Multi-stage flash evaporation adsorption flue gas carbon capture system and method

Abstract

The invention provides a multi-stage flash evaporation adsorption flue gas carbon capture system and method, and relates to the technical field of carbon dioxide capture. The system comprises a plurality of adsorption towers, a plurality of tube nests are arranged in tower bodies, adsorbents are stored in the tube nests, and the adsorbents adsorb carbon dioxide in flue gas to become saturated adsorbents; the steam supply device is used for supplying steam into the adsorption tower, the steam exchanges heat with the saturated adsorbent to release carbon dioxide in the saturated adsorbent, and the saturated adsorbent becomes the adsorbent again; the outlet of each adsorption tower is connected with a pressure adjusting device so as to adjust the pressure values in the plurality of tubes in the corresponding adsorption tower during desorption; and the cooling device is used for supplying cooling water into each adsorption tower so as to cool the desorbed saturated adsorbent. According to the multi-stage flash evaporation adsorption flue gas carbon capture system and method, the problem that in the prior art, when steam extracted from a steam turbine is used for flue gas carbon capture, waste heat of the steam cannot be fully utilized is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide capture, and in particular to a multi-stage flash adsorption flue gas carbon capture system and a multi-stage flash adsorption flue gas carbon capture method. Background Art

[0002] Existing post-combustion capture technology is currently the most mature and widely used carbon capture technology. Traditional absorption carbon capture technology has achieved large-scale industrial demonstration, but there are still problems such as high energy consumption in the regeneration process and oxidative degradation and thermal degradation of the absorbent. In the current carbon capture technology, steam is extracted from the steam turbine of the power plant as the main heat supply for the carbon dioxide desorption process. After the steam enters the primary desorption tower to complete the carbon dioxide desorption, a large amount of waste heat is still retained and is not fully utilized, resulting in low utilization of steam waste heat. In addition, parameters such as the temperature and pressure of the steam extracted from the steam turbine may fluctuate due to changes in the unit load, making the extracted steam unable to adapt to the current carbon capture technology due to unstable parameters.

[0003] Therefore, there is an urgent need for a device that can solve at least one of the above problems. Summary of the invention

[0004] The purpose of the embodiments of the present invention is to provide a multi-stage flash adsorption flue gas carbon capture system and method, which is used to solve the problem in the prior art that the waste heat of steam extracted from a steam turbine cannot be fully utilized when used for flue gas carbon capture.

[0005] In order to achieve the above object, the present invention provides a multi-stage flash adsorption flue gas carbon capture system on one hand, and the multi-stage flash adsorption flue gas carbon capture system comprises: Multiple adsorption towers, each of which is provided with a flue gas inlet and a flue gas outlet, and the tower body is provided with multiple tubes connected with the flue gas inlet and the flue gas outlet, wherein adsorbent is stored in the tubes; flue gas enters the tubes through the flue gas inlet, and the adsorbent becomes a saturated adsorbent after adsorbing carbon dioxide in the flue gas, and the flue gas without carbon dioxide is discharged through the flue gas outlet; A steam supply device is used to supply steam to the adsorption tower. The steam flows through each adsorption tower in turn and exchanges heat with the saturated adsorbent in the tube array in the adsorption tower to desorb carbon dioxide from the saturated adsorbent. The carbon dioxide released by the saturated adsorbent after desorption is discharged from the flue gas outlet. The saturated adsorbent after desorption becomes an adsorbent again. The flue gas outlet of each adsorption tower is connected to a pressure regulating device, which is used to adjust the pressure value in the multiple tubes in the corresponding adsorption tower; The cooling device is used to supply cooling water to each adsorption tower to cool down the saturated adsorbent after desorption treatment.

[0006] Specifically, a steam channel is formed in the adsorption tower between the steam inlet and the steam outlet of the adsorption tower; The steam channels of multiple adsorption towers are connected in sequence, the steam inlet of the first-stage adsorption tower serves as the steam total inlet, and the steam outlet of the last-stage adsorption tower serves as the steam total outlet. The steam enters from the steam total inlet and flows through the steam channel of each adsorption tower before being discharged from the steam total outlet.

[0007] Specifically, the pressure in the adsorption tower decreases step by step from the first adsorption tower to the last adsorption tower.

[0008] Specifically, a cooling water channel is formed in the adsorption tower between the cooling water inlet and the cooling water outlet of the adsorption tower, and the cooling water channel is connected to the steam channel; The cooling water channels of multiple adsorption towers are connected in sequence, the cooling water inlet of the first-stage adsorption tower serves as the total water inlet, and the cooling water outlet of the last-stage adsorption tower serves as the total water outlet, wherein the steam flowing through the adsorption tower partially becomes condensed water after heat exchange with the saturated adsorbent in the tubes in the adsorption tower, and the steam-water mixture of the steam and condensed water enters the next-stage adsorption tower through the steam channel and can undergo flash evaporation.

[0009] Specifically, the cooling device includes a cooling water pump and a heat exchanger; The water outlet of the cooling water pump is connected to the cooling water inlet of each adsorption tower, the water inlet of the cooling water pump is connected to the heat exchange water outlet of the heat exchanger, and the heat exchange water inlet of the heat exchanger is connected to the cooling water outlet of each adsorption tower; The cooling water pump is used to pump the cooling water provided by the heat exchanger from the cooling water inlet of the adsorption tower into the adsorption tower. The cooling water absorbs the residual heat of the saturated adsorbent after desorption treatment and becomes heated water. The water is discharged from the cooling water outlet of the adsorption tower and enters the heat exchanger through the heat exchange water inlet of the heat exchanger. The heat exchanger is used to exchange heat between the heated water entering the heat exchanger and the heat exchange medium entering the heat exchanger. After the heated water loses heat, it becomes cooling water again and is provided to the cooling water pump.

[0010] Specifically, a control valve is arranged on the connecting pipe between the water outlet of the cooling water pump and the cooling water inlet of each adsorption tower.

[0011] Specifically, the pressure regulating device is a vacuum pump.

[0012] Another aspect of the present invention provides a multi-stage flash adsorption flue gas carbon capture method, which is implemented based on any of the multi-stage flash adsorption flue gas carbon capture systems described above, and the multi-stage flash adsorption flue gas carbon capture method comprises: The carbon dioxide in the flue gas is absorbed by the adsorption tower, and the flue gas without carbon dioxide is discharged; wherein the carbon dioxide in the flue gas is absorbed by the adsorbent stored in the tubes of the adsorption tower, and the adsorbent becomes a saturated adsorbent after adsorbing carbon dioxide; Steam is supplied to the adsorption tower, and the carbon dioxide released by the saturated adsorbent after steam desorption is discharged from the flue gas outlet, and the saturated adsorbent after desorption becomes an adsorbent again; The saturated adsorbent is cooled after desorption.

[0013] Specifically, during the process of supplying steam into the adsorption tower, the pressure value in the tube array of the adsorption tower is adjusted in real time.

[0014] Specifically, the pressure value in the tubes of each adsorption tower is adjusted by a corresponding vacuum pump.

[0015] Specifically, the pressure value in the tubes of the adsorption tower is adjusted in real time, including: Obtain the temperature value of the steam entering the adsorption tower in real time; The rotation speed of the vacuum pump corresponding to the adsorption tower is adjusted based on the temperature value to adjust the pressure value in the multiple tubes of the adsorption tower.

[0016] The multi-stage flash adsorption flue gas carbon capture system provided by the present invention is provided with a plurality of adsorption towers, and a plurality of array tubes are provided in each adsorption tower, each array tube is filled with an adsorbent, the array tube inlet in each adsorption tower is connected with the flue gas inlet of the adsorption tower, and the array tube outlet of the array tube is connected with the flue gas outlet of the adsorption tower, and the flue gas enters each array tube in the corresponding adsorption tower from the flue gas inlet of the adsorption tower, and the adsorbent in the array tube can adsorb carbon dioxide in the flue gas, and the flue gas without carbon dioxide is discharged from the flue gas outlet of the corresponding adsorption tower, and the adsorbent adsorbed with carbon dioxide becomes a saturated adsorbent, and in order to release the carbon dioxide adsorbed by the saturated adsorbent, steam is transported to the adsorption tower, and the steam enters each adsorption tower in turn and exchanges heat with the saturated adsorbent in the array tube in the adsorption tower, and the saturated adsorbent absorbs the heat of the steam. The carbon dioxide in the saturated adsorbent is released, thereby completing the desorption treatment of the saturated adsorbent. After releasing the carbon dioxide, the saturated adsorbent becomes an adsorbent again, and the released carbon dioxide is discharged from the flue gas outlet. During the heat exchange process between the steam and the saturated adsorbent, in order to provide the best conditions for the saturated adsorbent to release carbon dioxide, a pressure regulating device is connected to the flue gas outlet. The pressure regulating device adjusts the pressure value in multiple tubes in the adsorption tower according to the temperature of the steam entering the corresponding adsorption tower, so that the carbon dioxide in the saturated adsorbent can be completely released. The temperature of the saturated adsorbent that has completed the desorption treatment is relatively high, which is not conducive to the subsequent absorption of carbon dioxide in the flue gas. Cooling water is supplied to the adsorption tower through the cooling device, and the cooling water exchanges heat with the saturated adsorbent after the desorption treatment, thereby cooling the saturated adsorbent after the desorption treatment. The multi-stage flash adsorption flue gas carbon capture system and method provided by the present invention, after the carbon dioxide in the flue gas is adsorbed by the adsorbent, the steam then enters the adsorption tower to desorb the saturated adsorbent, so that the carbon dioxide in the saturated adsorbent is released. In order to improve the desorption effect of the carbon dioxide in the saturated adsorbent, the pressure regulating device adjusts the pressure values ​​in the corresponding multiple tubes in the adsorption tower according to the steam temperature entering each stage of the adsorption tower, so that the steam temperature and the pressure in the tubes reach the optimal conditions for the desorption treatment of the saturated adsorbent, so that the carbon dioxide in the saturated adsorbent is completely released. At the same time, the pressure regulating device is used to fully utilize the waste heat of the steam, which solves the problem in the prior art that the waste heat of the steam extracted from the turbine cannot be fully utilized when used for flue gas carbon capture, thereby improving the efficiency and economy of carbon dioxide capture.

[0017] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings: Figure 1 It is a schematic diagram of the layout of the multi-stage flash adsorption flue gas carbon capture system provided by the present invention.

[0019] Description of Reference Numerals 1-adsorption tower; 2-tube; 3-pressure regulating device; 4-cooling device; 41-cooling water pump; 42-heat exchanger. DETAILED DESCRIPTION

[0020] The specific implementation of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the present invention, and is not used to limit the embodiment of the present invention.

[0021] Figure 1 The following is a schematic diagram of the layout of a multi-stage flash adsorption flue gas carbon capture system. Figure 1 As shown, the present invention provides a multi-stage flash adsorption flue gas carbon capture system on one hand, and the multi-stage flash adsorption flue gas carbon capture system comprises: A plurality of adsorption towers 1 are provided with a flue gas inlet and a flue gas outlet on the tower body of the adsorption tower 1, and a plurality of tubes 2 are provided in the tower body to connect the flue gas inlet and the flue gas outlet, and adsorbent is stored in the tubes 2; flue gas enters the tubes 2 through the flue gas inlet, and the adsorbent becomes a saturated adsorbent after adsorbing carbon dioxide in the flue gas, and the flue gas without carbon dioxide is discharged through the flue gas outlet; A steam supply device is used to supply steam to the adsorption tower 1. The steam flows through each adsorption tower 1 in turn and exchanges heat with the saturated adsorbent in the tube array 2 in the adsorption tower 1 to desorb carbon dioxide from the saturated adsorbent. The carbon dioxide released by the saturated adsorbent after desorption is discharged from the flue gas outlet. The saturated adsorbent after desorption becomes an adsorbent again. The flue gas outlet of each adsorption tower 1 is connected to a pressure regulating device 3, and the pressure regulating device 3 is used to adjust the pressure value in the multiple tubes 2 in the corresponding adsorption tower 1; The cooling device 4 is used to supply cooling water to each adsorption tower 1 to cool down the saturated adsorbent after desorption treatment.

[0022] The multi-stage flash adsorption flue gas carbon capture system provided by the present invention is as follows: Figure 1As shown, a plurality of adsorption towers 1 are provided, and a plurality of array tubes 2 are provided in each adsorption tower 1, and an adsorbent is filled in each array tube 2. The array tube inlet of each array tube 2 is connected with the flue gas inlet of the corresponding adsorption tower 1, and the array tube outlet of each array tube 2 is connected with the flue gas outlet of the adsorption tower 1. The flue gas enters from the flue gas inlet of the adsorption tower 1 and then enters each array tube 2 in the adsorption tower 1. The carbon dioxide in the flue gas is adsorbed by the adsorbent in each array tube 2. The adsorbent becomes a saturated adsorbent after adsorbing carbon dioxide, and the adsorption capacity of the saturated adsorbent decreases. The flue gas that has lost carbon dioxide is discharged from the flue gas outlet of the adsorption tower 1 as decarbonized flue gas. In order to restore the adsorption capacity of the saturated adsorbent in the tubes 2, the supply of flue gas to the tubes 2 in the adsorption tower 1 is stopped, and steam is started to be supplied to the adsorption tower 1. The pressure in each adsorption tower 1 is adjustable, and the steam can be extracted from the steam turbine. The pressure in the corresponding adsorption tower 1 can be adjusted so that the steam entering the adsorption tower 1 can flash. After entering the adsorption tower 1, the steam exchanges heat with the saturated adsorbent in the tubes 2. While supplying steam to the adsorption tower 1, the pressure values ​​in the multiple tubes 2 in the adsorption tower 1 are adjusted according to the temperature of the steam entering the adsorption tower 1 through the corresponding pressure regulating device 3, so that the steam temperature and the pressure in the tubes 2 reach the optimal conditions for the saturated adsorbent to perform desorption treatment. In this way, the pressure value in the tubes 2 in the corresponding adsorption tower 1 is adjusted according to the temperature of the steam entering the adsorption tower 1. When the steam parameters in the adsorption tower 1 change, the pressure in the tubes 2 can also be adjusted to provide the saturated adsorbent with the best desorption treatment conditions. The saturated adsorbent is being subjected to desorption treatment. During the desorption process, carbon dioxide is released and discharged from the flue gas outlet of the adsorption tower 1. In order to make the adsorbent have a better adsorption effect, the temperature of the saturated adsorbent that has completed the desorption process is reduced to a working temperature that has a better effect on absorbing carbon dioxide in the flue gas. Cooling water is transported to the adsorption tower 1 through the cooling device 4. The cooling water exchanges heat with the saturated adsorbent after the desorption process to cool the saturated adsorbent after the desorption process, so that the saturated adsorbent after the desorption process can adsorb carbon dioxide in the flue gas again after the cooling. The pressure regulating device 3 adjusts the pressure values ​​in the corresponding multiple tubes 2 in the adsorption tower 1 according to the steam temperature entering the adsorption tower 1, so that the steam temperature and the pressure in the tubes 2 reach the optimal conditions for the saturated adsorbent to perform desorption treatment, so that the waste heat of the steam is fully utilized, which solves the problem in the prior art that the waste heat of the steam extracted from the steam turbine cannot be fully utilized when used for flue gas carbon capture, thereby improving the efficiency and economy of carbon dioxide capture.

[0023] In one embodiment, in order to perform a desorption process on the saturated adsorbent, a steam channel is formed in the adsorption tower 1 between the steam inlet and the steam outlet of the adsorption tower 1; The steam channels of multiple adsorption towers 1 are connected in sequence, the steam inlet of the first-stage adsorption tower 1 serves as the steam total inlet, and the steam outlet of the last-stage adsorption tower 1 serves as the steam total outlet. Steam enters from the steam total inlet, flows through the steam channel of each adsorption tower 1, and is discharged from the steam total outlet.

[0024] From the first adsorption tower 1 to the last adsorption tower 1, the pressure in the adsorption tower 1 decreases step by step.

[0025] A cooling water channel is formed in the adsorption tower 1 between the cooling water inlet and the cooling water outlet, and the cooling water channel is connected to the steam channel; The cooling water channels of multiple adsorption towers 1 are connected in sequence, the cooling water inlet of the first-stage adsorption tower 1 serves as the total water inlet, and the cooling water outlet of the last-stage adsorption tower 1 serves as the total water outlet, wherein the steam flowing through the adsorption tower 1 partially becomes condensed water after heat exchange with the saturated adsorbent in the tube array 2 in the adsorption tower 1, and the steam-water mixture of the steam and condensed water enters the next-stage adsorption tower 1 through the steam channel and can undergo flash evaporation.

[0026] A temperature measuring instrument is provided at the steam inlet of each adsorption tower 1 .

[0027] like Figure 1 As shown, multiple adsorption towers 1 are arranged, the steam inlet of the first-stage adsorption tower 1 is used as the total steam inlet, and the steam outlet of the last-stage adsorption tower 1 is used as the total steam outlet. The steam outlet of the first-stage adsorption tower 1 is connected to the steam inlet of the second-stage adsorption tower 1 through a pipeline, and the steam outlet of the second-stage adsorption tower 1 is connected to the steam inlet of the third-stage adsorption tower 1, and so on, until it is connected to the steam inlet of the last-stage adsorption tower 1. In this way, the steam channels of the multiple adsorption towers 1 are connected, and the steam enters from the steam inlet of the first-stage adsorption tower 1, flows through each adsorption tower 1 in sequence, and then flows out from the steam inlet of the last-stage adsorption tower 1. The steam flows through each adsorption tower 1 step by step to exchange with the saturated adsorbent After heating, the temperature will decrease, and part of the steam will condense into condensed water. The steam-water mixture formed by the cooled steam and the condensed water has a certain temperature and pressure. The steam-water mixture enters the next-stage adsorption tower 1 through the steam channel. In order to meet the temperature conditions required for desorption of carbon dioxide from the saturated adsorbent in the tubes 2 in the next-stage adsorption tower 1, the pressure value in the next-stage adsorption tower 1 is adjusted to be lower than the pressure value of the previous-stage adsorption tower 1, so that the steam-water mixture discharged from the adsorption tower 1 with a higher pressure can flash after entering the next-stage adsorption tower 1 with a lower pressure to generate flash steam. The flash steam is used as steam in the next-stage adsorption tower 1 for heat exchange with the saturated adsorbent in the adsorption tower 1 of this stage.

[0028] Steam first enters the first-stage adsorption tower 1 from the steam main inlet, and exchanges heat with the saturated adsorbent in the first-stage adsorption tower 1 in the first-stage adsorption tower 1. At the same time, the pressure regulating device 3 connected to the flue gas outlet of the first-stage adsorption tower 1 adjusts the pressure value in the multiple tubes 2 in the first-stage adsorption tower 1 according to the temperature of the steam entering the first-stage adsorption tower 1. The pressure regulating device 3 is a vacuum pump. A thermometer arranged at the steam inlet of the first-stage adsorption tower 1 detects the temperature of the steam entering the adsorption tower 1. The vacuum pump adjusts the pressure value in the tubes 2 in the first-stage adsorption tower 1 according to the temperature of the steam entering the first-stage adsorption tower 1 to achieve the best conditions for the desorption treatment of the saturated adsorbent. The temperature of the steam decreases after heat exchange with the saturated adsorbent in the first-stage adsorption tower 1 in the first-stage adsorption tower 1. The steam with reduced temperature enters the second-stage adsorption tower 1 through the steam inlet of the second-stage adsorption tower 1. At this time, the cooling device 4 transports cooling water into the first-stage adsorption tower 1. The cooling water exchanges heat with the saturated adsorbent in the tubes 2 of the first-stage adsorption tower 1 after the desorption treatment to cool the saturated adsorbent after the desorption treatment, so that the first The saturated adsorbent in the tubes 2 of the first-stage adsorption tower 1 becomes the adsorbent again. At the same time, the steam discharged from the first-stage adsorption tower 1 enters the second-stage adsorption tower 1 and exchanges heat with the saturated adsorbent in the second-stage adsorption tower 1. The temperature of the steam entering the second-stage adsorption tower 1 is lower than the temperature of the steam entering the first-stage adsorption tower 1. In order to provide the best desorption condition for the saturated adsorbent in the tubes 2 in the second-stage adsorption tower 1, the pressure regulating device 3 arranged at the flue gas outlet of the second-stage adsorption tower 1 is used to adjust the pressure value in the multiple tubes 2 in the secondary adsorption tower 1. The pressure value in the multiple tubes 2 in the second-stage adsorption tower 1 is higher than the pressure value in the multiple tubes 2 in the first-stage adsorption tower 1. The temperature of the steam gradually decreases during the process of flowing through the multiple adsorption towers 1 in sequence. Correspondingly, the pressure in the tubes 2 of the corresponding adsorption tower 1 can be adjusted to provide the best desorption condition for the saturated adsorbent. While the saturated adsorbent in one adsorption tower 1 is being desorbed, the saturated adsorbent after desorption is being cooled in the upper-stage adsorption tower 1. In this way, the flue gas absorption efficiency can be improved and the waste heat of steam can be fully utilized.

[0029] In order to enable the saturated adsorbent after desorption to perform carbon dioxide adsorption again, the cooling device 4 includes a cooling water pump 41 and a heat exchanger 42; The water outlet of the cooling water pump 41 is connected to the cooling water inlet of each adsorption tower 1, the water inlet of the cooling water pump 41 is connected to the heat exchange water outlet of the heat exchanger 42, and the heat exchange water inlet of the heat exchanger 42 is connected to the cooling water outlet of each adsorption tower 1; The cooling water pump 41 is used to pump the cooling water provided by the heat exchanger 42 from the cooling water inlet of the adsorption tower 1 into the adsorption tower 1. The cooling water absorbs the residual heat of the saturated adsorbent after the desorption process and becomes heated water, which is discharged from the cooling water outlet of the adsorption tower 1 and enters the heat exchanger 42 through the heat exchange water inlet of the heat exchanger 42. The heat exchanger 42 is used to exchange heat between the heated water entering the heat exchanger 42 and the heat exchange medium entering the heat exchanger 42 . After the heated water loses heat, it becomes cooling water again and is provided to the cooling water pump 41 .

[0030] like Figure 1 As shown, the cooling water pump 41 supplies cooling water to each adsorption tower 1. The cooling water enters the adsorption tower 1 from the cooling water inlet of the adsorption tower 1 and exchanges heat with the saturated adsorbent after the desorption treatment, so that the saturated adsorbent after the desorption treatment is cooled down. The cooling water absorbs the residual heat of the saturated adsorbent after the desorption treatment and becomes heated water. The heated water is discharged from the cooling water outlet of the adsorption tower 1 and enters the heat exchanger 42. The heated water exchanges heat with the heat exchange medium in the heat exchanger 42. The heated water is cooled down and becomes cooling water again and is discharged from the heat exchange outlet of the heat exchanger 42. The cooling water pump 41 sends the cooling water discharged from the heat exchange outlet of the heat exchanger 42 into the adsorption tower 1. In this way, a cooling water circulation loop is formed between the cooling water pump 41, the heat exchanger 42 and each adsorption tower 1. The heat exchange medium can be water, oil or air. The heat of the heated water is absorbed by the heat exchange medium to cool the heated water down to become cooling water.

[0031] After the steam enters each adsorption tower 1 and exchanges heat with the saturated adsorbent, part of the steam condenses into condensed water. The condensed water accumulates in the adsorption tower 1 and can be used as cooling water. Since the cooling water channel and the steam channel are connected, part of the condensed water condensed from the steam will mix with the heated water in the adsorption tower 1 and then be discharged from the cooling water outlet of the adsorption tower 1 into the heat exchanger 42, and after heat exchange with the heat exchange medium, it will be cooled down to become cooling water.

[0032] In order to control the flow state of cooling water in the connecting pipe between the outlet of the cooling water pump 41 and the cooling water inlet of each adsorption tower 1, a control valve is arranged on the connecting pipe between the outlet of the cooling water pump 41 and the cooling water inlet of each adsorption tower 1. When the control valve is opened, the cooling water pumped by the cooling water pump 41 enters the corresponding adsorption tower 1. When the control valve is closed, the cooling water cannot enter the corresponding adsorption tower 1.

[0033] Another aspect of the present invention provides a multi-stage flash adsorption flue gas carbon capture method, which is implemented based on any of the multi-stage flash adsorption flue gas carbon capture systems described above, and the multi-stage flash adsorption flue gas carbon capture method comprises: The carbon dioxide in the flue gas is absorbed by the adsorption tower, and the flue gas without carbon dioxide is discharged; wherein the carbon dioxide in the flue gas is absorbed by the adsorbent stored in the tubes of the adsorption tower, and the adsorbent becomes a saturated adsorbent after adsorbing carbon dioxide; Steam is supplied to the adsorption tower, and the carbon dioxide released by the saturated adsorbent after steam desorption is discharged from the flue gas outlet, and the saturated adsorbent after desorption becomes an adsorbent again; The saturated adsorbent after the desorption treatment is cooled.

[0034] The supplying of steam into the adsorption tower also includes: connecting a steam channel of a plurality of adsorption towers, using a steam inlet of one adsorption tower as a steam total inlet, using a steam outlet of another adsorption tower as a steam total outlet, transporting steam into the adsorption tower through the steam total inlet, and discharging the steam from the steam total outlet after passing through each adsorption tower.

[0035] In the process of supplying steam to the adsorption tower, the pressure value in the tubes of the adsorption tower is adjusted in real time. The pressure value in the tubes of each adsorption tower is adjusted by a corresponding vacuum pump.

[0036] Real-time adjustment of the pressure value in the tubes of the adsorption tower, including: Obtain the temperature value of the steam entering the adsorption tower in real time; The rotation speed of the vacuum pump corresponding to the adsorption tower is adjusted based on the temperature value to adjust the pressure value in the multiple tubes of the adsorption tower.

[0037] The multi-stage flash adsorption flue gas carbon capture system provided by the present invention is provided with a plurality of adsorption towers, and a plurality of array tubes are provided in each adsorption tower, each array tube is filled with an adsorbent, the array tube inlet in each adsorption tower is connected with the flue gas inlet of the adsorption tower, and the array tube outlet of the array tube is connected with the flue gas outlet of the adsorption tower, and the flue gas enters each array tube in the corresponding adsorption tower from the flue gas inlet of the adsorption tower, and the adsorbent in the array tube can adsorb carbon dioxide in the flue gas, and the flue gas without carbon dioxide is discharged from the flue gas outlet of the corresponding adsorption tower, and the adsorbent adsorbed with carbon dioxide becomes a saturated adsorbent, and in order to release the carbon dioxide adsorbed by the saturated adsorbent, steam is transported to the adsorption tower, and the steam enters each adsorption tower in turn and exchanges heat with the saturated adsorbent in the array tube in the adsorption tower, and the saturated adsorbent absorbs the heat of the steam. The carbon dioxide in the saturated adsorbent is released, thereby completing the desorption treatment of the saturated adsorbent. After releasing the carbon dioxide, the saturated adsorbent becomes an adsorbent again, and the released carbon dioxide is discharged from the flue gas outlet. During the heat exchange process between the steam and the saturated adsorbent, in order to provide the best conditions for the saturated adsorbent to release carbon dioxide, a pressure regulating device is connected to the flue gas outlet. The pressure regulating device adjusts the pressure value in multiple tubes in the adsorption tower according to the temperature of the steam entering the corresponding adsorption tower, so that the carbon dioxide in the saturated adsorbent can be completely released. The temperature of the saturated adsorbent that has completed the desorption treatment is relatively high, which is not conducive to the subsequent absorption of carbon dioxide in the flue gas. Cooling water is supplied to the adsorption tower through the cooling device, and the cooling water exchanges heat with the saturated adsorbent after the desorption treatment, thereby cooling the saturated adsorbent after the desorption treatment. The multi-stage flash adsorption flue gas carbon capture system and method provided by the present invention, after the carbon dioxide in the flue gas is adsorbed by the adsorbent, the steam then enters the adsorption tower to desorb the saturated adsorbent, so that the carbon dioxide in the saturated adsorbent is released. In order to improve the desorption effect of the carbon dioxide in the saturated adsorbent, the pressure regulating device adjusts the pressure values ​​in the corresponding multiple tubes in the adsorption tower according to the steam temperature entering each stage of the adsorption tower, so that the steam temperature and the pressure in the tubes reach the optimal conditions for the desorption treatment of the saturated adsorbent, so that the carbon dioxide in the saturated adsorbent is completely released. At the same time, the pressure regulating device is used to fully utilize the waste heat of the steam, which solves the problem in the prior art that the waste heat of the steam extracted from the turbine cannot be fully utilized when used for flue gas carbon capture, thereby improving the efficiency and economy of carbon dioxide capture.

[0038] The optional implementation modes of the embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above implementation modes. Within the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical scheme of the embodiments of the present invention, and these simple modifications all belong to the protection scope of the embodiments of the present invention.

[0039] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the embodiments of the present invention will not further describe various possible combinations.

[0040] In addition, various implementations of the embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the embodiments of the present invention, they should also be regarded as the contents disclosed in the embodiments of the present invention.

Claims

1. A multi-stage flash adsorption flue gas carbon capture system, characterized in that: The multi-stage flash adsorption flue gas carbon capture system comprises: A plurality of adsorption towers (1), wherein a smoke inlet and a smoke outlet are provided on the tower body of the adsorption tower (1), a plurality of tube arrays (2) communicating with the smoke inlet and the smoke outlet are provided in the tower body, and an adsorbent is stored in the tube arrays (2); smoke enters the tube arrays (2) through the smoke inlet, the adsorbent adsorbs carbon dioxide in the smoke to become a saturated adsorbent, and the smoke that has lost carbon dioxide is discharged through the smoke outlet; A steam supply device is used to supply steam to the adsorption tower (1), the steam flows through each adsorption tower (1) in turn and exchanges heat with the saturated adsorbent in the tube array (2) in the adsorption tower (1) to desorb carbon dioxide from the saturated adsorbent, the carbon dioxide released from the saturated adsorbent after desorption is discharged from the flue gas outlet, and the saturated adsorbent after desorption becomes an adsorbent again; The flue gas outlet of each adsorption tower (1) is connected to a pressure regulating device (3), and the pressure regulating device (3) is used to regulate the pressure value in the plurality of tube arrays (2) in the corresponding adsorption tower (1); The cooling device (4) is used to supply cooling water to each adsorption tower (1) to cool down the saturated adsorbent after the desorption treatment.

2. The multi-stage flash adsorption flue gas carbon capture system according to claim 1 is characterized in that: A steam channel is formed in the adsorption tower (1) between the steam inlet and the steam outlet of the adsorption tower (1); The steam channels of the plurality of adsorption towers (1) are connected in sequence, the steam inlet of the first-stage adsorption tower (1) serves as a steam total inlet, the steam outlet of the last-stage adsorption tower (1) serves as a steam total outlet, and the steam enters from the steam total inlet and flows through the steam channels of each adsorption tower (1) before being discharged from the steam total outlet.

3. The multi-stage flash adsorption flue gas carbon capture system according to claim 2 is characterized in that: From the first stage adsorption tower (1) to the last stage adsorption tower (1), the pressure in the adsorption tower (1) decreases step by step.

4. The multi-stage flash adsorption flue gas carbon capture system according to claim 3 is characterized in that: A cooling water channel is formed in the adsorption tower (1) between the cooling water inlet and the cooling water outlet of the adsorption tower (1), and the cooling water channel is connected to the steam channel; The cooling water channels of the plurality of adsorption towers (1) are connected in sequence, the cooling water inlet of the first-stage adsorption tower (1) serves as the total water inlet, and the cooling water outlet of the last-stage adsorption tower (1) serves as the total water outlet, wherein the steam flowing through the adsorption tower (1) partially becomes condensed water after heat exchange with the saturated adsorbent in the tube array (2) in the adsorption tower (1), and the steam-water mixture of the steam and the condensed water enters the next-stage adsorption tower (1) through the steam channel and can undergo flash evaporation.

5. The multi-stage flash adsorption flue gas carbon capture system according to claim 1, characterized in that: The cooling device (4) comprises a cooling water pump (41) and a heat exchanger (42); The water outlet of the cooling water pump (41) is connected to the cooling water inlet of each adsorption tower (1), the water inlet of the cooling water pump (41) is connected to the heat exchange water outlet of the heat exchanger (42), and the heat exchange water inlet of the heat exchanger (42) is connected to the cooling water outlet of each adsorption tower (1); The cooling water pump (41) is used to pump cooling water provided by the heat exchanger (42) from the cooling water inlet of the adsorption tower (1) into the adsorption tower (1); the cooling water absorbs the residual heat of the saturated adsorbent after the desorption treatment to become heated water, which is discharged from the cooling water outlet of the adsorption tower (1) and enters the heat exchanger (42) through the heat exchange water inlet of the heat exchanger (42); The heat exchanger (42) is used to exchange heat between the heated water entering the heat exchanger (42) and the heat exchange medium entering the heat exchanger (42); the heated water loses heat and becomes cooling water again, which is provided to the cooling water pump (41).

6. The multi-stage flash adsorption flue gas carbon capture system according to claim 1, characterized in that: The pressure regulating device (3) is a vacuum pump.

7. A multi-stage flash adsorption flue gas carbon capture method, implemented based on the multi-stage flash adsorption flue gas carbon capture system according to any one of claims 1 to 6, characterized in that: The multi-stage flash adsorption flue gas carbon capture method comprises: The carbon dioxide in the flue gas is absorbed by the adsorption tower, and the flue gas without carbon dioxide is discharged; wherein the carbon dioxide in the flue gas is absorbed by the adsorbent stored in the tubes of the adsorption tower, and the adsorbent becomes a saturated adsorbent after adsorbing carbon dioxide; Steam is supplied to the adsorption tower, and the carbon dioxide released by the saturated adsorbent after steam desorption is discharged from the flue gas outlet, and the saturated adsorbent after desorption becomes an adsorbent again; The saturated adsorbent after the desorption treatment is cooled.

8. The multi-stage flash adsorption flue gas carbon capture method according to claim 7, characterized in that: In the process of supplying steam into the adsorption tower, the pressure value in the tube array of the adsorption tower is adjusted in real time.

9. The multi-stage flash adsorption flue gas carbon capture method according to claim 7, characterized in that: The pressure value in the tubes of each adsorption tower is adjusted by the corresponding vacuum pump.

10. The multi-stage flash adsorption flue gas carbon capture method according to claim 8, characterized in that: Real-time adjustment of the pressure value in the tubes of the adsorption tower, including: Obtain the temperature value of the steam entering the adsorption tower in real time; The rotation speed of the vacuum pump corresponding to the adsorption tower is adjusted based on the temperature value to adjust the pressure value in the multiple tubes of the adsorption tower.

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