An on-line purification system and method for a carbon capture absorbent

Abstract

The application provides an online purification device system and method for a carbon capture absorbent, the online purification device system comprising a carbon capture unit, a CO2 concentration detection device, a CO2 load detection device, an absorbent replacement purification unit and a control unit; the application adopts double detection devices, can more reliably determine the health degree of the absorbent, avoids the case that energy is wasted due to the misstart of the absorbent replacement purification unit caused by interference signals, and simultaneously coordinates and matches each device and unit through the control unit, adopts a more energy-saving and efficiency-increasing method to purify the absorbent under the premise that the continuous operation of the carbon capture unit is not affected, so as to achieve the purposes of guaranteeing continuous production of the device system, improving the performance of the absorbent, reducing cost and increasing efficiency, saving energy and reducing consumption, and automatic operation.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon capture, and relates to an online purification device system and method for a carbon capture absorbent. Background Art

[0002] Carbon capture technology is a key technology for climate change mitigation, aiming to reduce atmospheric carbon dioxide emissions from industrial processes and energy production. Chemical absorption, particularly organic amine absorption, is widely used in this process. However, prolonged exposure to high temperatures, pressures, and high CO2 concentrations can lead to denaturation or degradation of absorbents, reducing their absorption performance, increasing operating costs, and impacting production.

[0003] There are two common modes of absorbent purification technology: online and offline. In the online purification mode, an absorbent purification device is connected in series with the absorbent path to achieve purification. The absorbent circulates and purifies simultaneously. However, if the purification device breaks down after a period of operation, the entire system must be shut down and the purification device restored. In the offline purification mode, the absorbent is directed to a separate purification system and then returned to the carbon capture system for continued use.

[0004] CN117695821A discloses a carbon capture system comprising a flue gas carbon capture unit and an absorbent purification unit; the carbon capture unit includes an absorption tower, a lean-rich liquid heat exchanger, a regeneration tower, and a lean liquid cooler; and the absorbent purification unit includes an ultrafiltration device, an electrodialysis device, and a vacuum distillation device. The carbon capture system transports the regenerated lean liquid to the absorbent purification unit for purification, and then transports the purified absorbent to the absorption tower for reuse. The system switches on and off switches based on the content of solid particulate matter and heat-stable salts in the absorbent to determine whether to use the electrodialysis device and the vacuum distillation device. The absorbent purification unit operates in an online purification mode. Although the ultrafiltration, electrodialysis, and vacuum distillation devices in the carbon capture unit are highly effective in removing suspended particles and heat-stable salts from the absorbent, their investment and operating costs are high. Furthermore, the electrodialysis and vacuum distillation devices require power and heat during operation, resulting in high energy consumption and high operating costs. In addition, although it is an online purification mode, after running for a period of time, when the ultrafiltration, electrodialysis, vacuum distillation and other devices reach their limit values, the carbon capture system needs to be shut down, and then the absorbent purification unit needs to be cleaned and maintained, which will affect the continuity of the carbon capture unit production and reduce production efficiency.

[0005] CN118384675A discloses a carbon capture amine solution purification system and method, comprising a scrubbing tower, an adsorption tower, a regeneration tower, and an anion exchange resin unit. This system couples conventional carbon capture processes with ion exchange resin amine solution purification, removing heat-stable salts from organic amine absorbents and treating alkaline wastewater generated during ion exchange resin regeneration. This improves the operational stability and reliability of the carbon capture amine solution purification system and addresses the disposal issues associated with alkaline wastewater purification. While this method can maintain the absorbent in a relatively healthy state for extended periods, the anion exchange resin unit is connected in series to the amine solution circulation loop, requiring the amine solution to pass through it in real time. Therefore, when the anion exchange resin needs to be cleaned or maintained, the amine solution must be shut off, halting the amine solution circulation loop. This can affect the continuity of the carbon capture system's operation and reduce production efficiency.

[0006] CN113041786A discloses a method for purifying a carbon dioxide capture amine solution and its application, wherein electrodialysis is used to purify the carbon dioxide capture amine solution, wherein the water replenishment of the concentration chamber of the electrodialysis regeneration device is a low-concentration amine absorbent solution, which is obtained after the gas-phase amine absorbent entrained in the flue gas after carbon dioxide is captured is recovered. This method utilizes the low-concentration amine absorbent solution recovered by the gas-phase absorbent water scrubber as the water replenishment of the electrodialysis concentrated water through electrodialysis concentrated water resource utilization, thereby reducing the amine loss of the electrodialysis purification method to a certain extent. However, the total amount of absorbent in the entire carbon capture system is still continuously lost, and the disadvantage of the high amine loss rate of the electrodialysis method cannot be effectively solved. In addition, this purification mode is to connect the electrodialysis device in series in the amine liquid circulation loop, and the process of purifying the absorbent depends on the circulation process of the absorbent. When the electrodialysis device needs to be cleaned or maintained, the operation of the carbon capture system needs to be stopped accordingly. In addition, there is power consumption during the electrodialysis operation, which increases the operating cost of the entire system.

[0007] However, existing carbon capture absorbent purification technologies, whether in online or offline mode, require the entire system to be shut down after a period of operation. This impacts production continuity and reduces profitability. Furthermore, existing carbon capture absorbent purification technologies lack timely monitoring of absorbent health, relying primarily on manual sampling to determine whether purification is necessary. Summary of the Invention

[0008] The purpose of the present invention is to provide an online purification device system and method for carbon capture absorbent, which coordinates the various devices and units through a control unit, and adopts more energy-saving and efficiency-enhancing means to purify the absorbent without affecting the continuous operation of the carbon capture unit, so as to achieve the purpose of ensuring continuous production of the device system, improving absorbent performance, reducing costs and increasing efficiency, saving energy and reducing consumption, and automating operation.

[0009] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides an online purification device system for a carbon capture absorbent, the online purification device system comprising a carbon capture unit, a CO2 concentration detection device, a CO2 load detection device, an absorbent replacement purification unit, and a control unit;

[0011] The carbon capture unit includes an absorption tower and a desorption tower connected in a bidirectional manner;

[0012] The bottom of the absorption tower is independently provided with a flue gas inlet and a rich liquid outlet; the top of the absorption tower is independently provided with a flue gas outlet and a lean liquid inlet; the lean liquid pipeline between the desorption tower and the absorption tower is independently provided with an absorbent replacement inlet and an absorbent replacement outlet; a first shut-off valve is provided between the absorbent replacement inlet and the absorbent replacement outlet;

[0013] The CO2 concentration detection device is used to detect the CO2 concentration values ​​at the flue gas inlet and flue gas outlet in the absorption tower and feed back to the control unit; the CO2 load detection device is used to detect the absorbent CO2 load value at the rich liquid outlet and lean liquid inlet in the absorption tower and feed back to the control unit;

[0014] The absorbent replacement purification unit includes a purified absorbent storage tank, an absorbent storage tank to be purified, a pneumatic device, a purification component, several shut-off valves and several check valves;

[0015] The purified absorbent storage tank is arranged in parallel with the absorbent storage tank to be purified; the outlet of the purified absorbent storage tank is connected to the absorbent replacement outlet via a pipeline, and a shut-off valve is provided on the connected pipeline; the inlet of the absorbent storage tank to be purified is connected to the absorbent replacement inlet via a pipeline, and a plurality of shut-off valves and check valves are provided on the connected pipeline;

[0016] The control unit is used to control the start and stop of the CO2 load detection device and the absorbent replacement purification unit, and monitor the operating status and parameter changes of each device and unit.

[0017] In the present invention, the rich liquid is the liquid after absorbing carbon dioxide; the lean liquid is the liquid after desorbing carbon dioxide. The carbon capture unit uses an amine process for carbon capture; the desorption tower is used to desorb the rich liquid after carbon dioxide absorption in the absorption tower into lean liquid and carbon dioxide; the purified absorbent storage tank stores a certain amount of fresh absorbent; and the pneumatic device includes a pneumatic pump.

[0018] In the present invention, the carbon capture unit further includes a heat exchange device, a reboiler, etc. The specific configuration of each device and the connection relationship are not further limited. Those skilled in the art can make specific configurations with reference to the carbon capture unit disclosed in the prior art.

[0019] The online purification device system provided by the present invention includes a carbon capture unit, a CO2 concentration detection device, a CO2 load detection device, an absorbent replacement purification unit and a control unit. The dual detection device is used to more reliably determine the health of the absorbent, avoid interference signals that lead to erroneous start-up of the absorbent replacement purification unit, and cause energy waste. At the same time, the control unit coordinates and cooperates with each unit and device, and adopts more energy-saving and efficiency-enhancing means to perform online independent purification of the absorbent without affecting the continuous operation of the carbon capture unit, so as to achieve the purpose of ensuring continuous production of the device system, improving absorbent performance, reducing costs and increasing efficiency, saving energy and reducing consumption, and automatic operation.

[0020] It is worth noting that the carbon capture unit and the absorbent replacement purification unit are independent of each other, which can ensure that the online independent purification of the absorbent in the carbon capture system is completed without stopping the carbon capture system and reducing the absorbent holding amount. This not only ensures the continuous production of the carbon capture unit, but also realizes the purification of the absorbent, avoids the occurrence of idle periods in the CO2 capture process, and improves the CO2 capture efficiency.

[0021] As a preferred technical solution of the present invention, an absorbent is provided in the absorption tower.

[0022] In the present invention, the absorbent includes an amine absorbent.

[0023] Preferably, a first CO2 concentration sampling point is provided at the flue gas inlet of the absorption tower.

[0024] Preferably, a second CO2 concentration sampling point is provided at the flue gas outlet of the absorption tower.

[0025] Preferably, the first CO2 concentration sampling point and the second CO2 concentration sampling point are independently connected to the CO2 concentration detection device.

[0026] As a preferred technical solution of the present invention, a first absorbent CO2 load sampling point is provided at the rich liquid outlet of the absorption tower.

[0027] Preferably, a second absorbent CO2 load sampling point is provided at the lean liquid inlet of the absorption tower.

[0028] Preferably, the first absorbent CO2 load sampling point and the second absorbent CO2 load sampling point are independently connected to the CO2 load detection device respectively.

[0029] As a preferred technical solution of the present invention, both the purified absorbent storage tank and the absorbent storage tank to be purified are provided with liquid level gauges.

[0030] Preferably, the pneumatic device, the shut-off valve and the liquid level gauge are all controlled by the control unit.

[0031] As a preferred technical solution of the present invention, the purification absorbent storage tank and the pneumatic device are connected through a pipeline to form a circulation pipeline, and a plurality of shut-off valves and check valves are provided on the connected pipeline.

[0032] As a preferred technical solution of the present invention, the purification component includes a resin adsorption device and a ceramic membrane filtration device connected in sequence.

[0033] In the present invention, the resin adsorption device is filled with ion exchange resin.

[0034] Preferably, the outlet of the absorbent storage tank to be purified is connected to two pipelines, one pipeline is connected to the pneumatic device, the resin adsorption device, and the ceramic membrane filtration device in sequence, and the other pipeline is connected to the pneumatic device and the purified absorbent storage tank in sequence.

[0035] Preferably, the outlet of the ceramic membrane filtration device is connected to the absorbent storage tank to be purified through a pipeline, and a plurality of check valves and cut-off valves are provided on the connecting pipeline.

[0036] In the present invention, the absorbent storage tank to be purified, the pneumatic device, the resin adsorption device and the ceramic membrane filtration device form a circulation pipeline through a pipeline, and a plurality of cut-off valves and a plurality of check valves are provided on the connected pipeline.

[0037] In a second aspect, the present invention provides an online purification method for a carbon capture absorbent, wherein the online purification method is performed using the online purification device system described in the first aspect, and specifically comprises:

[0038] A CO2 concentration detection device is used to continuously detect the CO2 concentration values ​​at the flue gas inlet and outlet of the carbon capture unit and feed back the values ​​to the control unit. If the calculated CO2 absorption efficiency of the absorbent is lower than a first set value, the control unit activates the CO2 load detection device to detect the CO2 load values ​​of the absorbent at the rich liquid outlet and the lean liquid inlet of the carbon capture unit and feeds the values ​​back to the control unit. If the calculated CO2 load value of the absorbent is lower than a second set value, the control unit activates the absorbent replacement and purification unit to perform online replacement and purification of the absorbent in the carbon capture unit.

[0039] The absorbent replacement purification unit replaces the absorbent to be purified in the carbon capture unit and performs purification treatment during the operation of the carbon capture unit, and at the same time replenishes the same volume of purification absorbent into the carbon capture unit to keep the total amount of absorbent in the carbon capture unit unchanged.

[0040] In the present invention, the CO2 concentration detection device is in an activated state throughout the entire process. Since the amount of flue gas sampled by the CO2 concentration detection device is very small, continuous detection will not affect the production capacity of the carbon capture unit.

[0041] In the present invention, the CO2 absorption efficiency of the absorbent is calculated using the following formula (I):

[0042]

[0043] Where: η is the CO2 absorption efficiency of the absorbent; C2 is the CO2 concentration at the flue gas outlet of the carbon capture unit; C1 is the CO2 concentration at the flue gas inlet of the carbon capture unit.

[0044] In the online purification method provided by the present invention, the CO2 load detection device is started for detection only when the CO2 absorption efficiency of the absorbent is lower than the first set value after the CO2 concentration detection device performs detection and calculation. When it is confirmed that the health of the absorbent has dropped to a certain level, the CO2 load detection device is adjusted to a shutdown state.

[0045] It is worth noting that the present invention not only achieves the function of verifying the health of the absorbent by further retesting the health of the absorbent, but also reduces the startup frequency, avoiding excessive extraction of absorbent for testing, which in turn affects the absorbent holding capacity in the carbon capture unit.

[0046] In the online purification method provided by the present invention, the replacement condition of the absorbent to be purified in the carbon capture unit is: when the CO2 absorption efficiency of the absorbent calculated after detection by the CO2 concentration detection device is lower than a first set value and the CO2 load value of the absorbent calculated after detection by the CO2 load detection device is lower than a second set value, the absorbent replacement and purification unit is started by the control unit to perform online replacement and purification of the absorbent in the carbon capture unit.

[0047] It's worth noting that the absorbent replacement purification unit is activated only when the calculated results of both detection devices are below the set values. Under other conditions, the absorbent replacement purification unit is in standby mode. While in standby mode, the resin adsorption device and ceramic membrane filtration device within the absorbent replacement purification unit can be cleaned or maintained independently, without shutting down the carbon capture unit and thus without affecting its continuous operation, thus ensuring stable production.

[0048] As a preferred technical solution of the present invention, the first setting value is 75-85%, for example, it can be 76%, 77%, 78%, 79%, 80%, 81%, 82% or 84%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0049] In the present invention, the first set value is 75-85% of the designed CO2 absorption efficiency.

[0050] As a preferred technical solution of the present invention, when the second set value in the rich liquid outlet is 4-5 mol / kg and the second set value in the lean liquid outlet is 0.5-1 mol / kg, the absorbent replacement purification unit is started.

[0051] In the present invention, the first set value and the second set value are both threshold points of absorbent health.

[0052] As a preferred technical solution of the present invention, the online replacement and purification includes pre-operation, replacement, purification and filling performed in sequence.

[0053] Preferably, the pre-operation process includes: keeping the first shut-off valve open, and using a pneumatic device to extract the absorbent in the purification absorbent storage tank and pressurize it.

[0054] In the present invention, when the CO2 load detection device re-measures the CO2 load concentration in the absorbent and determines that the health of the absorbent has dropped below a certain level, the control unit then sends a start-up command to the absorbent replacement purification unit, and the absorbent replacement purification unit enters the pre-operation stage from the standby stage; at the same time, the CO2 load detection device enters the shutdown state.

[0055] In the present invention, during the pre-operation process, the absorbent in the purification absorbent storage tank is extracted and pressurized by a pneumatic device, so that the absorbent circulates in the pipeline and has a certain pressure, so that it can be quickly replenished into the carbon capture unit during the next replacement, avoiding the absorbent from being interrupted in the absorption tower.

[0056] Preferably, the replacement process includes: closing the first shut-off valve, transporting the absorbent to be purified in the desorption tower to the absorbent storage tank to be purified through the absorbent replacement inlet, and at the same time using a pneumatic device to transport the absorbent in the purification absorbent storage tank to the absorption tower through the absorbent replacement outlet, while keeping the total amount of absorbent in the carbon capture unit unchanged.

[0057] In the present invention, when the absorbent circulation pressure is stabilized, the replacement phase begins; during the replacement process, the volume of the purified absorbent added to the purified absorbent storage tank equals the volume of the absorbent to be purified replaced from the carbon capture unit.

[0058] Preferably, the purification process includes: keeping the first shut-off valve open, and using a pneumatic device to circulate the absorbent in the absorbent storage tank to be purified through the resin adsorption device and the ceramic membrane filtration device for purification.

[0059] In the present invention, the purification time is determined according to actual conditions and is not specifically limited here.

[0060] In this invention, the absorbent to be purified circulates through a resin adsorption device and a ceramic membrane filtration device in the aforementioned loop to remove heat-stable salts, suspended particles, and other substances from the absorbent, restoring the absorbent's health. Compared to purification devices such as ultrafiltration, nanofiltration, electrodialysis, and vacuum distillation, the combination of a resin adsorption device and a ceramic membrane filtration device is more streamlined, reduces investment costs, and requires no additional energy during operation, thus lowering the operating costs of the purification process, thereby reducing costs, increasing efficiency, and saving energy.

[0061] Preferably, the filling process includes: keeping the first shut-off valve open, and using a pneumatic device to transport the absorbent in the absorbent storage tank to be purified into the purified absorbent storage tank.

[0062] In the present invention, when the absorbent replacement purification unit completes the work in the filling stage, one absorbent online purification process cycle is completed, and then the absorbent replacement purification unit enters the standby stage.

[0063] Compared with the prior art, the present invention has the following beneficial effects:

[0064] (1) The online purification device system and method provided by the present invention coordinates the various units and devices through a control unit, and adopts a dual detection device, which can more reliably determine the health of the absorbent, avoid the situation where interference signals cause the absorbent replacement purification unit to be mistakenly started, resulting in energy waste; in addition, the carbon capture unit and the absorbent replacement purification unit are independent of each other, which can ensure that the online independent purification of the absorbent in the carbon capture system is completed without stopping the carbon capture system and reducing the amount of absorbent held, thereby ensuring the continuous production of the carbon capture unit and realizing the purification of the absorbent, thereby achieving the purpose of ensuring the continuous production of the device system, improving the performance of the absorbent, reducing costs and increasing efficiency, saving energy and reducing consumption, and automating operation;

[0065] (2) Compared with manual sampling and detection, the online purification device system provided by the present invention has the characteristics of being more convenient, rapid and intelligent. The CO2 concentration detection device and the CO2 load detection device can automatically and quickly feedback the health status of the absorbent and take timely measures to restore the health of the absorbent, thus avoiding the situation where the absorbent to be purified is operated for a long time due to human carelessness, maintaining the carbon capture unit operating at a high efficiency, and achieving the purpose of energy saving and consumption reduction;

[0066] (3) The online purification method provided by the present invention includes four process stages of pre-operation, replacement, purification and filling after the absorbent replacement purification unit is started. The absorbent to be purified in the carbon capture unit can be replaced into the absorbent replacement purification unit through the cyclic operation of the four process flows, and an equal amount of purified absorbent can be added into the carbon capture unit at the same time. The absorbent can be purified online independently without affecting the continuous operation of the carbon capture system or reducing the amount of absorbent held by the carbon capture system. Moreover, when the absorbent replacement purification unit is in the standby stage, the purification equipment of the absorbent (resin adsorption device and ceramic membrane filtration device) can be cleaned and maintained without stopping the operation of the carbon capture unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 A block diagram of the composition of the online purification device system for the carbon capture absorbent provided in Example 1;

[0068] Figure 2 A schematic structural diagram of an online purification device system for a carbon capture absorbent provided in Example 1;

[0069] Among them, 100-carbon capture unit, 21-CO2 concentration detection device, 31-CO2 load detection device, 400-absorbent replacement purification unit, 500-control unit, 01-washing water storage device, 02-washing pump, 11-induced draft fan, 12-pretreatment tower, 13-absorption tower, 14-first delivery pump, 15-second delivery pump, 16-desorption tower, 17-first heat exchange device, 18-second heat exchange device, 19-reboiling device, 22-first CO2 concentration sampling point, 23- The second CO2 concentration sampling point, 32-the first absorbent CO2 load sampling point, 33-the second absorbent CO2 load sampling point, 41-the absorbent replacement outlet, 42-the absorbent replacement inlet, 51-59 are the first to ninth electric shut-off valves, 61-63 are the first to third check valves, 71-the purified absorbent storage tank, 72-the absorbent storage tank to be purified, 73-74 are the first to second liquid level gauges, 75-the pneumatic device, 76-the resin adsorption device, 77-the ceramic membrane filtration device;

[0070] Figure 3 A schematic diagram of the start and stop of various devices and valves in the absorbent replacement purification unit during the pre-operation process provided in Application Example 1;

[0071] Figure 4 A schematic diagram of the start and stop of various devices and valves in the absorbent replacement purification unit during the replacement process provided in Application Example 1;

[0072] Figure 5 A schematic diagram of the start and stop of each device and valve in the absorbent replacement purification unit during the purification process provided in Application Example 1;

[0073] Figure 6 A schematic diagram of the start and stop of various devices and valves in the absorbent replacement purification unit during the filling process provided in Application Example 1;

[0074] in, Figure 3-Figure 6 The red line in the absorbent replacement purification unit indicates the open state, and the blue line indicates the closed state. DETAILED DESCRIPTION

[0075] It should be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "disposed," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0076] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0077] In the following specific implementation manner, the specific values ​​of the first set value and the second set value can be determined according to the type and material of the selected amine absorbent. There is no specific limitation on the materials used for the amine absorbent and the ion exchange resin, and they can be selected according to actual needs.

[0078] Example 1

[0079] This embodiment provides an online purification device system for carbon capture absorbent, the online purification device system (the composition block diagram and the structural schematic diagram are shown in FIG. Figure 1 and Figure 2 ) includes a carbon capture unit 100, a CO2 concentration detection device 21, a CO2 load detection device 31, an absorbent replacement purification unit 400 and a control unit 500;

[0080] The carbon capture unit includes a pretreatment tower 12, an absorption tower 13, a first heat exchange device 17, and a desorption tower 16, which are connected in sequence; the pretreatment tower 12 is provided with a flue gas inlet; the absorption tower 13 is provided with an amine absorbent; the bottom of the absorption tower 13 is independently provided with a flue gas inlet and a rich liquid outlet; the top of the absorption tower 13 is independently provided with a flue gas outlet and a lean liquid inlet; the top of the absorption tower 13 is connected to a water washing assembly; the water washing assembly includes a washing water storage device 01 and a washing pump 02 connected in sequence; a first delivery pump 14 is provided on the pipeline connecting the rich liquid outlet of the bottom of the absorption tower 13 and the first heat exchange device 17;

[0081] A first CO2 concentration sampling point 22 is provided at the flue gas inlet of the absorption tower 13; a second CO2 concentration sampling point 23 is provided at the flue gas outlet of the absorption tower 13; the first CO2 concentration sampling point 22 and the second CO2 concentration sampling point 23 are independently connected to the CO2 concentration detection device 21; the CO2 concentration detection device 21 is used to continuously detect the CO2 concentration value of the flue gas at the inlet and outlet of the absorption tower 13 and feed it back to the control unit 500;

[0082] The rich liquid outlet of the absorption tower 13 is provided with a first absorbent CO2 load sampling point 32; the lean liquid inlet of the absorption tower 13 is provided with a second absorbent CO2 load sampling point 33; the first absorbent CO2 load sampling point 32 and the second absorbent CO2 load sampling point 33 are independently connected to the CO2 load detection device 31; the CO2 load detection device 31 is used to detect the absorbent CO2 load values ​​at the rich liquid outlet and the lean liquid inlet of the absorption tower 13 and feed them back to the control unit 500;

[0083] The lean liquid outlet of the desorption tower 16 is connected to the second delivery pump 15, the first heat exchange device 17, the second heat exchange device 18, the first electric shut-off valve 51, and the absorption tower 13 in sequence through pipelines; the desorption tower 16 is connected to the tower bottom with a reboiler 19; an absorbent replacement inlet 42 and an absorbent replacement outlet 41 are independently provided on the lean liquid pipeline between the desorption tower 16 and the absorption tower 13; a first electric shut-off valve 51 is provided between the absorbent replacement inlet 42 and the absorbent replacement outlet 41; the absorbent replacement inlet 42 and the absorbent replacement outlet 41 are independently connected to the absorbent replacement purification unit;

[0084] The absorbent replacement purification unit includes a purified absorbent storage tank 71, a storage tank for the absorbent to be purified 72, a pneumatic device 75, a resin adsorption device 76, a ceramic membrane filtration device 77, 9 electric shut-off valves (51-59), 3 check valves (61-63) and 2 liquid level gauges (73-74); the pneumatic device 75, the electric shut-off valves (51-59) and the liquid level gauges (73-74) are all controlled by the control unit; the resin adsorption device 76 is filled with ion exchange resin;

[0085] The purification absorbent storage tank 71 stores 0.5m 3 Amine absorbent; the purification absorbent storage tank 71 and the absorbent storage tank to be purified 72 are arranged in parallel; the purification absorbent storage tank 71 and the absorbent storage tank to be purified 72 are both provided with liquid level gauges (73-74);

[0086] The purified absorbent storage tank 71 is connected to the pneumatic device 75 via a pipeline to form a circulation pipeline, and the connected pipeline is sequentially provided with a sixth electric shut-off valve 56, a fourth electric shut-off valve 54, a second check valve 62 and an eighth electric shut-off valve 58;

[0087] The outlet of the purified absorbent storage tank 71 is connected to the absorbent replacement outlet 41 through a pipeline, and a second electric shut-off valve 52 is provided on the connected pipeline;

[0088] The inlet of the absorbent storage tank 72 to be purified is connected to the absorbent replacement inlet 42 through a pipeline, and the connecting pipeline is sequentially provided with a ninth electric shut-off valve 59, a third check valve 63 and a third electric shut-off valve 53;

[0089] The outlet of the absorbent storage tank 72 to be purified is connected to two branch pipelines. One branch pipeline is sequentially connected to the pneumatic device 75, the resin adsorption device 76, and the ceramic membrane filtration device 77, and the seventh electric shut-off valve 57 and the fifth electric shut-off valve 55 are sequentially provided on the connected pipelines. The other branch pipeline is sequentially connected to the pneumatic device 75 and the purified absorbent storage tank 71, and the seventh electric shut-off valve 57, the fourth electric shut-off valve 54, the second check valve 62, and the eighth electric shut-off valve 58 are sequentially provided on the connected pipelines.

[0090] The outlet of the ceramic membrane filtration device 77 is connected to the absorbent storage tank 72 to be purified via a pipeline, and the connecting pipeline is provided with a first check valve 61, a third check valve 63 and a ninth electric shut-off valve 59;

[0091] The control unit 500 is used to control the start and stop of the CO2 load detection device 31 and the absorbent replacement purification unit 400, and monitor the operating status and parameter changes of each device and unit.

[0092] Example 2

[0093] This embodiment provides an online purification device system for carbon capture absorbent. Except that the resin adsorption device is not provided, other conditions are the same as those in Example 1.

[0094] Example 3

[0095] This embodiment provides an online purification device system for carbon capture absorbent. Except that the ceramic membrane filtration device is not provided, other conditions are the same as those in Example 1.

[0096] Comparative Example 1

[0097] This comparative example provides an online purification device system for carbon capture absorbent, which is the same as Example 1 except that the CO2 load detection device is not provided.

[0098] Application Example 1

[0099] This application example provides an online purification method for carbon capture absorbent, which is carried out using the online purification device system provided in Example 1. The holding amount of amine absorbent in the carbon capture unit is 1.6m 3 ; Specifically including the following steps:

[0100] (1) The untreated flue gas is heated at 1280 Nm 3The flow rate of / h is transported to the pretreatment tower 12 through the induced draft fan 11, and then enters the absorption tower 13 after being cooled to 40℃ in the pretreatment tower 12, where the untreated flue gas is fully contacted with the amine absorbent to carry out carbon capture reaction. After the absorption is completed, the rich liquid is transported to the desorption tower 16 through the first delivery pump 14 and the first heat exchange device 17. The rich liquid is heated to 122℃ by the reboiler 19, and the pressure of the desorption tower 16 is maintained at 60kPa. The CO2 in the rich liquid is desorbed to become lean liquid, and then the lean liquid is transported to the desorption tower 16 through the second delivery pump 15 at a speed of 4m 3 The flow rate of / h passes through the first heat exchange device 17 to exchange heat with the rich liquid flowing through it and is cooled down. It then passes through the second heat exchange device 18 to be cooled down to 40°C before entering the absorption tower 13 to continue to participate in carbon capture.

[0101] The washing pump 02 delivers deionized water from the washing water storage device 01 to the top outlet of the absorption tower 13 to ensure that the flue gas temperature after washing and absorption is 40°C, and recovers the amine absorbent, dissolves it in deionized water, and then overflows back to the absorption tower 13;

[0102] (2) During the operation of step (1), part of the flue gas is respectively extracted from the first CO2 concentration sampling point 22 and the second CO2 concentration sampling point 23 and enters the CO2 concentration detection device 21 for continuous detection and feedback to the control unit. The sampled flue gas volume is 12L / h. If the calculated CO2 absorption efficiency of the absorbent is lower than the first set value, the CO2 load detection device 31 is started by the control unit, and then part of the amine absorbent is respectively extracted from the first absorbent CO2 load sampling point 32 and the second absorbent CO2 load sampling point 33 and enters the CO2 load detection device 31 for re-testing and feedback to the control unit. The sampled amine absorbent dosage is 10mL / time. If the calculated CO2 load value of the absorbent is lower than the second set value, the absorbent replacement purification unit is then started by the control unit to perform online replacement and purification of the absorbent in the carbon capture unit;

[0103] Among them, when the absorbent replacement purification unit is started, the CO2 load detection device 31 enters the shutdown state;

[0104] (3) The online replacement and purification in step (2) includes pre-running, replacement, purification and filling in sequence;

[0105] The pre-operation (the start and stop status of each device and valve is as follows Figure 3 The process (shown) includes: after opening the fourth electric shut-off valve 54, the sixth electric shut-off valve 56 and the eighth electric shut-off valve 58, the pneumatic device 75 is turned on, and the amine absorbent in the purification absorbent storage tank 71 is extracted and circulated and pressurized by the pneumatic device 75 until the pressure is stabilized at 0.4 MPa;

[0106] The replacement (the start and stop status of each device and valve is as follows Figure 4 The process shown in FIG. 1 includes: after opening the third electric shut-off valve 53 and the ninth electric shut-off valve 59, closing the first electric shut-off valve 51, and transferring the amine absorbent to be purified in the carbon capture unit to the absorbent storage tank 72 through the absorbent replacement inlet 42; after closing the first electric shut-off valve 51, opening the second electric shut-off valve 52 and closing the fourth electric shut-off valve 54 and the eighth electric shut-off valve 58 at the same time; and transferring the amine absorbent in the purified absorbent storage tank 71 to the absorption tower 13 through the absorbent replacement outlet 41 by using the pneumatic device 75; when the amine absorbent to be purified replaced in the absorbent storage tank 72 reaches 0.4 m 3 When the first electric shut-off valve 51 is opened and the third electric shut-off valve 53 and the ninth electric shut-off valve 59 are closed, the purified amine absorbent replaced in the purified absorbent storage tank 71 reaches 0.4 m 3 When the second electric shut-off valve 52, the sixth electric shut-off valve 56 and the pneumatic device 75 are closed simultaneously, the replenishment of the amine absorbent into the carbon capture unit is stopped;

[0107] The purification (the start and stop status of each device and valve is as follows Figure 5 The process (shown) includes: keeping the first electric shut-off valve 51 open, opening the fifth electric shut-off valve 55, the seventh electric shut-off valve 57, the ninth electric shut-off valve 59 and the pneumatic device 75, and using the pneumatic device 75 to circulate the amine absorbent in the absorbent storage tank 72 to be purified through the resin adsorption device 76 and the porcelain membrane filtration device 77 for purification, wherein the cycle operation time is 1 hour;

[0108] The loading (the start and stop status of each device and valve is as follows Figure 6 The process (shown) includes: keeping the first electric shut-off valve 51 open, opening the fourth electric shut-off valve 54 and the eighth electric shut-off valve 58, and closing the fifth electric shut-off valve 55 and the ninth electric shut-off valve 59, and using the pneumatic device 75 to transfer the amine absorbent in the absorbent storage tank 72 to the purified absorbent storage tank 71;

[0109] Among them, after the filling work is completed, the absorbent replacement purification unit is in a standby state.

[0110] By adopting the online purification device system and method provided in this application example, the absorbent can be independently purified online without affecting the continuous operation of the carbon capture unit or reducing the absorbent holding amount of the carbon capture unit. This not only ensures the continuous production of the carbon capture unit, but also realizes the purification of the absorbent, achieving the purpose of ensuring the continuous production of the device system, improving the performance of the absorbent, reducing costs and increasing efficiency, saving energy and reducing consumption, and automating operation.

[0111] Application Example 2

[0112] This application example provides an online purification method for a carbon capture absorbent. Except for using the online purification device system provided in Example 2, other conditions are the same as those in Application Example 1.

[0113] The online purification device system and method provided in this application example do not have a resin adsorption device, which makes it impossible to perform ion exchange on the heat-stable salts in the amine absorbent. Consequently, HSS components such as oxalate and sulfate in the amine absorbent cannot be removed, making it impossible to effectively restore the activity of the amine absorbent, thereby affecting the purification efficiency and the purification work of the amine absorbent in the carbon capture unit.

[0114] Application Example 3

[0115] This application example provides an online purification method for a carbon capture absorbent. Except for using the online purification device system provided in Example 3, other conditions are the same as those in Application Example 1.

[0116] The online purification device system and method provided in this application example do not have a ceramic membrane filtration device. Although the activity of the amine absorbent can be effectively restored, impurities such as suspended solids in the absorbent cannot be removed, which affects the cleanliness of the absorbent, resulting in problems such as shortened service life of the system equipment and reduced CO2 absorption efficiency of the absorbent, affecting the production capacity of the carbon capture unit.

[0117] Comparative Application Example 1

[0118] This comparative application example provides an online purification method for a carbon capture absorbent. Except for using the online purification device system provided in Comparative Example 1, other conditions are the same as those in Application Example 1.

[0119] The online purification device system and method provided in this comparative application example are adopted. Since a CO2 load detection device is not provided, when the CO2 absorption efficiency of the amine absorbent calculated after detection by the CO2 concentration detection device is lower than the first set value, the absorbent replacement purification unit is activated by the control unit. The presence of only one detection device leads to a decrease in the reliability of the judgment of the health status of the amine absorbent, and the absorbent replacement purification unit is mistakenly activated in the presence of an interference signal, resulting in energy waste.

[0120] The applicant declares that the present invention is intended to illustrate the detailed structural features of the present invention through the above-described embodiments, but the present invention is not limited to the above-described detailed structural features. This does not mean that the present invention must rely on the above-described detailed structural features in order to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent replacements for selected components, additions of auxiliary components, and selection of specific embodiments, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. An online purification device system for carbon capture absorbent, characterized in that: The online purification device system includes a carbon capture unit, a CO2 concentration detection device, a CO2 load detection device, an absorbent replacement purification unit and a control unit; The carbon capture unit includes an absorption tower and a desorption tower connected in a bidirectional manner; The bottom of the absorption tower is independently provided with a flue gas inlet and a rich liquid outlet; the top of the absorption tower is independently provided with a flue gas outlet and a lean liquid inlet; the lean liquid pipeline between the desorption tower and the absorption tower is independently provided with an absorbent replacement inlet and an absorbent replacement outlet; a first shut-off valve is provided between the absorbent replacement inlet and the absorbent replacement outlet; The CO2 concentration detection device is used to detect the CO2 concentration values ​​at the flue gas inlet and flue gas outlet in the absorption tower and feed back to the control unit; the CO2 load detection device is used to detect the absorbent CO2 load value at the rich liquid outlet and lean liquid inlet in the absorption tower and feed back to the control unit; The absorbent replacement purification unit includes a purified absorbent storage tank, an absorbent storage tank to be purified, a pneumatic device, a purification component, several shut-off valves and several check valves; the purification component includes a resin adsorption device and a ceramic membrane filtration device connected in sequence; The purification absorbent storage tank is arranged in parallel with the absorbent storage tank to be purified; the outlet of the purification absorbent storage tank is connected to the absorbent replacement outlet through a pipeline, and a shut-off valve is provided on the connected pipeline; the purification absorbent storage tank and the pneumatic device are connected through a pipeline to form a circulation pipeline, and a plurality of shut-off valves and check valves are provided on the connected pipeline; the inlet of the absorbent storage tank to be purified is connected to the absorbent replacement inlet through a pipeline, and a plurality of shut-off valves and check valves are provided on the connected pipeline; the outlet of the absorbent storage tank to be purified is connected to two branch pipelines, one branch pipeline is connected to the pneumatic device, the resin adsorption device, and the ceramic membrane filtration device in sequence, and the other branch pipeline is connected to the pneumatic device and the purification absorbent storage tank in sequence; the outlet of the ceramic membrane filtration device is connected to the absorbent storage tank to be purified through a pipeline, and a plurality of check valves and shut-off valves are provided on the connected pipeline; The control unit is used to control the start and stop of the CO2 load detection device and the absorbent replacement purification unit, and monitor the operating status and parameter changes of each device and unit.

2. The online purification device system according to claim 1, characterized in that: An absorbent is arranged in the absorption tower.

3. The online purification device system according to claim 1, characterized in that: The flue gas inlet of the absorption tower is provided with a first CO2 concentration sampling point; A second CO2 concentration sampling point is provided at the flue gas outlet of the absorption tower; The first CO2 concentration sampling point and the second CO2 concentration sampling point are independently connected to the CO2 concentration detection device.

4. The online purification device system according to claim 1, characterized in that: The rich liquid outlet of the absorption tower is provided with a first absorbent CO2 load sampling point; The lean liquid inlet of the absorption tower is provided with a second absorbent CO2 load sampling point; The first absorbent CO2 load sampling point and the second absorbent CO2 load sampling point are independently connected to the CO2 load detection device.

5. The online purification device system according to claim 1, characterized in that: The purified absorbent storage tank and the absorbent storage tank to be purified are both provided with liquid level gauges.

6. The online purification device system according to claim 5, characterized in that: The pneumatic device, the shut-off valve and the liquid level gauge are all controlled by the control unit.

7. An online purification method for carbon capture absorbent, characterized in that: The online purification method is performed using the online purification device system according to any one of claims 1 to 6, and specifically comprises: A CO2 concentration detection device is used to continuously detect the CO2 concentration values ​​at the flue gas inlet and outlet of the carbon capture unit and feed back the values ​​to the control unit. If the calculated CO2 absorption efficiency of the absorbent is lower than a first set value, the control unit activates the CO2 load detection device to detect the CO2 load values ​​of the absorbent at the rich liquid outlet and the lean liquid inlet of the carbon capture unit and feeds the values ​​back to the control unit. If the calculated CO2 load value of the absorbent is lower than a second set value, the control unit activates the absorbent replacement and purification unit to perform online replacement and purification of the absorbent in the carbon capture unit. The absorbent replacement purification unit replaces the absorbent to be purified in the carbon capture unit during the operation of the carbon capture unit and performs purification treatment, while replenishing the purified absorbent in the carbon capture unit.

8. The online purification method according to claim 7, characterized in that: The first setting value is 75-85%.

9. The online purification method according to claim 7, characterized in that: When the second set value in the rich liquid outlet is 4-5 mol / kg and the second set value in the lean liquid inlet is 0.5-1 mol / kg, the absorbent replacement purification unit is started.

10. The online purification method according to claim 7, characterized in that: The online replacement and purification includes pre-operation, replacement, purification and filling performed in sequence.

11. The online purification method according to claim 10, characterized in that: The pre-operation process includes: keeping the first shut-off valve open, and using a pneumatic device to extract the absorbent in the purification absorbent storage tank and pressurize it.

12. The online purification method according to claim 10, characterized in that: The replacement process includes: closing the first shut-off valve, transporting the absorbent to be purified in the desorption tower to the absorbent storage tank to be purified through the absorbent replacement inlet, and at the same time using a pneumatic device to transport the absorbent in the purification absorbent storage tank to the absorption tower through the absorbent replacement outlet, while keeping the total amount of absorbent in the carbon capture unit unchanged.

13. The online purification method according to claim 10, characterized in that: The purification process includes: keeping the first shut-off valve open, and using a pneumatic device to circulate the absorbent in the absorbent storage tank to be purified through a resin adsorption device and a ceramic membrane filtration device for purification.

14. The online purification method according to claim 10, characterized in that: The filling process includes: keeping the first shut-off valve open, and using a pneumatic device to transport the absorbent in the absorbent storage tank to be purified into the purified absorbent storage tank.

Images