Multi-channel intelligent carbon dioxide trapping system and trapping method

Abstract

The invention discloses a multi-channel intelligent carbon dioxide trapping system and a trapping method. The trapping system comprises a main pipeline system, a high-pressure desorption system, a decarburized gas washing reflux pipeline system, an absorption liquid self-circulation pipeline system, a semi-barren liquid reflux pipeline system, an interstage cooling pipeline system and a product gas separation and purification system, the main pipeline system comprises a pretreatment tower, an absorption tower, a heat exchanger, a regeneration tower, a first-stage water washing tower and a second-stage water washing tower; and the high-pressure desorption system comprises a flash tank. According to the embodiment of the invention, on the basis of the main pipeline system, a sufficient bypass pipeline system is arranged and comprises a high-pressure desorption system, a decarburized gas washing reflux pipeline system, an absorption liquid self-circulation pipeline system, a semi-barren solution reflux pipeline system, an interstage cooling pipeline system and a product gas separation and purification system; due to the design of the bypass pipeline system, materials in the carbon dioxide capturing process can be remarkably saved, capturing energy consumption is reduced, and the application range of the device is widened.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon capture, and in particular to a multi-channel intelligent carbon dioxide capture system and a capture method. Background Art

[0002] Carbon Capture, Utilization and Storage (CCUS) technology is the key to achieving the dual carbon goals. As of December 2022, my country has more than 40 CCUS projects with an annual capture capacity of more than 4 million tons of CO2.

[0003] CO2 capture technologies include chemical absorption, physical adsorption, physical absorption and membrane separation. Chemical absorption is widely used due to its wide range of applications, low capture cost and high product purity. MEA alcohol amine solution is a commonly used absorbent in chemical absorption. The process flow is that after gas pretreatment, CO2 reacts with MEA to generate rich liquid, which is then transferred to the regeneration tower through heat exchange, and then thermally desorbed in the regeneration tower to release pure CO2 for recycling. Therefore, the conventional chemical absorption carbon capture device includes core units such as pretreatment tower, absorption tower, heat exchanger, regeneration tower and supporting water washing and cooling systems. However, the existing devices have the following problems: 1) The device has a low degree of integration and cannot adapt to a variety of gas source environments and operating conditions. The chemical composition of different gas sources varies, and the optimal capture operating conditions (such as temperature, pressure, etc.) of different gas sources are also different; 2) The bypass pipeline design of the device is inadequate, resulting in high carbon capture energy consumption and absorbent loss; 3) The automation and intelligence level of the device is low, and the gas flow and liquid flow fluctuate greatly during project operation. It relies on frequent manual adjustments, and the existing device system does not realize functional coupling control of gas flow and liquid flow.

[0004] In summary, existing carbon capture devices have technical problems such as low integration, high energy consumption and loss, and poor automation, which need to be solved urgently. Summary of the invention

[0005] The purpose of this application is to overcome the above-mentioned technical deficiencies, propose a multi-channel intelligent carbon dioxide capture system and capture method, and solve the technical problems of low integration, high energy consumption and loss, and poor automation in the existing technology.

[0006] In order to achieve the above technical objectives, this application adopts the following technical solutions: In the first aspect, the present application provides a multi-channel intelligent carbon dioxide capture system, including a main pipeline system, a high-pressure desorption system, a decarbonized gas washing reflux pipeline system, an absorption liquid self-circulation pipeline system, a semi-lean liquid reflux pipeline system, an interstage cooling pipeline system, and a product gas separation and purification system: The main pipeline system includes a pretreatment tower, an absorption tower, a heat exchanger, a regeneration tower, a primary water scrubber and a secondary water scrubber, wherein the pretreatment tower is connected to the absorption tower, the heat exchanger and the regeneration tower in sequence, and the absorption tower is also connected to the primary water scrubber and the secondary water scrubber in sequence; A high-pressure desorption system, comprising a flash tank, wherein the flash tank is connected to the absorption tower and the regeneration tower respectively; A decarbonized gas washing reflux pipeline system is respectively connected to the primary water washing tower, the secondary water washing tower, and the absorption tower; The absorption liquid self-circulation pipeline system is respectively connected to the bottom and the middle of the absorption tower; A semi-lean liquid reflux pipeline system is respectively connected to the flash tank, the regeneration tower, and the absorption tower; An interstage cooling pipe system is connected to the upper part and the lower part of the absorption tower respectively; The product gas separation and purification system is connected with the regeneration tower and the high-pressure desorption system.

[0007] In some embodiments of the present application, the liquid inlet of the flash tank is connected to the bottom of the absorption tower, and the gas inlet is connected to the regeneration tower. The gas outlet of the flash tank is connected to the product separation and purification system, and the liquid outlet is connected to the absorption tower and the regeneration tower respectively.

[0008] In some embodiments of the present application, the outlet of the regeneration tower is connected to the flash tank through a valve and to the regeneration gas cooler through another valve.

[0009] In some embodiments of the present application, the decarbonization gas washing reflux pipeline system includes a gas pipeline and a liquid pipeline. The top of the absorption tower is connected to the primary water washing tower and the secondary water washing tower in sequence through the gas pipeline, and the bottom of the secondary water washing tower is connected to the primary water washing tower and the absorption tower in sequence through the liquid pipeline.

[0010] In some embodiments of the present application, the decarbonized gas washing reflux pipeline system also includes a first water washing pump, a first water washing cooler, a second water washing pump and a second water washing cooler. The inlet of the first water washing pump is connected to the primary water washing tower, and the outlet is connected to the absorption tower through a valve and to the primary water washing tower through the first water washing cooler. The inlet of the second water washing pump is connected to the secondary water washing tower, and the outlet is connected to the primary water washing tower through another valve and to the secondary water washing tower through the second water washing cooler.

[0011] In some embodiments of the present application, the semi-lean liquid reflux pipeline system includes a semi-lean liquid pump, an inlet of the semi-lean liquid pump is connected to the flash tank, and an outlet is connected to the middle of the absorption tower.

[0012] In some embodiments of the present application, the interstage cooling pipe system includes a stage cooling pump and an interstage cooler, the inlet of the stage cooling pump is connected to the upper part of the absorption tower, and the outlet is connected to the lower part of the absorption tower through the interstage cooler.

[0013] In some embodiments of the present application, the product gas separation and purification system comprises an adsorption tower, a regeneration gas separation tank, and a regeneration gas cooler, and the adsorption tower is connected to the regeneration gas separation tank and the regeneration gas cooler in sequence; The absorption liquid self-circulation pipeline system comprises a self-circulation pump, the inlet of the self-circulation pump is connected to the bottom of the absorption tower, and the outlet of the self-circulation pump is connected to the middle of the absorption tower.

[0014] In some embodiments of the present application, a rich liquid pump, a lean liquid pump and a monitoring device are further included, wherein the inlet of the rich liquid pump is respectively connected to the bottom of the flash tank and the bottom of the absorption tower, and the outlet of the rich liquid pump is connected to the heat exchanger; the inlet of the lean liquid pump is connected to the heat exchanger, and the outlet of the lean liquid pump is connected to the top of the absorption tower, and the monitoring device is installed on the main pipeline system and the bypass pipeline system connected to the main pipeline system.

[0015] In a second aspect, the present application further provides a multi-channel intelligent carbon dioxide capture method, using the multi-channel intelligent carbon dioxide capture system as described in any embodiment of the first aspect, comprising the following steps: After the mixed gas is treated in the pretreatment tower, it reacts with the absorbent in the absorption tower to form a rich liquid; The decarbonized gas discharged from the absorption tower is washed by a primary water washing tower and a secondary water washing tower, and a portion of the washing liquid is brought back by a decarbonized gas washing reflux pipeline system; The absorbent in the absorption tower is cooled by an interstage cooling pipeline system, wherein the main pipeline system and the bypass pipeline system corresponding to the main pipeline system monitor and automatically adjust the liquid and gas parameters in the pipeline according to the function control formula; Wherein, under normal pressure conditions, the rich liquid is sent to the regeneration tower after heat exchange in the heat exchanger to desorb pure carbon dioxide; Under high-pressure conditions, two desorption processes are carried out: semi-lean liquid diversion process: after the rich liquid passes through the high-pressure desorption system, a part of the semi-lean liquid is refluxed to the middle section of the absorption tower through the semi-lean liquid pump, and the other part of the semi-lean liquid enters the regeneration tower through the rich liquid pump, with a diversion ratio of 0-30%; rich liquid diversion process: after a part of the rich liquid passes through the high-pressure desorption system, all of it is refluxed to the middle section of the absorption tower through the semi-lean liquid pump; the other part of the rich liquid enters the regeneration tower through the rich liquid pump, with a diversion ratio of 0-30%.

[0016] Compared with the prior art, the technical solution provided by this application has the following beneficial technical effects: The embodiment of the present application is based on the main pipeline system and has set up sufficient bypass pipeline systems, including a high-pressure desorption system, a decarbonization gas washing reflux pipeline system, an absorption liquid self-circulation pipeline system, a semi-lean liquid reflux pipeline system, an interstage cooling pipeline system, and a product gas separation and purification system. The design of the above-mentioned bypass pipeline system can significantly save materials in the capture process, reduce capture energy consumption, and improve the scope of application of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solution in this application, the following is a brief introduction to the drawings required for use in the embodiments: Figure 1 It is a structural schematic diagram of a multi-channel intelligent carbon dioxide capture system provided in an embodiment of the present application.

[0018] Reference numerals: 1-pretreatment tower, 2-absorption tower, 3-heat exchanger, 4-regeneration tower, 5-primary water washing tower, 6-secondary water washing tower, 7-flash tank, 8-regeneration gas cooler, 9-first water washing pump, 10-first water washing cooler, 11-second water washing pump, 12-second water washing cooler, 13-semi-lean liquid pump, 14-stage cooling pump, 15-interstage cooler, 16-regeneration gas separation tank, 17-adsorption tower, 18-rich liquid pump, 19-lean liquid pump, 20-rotor flowmeter, 21-electric valve, 22-check valve, 23-proportional pressure regulating valve, 24-self-circulation pump, 25-chiller. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0020] Those skilled in the art will appreciate that in this specification, the wording "including" is an open-ended expression, which means that the described features exist but does not exclude other features. The directional words "up", "down", "left", "right", etc. are exemplary directions based on the drawings. Features defined as "first" and "second" implicitly include one or more of the features. Singular expressions can also be used in the plural. "Multiple" means two or more. The terms "installed", "connected", and "connected" can be fixed connections, detachable connections, or integrated connections; they can be directly connected, or indirectly connected through an intermediate medium, or they can be internal connections between two elements. In addition, "connected" can include wireless connections.

[0021] The purpose of this application is to overcome the above-mentioned technical deficiencies, propose a multi-channel intelligent carbon dioxide capture system and capture method, and solve the technical problems of low integration, high energy consumption and loss, and poor automation in the existing technology.

[0022] In order to achieve the above technical objectives, this application adopts the following technical solutions: In the first aspect, the present application provides a multi-channel intelligent carbon dioxide capture system, such as Figure 1 As shown, Figure 1 It is a structural schematic diagram of a multi-channel intelligent carbon dioxide capture system provided in an embodiment of the present application.

[0023] A multi-channel intelligent carbon dioxide capture system, including a main pipeline system, a high-pressure desorption system, a decarbonized gas washing reflux pipeline system, an absorption liquid self-circulation pipeline system, a semi-lean liquid reflux pipeline system, an interstage cooling pipeline system, and a product gas separation and purification system: The main pipeline system includes a pretreatment tower 1, an absorption tower 2, a heat exchanger 3, a regeneration tower 4, a primary water scrubber 5 and a secondary water scrubber 6, wherein the pretreatment tower 1 is connected to the absorption tower 2, the heat exchanger 3 and the regeneration tower 4 in sequence, and the absorption tower 2 is also connected to the primary water scrubber 5 and the secondary water scrubber 6 in sequence; A high-pressure desorption system, comprising a flash tank 7, wherein the flash tank 7 is connected to the absorption tower 2 and the regeneration tower 4 respectively; The decarbonized gas washing reflux pipeline system is respectively connected to the primary water washing tower 5, the secondary water washing tower 6, and the absorption tower 2; The absorption liquid self-circulation pipeline system is connected to the bottom and the middle of the absorption tower 2 respectively; A semi-lean liquid reflux pipeline system is respectively connected to the flash tank 7, the regeneration tower 4, and the absorption tower 2; An interstage cooling pipe system is connected to the upper part and the lower part of the absorption tower 2 respectively; The product gas separation and purification system is connected to the regeneration tower 4 and the flash tank 7 .

[0024] The embodiment of the present application is based on the main pipeline system and has set up sufficient bypass pipeline systems, including a high-pressure desorption system, a decarbonization gas washing reflux pipeline system, an absorption liquid self-circulation pipeline system, a semi-lean liquid reflux pipeline system, an interstage cooling pipeline system, and a product gas separation and purification system. The design of the above-mentioned bypass pipeline system can significantly save materials in the capture process, reduce capture energy consumption, and improve the scope of application of the device.

[0025] The main pipeline system also includes a flue gas fan, a water bath device and a pretreatment pump. The flue gas fan is connected to the inlet of the pretreatment tower through a valve. The liquid outlet of the pretreatment tower passes through the water bath device and the pretreatment pump and then flows back to the pretreatment tower. The gas outlet of the pretreatment tower is connected to the lower layer of the absorption tower. The valve includes an electric valve 21.

[0026] In some embodiments of the present application, the inlet of the flash tank 7 is connected to the bottom of the absorption tower 2 and the top of the regeneration tower 4, the gas outlet of the flash tank 7 is connected to the product separation and purification system through the regeneration gas cooler 8, and the liquid outlet is connected to the absorption tower 2 and the regeneration tower 4 respectively.

[0027] In some embodiments of the present application, the outlet of the regeneration tower 4 is connected to the flash tank 7 through a valve and to the regeneration gas cooler 8 through another valve.

[0028] In this embodiment, under normal pressure conditions, the rich liquid discharged from the bottom of the absorption tower 2 enters the heat exchanger 3 through the rich liquid pump 18 to perform heat exchange between the lean and rich liquids. The rich liquid after heat exchange enters the regeneration tower 4 to complete CO2 desorption.

[0029] In this embodiment, two desorption processes can be performed under high pressure conditions: 1) semi-lean liquid diversion process: the rich liquid discharged from the bottom of the absorption tower 2 enters the flash tank 7 through the proportional pressure regulating valve 23 to complete flash desorption, and a part of the semi-lean liquid formed after desorption is refluxed to the middle section of the absorption tower 2 through the semi-lean liquid pump 13, and the other part of the semi-lean liquid enters the regeneration tower 4 through the rich liquid pump 18, with a diversion ratio of 0-30%; 2) rich liquid diversion process: a part of the rich liquid discharged from the bottom of the absorption tower 2 enters the flash tank 7 through the proportional pressure regulating valve 23 to complete flash desorption, and all the semi-lean liquid formed after desorption is refluxed to the middle section of the absorption tower 2 through the semi-lean liquid pump 13; the other part of the rich liquid enters the regeneration tower 4 through the rich liquid pump 18, with a diversion ratio of 0-30%.

[0030] To facilitate the high-pressure carbon capture work, all devices are designed to withstand a pressure of 1.6 MPa, and all high-pressure pipelines directly connected to normal-pressure pipelines are equipped with check valves or pressure regulating valves to ensure safety. The high-pressure rich liquid at the bottom of the absorption tower 2 enters the flash tank 7 through the pressure regulating valve, and is sprayed out through the 4 needle valve nozzles inside the flash tank 7 to achieve flash evaporation.

[0031] In addition, under high-pressure operating conditions, the high-purity CO2 gas regenerated by the regeneration tower 4 no longer flows directly to the regeneration gas cooler 8, but is directly introduced into the bottom of the flash tank 7, and flows to the regeneration gas cooler 8 through the top outlet together with the CO2 physically desorbed by the flash tank 7.

[0032] Design advantages: 1) The capture system has the ability to capture CO2 under high pressure, and the CO2 absorption load of the absorbent under high pressure conditions is significantly improved; 2) The physical desorption of CO2 is achieved through the pressure drop of the flash tank 7, which significantly reduces the energy consumption of CO2 desorption; 3) The high-purity CO2 regenerated by the regeneration tower 4 is introduced into the bottom of the flash tank 7, which has an obvious mass transfer effect and can significantly promote the physical desorption of CO2 in the flash tank 7.

[0033] In some embodiments of the present application, the decarbonization gas washing reflux pipeline system includes a gas pipeline and a liquid pipeline. The top of the absorption tower 2 is connected to the primary water washing tower 5 and the secondary water washing tower 6 in sequence through the gas pipeline, and the bottom of the secondary water washing tower 6 is connected to the primary water washing tower 5 and the absorption tower 2 in sequence through the liquid pipeline.

[0034] In some embodiments of the present application, the decarbonized gas washing reflux pipeline system also includes a first water washing pump 9, a first water washing cooler 10, a second water washing pump 11 and a second water washing cooler 12, the inlet of the first water washing pump 9 is connected to the primary water washing tower 5, and the outlet is connected to the absorption tower 2 through a valve and to the primary water washing tower 5 through the first water washing cooler, the inlet of the second water washing pump 11 is connected to the secondary water washing tower 6, and the outlet is connected to the primary water washing tower 5 through another valve and to the secondary water washing tower 6 through the second water washing cooler.

[0035] In this embodiment, the decarbonized gas washing reflux pipeline system: after the flue gas reacts with the amine liquid in the absorption tower 2, the decarbonized gas will take away part of the amine liquid. In the traditional design, the amine liquid is washed by water to prevent the amine liquid from escaping and causing pollution. However, in the actual operation process, due to the dry state of the flue gas, the liquid of the device will gradually be lost. Based on the above considerations, this system connects the bottom pipeline of the secondary water washing tower 6 to the tower body of the primary water washing tower 5, and at the same time connects the bottom pipeline of the primary water washing tower 5 to the top of the absorption tower 2. The above design can make the liquid (containing a low proportion of amine liquid) in the secondary water washing tower 6 and the primary water washing tower 5 partially flow back to the absorption tower 2 to achieve the recovery of the amine liquid.

[0036] Design advantages: As the device operates, the amine content in the liquid of the secondary water washing tower 6 and the primary water washing tower 5 will gradually increase. When the liquid loss in the device is serious, the liquid in the water washing tower can be refluxed to achieve partial recovery of the amine liquid and reduce the system operation cost.

[0037] Absorption liquid self-circulation pipeline system: the rich liquid part at the bottom of the absorption tower 2 is refluxed from the pipeline part to the middle section of the absorption tower 2 through the self-circulation pump 24. The reflux ratio is set according to the performance of the amine liquid. The reflux ratio after the device is stably operated is generally 0-30%.

[0038] Design advantages: 1) In the initial stage of device operation, the self-circulation of absorption liquid can significantly shorten the time for the amine liquid to reach the saturated state of CO2 absorption; 2) During the stable operation of the device, by setting a certain self-circulation reflux ratio, the saturated CO2 load of the amine liquid can be increased and the desorption energy consumption can be reduced.

[0039] In some embodiments of the present application, the semi-lean liquid reflux pipeline system includes a semi-lean liquid pump 13 , the inlet of the semi-lean liquid pump 13 is connected to the flash tank 7 , and the outlet is connected to the middle of the absorption tower 2 .

[0040] In this embodiment, under high pressure conditions, the absorption liquid can be diverted before entering the flash tank 7 (rich liquid diversion) or after entering the flash tank 7 (semi-lean liquid diversion) by relying on the semi-lean liquid reflux pipeline system. 1) Semi-lean liquid diversion process: the rich liquid discharged from the bottom of the absorption tower 2 enters the flash tank 7 through the proportional pressure regulating valve 23 to complete flash desorption. A part of the semi-lean liquid formed after desorption is refluxed to the middle section of the absorption tower 2 through the semi-lean liquid pump 13, and the other part of the semi-lean liquid enters the regeneration tower 4 through the rich liquid pump 18; 2) Rich liquid diversion process: a part of the rich liquid discharged from the bottom of the absorption tower 2 enters the flash tank 7 through the proportional pressure regulating valve 23 to complete flash desorption. All the semi-lean liquid formed after desorption is refluxed to the middle section of the absorption tower 2 through the semi-lean liquid pump 13; the other part of the rich liquid enters the regeneration tower 4 through the rich liquid pump 18. The diversion ratio is set according to the performance of the amine liquid. The diversion ratio after the device is stably operated is generally 0-30%.

[0041] Design advantages: After the high-pressure rich liquid is flash desorbed in the flash tank 7, the temperature and pressure are significantly reduced. By returning the semi-lean liquid to the absorption tower 2, the temperature of the absorption tower 2 can be reduced, the CO2 load of the absorption liquid can be increased, the heat exchange load of the heat exchanger 3 can be reduced, and the heating amount of the regeneration tower 4 can be reduced, which significantly reduces the desorption energy consumption. In some embodiments of the present application, the interstage cooling pipe system includes a stage cooling pump 14 and an interstage cooler 15, the inlet of the stage cooling pump 14 is connected to the upper part of the absorption tower 2, and the outlet is connected to the lower part of the absorption tower 2 through the interstage cooler 15.

[0042] In this embodiment, the interstage cooling pipeline system: the reaction between CO2 in the flue gas and the alcohol amine solution is an exothermic reaction, resulting in a temperature rise of 10-20°C from the bottom to the top of the absorption tower 2, and high temperature is not conducive to the CO2 capture reaction. The absorption liquid at the top of the absorption tower 2 is pumped out and cooled by the interstage pump / interstage cooler 15 and then injected into the bottom of the absorption tower 2.

[0043] Design advantages: 1) The reaction temperature in absorption tower 2 can be maintained in the normal range of 40-50°C to ensure that the reaction process is carried out under optimal operating conditions; 2) Relying on the suction of the interstage pump, the absorption liquid accumulated in the upper packing of absorption tower 2 can be quickly extracted to avoid liquid flooding at the top of absorption tower 2.

[0044] In some embodiments of the present application, the product gas separation and purification system includes a regeneration gas separation tank 16 and an adsorption tower 17, and the regeneration tower 4 and the flash tank 7 are connected to the regeneration gas separation tank 16 and the adsorption tower 17 in sequence.

[0045] In this embodiment, the product gas separation and purification system: the gas components of different gas sources are quite different, among which the sulfur components (mainly SO2, H2S, COS, etc.) are the substances that mainly react with the amine liquid except CO2, and such substances will also be released in the desorption of the regeneration tower 4 and the flash tank 7. A heater is arranged at the bottom of the regeneration tower 4.

[0046] Therefore, in order to ensure the purity of CO2 product gas, the outlet of the regeneration gas separation tank 16 is connected to the adsorption tower 17 through a pipeline. The adsorption tower 17 is filled with iron-based desulfurization adsorbent, and the fully desulfurized CO2 product gas is collected and stored. The gas outlet of the regeneration tower 4 is connected to the flash tank 7 and the regeneration gas cooler 8 through two branches. Each branch is provided with a valve, and the valve can control any one branch to be connected or both branches to be connected. The liquid outlet of the regeneration gas separation tank 16 is connected to the top of the regeneration tower 4 to ensure the water balance of the system.

[0047] Design advantages: This carbon capture device can realize integrated desulfurization and decarbonization of flue gas. The carbon and sulfur components in the flue gas are separated through integrated absorption, integrated desorption and adsorption, and finally produce qualified CO2 product gas, eliminating the complex steps of front-end desulfurization and significantly reducing engineering costs.

[0048] In some embodiments of the present application, a rich liquid pump 18, a lean liquid pump 19 and a rotor flowmeter 20 are also included. The inlet of the rich liquid pump 18 is connected to the flash tank 7 and the absorption tower 2 respectively, and the outlet is connected to the heat exchanger 3; the inlet of the lean liquid pump 19 is connected to the heat exchanger 3, and the outlet is connected to the absorption tower 2. Furthermore, the pipeline system is equipped with a monitoring device, through which the liquid and gas parameters in the pipeline system can be monitored and automatically adjusted. .

[0049] In this embodiment, the monitoring device includes temperature, pressure, gas flow, and liquid flow monitoring devices. The chiller 25 is connected to all coolers of the system through a rotor flowmeter 20, and the circulating cooling water flow is adjusted through the rotor flowmeter.

[0050] Temperature, pressure, gas flow, and liquid flow monitoring devices are arranged on the main pipeline system and all bypass pipeline systems of the carbon capture device to monitor the operating status of the carbon capture device. Since the inlet flue gas conditions fluctuate (including flow, temperature, pressure, etc.) during the actual operation of the device, and the liquid flow pumps also fluctuate, it is easy to cause the operating state of the carbon capture device to deviate from the predetermined parameters. After long-term operation, there is a risk of imbalance in the liquid levels of the absorption tower 2, flash tank 7, and regeneration tower 4 (for example, too low a liquid level in the regeneration tower 4 will cause dry burning, posing a safety hazard). Traditionally, manual monitoring of the operation interface and timely adjustment of parameters are relied upon, while the present invention can realize real-time functional control of the flow parameters according to the established operating requirements of the system, saving labor costs while significantly improving the automation level of the system. The specific automation design is as follows: 1. Automatic control of the flow rate of the lean liquid pump 19: The liquid-gas ratio (generally 0.005-0.015) is the most important parameter in the operation of the carbon capture device, which affects the final capture energy consumption of the system. However, in the actual operation process, the conditions of the inlet gas source at the front end of the pretreatment tower are constantly fluctuating, resulting in the system liquid-gas ratio being unable to stabilize at the expected parameters for a long time. The present invention monitors the working conditions of the inlet gas source, based on the ideal gas equation and the established liquid-gas ratio, to achieve real-time regulation of the flow rate of the lean liquid pump 19. The function control formula is as follows: L1=(P1*V1*T0)*R / (T1*P0) In the formula: L1-flow rate of lean liquid pump 19; P1-inlet gas source pressure under real-time state; V1-inlet gas source volume under real-time state; T0-standard temperature under standard gas state; R-established liquid-gas ratio; T1-inlet gas source temperature under real-time state; P0-standard pressure under standard gas state.

[0051] 2. Automatic flow control of the rich liquid pump 18: During the operation of the carbon capture device, in order to avoid the risk of dry burning of the tower kettle due to the low liquid level in the regeneration tower 4, the liquid level in the regeneration tower 4 needs to be maintained at a reasonable level (generally 40%). The automatic flow control of the rich liquid pump 18 can be achieved by coupling the function based on the flow of the lean liquid pump 19 and the liquid level of the regeneration tower 4. The control formula is as follows: L2= L1*(1+C1*(40%-C2)) Wherein: L2 is the flow rate of the rich liquid pump 18; L1 is the flow rate of the lean liquid pump 19; C1 is the scaling factor, which is generally 0.6-0.9; C2 is the actual liquid level of the regeneration tower 4.

[0052] 3. Automatic control of the opening and closing degree of the pressure regulating valve of the flash tank 7: During the high-pressure operation of the carbon capture device, in order to avoid the risk of dry pumping due to the excessively low liquid level of the flash tank 7, the liquid level of the flash tank 7 needs to be maintained at a reasonable level for liquid sealing (generally 30%). The opening and closing degree of the pressure regulating valve can be automatically controlled by coupling the function based on the flow rate of the lean liquid pump 19 and the liquid level of the flash tank 7 (the flow rate is maximum when fully open, and the flow rate returns to zero when fully closed), thereby controlling the flash flow rate of the high-pressure rich liquid. The control formula is as follows: K= L1*(1+C3*(30%-C4)) / L0 In the formula: K-opening degree of pressure regulating valve; L1-flow rate of lean liquid pump 19; C3-scaling coefficient, generally 0.6-0.9; C4-actual liquid level of flash tank 7; L0-maximum flow rate when pressure regulating valve is fully opened.

[0053] Temperature, pressure, gas flow and liquid flow monitoring devices are arranged at the core part of each pipeline to monitor the operating status of the carbon capture system and implement functional regulation of the flow parameters according to the operating requirements, which saves labor costs and significantly improves the automation level of the system.

[0054] In a second aspect, the present application further provides a multi-channel intelligent carbon dioxide capture method, using the multi-channel intelligent carbon dioxide capture system as described in any embodiment of the first aspect, comprising the following steps: After the mixed gas is treated in the pretreatment tower 1, it reacts with the absorbent in the absorption tower 2 to form a rich liquid; The decarbonized gas discharged from the absorption tower 2 is washed by the primary water washing tower 5 and the secondary water washing tower 6, and a part of the washing liquid is brought back by the decarbonized gas washing reflux pipeline system; The absorbent in the absorption tower 2 is cooled by using an interstage cooling pipeline system, wherein the main pipeline system and the bypass pipeline system corresponding to the main pipeline system monitor and automatically adjust the liquid and gas parameters in the pipeline according to the function control formula; Under normal pressure, the rich liquid is sent to the regeneration tower after heat exchange in the heat exchanger to desorb pure carbon dioxide; Under high pressure conditions, two desorption processes can be carried out: 1) Semi-lean liquid diversion process: after the rich liquid passes through the high-pressure desorption system, a part of the semi-lean liquid is refluxed to the middle section of the absorption tower through the semi-lean liquid pump, and the other part of the semi-lean liquid enters the regeneration tower through the rich liquid pump, with a diversion ratio of 0-30%; 2) Rich liquid diversion process: after a part of the rich liquid passes through the high-pressure desorption system, all of it is refluxed to the middle section of the absorption tower through the semi-lean liquid pump; the other part of the rich liquid enters the regeneration tower through the rich liquid pump, with a diversion ratio of 0-30%.

[0055] Carbon capture system operating condition 1: 120L 30% MEA chemical absorption liquid is injected into the carbon capture system, of which 60% is injected into absorption tower 2 and 40% is injected into regeneration tower 4. Inlet flue gas flow rate 10 Nm 3 / h, and manually controlled the liquid-gas ratio to 0.01 (i.e., the flow rate of the lean liquid pump 19 was 100 L / h, and the flow rate of the rich liquid pump 18 was 100 L / h). After the system ran stably for 168 hours, the experimentally measured CO2 desorption energy consumption was 3.8 GJ / tCO2, and the sulfur content of the terminal desorbed gas (in terms of SO2) was 50 ppm.

[0056] Carbon capture system operation condition 2: 120L 30% MEA chemical absorption liquid is injected into the carbon capture system, of which 60% is injected into absorption tower 2 and 40% is injected into regeneration tower 4. Inlet flue gas flow rate 10 Nm 3 / h, and the liquid-gas ratio is controlled by the system intelligently at 0.01 (i.e., the flow rate of the lean liquid pump 19 is 100 L / h, and the flow rate of the rich liquid pump 18 is 100 L / h). The interstage cooling pipeline system is turned on, and the flow rate of the interstage cooling pump is set to 120L / h; the absorption liquid self-circulation pipeline system is turned on 10 hours before operation, and the self-circulation flow rate is set to 50L / h; the product gas separation and purification system is turned on, and the adsorption tower 17 is filled with iron-based desulfurization materials. After the system has been running stably for 168 hours, the experimental measurement shows that the energy consumption of CO2 desorption is 3.2 GJ / tCO2, and the sulfur component content (in terms of SO2) of the terminal desorbed gas has dropped to 10 ppm.

[0057] Carbon capture system operation condition 3: 150L 30% MEA chemical absorption liquid is injected into the carbon capture system, of which 50% is injected into the absorption tower 2, 25% is injected into the flash tank 7, and 25% is injected into the regeneration tower 4. The whole system is pressurized to 1.0MPa through the fan, and the inlet flue gas flow rate is 10 Nm 3 / h, and the liquid-gas ratio is controlled by the system intelligently to 0.01 (i.e., the flow rate of the lean liquid pump 19 is 90 L / h, the flow rate of the flash tank 7 is 100 L / h, the flow rate of the rich liquid pump 18 is 90 L / h, and the flow rate of the semi-lean liquid pump is 10 L / h). The high-pressure desorption system pipeline is opened, and the rich liquid enters the flash tank 7 at a flow rate of 100 L / h for physical desorption to form a semi-lean liquid; the semi-lean liquid reflux pipeline system is opened, of which 10 L / h of the semi-lean liquid is refluxed to the absorption tower 2, and the remaining 90 L / h of the semi-lean liquid enters the regeneration tower 4 for thermal desorption; the interstage cooling pipeline system is opened, and the interstage cooling flow pump is set to 120 L / h; 10 hours before operation (i.e., before the semi-lean liquid is refluxed), the absorption liquid self-circulation pipeline system is opened, and the self-circulation flow rate is set to 50 L / h; the product gas separation and purification system is opened, and the adsorption tower 17 is filled with iron-based desulfurization materials. After the system ran stably for 168 hours, the experimentally measured energy consumption for CO2 desorption was 2.3 GJ / tCO2, and the sulfur content (in terms of SO2) in the terminal desorption gas dropped to 10 ppm.

[0058] Compared with the prior art, the technical solution provided by this application has the following beneficial technical effects: The embodiment of the present application is based on the main pipeline system and has set up sufficient bypass pipeline systems, including a high-pressure desorption system, a decarbonization gas washing reflux pipeline system, an absorption liquid self-circulation pipeline system, a semi-lean liquid reflux pipeline system, an interstage cooling pipeline system, and a product gas separation and purification system. The design of the above-mentioned bypass pipeline system can significantly save materials in the capture process, reduce capture energy consumption, and improve the scope of application of the device.

[0059] Those skilled in the art will appreciate that the various operations, methods, steps, measures, and schemes in the processes discussed in this application may be alternated, modified, rearranged, decomposed, combined, or deleted.

[0060] The specific implementation methods of the present application described above do not constitute a limitation on the protection scope of the present application. Any other corresponding changes and modifications made according to the technical concept of the present application should be included in the protection scope of the claims of the present application.

Claims

1. A multi-channel intelligent carbon dioxide capture system, characterized in that: include: The main pipeline system includes a pretreatment tower, an absorption tower, a heat exchanger, a regeneration tower, a primary water scrubber and a secondary water scrubber, wherein the pretreatment tower is connected to the absorption tower, the heat exchanger and the regeneration tower in sequence, and the absorption tower is also connected to the primary water scrubber and the secondary water scrubber in sequence; A high-pressure desorption system, comprising a flash tank, wherein the flash tank is connected to the absorption tower and the regeneration tower respectively; A decarbonized gas washing reflux pipeline system is respectively connected to the primary water washing tower, the secondary water washing tower, and the absorption tower; The absorption liquid self-circulation pipeline system is respectively connected to the bottom and the middle of the absorption tower; A semi-lean liquid reflux pipeline system is respectively connected to the flash tank, the regeneration tower, and the absorption tower; An interstage cooling pipe system connected to the upper and lower parts of the absorption tower; The product gas separation and purification system is connected with the regeneration tower and the high-pressure desorption system.

2. A multi-channel intelligent carbon dioxide capture system according to claim 1, characterized in that: The liquid inlet of the flash tank is connected to the bottom of the absorption tower, and the gas inlet is connected to the regeneration tower. The gas outlet of the flash tank is connected to the product separation and purification system, and the liquid outlet is connected to the absorption tower and the regeneration tower respectively.

3. A multi-channel intelligent carbon dioxide capture system according to claim 2, characterized in that: The outlet of the regeneration tower is connected to the flash tank through a valve and to the regeneration gas cooler through another valve.

4. A multi-channel intelligent carbon dioxide capture system according to claim 1, characterized in that: The decarbonization gas washing reflux pipeline system includes a gas pipeline and a liquid pipeline. The top of the absorption tower is connected to the primary water washing tower and the secondary water washing tower in sequence through the gas pipeline, and the bottom of the secondary water washing tower is connected to the primary water washing tower and the absorption tower in sequence through the liquid pipeline.

5. A multi-channel intelligent carbon dioxide capture system according to claim 4, characterized in that: The decarbonized gas washing reflux pipeline system also includes a first water washing pump, a first water washing cooler, a second water washing pump and a second water washing cooler. The inlet of the first water washing pump is connected to the primary water washing tower, and the outlet is connected to the absorption tower through a valve and to the primary water washing tower through the first water washing cooler. The inlet of the second water washing pump is connected to the secondary water washing tower, and the outlet is connected to the primary water washing tower through another valve and to the secondary water washing tower through the second water washing cooler.

6. A multi-channel intelligent carbon dioxide capture system according to claim 1, characterized in that: The semi-lean liquid reflux pipeline system comprises a semi-lean liquid pump, the inlet of the semi-lean liquid pump is connected to the flash tank, and the outlet is connected to the middle of the absorption tower.

7. The multi-channel intelligent carbon dioxide capture system according to claim 1, characterized in that: The interstage cooling pipeline system comprises a stage cooling pump and an interstage cooler. The inlet of the stage cooling pump is connected to the upper part of the absorption tower, and the outlet is connected to the lower part of the absorption tower through the interstage cooler.

8. The multi-channel intelligent carbon dioxide capture system according to claim 1, characterized in that: The product gas separation and purification system comprises an adsorption tower, a regeneration gas separation tank, and a regeneration gas cooler, wherein the adsorption tower is connected to the regeneration gas separation tank and the regeneration gas cooler in sequence; The absorption liquid self-circulation pipeline system comprises a self-circulation pump, the inlet of the self-circulation pump is connected to the bottom of the absorption tower, and the outlet of the self-circulation pump is connected to the middle of the absorption tower.

9. The multi-channel intelligent carbon dioxide capture system according to claim 1, characterized in that: It also includes a rich liquid pump, a lean liquid pump and a monitoring device. The inlet of the rich liquid pump is connected to the bottom of the flash tank and the bottom of the absorption tower respectively, and the outlet of the rich liquid pump is connected to the heat exchanger; the inlet of the lean liquid pump is connected to the heat exchanger, and the outlet of the lean liquid pump is connected to the top of the absorption tower. The monitoring device is installed on the main pipeline system and the bypass pipeline system connected to the main pipeline system.

10. A multi-channel intelligent carbon dioxide capture method, characterized in that: The multi-channel intelligent carbon dioxide capture system according to any one of claims 1 to 9 comprises the following steps: After the mixed gas is treated in the pretreatment tower, it reacts with the absorbent in the absorption tower to form a rich liquid; The decarbonized gas discharged from the absorption tower is washed by a primary water washing tower and a secondary water washing tower, and a portion of the washing liquid is brought back by a decarbonized gas washing reflux pipeline system; The absorbent in the absorption tower is cooled by an interstage cooling pipeline system, wherein the main pipeline system and the bypass pipeline system corresponding to the main pipeline system monitor and automatically adjust the liquid and gas parameters in the pipeline according to the function control formula; Wherein, under normal pressure conditions, the rich liquid is sent to the regeneration tower after heat exchange in the heat exchanger to desorb pure carbon dioxide; Under high-pressure conditions, two desorption processes are carried out: semi-lean liquid diversion process: after the rich liquid passes through the high-pressure desorption system, a part of the semi-lean liquid is refluxed to the middle section of the absorption tower through the semi-lean liquid pump, and the other part of the semi-lean liquid enters the regeneration tower through the rich liquid pump, with a diversion ratio of 0-30%; rich liquid diversion process: after a part of the rich liquid passes through the high-pressure desorption system, all of it is refluxed to the middle section of the absorption tower through the semi-lean liquid pump; the other part of the rich liquid enters the regeneration tower through the rich liquid pump, with a diversion ratio of 0-30%.

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