inlet pipe via pipes equipped with switching valves to allow air intake. The air outlets of the first and second adsorption beds are connected to the treated gas outlet pipe, vacuum exhaust outlet pipe, and gas production pipeline, respectively, via branches equipped with switching valves. These outlets output post-adsorption treated gas, pre-desorption vacuum, and produced gas, respectively. The gas production pipeline outlet is connected to the condensation pipeline of the first condenser. After condensation, the gas is compressed by the first compressor and ultimately enters the CO2 storage cylinder for collection.

[0015] As an embodiment, it further includes a cooling tower; the cooling tower is connected to the heat exchange channels of the first adsorption bed and the second adsorption bed through a liquid inlet pipeline with an eleventh switching valve and a liquid return pipeline with a twelfth switching valve, respectively, to form an internal cold source circulation pipeline.

[0016] In one embodiment, the internal cooling source circulation pipeline further includes a cooling water tank and a cooling water pump, which are disposed on the internal cooling source circulation pipeline between the cooling water outlet of the cooling tower and the eleventh switching valve. With this solution, the heat exchange channel provides an adsorption internal cooling source to the adsorption bed in the adsorption state, while the heat pump condenser provides desorption heat to the adsorption bed in the desorption state.

[0017] Preferably, the eleventh and twelfth switching valves are three-way switching valves. When an adsorption bed enters the adsorption state, the heat supply circulation loop is closed, the internal cooling source circulation pipeline is opened, and cooling water enters the corresponding adsorption bed from the cooling tower and the liquid inlet pipeline. After cooling and heat exchange, it is returned to the cooling tower through the liquid return pipeline. For adsorption beds that need to enter the desorption state, the internal cooling source circulation pipeline is closed, and the internal heat source circulation pipeline is activated to provide desorption heat.

[0018] As an optional solution, a fourteenth switching valve is provided on the internal heat source circulation pipeline between the heat pump condenser outlet and the ninth switching valve; a fifteenth switching valve is provided on the internal heat source circulation pipeline between the heat pump condenser reflux port and the tenth switching valve; the fourteenth switching valve and the fifteenth switching valve are three-way switching valves, wherein the third port of the fourteenth switching valve is connected to the internal heat source circulation pipeline between the heat pump condenser reflux port and the fifteenth switching valve, and the third port of the fifteenth switching valve is connected to the internal heat source circulation pipeline between the fourteenth switching valve and the ninth switching valve.

[0019] Furthermore, the fourteenth switching valve is arranged on the internal heat source circulation pipeline between the hot water pump and the ninth switching valve.

[0020] With this technical solution, after the first and second adsorption beds complete desorption / adsorption, the adsorption bed corresponding to the desorption operation is at a high temperature, while the adsorption bed corresponding to the adsorption operation is at a low temperature. This technical solution enables a cascade heat recovery process to improve the system's energy efficiency and overall profitability.

[0021] Specifically, during the series heat recovery process, the ninth switching valve, the tenth switching valve, the eleventh switching valve, the twelfth switching valve, the fourteenth switching valve, and the fifteenth switching valve open and close the corresponding valves. The cooling water flowing out of the cooling tower flows through the adsorption bed that has completed the desorption operation and the adsorption bed that has completed the adsorption operation in sequence, and finally returns to the cooling tower to complete the cycle. The specific process is as follows: at this time, driven by the cooling water pump, the cooling water flows out from the cooling water outlet end of the cooling tower, passes through the cooling water tank and the cooling water pump in sequence, and enters the adsorption bed that has completed the desorption operation to take away the residual heat during the desorption process; the heated cooling water flows out from the adsorption bed that has completed the desorption operation, passes through the tenth switching valve, the fifteenth switching valve, and the ninth switching valve in sequence, and enters the adsorption bed that has completed the adsorption operation to preheat the adsorption bed that has completed the adsorption operation; finally, the cooling water flowing out of the adsorption bed that has completed the adsorption operation flows back to the cooling tower through the twelfth switching valve, completing the series heat recovery process.

[0022] During the series heat recovery process, the end of the fourteenth switching valve connected to the ninth switching valve is closed, bypassing the hot water produced in the heat pump condenser and no longer serving as an internal heat source for the adsorption bed. Driven by the hot water pump, the hot water produced by the heat pump condenser flows out of the heat pump hot water outflow pipe, passes through the hot water tank, the hot water pump, and the fourteenth switching valve, and finally returns to the heat pump condenser through the heat pump hot water inflow pipe.

[0023] As one embodiment, a cooling tower is further included. The DAC subsystem is further provided with a second condenser connected in series with the first condenser for preliminary condensation of the produced gas. The cooling tower is connected to the medium pipeline of the second condenser via a pipeline to form a preliminary condensation circulation pipeline. The inlet of the condensation pipeline of the second condenser is connected to the gas production pipeline of the DAC subsystem, and the outlet is connected to the condensation pipeline of the first condenser. The preliminary condensation circulation pipeline can achieve preliminary condensation of the produced gas, and the first condenser can achieve further condensation of the produced gas.

[0024] As an embodiment, the preliminary condensation circulation pipeline further includes a cooling water tank and a cooling water pump, and the cooling water tank and the cooling water pump are arranged on the internal cold source circulation pipeline between the cooling water outlet of the cooling tower and the second condenser medium pipeline.

[0025] As an embodiment, it also includes an evaporative cooler; the evaporative cooler is connected to the first adsorption bed and the second adsorption bed heat exchange channels through a liquid inlet pipeline with an eleventh switching valve and a liquid return pipeline with a twelfth switching valve to form an internal cold source circulation pipeline.

[0026] As an embodiment, the internal cold source circulation pipeline also includes an evaporative cooling water tank and an evaporative cooling water pump, and the evaporative cooling water tank and evaporative cooling water pump are arranged on the internal cold source circulation pipeline between the outlet end of the evaporative cooling tower and the eleventh switching valve.

[0027] As an implementation, the DAC subsystem's treated air outlet pipe is combined with a second air inlet pipe equipped with a switching valve. The air then enters the evaporative cooler through the mixed air inlet pipe, absorbing heat from the evaporative cooling water and cooling it. The air then exits the system through the exhaust pipe. This technical solution recovers the latent heat of the treated air and provides an internal cooling source for the adsorption bed, allowing the cold water to promptly remove heat generated during the adsorption process, eliminating adverse effects of the adsorption reaction and promoting CO2 capture.

[0028] By adopting the above technical solution, after the first adsorption bed and the second adsorption bed complete desorption / adsorption, the adsorption bed that has completed the desorption state remains in a high-temperature state and has a portion of high-grade heat. In order to fully utilize this portion of heat and improve the energy utilization efficiency of the system, this embodiment adds a passive heat recovery process. The passive heat recovery process includes: the evaporative cooling water flowing out of the evaporative cooler flows through the evaporative cooling water tank and the evaporative cooling water pump in sequence, and enters the adsorption bed that has completed the desorption process through the corresponding switching valve, forcing the hot water inside the adsorption bed to flow into the heat pump condenser through the corresponding switching valve and the heat pump hot water inlet pipe; the hot water flows through the heat pump hot water outflow pipe, the hot water tank, the hot water pump and the corresponding switching valve in sequence into the adsorption bed that has completed the adsorption operation; the evaporative cooling water originally in the coil inside the adsorption bed is driven by the evaporative cooling water pump and flows back to the evaporative cooler through the corresponding switching valve, completing the passive heat recovery process.

[0029] After the passive reheating process is complete, the adsorption beds switch operating modes, with desorption and adsorption cycles alternating between the first and second beds, enabling the DAC unit to achieve continuous adsorption or gas production. The passive reheating process fully utilizes the residual waste heat from the desorption bed after desorption to preheat the adsorption bed that completes the adsorption process, thereby improving the system's overall energy efficiency.

[0030] As an option, the DAC subsystem is a direct air carbon capture subsystem adopting a temperature swing vacuum adsorption operation mode.

[0031] As a specific option, the DAC subsystem mainly includes:

[0032] A first adsorption bed and a second adsorption bed having heat exchange channels and alternately performing adsorption and desorption operations;

[0033] Air inlet pipes connected to the air inlets of the first adsorption bed and the second adsorption bed respectively, and the two air inlet pipes are connected to the fan through a switching valve;

[0034] The treated gas outlet pipe, vacuum exhaust outlet pipe and produced gas exhaust pipe are respectively connected to the air outlet of the first adsorption bed and the second adsorption bed, and one or more switching valves are provided on the treated gas outlet pipe, vacuum exhaust outlet pipe and produced gas exhaust pipe; the vacuum exhaust outlet pipe is connected to the vacuum pump, and the other end of the produced gas exhaust pipe is connected to the condensation pipeline of the first condenser.

[0035] As another embodiment, the coupling matching of cold and heat between the heat pump subsystem and the DAC subsystem can adopt a direct heat exchange method; specifically, the heat pump subsystem also includes a second compressor and an expansion valve; the outlet of the second compressor is connected to the heat exchange channels of the first adsorption bed and the second adsorption bed respectively through a liquid inlet pipeline with a ninth switching valve; the inlet of the second compressor is connected to the outlet end of the medium pipeline of the first condenser through a pipeline; the inlet end of the medium pipeline of the first condenser is connected to one end of the expansion valve, and the other end of the expansion valve is connected to the heat exchange channels of the first adsorption bed and the second adsorption bed respectively through a return liquid pipeline with a tenth switching valve.

[0036] This technical solution directly replaces the evaporator and condenser in the heat pump subsystem with the first condenser and desorption bed in the DAC subsystem, uses the second compressor to generate high-temperature and high-pressure refrigerant, and uses the condensation and heat release process of the refrigerant to heat the desorption bed to promote desorption. The low-temperature and low-pressure refrigerant generated by the expansion valve provides a cold source for the first condenser, creating a low-temperature environment for the condensation of water vapor; at the same time, the direct heat exchange with the refrigerant avoids the energy loss caused by the heat exchange between the refrigerant and other media, which can effectively reduce the condensation temperature of the heat pump subsystem and increase its evaporation temperature, thereby greatly improving the efficiency of the heat pump subsystem and the overall performance of the device.

[0037] Compared with the existing DAC system or heat pump-DAC system, the present invention has the following advantages:

[0038] 1) Based on the TVSA (Temperature Vacuum Swing Adsorption) DAC subsystem, the present invention deeply couples the DAC subsystem with the hot and cold ends of the heat pump. This utilizes the cooling capacity of the heat pump subsystem for the condensation of H2O in the DAC gas, while the high-quality heat of the heat pump subsystem is used for the internal heat desorption process of the desorption bed. This achieves efficient energy supply, effectively improves the thermodynamic utilization efficiency of the heat pump subsystem, and reduces the desorption, condensation, and total energy consumption of the DAC subsystem, significantly improving the overall energy utilization efficiency of the system.

[0039] 2) The present invention utilizes the latent heat of the processed gas at the outlet of the adsorption bed to generate evaporative cooling water using an evaporative cooler or uses a cooling tower to generate a natural cooling source for the internal cooling adsorption process of the adsorption bed in the DAC subsystem. This helps to reduce the adverse effects of adsorption heat on the adsorption process, effectively improves the adsorption rate and equilibrium adsorption capacity of the adsorbent, and thus improves the capture efficiency and capture capacity of the DAC subsystem.

[0040] 3) Based on the scheme of internal cooling adsorption and internal heating desorption in the DAC subsystem, the present invention also introduces passive heat recovery and series heat recovery technology, which helps to reduce the desorption energy consumption required by the DAC subsystem, significantly reducing the overall operating energy consumption of the heat pump-DAC system and improving the comprehensive energy utilization efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] FIG1 is a schematic structural diagram of a heat pump driven regenerative direct air carbon capture system in Example 1;

[0042] FIG2 is a schematic structural diagram of a heat pump driven regenerative direct air carbon capture system in Example 2;

[0043] FIG3 is a schematic structural diagram of a heat pump driven regenerative direct air carbon capture system in Example 3;

[0044] FIG4 is a schematic structural diagram of a heat pump driven regenerative direct air carbon capture system in Example 4;

[0045] In the picture:

[0046] 1. Fan 17, first compressor 33, cooling tower

[0047] 2. First air inlet pipe 18, CO2 storage cylinder 34, cooling water tank

[0048] 3. First switching valve 19, heat pump 35, cooling water pump

[0049] 4. Second switching valve 20, heat pump evaporator 36, eleventh switching valve

[0050] 5. First adsorption bed 21, heat pump condenser 37, twelfth switching valve

[0051] 6. Second adsorption bed 22, heat pump cold water inlet pipe 38, second air inlet pipe

[0052] 7. Third switching valve 23, heat pump cold water outflow pipe 39, thirteenth switching valve

[0053] 8. Fourth switching valve 24, cold water tank 40, mixed air inlet pipe

[0054] 9. Fifth switching valve 25, cold water pump 41, evaporative cooler

[0055] 10. Sixth switching valve 26, heat pump hot water inlet pipe 42, exhaust gas outlet pipe

[0056] 11. Processed gas outlet pipe 27, heat pump hot water outlet pipe 43, evaporative cooling water tank

[0057] 12. Seventh switching valve 28, hot water tank 44, evaporative cooling water pump

[0058] 13. Vacuum pump 29, hot water pump 45, fourteenth switching valve

[0059] 14. Vacuum exhaust outlet pipe 30, ninth switching valve 46, fifteenth switching valve

[0060] 15. Eighth switching valve 31, tenth switching valve 47, expansion valve

[0061] 16. First condenser 32, second condenser 48, second compressor DETAILED DESCRIPTION

[0062] The following describes various embodiments with reference to the accompanying drawings.

[0063] Example 1: Cooling tower cooling water is used as the initial condensation cold source, heat pump evaporator cold water is used as the deep condensation cold source to provide cold capacity for H2O condensation, and heat pump condenser hot water is used as the internal heat source to promote desorption.

[0064] Connection method:

[0065] Referring to Figure 1, in this device, the air inlet of the first adsorption bed 5 is connected to the first air inlet pipe 2 through the first switching valve 3, and the air outlet is connected to the treated gas outlet pipe 11 through the fifth switching valve 9; the air inlet of the second adsorption bed 6 is connected to the first air inlet pipe 2 through the second switching valve 4, and the air outlet is also connected to the treated gas outlet pipe 11 through the sixth switching valve 10; the fan 1 is installed at the inlet of the first air inlet pipe 2 to drive the air flow.

[0066] One end of the third switching valve 7 is connected to the pipeline between the fifth switching valve 9 and the first adsorption bed 5, and the other end is connected to the fourth switching valve 8 through a pipeline; the other end of the fourth switching valve 8 is connected to the pipeline between the sixth switching valve 10 and the second adsorption bed 6; one end of the seventh switching valve 12 is connected to the pipeline between the third switching valve 7 and the fourth switching valve 8, and the other end is connected to the vacuum exhaust outlet pipe 14 provided with a vacuum pump 13.

[0067] One end of the eighth switching valve 15 is connected to the pipeline between the third switching valve 7 and the fourth switching valve 8 through a pipeline, and the other end is connected to the inlet end of the condensation pipeline in the second condenser 32; the outlet end of the condensation pipeline in the second condenser 32 is connected to the inlet end of the condensation pipeline of the first condenser 16; the outlet end of the condensation pipeline of the first condenser 16 is connected to one end of the first compressor 17, and the other end of the first compressor 17 is connected to the CO2 storage cylinder 18.

[0068] The heat pump cold water outflow pipe 23 on the heat pump evaporator 20 is connected to the water inlet of the cold water tank 24, and the water outlet of the cold water tank 24 is connected to the cold water pump 25; the other end of the cold water pump 25 is connected to the medium pipeline inlet end of the first condenser 16; the medium pipeline outlet end of the first condenser 16 is connected to the heat pump evaporator 20 through the heat pump cold water inlet pipe 22.

[0069] The heat pump hot water outflow pipe 27 on the heat pump condenser 21 is connected to the water inlet of the hot water tank 28, and the water outlet of the hot water tank 28 is connected to the hot water pump 29; the other end of the hot water pump 29 is connected to one end of the ninth switching valve 30; the second end and the third end of the ninth switching valve 30 are respectively connected to the medium inlets of the first adsorption bed 5 and the second adsorption bed 6; the second end and the third end of the tenth switching valve 31 are connected to the medium outlets of the first adsorption bed 5 and the second adsorption bed 6, and the first end is connected to the heat pump condenser 21 through the heat pump hot water inflow pipe 26.

[0070] The cooling water outlet end of the cooling tower 33 is connected to the water inlet of the cooling water tank 34, and the water outlet of the cooling water tank 34 is connected to the cooling water pump 35; the other end of the cooling water pump 35 is connected to the medium pipeline inlet end of the second condenser 32; the medium pipeline outlet end of the second condenser 32 is connected back to the cooling tower 33 from the cooling water inlet end of the cooling tower 33.

[0071] Workflow: Take the second adsorption bed 6 in the adsorption state and the first adsorption bed 5 in the desorption state as an example:

[0072] Before adsorption begins, it is necessary to open the second switching valve 4 and the sixth switching valve 10 and close the first switching valve 3; driven by the fan 1, air enters the second adsorption bed 6 through the air inlet pipe 2 and the second switching valve 4; the second adsorption bed 6 is provided with a solid adsorbent that can adsorb CO2 and H2O in the air. The low CO2 concentration and low moisture content air generated after adsorption passes through the sixth switching valve 10 and flows out of the system from the treated gas outlet pipe 11.

[0073] Before desorption begins, it is necessary to open the third switching valve 7 and the seventh switching valve 12, close the fourth switching valve 8 and the eighth switching valve 15, and start the vacuum pump 13. Driven by the vacuum pump 13, the air in the first adsorption bed 5 flows sequentially through the third switching valve 7, the seventh switching valve 12, and the vacuum pump 13, and finally exits the system through the vacuum exhaust outlet pipe 14. The seventh switching valve 12 and the vacuum pump 13 are then closed, allowing the desorbed CO2-H2O mixed gas to pass through the third switching valve 7, the eighth switching valve 15, the second condenser 32, and the first condenser 16. The H2O is condensed in the second condenser 32 and the first condenser 16, and the remaining high-concentration CO2 gas is pressurized in the first compressor 17 and then enters the CO2 storage cylinder 18.

[0074] During the desorption process, hot water circulates between the heat pump condenser 21 and the first adsorption bed 5; the hot water flowing out of the heat pump condenser 21 enters the first adsorption bed 5 through the heat pump hot water outflow pipe 27, the hot water tank 28, the hot water pump 29, and the ninth switching valve 30, and serves as an internal heat source to provide desorption heat for the first adsorption bed 5, thereby promoting CO2 regeneration; then the hot water flows back to the heat pump condenser 21 from the heat pump hot water inflow pipe 26 through the tenth switching valve 31.

[0075] Driven by the cold water pump 25, cold water circulates between the heat pump evaporator 20 and the first condenser 16; the cold water flowing out of the heat pump evaporator 20 enters the first condenser 16 through the heat pump cold water outflow pipe 23, the cold water tank 24, and the cold water pump 25, and serves as a deep condensation cold source to promote the full condensation of H2O in the produced gas; then the cold water flows back to the heat pump evaporator 20 through the heat pump cold water inflow pipe 22.

[0076] Driven by the cooling water pump 35, the cooling water circulates between the cooling tower 33 and the second condenser 32. The cooling water flowing out of the cooling tower 33 enters the second condenser 32 through the cooling water tank 34 and the cooling water pump 35, and serves as a preliminary condensation cold source to promote the preliminary condensation of H2O in the produced gas, and then flows back to the cooling tower 33.

[0077] During actual operation, the second adsorption bed 6 and the first adsorption bed 5 perform desorption and adsorption operations respectively, and each adsorption bed performs adsorption and desorption alternately.

[0078] Advantages:

[0079] This embodiment utilizes the heat from the condensing side of the heat pump to accelerate the desorption process of CO2 and H2O in the DAC, and uses the cooling capacity from the evaporating side of the heat pump for deep condensation of the produced gas, effectively improving the energy utilization efficiency of the system and significantly increasing the concentration of the CO2 product gas. At the same time, this embodiment utilizes the natural cooling source of the cooling tower to initially condense some water vapor, thereby reducing the system's condensation energy consumption and promoting the condensation and separation of H2O in the produced gas.

[0080] To further illustrate the advantages of this embodiment, thermodynamic analysis and calculation show that under the condition of an auxiliary electrically driven secondary condenser (cooling the stored gas temperature to 18°C), the total energy consumption for capture and condensation of the traditional DAC system is approximately 2.41 kWh / kgCO2. In comparison, the CO2 capture concentration of this embodiment can be as high as 98%, and the total energy consumption for capture and condensation is approximately 1.55 kWh / kgCO2, which is significantly better than the traditional DAC system.

[0081] Example 2: Evaporative cooling water is used as an internal cold source to promote adsorption, cooling tower cooling water is used as a preliminary condensation cold source, heat pump evaporator cold water is used as a deep condensation cold source to provide cooling capacity, and heat pump condenser hot water is used as an internal heat source to promote desorption, using a passive heat recovery solution.

[0082] Connection method:

[0083] Referring to Figure 2, in Example 2, the connection methods of the system's vacuum pipeline, gas production pipeline, preliminary condensation cold source pipeline, and deep condensation cold source pipeline are exactly the same as in Example 1 and will not be repeated here. Compared with Example 1, the difference of Example 2 is mainly reflected in the connection methods of the processed gas pipeline, internal heat source pipeline, and internal cold source pipeline. Compared with Example 1, Example 2 is additionally provided with an eleventh switching valve 36, a twelfth switching valve 37, a second air inlet pipe 38, a thirteenth switching valve 39, a mixed air inlet pipe 40, an evaporative cooler 41, an exhaust gas exhaust pipe 42, an evaporative cooling water tank 43, and an evaporative cooling water pump 44. The numbering of the components omitted in Figure 2 is the same as the corresponding component numbering in Figure 1. In the following description, for the components omitted in Figure 2, when the number appears, refer to the component corresponding to the number in Figure 1.

[0084] In the treated gas pipeline, the fan 1 is installed at the inlet of the first air inlet pipe 2 to drive the air flow; the air inlet of the first adsorption bed 5 is connected to the first air inlet pipe 2 through the first switching valve 3, and the air outlet is connected to the treated gas outlet pipe 11 through the fifth switching valve 9; the air inlet of the second adsorption bed 6 is connected to the first air inlet pipe 2 through the second switching valve 4, and the air outlet is connected to the treated gas outlet pipe 11 through the sixth switching valve 10; the treated gas outlet pipe 11 is connected to the evaporative cooler 41 through the mixed air inlet pipe 40; the second air inlet pipe 38 is connected to the pipeline between the treated gas outlet pipe 11 and the mixed air inlet pipe 40 through the thirteenth switching valve 39; the exhaust gas exhaust pipe 42 is connected to the evaporative cooler 41.

[0085] In the internal heat source pipeline, the heat pump hot water outflow pipe 27 of the heat pump condenser 21 is connected to the water inlet of the hot water tank 28, and the water outlet of the hot water tank 28 is connected to the hot water pump 29; the other end of the hot water pump 29 is connected to one end of the ninth switching valve 30; the second end of the ninth switching valve 30 is connected to the first adsorption bed 5, and the third end is connected to the pipeline between the second adsorption bed 6 and the eleventh switching valve 36; the first end of the tenth switching valve 31 is connected to the heat pump condenser 21 through the heat pump hot water inflow pipe 26, the second end is connected to the first adsorption bed 5, and the third end is connected to the pipeline between the second adsorption bed 6 and the twelfth switching valve 37.

[0086] In the internal cold source pipeline, the water outlet of the evaporative cooler 41 is connected to the water inlet of the evaporative cooling water tank 43, and the water outlet of the evaporative cooling water tank 43 is connected to the evaporative cooling water pump 44; the other end of the evaporative cooling water pump 44 is connected to one end of the eleventh switching valve 36; the second end of the eleventh switching valve 36 is connected to the pipeline between the first adsorption bed 5 and the ninth switching valve 30, and the third end is connected to the second adsorption bed 6; the second end of the twelfth switching valve 37 is connected to the pipeline between the first adsorption bed 5 and the tenth switching valve 31, the third end is connected to the second adsorption bed 6, and the first end is connected back to the water inlet of the evaporative cooler 41.

[0087] Workflow: Take the second adsorption bed 6 in the adsorption state and the first adsorption bed 5 in the desorption state as an example:

[0088] In Example 2, the work processes of the system's vacuum pipeline, gas production pipeline, preliminary condensation cold source pipeline, and deep condensation cold source pipeline are exactly the same as those in Example 1, so they are not repeated here; compared with Example 1, the differences in Example 2 are mainly reflected in the work processes of the gas processing pipeline, internal heat source pipeline, internal cold source pipeline, and the passive heat recovery process.

[0089] In the treated gas pipeline, when the second adsorption bed 6 is in the adsorption state, it is necessary to first close the first switching valve 3 and the fourth switching valve 8, and open the second switching valve 4 and the sixth switching valve 10; driven by the fan 1, the air passes through the first air inlet pipe 2 and the second switching valve 4 in turn into the second adsorption bed 6; the second adsorption bed 6 is provided with a solid adsorbent, which can fully adsorb CO2 and H2O in the air; after the adsorption is completed, the treated gas with low CO2 concentration and low moisture content will be discharged from the sixth switching valve 10, flow along the treated gas outlet pipe 11, and be mixed with the air flowing in through the second air inlet pipe 38 and the thirteenth switching valve 39 in a certain proportion; the mixed air enters the evaporative cooler 41 through the mixed air inlet pipe 40, absorbs the heat of the evaporative cooling water to cool it, and then is discharged from the system through the exhaust gas exhaust pipe 42.

[0090] In the internal heat source pipeline, hot water circulates between the heat pump condenser 21 and the first adsorption bed 5 under the drive of the hot water pump 29; at this time, the end of the ninth switching valve 30 connected to the pipeline between the eleventh switching valve 36 and the second adsorption bed 6 is closed, and the end of the tenth switching valve 31 connected to the pipeline between the twelfth switching valve 37 and the second adsorption bed 6 is closed; the heat pump condenser 21 transfers the released condensation heat to the hot water circuit to generate hot water, and discharges it from the heat pump hot water outflow pipe 27; the produced hot water flows through the hot water tank 28, the hot water pump 29 and the ninth switching valve 30 in turn, and finally flows into the first adsorption bed 5 to serve as the heat source of the DAC desorption bed, promoting the regeneration of H2O and CO2; the hot water flowing out of the first adsorption bed 5 passes through the tenth switching valve 31 and flows back to the heat pump condenser 21 from the heat pump hot water inflow pipe 26.

[0091] In the internal cold source pipeline, the evaporative cooling water circulates between the evaporative cooler 41 and the second adsorption bed 6 under the drive of the evaporative cooling water pump 44; at this time, the eleventh switching valve 36 is connected to the end of the pipeline between the ninth switching valve 30 and the first adsorption bed 5 is closed, and the twelfth switching valve 37 is connected to the end of the pipeline between the tenth switching valve 31 and the first adsorption bed 5 is closed; the evaporative cooling water flowing out of the evaporative cooler 41 passes through the evaporative cooling water tank 43, the evaporative cooling water pump 44 and the eleventh switching valve 36 in sequence and flows into the second adsorption bed 6, taking away the adsorption heat generated during the adsorption process, thereby avoiding the adverse effects of high temperature on the adsorption process; the evaporative cooling water flowing out of the second adsorption bed 6 passes through the twelfth switching valve 37 and finally flows back to the evaporative cooler 41 from the water inlet of the evaporative cooler 41.

[0092] After the first adsorption bed 5 completes desorption and the second adsorption bed 6 completes adsorption, the first adsorption bed 5 still remains in a high-temperature state and has a portion of high-grade heat. In order to make full use of this portion of heat and improve the energy utilization efficiency of the system, this embodiment adds a passive heat recovery process. The passive heat recovery process requires closing the end of the ninth switching valve 30 connected to the first adsorption bed 5, closing the end of the tenth switching valve 31 connected to the pipeline between the second adsorption bed 6 and the twelfth switching valve 37, closing the end of the eleventh switching valve 36 connected to the second adsorption bed 6, and closing the end of the twelfth switching valve 37 connected to the pipeline between the first adsorption bed 5 and the tenth switching valve 31. end; the evaporative cooling water flowing out of the evaporative cooler 41 flows through the evaporative cooling water tank 43 and the evaporative cooling water pump 44 in sequence, and enters the first adsorption bed 5 through the eleventh switching valve 36, forcing the hot water inside the coil of the first adsorption bed 5 to flow into the heat pump condenser 21 through the tenth switching valve 31 and the heat pump hot water inlet pipe 26; the hot water flows into the second adsorption bed 6 through the heat pump hot water outflow pipe 27, the hot water tank 28, the hot water pump 29 and the ninth switching valve 30 in sequence; the evaporative cooling water originally in the coil inside the second adsorption bed 6 is driven by the evaporative cooling water pump 44 and flows back to the evaporative cooler 41 through the twelfth switching valve 37, completing the passive heat recovery process.

[0093] After the passive heat recovery process is completed, the adsorption bed will switch the operating state, and the desorption and adsorption states will be cycled alternately between the first adsorption bed 5 and the second adsorption bed 6, so that the DAC device as a whole can achieve the function of continuous adsorption or continuous gas production.

[0094] Advantages:

[0095] This embodiment couples the cooling and heating of the hot and cold ends of the heat pump to the regeneration energy consumption and condensation energy consumption respectively, thus achieving deep energy integration and improving the energy utilization efficiency of the heat pump; the cold sources provided by the cooling tower and the heat pump evaporator are used for preliminary condensation and deep condensation respectively, which not only reduces the condensation energy consumption but also increases the concentration of the CO2 product gas; at the same time, an evaporative cooling pipeline is added to the system to realize the recovery of the latent heat of the treated gas and provide an internal cooling source for the adsorption bed, so that the cold water can promptly take away the heat generated by the adsorption process, eliminate the adverse effects of the adsorption reaction, and promote the capture of CO2; in addition, through the passive heat recovery process, the sensible heat waste heat of the desorption bed after desorption is fully utilized, which is beneficial to improving the comprehensive energy utilization efficiency of the system.

[0096] Example 3: Cooling tower cooling water is used as an internal cold source to promote adsorption, heat pump evaporator cold water is used as a condensation cold source, and heat pump condenser hot water is used as an internal heat source to promote desorption, and a series heat recovery scheme is adopted.

[0097] Connection method:

[0098] Referring to Figure 3, in Example 3, the connection methods for the system's process gas pipeline, vacuum pipeline, and deep condensation cold source pipeline are identical to those in Example 1 and will not be repeated here. Compared to Example 1, Example 3 differs primarily in the connection methods for the gas production pipeline, internal heat source pipeline, and internal cold source pipeline. Similarly, for components whose numbers are omitted in Example 3, refer to the corresponding components in Figure 1.

[0099] In the gas production pipeline, one end of the eighth switching valve 15 is connected to the pipeline between the third switching valve 7 and the fourth switching valve 8, and the other end is connected to the inlet end of the condensation pipeline of the first condenser 16; the outlet end of the condensation pipeline of the first condenser 16 is connected to one end of the first compressor 17, and the other end of the first compressor 17 is connected to the CO2 storage cylinder 18.

[0100] In the internal heat source pipeline, the heat pump hot water outflow pipe 27 of the heat pump condenser 21 is connected to the water inlet of the hot water tank 28, and the water outlet of the hot water tank 28 leads to the hot water pump 29; the other end of the hot water pump 29 is connected to one end of the fourteenth switching valve 45; the second end of the fourteenth switching valve 45 is connected to the pipeline between the fifteenth switching valve 46 and the heat pump hot water inflow pipe 26, and the third end is connected to one end of the ninth switching valve 30 through the pipeline; the second end of the ninth switching valve 30 is connected to the first adsorption bed 5, and the third end is connected to the pipeline between the second adsorption bed 6 and the eleventh switching valve 36; the first end of the tenth switching valve 31 is connected to the first adsorption bed 5, the second end is connected to the pipeline between the second adsorption bed 6 and the twelfth switching valve 37, and the third end is connected to one end of the fifteenth switching valve 46; the second end of the fifteenth switching valve 46 is connected to the pipeline between the fourteenth switching valve 45 and the ninth switching valve 30, and the third end is connected to the heat pump condenser 21 through the heat pump hot water inflow pipe 26.

[0101] In the internal cold source pipeline, the cooling water outlet end of the cooling tower 33 leads to the water inlet of the cooling water tank 34, and the water outlet of the cooling water tank is connected to the cooling water pump 35; the other end of the cooling water pump 35 is connected to one end of the eleventh switching valve 36; the second end of the eleventh switching valve 36 is connected to the pipeline between the first adsorption bed 5 and the ninth switching valve 30, and the third end is connected to the second adsorption bed 6; the first end of the twelfth switching valve 37 is connected to the second adsorption bed 6, the second end is connected to the pipeline between the first adsorption bed 5 and the tenth switching valve 31, and the third end is returned to the cooling tower 33 through the cooling water inlet end of the cooling tower 33.

[0102] Workflow: Take the second adsorption bed 6 in the adsorption state and the first adsorption bed 5 in the desorption state as an example:

[0103] In Example 3, the work processes of the system's gas processing pipeline, vacuum pipeline, and deep condensation cold source pipeline are exactly the same as those in Example 1 and will not be repeated here; compared with Example 1, the differences in Example 3 are mainly reflected in the work processes of the gas production pipeline, internal heat source pipeline, internal cold source pipeline, and series heat recovery.

[0104] In the gas production pipeline, when the first adsorption bed 5 is in the desorption state, the seventh switching valve 12 and the vacuum pump 13 should be closed, and the eighth switching valve 15 should be opened to allow the desorbed CO2-H2O mixed gas to flow through the third switching valve 7, the eighth switching valve 15 and the first condenser 16 in sequence; the water vapor contained in the desorbed gas is condensed and discharged in the first condenser 16, and the remaining high-concentration CO2 gas is pressurized by the first compressor 17 and sent to the CO2 storage cylinder 18 for storage.

[0105] In the internal heat source pipeline, hot water is driven by the hot water pump 29 and circulates between the heat pump condenser 21 and the first adsorption bed 5; at this time, it is necessary to close the end of the ninth switching valve 30 connected to the pipeline between the eleventh switching valve 36 and the second adsorption bed 6, close the end of the tenth switching valve 31 connected to the pipeline between the twelfth switching valve 37 and the second adsorption bed 6, close the end of the fourteenth switching valve 45 connected to the pipeline between the fifteenth switching valve 46 and the heat pump hot water inlet pipe 26, close the end of the fifteenth switching valve 46 connected to the fourteenth switching valve 45 and the ninth switching valve 30; the heat pump condenser 21 transfers the released condensation heat to the hot water circuit to generate hot water, and discharges the hot water from the heat pump hot water outflow pipe 27; the produced hot water flows through the hot water tank 28, the hot water pump 29, the fourteenth switching valve 45 and the ninth switching valve 30 in sequence, and finally flows into the first adsorption bed 5 to serve as the internal heat source of the DAC desorption bed, promoting the desorption of H2O and CO2; the hot water flowing out of the first adsorption bed 5 passes through the tenth switching valve 31 and the fifteenth switching valve 46 in sequence, and flows back to the heat pump condenser 21 from the heat pump hot water inflow pipe 26.

[0106] In the internal cold source pipeline, the cooling water is driven by the cooling water pump 35 and circulates between the cooling tower 33 and the second adsorption bed 6; at this time, it is necessary to close the end of the eleventh switching valve 36 connected to the pipeline between the ninth switching valve 30 and the first adsorption bed 5, and close the end of the twelfth switching valve 37 connected to the pipeline between the tenth switching valve 31 and the first adsorption bed 5; the cooling water flowing out of the cooling tower 33 passes through the cooling water tank 34, the cooling water pump 35 and the eleventh switching valve 36 in sequence, and finally flows into the second adsorption bed 6, and is used for the internal cooling adsorption process of the adsorption bed, thereby reducing the adverse effect of the adsorption heat on the adsorption process; the cooling water flowing out of the second adsorption bed 6 passes through the twelfth switching valve 37 and flows back to the cooling tower 33 from the cooling water inlet end of the cooling tower 33.

[0107] After the first adsorption bed 5 completes desorption and the second adsorption bed 6 completes adsorption, the first adsorption bed 5 is still in a high-temperature state and the second adsorption bed 6 is still in a low-temperature state; in order to improve the energy utilization efficiency and overall benefits of the system, the system adds a series heat recovery process; in the series heat recovery process, the end of the fourteenth switching valve 45 connected to the ninth switching valve 30 is closed, and the hot water produced in the heat pump condenser 21 is bypassed and no longer participates in the reaction as an internal heat source of the adsorption bed; driven by the hot water pump 29, the hot water generated by the heat pump condenser 21 flows out from the heat pump hot water outflow pipe 27, passes through the hot water tank 28, the hot water pump 29, and the fourteenth switching valve 45, and finally flows back to the heat pump condenser 21 from the heat pump hot water inflow pipe 26.

[0108] During the series heat recovery process, the cooling water flowing out of the cooling tower 33 flows through the first adsorption bed 5 and the second adsorption bed 6 in sequence, and finally returns to the cooling tower 33 to complete the cycle; the series heat recovery process requires closing the end of the fifteenth switching valve 46 connected to the heat pump condenser, closing the end of the ninth switching valve 30 connected to the first adsorption bed 5, closing the end of the tenth switching valve 31 connected to the pipeline between the second adsorption bed 6 and the twelfth switching valve 37, closing the end of the eleventh switching valve 36 connected to the second adsorption bed 6, closing the end of the twelfth switching valve 37 connected to the pipeline between the first adsorption bed 5 and the tenth switching valve 31. one end of the connection; at this time, driven by the cooling water pump 35, the cooling water flows out from the cooling water outlet end of the cooling tower 33, passes through the cooling water tank 34, the cooling water pump 35 and the eleventh switching valve 36 in sequence, and enters the first adsorption bed 5 to take away the residual heat during the desorption process; the heated cooling water flows out from the first adsorption bed 5, passes through the tenth switching valve 31, the fifteenth switching valve 46 and the ninth switching valve 30 in sequence and enters the second adsorption bed 6 to preheat the second adsorption bed 6; finally, the cooling water flowing out of the second adsorption bed 6 flows back to the cooling tower 33 through the twelfth switching valve 37, completing the series heat recovery process.

[0109] After the series heat recovery process is completed, the adsorption bed will switch the operating state, and the first adsorption bed 5 and the second adsorption bed 6 will alternately enter the desorption and adsorption states, so that the DAC device as a whole can achieve the function of continuous adsorption or continuous gas production.

[0110] Advantages:

[0111] This embodiment utilizes the heat from the hot end of the heat pump to heat the desorption bed, promoting the regeneration of CO2 and H2O; the cooling capacity of the cold end of the heat pump is used in the condensation process of H2O in the DAC gas production, thereby achieving efficient energy supply and completing the separation and purification of the CO2 product gas; at the same time, a cooling water pipeline is added to the system to utilize a low-cost natural cold source to promote the internal cooling process of the adsorption bed, promptly remove the heat generated by the adsorption process, which is beneficial to reduce the adverse effects of adsorption heat, improve the adsorption kinetics and equilibrium adsorption capacity of the adsorbent, and improve the capture efficiency and capture capacity of the DAC subsystem; in addition, the use of a series heat recovery process to pre-cool and preheat the adsorption bed can reduce the adsorption and desorption energy consumption required by the DAC subsystem and improve the overall energy utilization efficiency of the device.

[0112] Example 4: The refrigerant on the evaporation side of the heat pump is used as a cold source for gas condensation, and the refrigerant on the condensation side of the heat pump is used as an internal heat source for desorption.

[0113] Connection method:

[0114] Referring to Figure 4, in Example 4, the connection methods of the system's processing gas pipeline, vacuum pipeline, and gas production pipeline are exactly the same as in Example 3 and will not be repeated here. Compared with Example 3, the difference of Example 4 is mainly reflected in the cancellation of the internal cold source pipeline and the connection method of the internal heat source pipeline and the deep condensation cold source pipeline. The specific connection method is described below. Similarly, the corresponding components of the omitted numbers in Example 4 refer to the corresponding components of the corresponding numbers in Figure 1:

[0115] In the internal heat source pipeline, the refrigerant outlet end of the second compressor 48 is connected to one end of the ninth switching valve 30, and the second end and the third end of the ninth switching valve 30 are connected to the first adsorption bed 5 and the second adsorption bed 6 respectively; the second end and the third end of the tenth switching valve 31 are also connected to the first adsorption bed 5 and the second adsorption bed 6 respectively, and the first end is communicated with the refrigerant inlet end of the expansion valve 47.

[0116] In the deep condensation cold source pipeline, the refrigerant outlet end of the expansion valve 47 is connected to the medium pipeline inlet end of the first condenser 16, and the medium pipeline outlet end of the first condenser 16 is communicated with the refrigerant inlet end of the second compressor 48.

[0117] Workflow: Take the second adsorption bed 6 in the adsorption state and the first adsorption bed 5 in the desorption state as an example:

[0118] In Example 4, the workflows of the system's gas processing pipeline, vacuum pipeline, and gas production pipeline are exactly the same as those in Example 3 and will not be repeated here. Compared with Example 3, the difference in Example 4 is mainly reflected in the workflows of the internal heat source pipeline and the deep condensation cold source pipeline. The specific workflows are described as follows:

[0119] In the internal heat source pipeline, the ends of the ninth switching valve 30 and the tenth switching valve 31 connected to the second adsorption bed 6 are both closed; the high-temperature and high-pressure refrigerant flows out from the outlet end of the second compressor 48, flows into the first adsorption bed 5 through the ninth switching valve 30 for condensation, and the released condensation heat is used to promote the desorption process of the desorption bed; the condensed low-temperature and high-pressure refrigerant flows out from the first adsorption bed 5, flows into the expansion valve 47 through the tenth switching valve 31, and becomes a low-temperature and low-pressure state.

[0120] In the deep condensation cold source pipeline, the refrigerant in a low-temperature and low-pressure state flows out from the outlet end of the expansion valve 47 and enters the medium pipeline of the first condenser 16. The refrigerant gas evaporates in the first condenser 16 and absorbs heat, providing a low-temperature environment for the condensation of water vapor in the produced gas; then the refrigerant flows from the outlet end of the medium pipeline of the first condenser 16 to the second compressor 48, and is processed into a high-temperature and high-pressure state in the second compressor 48.

[0121] Advantages:

[0122] This embodiment directly replaces the evaporator and condenser in the heat pump subsystem with the first condenser and desorption bed in the DAC subsystem, uses the second compressor to generate high-temperature and high-pressure refrigerant, and uses the condensation and heat release process of the refrigerant to heat the desorption bed to promote desorption. The low-temperature and low-pressure refrigerant generated by the expansion valve provides a cold source for the first condenser, creating a low-temperature environment for the condensation of water vapor; at the same time, the direct heat exchange with the refrigerant avoids the energy loss caused by the heat exchange between the refrigerant and other media, can effectively reduce the condensation temperature of the heat pump subsystem and increase its evaporation temperature, thereby greatly improving the efficiency of the heat pump subsystem and the overall performance of the device.

Claims

1. A heat pump driven heat recovery type direct air carbon capture system, characterized in that: include: a heat pump subsystem mainly composed of a heat pump condenser and a heat pump evaporator, and a DAC subsystem mainly composed of a first adsorption bed, a second adsorption bed and a first condenser for condensing product gas; The heat pump condenser is connected to the heat exchange channels of the first adsorption bed and the second adsorption bed through a liquid inlet pipeline with a ninth switching valve and a liquid return pipeline with a tenth switching valve to form an internal heat source circulation pipeline; The heat pump evaporator is connected to the medium pipeline of the first condenser through a pipeline to form a condensation circulation pipeline.

2. The heat pump driven heat recovery type direct air carbon capture system according to claim 1, characterized in that: It also includes a cooling tower; the cooling tower is connected to the heat exchange channels of the first adsorption bed and the second adsorption bed through a liquid inlet pipeline with an eleventh switching valve and a liquid return pipeline with a twelfth switching valve, respectively, to form an internal cold source circulation pipeline for providing an internal cold source used in the adsorption process of the DAC subsystem.

3. The heat pump driven heat recovery type direct air carbon capture system according to claim 2, characterized in that: A fourteenth switching valve is provided on the internal heat source circulation pipeline between the outlet of the heat pump condenser and the ninth switching valve; a fifteenth switching valve is provided on the internal heat source circulation pipeline between the reflux port of the heat pump condenser and the tenth switching valve; the fourteenth switching valve and the fifteenth switching valve are three-way switching valves, wherein the third port of the fourteenth switching valve is connected to the internal heat source circulation pipeline between the reflux port of the heat pump condenser and the fifteenth switching valve, and the third port of the fifteenth switching valve is connected to the internal heat source circulation pipeline between the fourteenth switching valve and the ninth switching valve.

4. The heat pump driven heat recovery type direct air carbon capture system according to claim 1, characterized in that: It also includes a cooling tower; the DAC subsystem is also provided with a second condenser connected in series with the first condenser for preliminary condensation of gas production; the cooling tower is connected to the medium pipeline of the second condenser through a pipeline to form a preliminary condensation circulation pipeline; the condensation pipeline inlet of the second condenser is connected to the desorption gas pipeline of the DAC subsystem, and the outlet is connected to the condensation pipeline of the first condenser.

5. The heat pump driven heat recovery type direct air carbon capture system according to claim 4, characterized in that: It also includes an evaporative cooler; the evaporative cooler is connected to the first adsorption bed and the second adsorption bed heat exchange channels through a liquid inlet pipeline with an eleventh switching valve and a liquid return pipeline with a twelfth switching valve to form an internal cold source circulation pipeline.

6. The heat pump driven heat recovery type direct air carbon capture system according to claim 5, characterized in that: After the processed air outlet pipe of the DAC subsystem is merged with the second air inlet pipe with a switching valve, it enters the evaporative cooler through the mixed air inlet pipe, absorbs the heat of the evaporative cooling water to cool it, and then is discharged from the system through the exhaust gas exhaust pipe.

7. The heat pump driven heat recovery type direct air carbon capture system according to claim 1, characterized in that: It also includes an evaporative cooler; the evaporative cooler is connected to the first adsorption bed and the second adsorption bed heat exchange channels through a liquid inlet pipeline with an eleventh switching valve and a liquid return pipeline with a twelfth switching valve to form an internal cold source circulation pipeline.

8. The heat pump driven heat recovery type direct air carbon capture system according to claim 1, characterized in that: The DAC subsystem is a direct air carbon capture subsystem that adopts a temperature-swing vacuum adsorption operation mode.

9. The heat pump driven heat recovery type direct air carbon capture system according to claim 8, characterized in that: The DAC subsystem mainly includes: A first adsorption bed and a second adsorption bed having heat exchange channels and performing adsorption and desorption operations alternately; An air inlet pipe connected to the air inlets of the first adsorption bed and the second adsorption bed respectively; The treated gas outlet pipe, vacuum exhaust outlet pipe and produced gas exhaust pipe are respectively connected to the air outlets of the first adsorption bed and the second adsorption bed, and one or more switching valves are provided on the treated gas outlet pipe, vacuum exhaust outlet pipe and produced gas exhaust pipe; the vacuum exhaust outlet pipe is connected to the vacuum pump, and the other end of the produced gas exhaust pipe is connected to the condensation pipeline of the first condenser.

10. The heat pump driven heat recovery type direct air carbon capture system according to any one of claims 1, 4, 8 and 9, characterized in that: The coupling matching between the heat pump subsystem and the DAC subsystem adopts a direct heat exchange mode, that is, the two adsorption beds and the first condenser of the DAC subsystem replace the heat pump condenser and the heat pump evaporator respectively. During operation, the adsorption bed in the desorption state acts as the condenser of the heat pump subsystem, and the first condenser acts as the evaporator of the heat pump subsystem.

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