A catalytic desorption system for carbon dioxide chemical absorption

Abstract

This utility model relates to the field of carbon dioxide capture and utilization, and more specifically, to a carbon dioxide chemical absorption catalytic desorption system, comprising a rich solution storage unit, a heat exchanger, a heater, a catalytic desorption device, a buffer tank, and a lean solution reflux unit; the heat exchanger is provided with a rich solution input end, a rich solution output end, a lean solution input end, and a lean solution output end; the rich solution storage unit is connected to the rich solution input end, and the lean solution reflux unit is connected to the lean solution output end; the heater is connected to the rich solution output end; one end of the catalytic desorption device is connected to the heater, and the other end is connected to the buffer tank; the buffer tank is connected to the lean solution input end; the catalytic desorption device is provided with an electrocatalytic generator and a catalyst loading area for placing the catalyst.

Description

Technical Field

[0001] This utility model relates to the field of carbon dioxide capture and utilization, and more specifically, to a carbon dioxide chemical absorption catalytic desorption system. Background Technology

[0002] Currently, chemical absorption is one of the most widely used technical routes in carbon dioxide capture engineering. Its basic principle is to use absorbents such as amines to undergo a reversible chemical reaction with carbon dioxide in flue gas, thereby achieving selective absorption of carbon dioxide. Subsequently, through heating and desorption, the absorbed carbon dioxide in the rich solution is released to obtain high-concentration carbon dioxide and realize the recycling of absorbents.

[0003] In existing engineering applications, carbon dioxide desorption is usually carried out in desorption towers, which mainly rely on external heat sources (steam heating or electric heating) to provide energy. This process requires maintaining a high temperature (generally above 100°C), resulting in huge energy consumption. According to research statistics, the energy consumption of the desorption stage accounts for about 70% of the total energy consumption of chemical absorption carbon capture, which is one of the main bottlenecks restricting the large-scale application and promotion of this technology.

[0004] However, existing thermal desorption processes have the following prominent problems:

[0005] 1. High energy consumption: The desorption method, which relies on high-temperature heating, has low thermal efficiency, resulting in high unit costs for carbon capture.

[0006] 2. Limited efficiency: Traditional heating methods mainly rely on heat conduction and convection, resulting in limited energy utilization and slow carbon dioxide release.

[0007] 3. Absorbent degradation: When operating in a high-temperature environment for a long time, the absorbent is prone to decomposition and deactivation, which increases replacement costs and reduces system stability.

[0008] 4. Lack of new verification platforms: Currently, there is a lack of experimental devices that can simulate actual desorption conditions and realize the coupling study of energy field enhancement and catalytic effect, making it difficult to provide systematic verification for new processes.

[0009] The main reasons for excessive energy consumption are:

[0010] 1) High thermodynamic requirements for reaction: Chemical absorbents (such as monoethanolamine MEA, piperazine, etc.) combine with carbon dioxide to form carbonate / bicarbonate bonds with strong bonds. To make them react in reverse to release carbon dioxide, a large amount of heat energy is required.

[0011] 2) Inefficient heating method: Traditional desorption towers mainly rely on reboilers to provide heat. The heat needs to be conducted through the liquid in the tower bottom and then desorption is achieved through gas-liquid contact. The heat transfer path is long and there is a lot of heat loss.

[0012] 3) Insufficient heat exchange in the system: In actual operation, the rich liquid-lean liquid heat exchanger is difficult to achieve complete energy recovery, resulting in insufficient thermal energy utilization.

[0013] 2. Reasons for limited efficiency

[0014] 1) Limited mass transfer process: The release of carbon dioxide from the liquid phase to the gas phase requires three steps: chemical reaction decomposition, molecular diffusion, and gas-liquid interface migration. When driven solely by thermal energy, the reaction rate is limited.

[0015] 2) Insufficient temperature gradient: The temperature at the top of the desorption tower is relatively low, and some rich liquids cannot complete the release of carbon dioxide within a short residence time, resulting in incomplete desorption.

[0016] 3) Limited energy utilization: Traditional heating only provides macroscopic heat energy and cannot directly act on chemical bonds at the molecular level, thus resulting in insufficient desorption motive force.

[0017] 3. Reasons for absorbent degradation

[0018] 1) High-temperature thermal decomposition: Under conditions of maintaining above 100℃ for a long time, amine absorbents are prone to thermal decomposition, generating ineffective byproducts.

[0019] 2) Increased side reactions: Under high temperature conditions, the absorbent reacts with impurities such as SOx, NOx, and oxygen to form heat-stable salts, which reduces the content of effective absorbent components.

[0020] 3) Evaporation loss: High-temperature operation increases the vapor pressure of the absorbent, and some absorbent is lost with carbon dioxide gas, requiring additional replenishment.

[0021] 4. Reasons for the lack of new verification platforms

[0022] 1) Existing devices are limited: Traditional desorption devices only have conventional heating methods and cannot be equipped with energy field enhancement methods such as plasma.

[0023] 2) Insufficient experimental conditions: Existing small-scale / pilot-scale devices are mostly based on conventional tower desorption, lacking experimental platforms with adjustable energy fields and catalyst modules, making it impossible to systematically verify new processes.

[0024] 3) Difficulty in assessing amplified risks: Without verification devices for new processes, it is difficult to obtain parameter support under experimental conditions, resulting in slow industrialization of new technologies.

[0025] Therefore, it is necessary to propose a carbon dioxide chemical absorption catalytic desorption system to solve the above problems. Utility Model Content

[0026] To overcome at least one of the defects (deficiencies) of the prior art, this invention provides a carbon dioxide chemical absorption catalytic desorption system.

[0027] To solve the above-mentioned technical problems, the technical solution of this utility model is as follows: a carbon dioxide chemical absorption catalytic desorption system, comprising a rich liquid storage unit, a heat exchanger, a heater, a catalytic desorption device, a buffer tank, and a lean liquid reflux unit;

[0028] The heat exchanger is provided with a rich liquid inlet, a rich liquid outlet, a lean liquid inlet, and a lean liquid outlet. The rich liquid storage unit is connected to the rich liquid inlet, and the lean liquid reflux unit is connected to the lean liquid outlet.

[0029] The heater is connected to the rich solution output end, one end of the catalytic desorption device is connected to the heater, and the other end is connected to the buffer tank. The buffer tank is connected to the lean solution input end.

[0030] The catalytic desorption device is equipped with an electrocatalytic generator and a catalyst loading area for placing the catalyst. This invention, by introducing an electrocatalytic generator and a catalyst loading area into the catalytic desorption device, differs from the traditional method of simply heating externally. Through the synergistic effect of the electrocatalytic generator and the catalyst, the energy barrier of the desorption reaction is lowered, achieving efficient desorption at lower temperatures, thus significantly reducing desorption energy consumption. Furthermore, the heating method and catalyst action can be coordinated with the volume of the liquid system to accelerate the dissociation kinetics of carbon dioxide and absorbent molecules. Compared to traditional heating methods, the desorption rate is faster and the efficiency is higher. The heat exchanger and buffer tank located between the rich and lean solutions, unlike the single heat supply mode of traditional desorption processes, achieve heat recovery and stable system operation, effectively improving the overall energy efficiency ratio of the system. The design of the electrocatalytic generator ensures a more uniform energy distribution in the liquid phase, avoiding the temperature unevenness of traditional heating methods, guaranteeing the stability of the desorption process and reducing absorbent degradation.

[0031] Furthermore, the catalytic desorption device includes a catalytic tank, a stainless steel screen, a grid plate, a demister mesh, a gas phase outlet, an electrocatalytic generator mounting port, a liquid inlet connected to a heater, and a first liquid outlet connected to a buffer tank.

[0032] The stainless steel screen is located in the middle of the catalytic tank, and the grating plate is installed on the stainless steel screen.

[0033] The liquid inlet is located on the catalytic tank below the stainless steel screen, and the first liquid outlet is located on the catalytic tank above the stainless steel screen.

[0034] The demister mesh is installed on the catalytic tank above the stainless steel screen, the gas phase outlet is located at the top of the catalytic tank, the electrocatalytic generator mounting port is located on the catalytic tank below the stainless steel screen, the electrocatalytic generator is installed at the electrocatalytic generator mounting port, and the catalyst filling area is located on the inner wall of the catalytic tank. In this invention, the electrocatalytic generator can adjust the catalytic efficiency as needed. Since the electrocatalytic generator is located at the electrocatalytic generator mounting port, the reaction of the rich liquid can be better controlled.

[0035] Furthermore, the electrocatalytic generator has three mounting ports, which are evenly arranged on the catalytic tank. Therefore, the angle between the three mounting ports is 120 degrees. This arrangement allows the electrocatalytic generator to better heat the rich liquid quickly and evenly in the catalytic desorption device.

[0036] Furthermore, it also includes a second drain port, which is located at the bottom of the catalytic tank. The second drain port facilitates drainage during cleaning of the catalytic tank.

[0037] Furthermore, the catalytic desorption device is equipped with instrument interfaces for temperature sensors and pressure sensors. The instrument interfaces facilitate the connection of temperature sensors and pressure sensors, thereby enabling people to easily detect the liquid temperature and pressure within the catalytic desorption device.

[0038] Furthermore, the catalytic desorption device is equipped with a liquid level sensor, which allows for the detection of the liquid level within the device.

[0039] Furthermore, the rich liquid storage unit, heat exchanger, heater, catalytic desorption device, buffer tank, and lean liquid reflux unit are all connected to bypass inlets. Through the bypass inlets, bypasses can be connected as needed, allowing for flexible switching within the carbon capture system to achieve experimental verification without affecting the operation of the main system.

[0040] Furthermore, this also includes rich solution pumps and lean solution pumps;

[0041] The rich solution pump delivers the rich solution from the rich solution storage unit to the rich solution input end of the heat exchanger, and the lean solution pump delivers the lean solution from the lean solution return unit to the lean solution output end of the heat exchanger. Through the rich solution pump and the lean solution pump, it is convenient to deliver the rich solution from the rich solution storage unit and the lean solution from the lean solution return unit to the heat exchanger.

[0042] Furthermore, the rich solution storage unit, the lean solution reflux unit, and the catalytic desorption device are all equipped with sampling ports. Through the setting of the sampling ports, the solutions in the rich solution storage unit, the lean solution reflux unit, and the catalytic desorption device can be sampled and tested.

[0043] Furthermore, the catalyst is one or more of a metal oxide, a supported catalyst, or an enhanced absorption material. In practical applications, the catalyst can be selected as needed, and all of them are alternatives that are easily conceived by those skilled in the art.

[0044] Compared with the prior art, the beneficial effects of this utility model's technical solution are:

[0045] The carbon dioxide chemical absorption catalytic desorption system disclosed in this utility model lowers the energy barrier of the desorption reaction through the synergistic effect of an electrocatalytic generator and a catalyst, achieving efficient desorption at lower temperatures and thus significantly reducing desorption energy consumption. In addition, the heating method and catalyst action can be combined according to the volume of the liquid system to accelerate the dissociation kinetics of carbon dioxide and absorbent molecules. Compared with traditional heating methods, the desorption rate is faster and the efficiency is higher. The heat exchanger and buffer tank set between the rich and poor liquids, unlike the single heat supply mode of traditional desorption processes, realize heat recovery and stable system operation, effectively improving the overall energy efficiency ratio of the system. The design of the electrocatalytic generator makes the energy distribution in the liquid phase more uniform, avoiding the temperature unevenness under traditional heating methods, ensuring the stability of the desorption process and reducing absorbent degradation. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the carbon dioxide chemical absorption catalytic desorption system in this utility model.

[0047] Figure 2 This is a schematic diagram of the catalytic desorption device in this utility model.

[0048] Figure 3 This is a cross-sectional view of the catalytic desorption device in this utility model.

[0049] In the diagram, 1 is the rich solution storage unit, 2 is the heat exchanger, 3 is the heater, 4 is the catalytic desorption device, 5 is the buffer tank, 6 is the lean solution reflux unit, 7 is the rich solution input end, 8 is the rich solution output end, 9 is the lean solution input end, 10 is the lean solution output end, 11 is the electrocatalytic generator, 12 is the catalyst filling area, 13 is the catalytic tank body, 14 is the stainless steel screen, 15 is the grating plate, 16 is the demister mesh, 17 is the gas phase outlet, 18 is the electrocatalytic generator mounting port, 19 is the liquid inlet, 20 is the first drain port, 21 is the second drain port, 22 is the instrument interface, 23 is the liquid level sensor, 24 is the bypass inlet, 25 is the rich solution pump, 26 is the lean solution pump, and 27 is the sampling port. Detailed Implementation

[0050] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this patent. To better illustrate this embodiment, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0051] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can be described as the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances. The technical solution of this utility model will be further described below with reference to the accompanying drawings and embodiments.

[0052] like Figure 1 As shown, a carbon dioxide chemical absorption catalytic desorption system includes a rich solution storage unit 1, a heat exchanger 2, a heater 3, a catalytic desorption device 4, a buffer tank 5, and a lean solution reflux unit 6. The heat exchanger has a rich solution inlet 7, a rich solution outlet 8, a lean solution inlet 9, and a lean solution outlet 10. The rich solution storage unit is connected to the rich solution inlet, and the lean solution reflux unit is connected to the lean solution outlet. The heater is connected to the rich solution outlet. One end of the catalytic desorption device is connected to the heater, and the other end is connected to the buffer tank. The buffer tank is connected to the lean solution inlet. The catalytic desorption device includes an electrocatalytic generator 11 and a catalyst loading area 12 for placing the catalyst. This invention differs from traditional methods by introducing an electrocatalytic generator and a catalyst loading area into the catalytic desorption device. External heating, through the synergistic effect of the electrocatalytic generator and catalyst, lowers the energy barrier of the desorption reaction, achieving highly efficient desorption at lower temperatures and significantly reducing desorption energy consumption. Furthermore, the heating method and catalyst action can be tailored to the volume of the liquid system, accelerating the dissociation kinetics of carbon dioxide and absorbent molecules. Compared to traditional heating methods, the desorption rate is faster and the efficiency is higher. The heat exchanger and buffer tank placed between the rich and lean solutions, unlike the single heat supply mode of traditional desorption processes, achieve heat recovery and stable system operation, effectively improving the overall energy efficiency ratio of the system. The design of the electrocatalytic generator ensures a more uniform energy distribution in the liquid phase, avoiding the temperature unevenness of traditional heating methods, guaranteeing the stability of the desorption process, and reducing absorbent degradation.

[0053] like Figure 2-3As shown, the catalytic desorption device includes a catalytic tank 13, a stainless steel screen 14, a grid plate 15, a demister mesh 16, a gas phase outlet 17, an electrocatalytic generator mounting port 18, a liquid inlet 19 connected to a heater, and a first drain port 20 connected to a buffer tank. The stainless steel screen is located in the middle of the catalytic tank, and the grid plate is installed on the stainless steel screen. The liquid inlet is located on the catalytic tank below the stainless steel screen, and the first drain port is located on the catalytic tank above the stainless steel screen. The demister mesh is located on the catalytic tank above the stainless steel screen, the gas phase outlet is located at the top of the catalytic tank, the electrocatalytic generator mounting port is located on the catalytic tank below the stainless steel screen, and the electrocatalytic generator is installed at the electrocatalytic generator mounting port. The catalyst filling area... The electrocatalytic generator, located on the inner wall of the catalytic tank, allows for adjustable catalytic efficiency. Because it is positioned at the mounting port, it provides better control over the rich liquid reaction. The catalytic generator has three mounting ports, evenly distributed across the catalytic tank with a 120-degree angle between them. This arrangement allows for faster and more uniform heating of the rich liquid within the catalytic desorption device. Additionally, a second drain port 21 is provided at the bottom of the catalytic tank, facilitating drainage during tank cleaning.

[0054] In this invention, an instrument interface 22 for a temperature sensor and a pressure sensor is provided in the catalytic desorption device. The instrument interface facilitates the connection of the temperature sensor and the pressure sensor, thereby making it convenient for people to detect the liquid temperature and pressure in the catalytic desorption device. In addition, a liquid level sensor 23 is provided in the catalytic desorption device, which can detect the liquid level in the catalytic desorption device.

[0055] In this invention, the rich liquid storage unit, heat exchanger, heater, catalytic desorption device, buffer tank, and lean liquid reflux unit are all connected to a bypass inlet 24. Through the bypass inlet, a bypass can be connected as needed, allowing for flexible switching within the carbon capture system to achieve experimental verification without affecting the operation of the main system. In addition, a rich liquid pump 25 and a lean liquid pump 26 are also included. The rich liquid pump transports the rich liquid in the rich liquid storage unit to the rich liquid input end of the heat exchanger, and the lean liquid pump transports the lean liquid in the lean liquid reflux unit to the lean liquid output end of the heat exchanger. Through the rich liquid pump and the lean liquid pump, it is convenient to transport the rich liquid in the rich liquid storage unit and the lean liquid in the lean liquid reflux unit to the heat exchanger.

[0056] In this invention, sampling ports 27 are provided in the rich liquid storage unit, the lean liquid reflux unit, and the catalytic desorption device. Through the sampling ports, the solutions in the rich liquid storage unit, the lean liquid reflux unit, and the catalytic desorption device can be sampled and tested. The catalyst is one or more of a metal oxide, a supported catalyst, or an enhanced absorption material. In practical applications, the catalyst can be selected as needed, and all of them are alternative solutions that are easy for those skilled in the art to conceive of.

[0057] In practical applications, the rich solution in the rich solution storage unit enters the heat exchanger via a rich solution pump, and the high-temperature lean solution in the lean solution reflux unit also enters the heat exchanger via a lean solution pump. At this time, the rich solution and the lean solution exchange heat in the heat exchanger, and the rich solution heats up. The heated rich solution then enters the heater and is heated to the preset desorption temperature. The rich solution that has reached the set temperature enters the catalytic desorption device, where it is released under the synergistic effect of the enhanced field and the catalyst. The released gas is discharged from the gas phase outlet at the top of the desorption device, and its concentration and flow rate can be detected through the sampling port. The desorbed lean solution enters the buffer tank, is cooled by the heat exchanger, and is then pumped back to the lean solution reflux unit.

[0058] The positional relationships described in the figures are for illustrative purposes only and should not be construed as limiting this patent. Clearly, the above embodiments of this utility model are merely examples to clearly illustrate the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the scope of protection of the claims of this utility model.

Claims

1. A catalytic desorption system for carbon dioxide chemical absorption, characterized in that: It includes a rich solution storage unit, a heat exchanger, a heater, a catalytic desorption device, a buffer tank, and a lean solution reflux unit; The heat exchanger is provided with a rich liquid inlet, a rich liquid outlet, a lean liquid inlet, and a lean liquid outlet. The rich liquid storage unit is connected to the rich liquid inlet, and the lean liquid reflux unit is connected to the lean liquid outlet. The heater is connected to the rich solution output end, one end of the catalytic desorption device is connected to the heater, and the other end is connected to the buffer tank. The buffer tank is connected to the lean solution input end. The catalytic desorption device is equipped with an electrocatalytic generator and a catalyst loading area for placing the catalyst.

2. The carbon dioxide chemical absorption catalytic desorption system according to claim 1, characterized in that: The catalytic desorption device includes a catalytic tank, a stainless steel screen, a grating plate, a demister mesh, a gas phase outlet, an electrocatalytic generator mounting port, a liquid inlet connected to a heater, and a first liquid outlet connected to a buffer tank. The stainless steel screen is installed in the middle of the catalytic tank, and the grating plate is installed on the stainless steel screen. The liquid inlet is located on the catalytic tank below the stainless steel screen, and the first liquid outlet is located on the catalytic tank above the stainless steel screen. The demister mesh is installed on the catalytic tank above the stainless steel screen, the gas phase outlet is located at the top of the catalytic tank, the electrocatalytic generator mounting port is located on the catalytic tank below the stainless steel screen, the electrocatalytic generator is installed at the electrocatalytic generator mounting port, and the catalyst filling area is located on the inner wall of the catalytic tank.

3. The carbon dioxide chemical absorption catalytic desorption system according to claim 2, characterized in that: The electrocatalytic generator has three mounting ports, which are evenly distributed on the catalytic tank.

4. The carbon dioxide chemical absorption catalytic desorption system according to claim 2, characterized in that: It also includes a second drain outlet, which is located at the bottom of the catalytic tank.

5. The carbon dioxide chemical absorption catalytic desorption system according to claim 1, characterized in that: The catalytic desorption device is equipped with instrument interfaces for temperature sensors and pressure sensors.

6. The carbon dioxide chemical absorption catalytic desorption system according to claim 1, characterized in that: The catalytic desorption device is equipped with a liquid level sensor.

7. The carbon dioxide chemical absorption catalytic desorption system according to claim 1, characterized in that: The rich liquid storage unit, heat exchanger, heater, catalytic desorption device, buffer tank, and lean liquid reflux unit are all connected to bypass inlets.

8. The carbon dioxide chemical absorption catalytic desorption system according to claim 1, characterized in that: It also includes rich solution pumps and lean solution pumps; The rich solution pump delivers the rich solution from the rich solution storage unit to the rich solution input end of the heat exchanger, and the lean solution pump delivers the lean solution from the lean solution return unit to the lean solution output end of the heat exchanger.

9. The carbon dioxide chemical absorption catalytic desorption system according to claim 1, characterized in that: The rich liquid storage unit, the lean liquid reflux unit, and the catalytic desorption device are all equipped with sampling ports.

10. The carbon dioxide chemical absorption catalytic desorption system according to claim 1, characterized in that: The catalyst is one or more of a metal oxide, a supported catalyst, or an absorption-enhancing material.

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