A system and method for adsorbing and recovering CO2 in flue gas

Abstract

The invention relates to the technical field of carbon capture and discloses a method for recovering CO in flue gas by adsorption. 2 The system and method include a moving bed adsorption tower, a desorption device, a cooling and lifting device, and a cooling and conveying device. The bottom outlet of the moving bed adsorption tower is connected to the inlet of the desorption device, the outlet of the desorption device is connected to the lower inlet of the cooling and lifting device, the upper outlet of the cooling and lifting device is connected to the inlet of the cooling and conveying device, and the outlet of the cooling and conveying device is connected to the top inlet of the moving bed adsorption tower; the desorption device includes a first shell and a first conveyor belt arranged inside the first shell; the cooling and conveying device includes a second shell and a second conveyor belt arranged inside the second shell. The system adopts a combination of "moving bed + conveyor belt + bucket elevator", which can greatly reduce the degree of wear of the adsorbent during operation, thereby ensuring the long-term efficient and stable operation of the device and reducing investment and operating costs.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon capture, and in particular to a system and method for adsorbing and recovering CO2 in flue gas. Background Art

[0002] Carbon capture, utilization and storage (CCUS) is an inevitable choice to achieve the global goal of addressing climate change, and is also an important part of my country's carbon neutrality technology system. Among the many carbon dioxide capture technologies, chemical adsorption carbon capture technology has the characteristics of low regeneration energy consumption and simple process flow, and is one of the more promising solutions.

[0003] At present, the chemical adsorption process system mainly uses a fluidized bed (fast fluidized bed and bubbling fluidized bed) to realize the adsorption and desorption process of CO2, as described in the literature "Continuous operation of the potassium-based drysorbent CO2 capture process with two fluidized-bed reactors", "Circulating Fluid-Bed Studies for CO2 Capture from Flue Gas using K2CO3 / Al2O3 Adsorbent", etc. However, the biggest problem faced is the wear of the adsorbent. On the one hand, there is collision wear between the adsorbent particles, and on the other hand, there is wear between the adsorbent particles and the wall of the reaction device and the gas-solid separation in the cyclone separator at the reactor outlet. This causes a large amount of fine powder to be generated during the operation of the adsorption device. New adsorbent particles must be added in time to ensure stable operation of the device, but this results in high operating and investment costs. Summary of the invention

[0004] The purpose of the present invention is to effectively overcome the problem of severe wear of adsorbent particles in the prior art and to provide a system and method for adsorbing and recovering CO2 in flue gas.

[0005] In order to achieve the above-mentioned object, the present invention provides a system for adsorbing and recovering CO2 in flue gas, the system comprising a moving bed adsorption tower, a desorption device, a cooling and lifting device and a cooling and conveying device, the bottom outlet of the moving bed adsorption tower is connected to the inlet of the desorption device, the outlet of the desorption device is connected to the lower inlet of the cooling and lifting device, the upper outlet of the cooling and lifting device is connected to the inlet of the cooling and conveying device, and the outlet of the cooling and conveying device is connected to the top inlet of the moving bed adsorption tower;

[0006] The desorption device comprises a first shell and a first conveyor belt arranged inside the first shell, wherein the first conveyor belt is used to convey the adsorbent from the bottom outlet of the moving bed adsorption tower to the lower inlet of the cooling and lifting device;

[0007] The cooling conveyor device comprises a second shell and a second conveyor belt arranged inside the second shell, and the second conveyor belt is used to convey the adsorbent from the upper outlet of the cooling lifting device to the top inlet of the moving bed adsorption tower.

[0008] Preferably, a flue gas outlet is provided at the upper portion of the moving bed adsorption tower, and a flue gas inlet is provided at the lower portion of the moving bed adsorption tower.

[0009] Preferably, a built-in cooling coil is provided inside the moving bed adsorption tower.

[0010] Preferably, a temperature monitor is provided inside the moving bed adsorption tower for monitoring the internal temperature of the moving bed adsorption tower during operation.

[0011] Preferably, a surface heating coil is provided on the surface of the first shell of the desorption device.

[0012] Preferably, a CO2 outlet is provided on the first shell of the desorption device, and the CO2 outlet is used to discharge the CO2 generated in the desorption of the desorption device.

[0013] Preferably, the cooling and lifting device comprises a bucket elevator;

[0014] Preferably, the bucket elevator is provided with a first cooling air inlet and a first cooling air outlet, wherein the first cooling air inlet and the first cooling air outlet are used for introducing and discharging cooling air respectively;

[0015] Preferably, the cooling gas is nitrogen.

[0016] Preferably, a second cooling air outlet and a second cooling air inlet are provided on the second shell of the cooling conveyor device, and the second cooling air inlet and the second cooling air outlet are used for introducing and discharging cooling air respectively;

[0017] Preferably, the cooling gas is nitrogen.

[0018] The second aspect of the present invention provides a method for adsorbing and recovering CO2 in flue gas, the method being implemented in the above-mentioned system;

[0019] The method comprises the following steps:

[0020] The flue gas to be treated is introduced into the moving bed adsorption tower, and is countercurrently contacted with the adsorbent with a particle size of 0.3-0.8mm moving from top to bottom, and CO2 in the flue gas is removed by chemical adsorption. The operating temperature of the moving bed adsorption tower is controlled to be 40-80°C by the built-in cooling coil, and the flue gas with CO2 removed is discharged from the moving bed adsorption tower; the adsorbent after adsorbing CO2 is discharged from the bottom of the moving bed adsorption tower by self-weight dropping, and then enters the first conveyor belt in the desorption device from the inlet of the desorption device for heating, desorption and conveying at the same time, and the operating temperature of the desorption device is controlled to be 100-300°C, and the generated CO2 gas is discharged from the CO2 outlet of the desorption device. The adsorbent after desorption is conveyed to the outlet of the desorption device, and then is sent into the cooling and lifting device from the lower inlet of the cooling and lifting device for lifting and preliminary cooling at the same time. The adsorbent after preliminary cooling is lifted to the upper outlet of the cooling and lifting device for discharge, and the temperature of the upper outlet is controlled to be 80-100°C when the adsorbent is discharged. Then the preliminarily cooled adsorbent is sent from the inlet of the cooling conveyor device to the second conveyor belt of the cooling conveyor device for cooling and conveying at the same time. The cooled adsorbent is conveyed to the outlet of the cooling conveyor device for discharge, and the temperature of the outlet is controlled to be 40-80°C when the adsorbent is discharged, and then enters the moving bed adsorption tower from the top inlet of the moving bed adsorption tower for reuse.

[0021] Preferably, the flue gas to be treated is the flue gas after purification and dehydration;

[0022] Preferably, the adsorbent is selected from at least one of a solid amine-based adsorbent and an alkali metal-based adsorbent.

[0023] In the present invention, the combination of "moving bed + conveyor belt + bucket elevator" is adopted, which can greatly reduce the degree of wear of adsorbent particles in the "adsorption-desorption" process, thereby ensuring the long-term efficient and stable operation of the device and reducing investment and operating costs. The moving bed is used to realize the contact adsorption process between the adsorbent and the flue gas. Compared with the bubbling fluidized bed and the fast fluidized bed, the adsorbent particles in the moving bed mainly move downward by gravity, the operating speed is lower, and the degree of particle wear is greatly reduced. At the same time, the moving bed makes the volume density of the bed particles larger than that of the bubbling and fast fluidized beds, which effectively improves the contact between the flue gas and the adsorbent, thereby improving the CO2 capture efficiency; when the adsorbent after adsorption runs in the desorption device, the cooling and lifting device and the cooling and conveying device, the conveyor belt and the bucket elevator are used to realize the transportation of the adsorbent, so that the adsorbent particles remain relatively static with the transportation device during transportation, and there is basically no particle wear. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the system for adsorbing and recovering CO2 in flue gas in the present invention.

[0025] Description of Reference Numerals

[0026] 1 Moving bed adsorption tower 2 Desorption device

[0027] 3Cooling lifting device 4Cooling conveying device

[0028] 11 Smoke outlet 12 Smoke inlet

[0029] 13 built-in cooling coil 21 first conveyor belt

[0030] 22 first shell 23 surface heating coil

[0031] 24CO2 export 31 bucket elevator

[0032] 32 first cooling air inlet 33 first cooling air outlet

[0033] 41 second conveyor belt 42 second housing

[0034] 43 second cooling air inlet 44 second cooling air outlet DETAILED DESCRIPTION

[0035] The specific implementation 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 present invention, and is not used to limit the present invention.

[0036] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0037] On the one hand, the present invention provides a system for adsorbing and recovering CO2 in flue gas, as shown in the schematic diagram Figure 1 As shown, the system includes a moving bed adsorption tower 1, a desorption device 2, a cooling and lifting device 3 and a cooling and conveying device 4, the bottom outlet of the moving bed adsorption tower 1 is connected to the inlet of the desorption device 2, the outlet of the desorption device 2 is connected to the lower inlet of the cooling and lifting device 3, the upper outlet of the cooling and lifting device 3 is connected to the inlet of the cooling and conveying device 4, and the outlet of the cooling and conveying device 4 is connected to the top inlet of the moving bed adsorption tower 1;

[0038] The desorption device 2 includes a first shell 22 and a first conveyor belt 21 disposed inside the first shell 22, and the first conveyor belt 21 is used to convey the adsorbent from the bottom outlet of the moving bed adsorption tower 1 to the lower inlet of the cooling and lifting device 2;

[0039] The cooling conveyor device 4 includes a second shell 42 and a second conveyor belt 41 disposed inside the second shell 42 . The second conveyor belt 41 is used to convey the adsorbent from the upper outlet of the cooling lifting device 3 to the top inlet of the moving bed adsorption tower 1 .

[0040] In the present invention, the moving bed adsorption tower 1 is used to complete the process of adsorption by countercurrent contact between the flue gas to be treated and the adsorbent particles.

[0041] In a preferred embodiment, a flue gas outlet 11 is provided at the upper portion of the moving bed adsorption tower 1, and a flue gas inlet 12 is provided at the lower portion of the moving bed adsorption tower.

[0042] In a preferred embodiment, a temperature monitor is provided inside the moving bed adsorption tower 1 to monitor the internal temperature of the moving bed adsorption tower 1 during operation.

[0043] In a preferred embodiment, a built-in cooling coil 13 is provided inside the moving bed adsorption tower 1. Since the adsorption process is an exothermic reaction, the built-in cooling coil 13 is provided inside the moving bed adsorption tower 1 to ensure that the moving bed adsorption tower 1 operates at an optimal temperature. Further preferably, a cooling water inlet and a cooling water outlet are provided on the built-in cooling coil 13, which can be used to introduce and discharge cooling water, respectively.

[0044] In the present invention, in the moving bed adsorption tower 1, the flue gas inlet 12 is arranged at the lower part of the moving bed adsorption tower 1, for sending the flue gas to be treated into the moving bed adsorption tower 1 for treatment; the flue gas outlet 11 is arranged at the upper part of the moving bed adsorption tower 1, for discharging the flue gas after adsorption of CO2 out of the moving bed adsorption tower 1; the top inlet is used to send the adsorbent into the moving bed adsorption tower 1; the bottom outlet is used to discharge the adsorbent adsorbed with CO2 out of the moving bed adsorption tower 1.

[0045] In a preferred embodiment, a surface heating coil 23 is provided on the surface of the first shell 22 of the desorption device 2. Since the reaction in the desorption device 2 is an endothermic reaction, the surface heating coil 23 can ensure that the desorption process is carried out at an optimal temperature.

[0046] Further preferably, the surface heating coil 23 is provided with a steam inlet and a steam outlet.

[0047] Preferably, the first conveyor belt 21 is horizontally arranged inside the first shell 22 .

[0048] In a preferred embodiment, a temperature monitor is provided inside the first housing 22 of the desorption device 2 for monitoring the temperature inside the desorption device 2 in real time.

[0049] In a preferred embodiment, a rotating sealing plate is provided between the bottom outlet of the moving bed adsorption tower 1 and the inlet of the desorption device 2. The rotating sealing plate can prevent the flue gas in the moving bed adsorption tower 1 from being brought into the desorption device 2 by the adsorbent particles, and on the other hand, can also ensure the uniform spreading of the adsorbent on the first conveyor belt 21.

[0050] In the present invention, the desorption device 2 is used to perform a desorption process on the adsorbent that has adsorbed CO2, and the desorption of the adsorbent is completed by heating, thereby obtaining a regenerated adsorbent.

[0051] In a preferred embodiment, the adsorbent adsorbed with CO2 from the bottom outlet of the moving bed adsorption tower 1 falls onto the first conveyor belt 21 through the inlet of the desorption device 2 by self-weight falling, and the desorption process and the conveying process are completed simultaneously on the first conveyor belt 21, that is, desorption and conveying are carried out simultaneously, and the adsorbent after desorption is conveyed to the outlet of the desorption device 2.

[0052] Preferably, the outlet of the desorption device 2 is arranged at the bottom of the desorption device 2. Further preferably, a rotating sealing plate is provided between the bottom outlet of the desorption device 2 and the inlet of the cooling and lifting device 3, and the rotating sealing plate can prevent the CO2 gas generated in the desorption device 2 from being brought into the cooling and lifting device 3 by the adsorbent particles, and on the other hand, can also ensure uniform delivery of the adsorbent.

[0053] Preferably, a CO2 outlet 24 is provided on the first shell 22 of the desorption device 2 , and the CO2 outlet 24 is used to discharge the CO2 generated by desorption of the desorption device 2 .

[0054] In the present invention, since the temperature in the desorption device 2 is higher than the bed temperature of the moving bed adsorption tower 1, the adsorbent particles obtained from the desorption device 2 must be cooled before entering the moving bed adsorption tower 1. Based on this, the cooling and lifting device 3 is used to preliminarily cool and transfer the adsorbent from the desorption device 2.

[0055] In a preferred embodiment, the cooling and lifting device 3 includes a bucket elevator 31; further preferably, the bucket elevator 31 is provided with a first cooling gas inlet 32 ​​and a first cooling gas outlet 33. The bucket elevator 31 is used to transfer the adsorbent from the desorption device 2 to the cooling and conveying device 4, and the first cooling gas inlet 32 ​​and the first cooling gas outlet 33 are used to introduce and discharge cooling gas, respectively, that is, in the cooling and lifting device 3, cooling and lifting are performed simultaneously.

[0056] Preferably, the cooling gas is nitrogen.

[0057] In a preferred embodiment, the gas discharged from the first cooling gas outlet 33 may enter an external heat exchanger for cooling, and then circulate for preliminary cooling of the adsorbent.

[0058] In a preferred embodiment, a temperature monitor is provided at the upper outlet of the cooling and lifting device 3 for real-time monitoring of the outlet temperature of the adsorbent when it is discharged.

[0059] In the present invention, the cooling conveyor 4 is used to transfer the adsorbent from the cooling lifting device 3 to the moving bed adsorption tower 1 .

[0060] Preferably, the second conveyor belt 41 is horizontally arranged inside the second shell 42 .

[0061] Preferably, a second cooling air outlet 44 and a second cooling air inlet 43 are provided on the second shell 42 of the cooling conveyor 4, and the second cooling air inlet 43 and the second cooling air outlet 44 are used for introducing and discharging cooling air respectively; the cooling air can directly contact the adsorbent to further cool it.

[0062] Preferably, the cooling gas is nitrogen.

[0063] More preferably, the gas discharged from the cooling conveyor 4 can enter an external heat exchanger for cooling, and then circulate for cooling the adsorbent.

[0064] In a preferred embodiment, a temperature monitor is provided at the outlet of the cooling conveyor 4 for real-time monitoring of the outlet temperature of the adsorbent when it is discharged.

[0065] The second aspect of the present invention provides a method for adsorbing and recovering CO2 in flue gas, the method being implemented in the above-mentioned system;

[0066] The method comprises the following steps:

[0067] The flue gas to be treated is introduced into the moving bed adsorption tower 1, and is countercurrently contacted with the adsorbent with a particle size of 0.3-0.8 mm moving from top to bottom, and CO2 in the flue gas is removed by chemical adsorption. The operating temperature of the moving bed adsorption tower 1 is controlled to be 40-80°C by the built-in cooling coil 13, and the flue gas from which CO2 is removed is discharged from the moving bed adsorption tower 1; the adsorbent after adsorbing CO2 is discharged from the bottom of the moving bed adsorption tower 1 by self-weight dropping, and then enters the first conveyor belt 21 in the desorption device 2 from the inlet of the desorption device 2 for heating, desorption and conveying at the same time, and the operating temperature of the desorption device 2 is controlled to be 100-300°C, and the generated CO2 gas is discharged from the CO2 outlet 24 of the desorption device 2 The adsorbent after desorption is conveyed to the outlet of the desorption device 2, and then is sent into the cooling and lifting device 3 from the lower inlet of the cooling and lifting device 3 for lifting and preliminary cooling at the same time. The adsorbent after preliminary cooling is lifted to the upper outlet of the cooling and lifting device 3 for discharge, and the temperature of the upper outlet is controlled to be 80-100°C when the adsorbent is discharged. Then the preliminarily cooled adsorbent is sent from the inlet of the cooling conveyor 4 to the second conveyor belt 41 of the cooling conveyor 4 for cooling and conveying at the same time. The cooled adsorbent is conveyed to the outlet of the cooling and conveyor 4 for discharge, and the temperature of the outlet is controlled to be 40-80°C when the adsorbent is discharged, and then enters the moving bed adsorption tower 1 from the top inlet for reuse.

[0068] In a specific embodiment, the flue gas to be treated is introduced into the flue gas inlet 12 at the bottom of the moving bed adsorption tower 1, and is countercurrently contacted with the adsorbent with a particle size of 0.3-0.8 mm moving from top to bottom, and CO2 in the flue gas is removed by chemical adsorption, and the operating temperature of the moving bed adsorption tower 1 is controlled to be 40-80°C by the built-in cooling coil 13; the flue gas after adsorption treatment is discharged from the flue gas outlet 11 at the top of the moving bed adsorption tower 1, and the adsorbent after CO2 adsorption is discharged from the bottom outlet of the moving bed adsorption tower 1 by self-weight dropping, and then enters the first conveyor belt 21 in the desorption device 2 from the inlet of the desorption device 2 for heating, desorption and transportation at the same time, and the operating temperature of the desorption device 2 is controlled to be 100-300°C by the surface heating coil 23, and the CO2 gas generated in the desorption device 2 is discharged from the CO2 outlet 24 of the desorption device 2. The adsorbent is conveyed to the outlet of the desorption device 2, and then sent into the cooling and lifting device 3 from the lower inlet of the cooling and lifting device 3 for lifting and preliminary cooling at the same time. The preliminary cooling is carried out by direct contact of the nitrogen introduced through the first cooling gas inlet of the cooling and lifting device 3 with the adsorbent. The preliminarily cooled adsorbent is lifted to the upper outlet of the cooling and lifting device 3 for discharge, and the temperature of the upper outlet is controlled to be 80-100°C when the adsorbent is discharged. Then the preliminarily cooled adsorbent enters the second conveyor belt 41 of the cooling and conveying device 4 from the inlet of the cooling conveyor 4 for simultaneous cooling and conveying. The cooling is carried out by nitrogen introduced through the second cooling gas inlet of the cooling and conveying device 4. The cooled adsorbent is conveyed to the outlet of the cooling and conveying device 4 for discharge, and the temperature of the outlet is controlled to be 40-80°C when the adsorbent is discharged. Then it enters the moving bed adsorption tower 1 from the top inlet of the moving bed adsorption tower 1 for reuse.

[0069] Preferably, the flue gas to be treated is the flue gas after purification and dehydration. Further preferably, the flue gas to be treated is obtained by purifying and dehydrating the flue gas from a coal-fired or gas-fired power plant.

[0070] Preferably, the adsorbent is selected from at least one of a solid amine-based adsorbent and an alkali metal-based adsorbent.

[0071] The present invention will be described in detail below through examples, but the protection scope of the present invention is not limited thereto.

[0072] Examples 1-3 all use the following system for CO2 adsorption and recovery: Figure 1As shown, the system includes a moving bed adsorption tower 1, a desorption device 2, a cooling and lifting device 3 and a cooling and conveying device 4, the bottom outlet of the moving bed adsorption tower 1 is connected to the inlet of the desorption device 2, the outlet of the desorption device 2 is connected to the lower inlet of the cooling and lifting device 3, the upper outlet of the cooling and lifting device 3 is connected to the inlet of the cooling and conveying device 4, and the outlet of the cooling and conveying device 4 is connected to the top inlet of the moving bed adsorption tower 1;

[0073] The desorption device 2 includes a first shell 22 and a first conveyor belt 21 disposed inside the first shell 22, and the first conveyor belt 21 is used to convey the adsorbent from the bottom outlet of the moving bed adsorption tower 1 to the lower inlet of the cooling and lifting device 2;

[0074] The cooling conveyor device 4 includes a second shell 42 and a second conveyor belt 41 disposed inside the second shell 42, and the second conveyor belt 41 is used to convey the adsorbent from the upper outlet of the cooling lifting device 3 to the top inlet of the moving bed adsorption tower 1;

[0075] The moving bed adsorption tower 1 is provided with a flue gas outlet 11 at the top and a flue gas inlet 12 at the bottom; the moving bed adsorption tower 1 is provided with a built-in cooling coil 13; the moving bed adsorption tower 1 is provided with a temperature monitor for monitoring the internal temperature of the moving bed adsorption tower 1 during operation;

[0076] The surface of the first shell 22 of the desorption device 2 is provided with a surface heating coil 23; the first conveyor belt 21 is horizontally arranged inside the first shell 22; the first shell 22 of the desorption device 2 is provided with a CO2 outlet 24;

[0077] The cooling and lifting device 3 includes a bucket elevator 31, and the bucket elevator 31 is provided with a first cooling air inlet 32 ​​and a first cooling air outlet 33, and the first cooling air inlet 32 ​​and the first cooling air outlet 33 are used for introducing and discharging cooling air (nitrogen) respectively;

[0078] The second conveyor belt 41 is horizontally arranged inside the second shell 42; the second shell 42 of the cooling conveyor 4 is provided with a second cooling air outlet 44 and a second cooling air inlet 43, and the second cooling air inlet 43 and the second cooling air outlet 44 are respectively used for introducing and discharging cooling air (nitrogen).

[0079] Examples 1-3

[0080] The flue gas to be treated is introduced into the flue gas inlet 12 at the bottom of the moving bed adsorption tower 1, and is countercurrently contacted with the adsorbent moving from top to bottom, and CO2 in the flue gas is removed by chemical adsorption, and the operating temperature of the moving bed adsorption tower 1 is controlled by the built-in cooling coil 13; the flue gas after adsorption treatment is discharged from the flue gas outlet 11 at the top of the moving bed adsorption tower 1, and the adsorbent after adsorbing CO2 is discharged from the bottom outlet of the moving bed adsorption tower 1 by self-weight dropping, and then enters the first conveyor belt 21 in the desorption device 2 from the inlet of the desorption device 2 for heating, desorption and transportation at the same time, and the operating temperature of the desorption device 2 is controlled by the surface heating coil 23, and the CO2 gas generated in the desorption device 2 is discharged from the CO2 outlet 24 of the desorption device 2, and the adsorbent after desorption is transported to the outlet of the desorption device 2 , and then it is sent into the cooling lifting device 3 from the lower inlet of the cooling lifting device 3 for lifting and preliminary cooling at the same time. The preliminary cooling is carried out by the nitrogen introduced through the first cooling gas inlet of the cooling lifting device 3 directly contacting the adsorbent. The preliminary cooled adsorbent is lifted to the upper outlet of the cooling lifting device 3 for discharge, and the temperature of the upper outlet is controlled when the adsorbent is discharged. Then the preliminary cooled adsorbent enters the second conveyor belt 41 of the cooling conveyor 4 from the inlet of the cooling conveyor 4 for simultaneous cooling and conveying. The cooling is carried out by the nitrogen introduced through the second cooling gas inlet of the cooling conveyor 4. The cooled adsorbent is conveyed to the outlet of the cooling conveyor 4 for discharge, and the temperature of the outlet is controlled when the adsorbent is discharged. Then it enters the moving bed adsorption tower 1 from the top inlet of the moving bed adsorption tower 1 for reuse.

[0081] The flue gas to be treated used in Examples 1-3 is the flue gas after purification and dehydration, the source of the flue gas is shown in Table 1, the source of the adsorbent is shown in Table 1, and the operating temperature in the moving bed adsorption tower 1 and the desorption device 2 is shown in Table 1.

[0082] Table 1

[0083]

[0084]

[0085] The system described in the present invention uses a moving bed adsorption tower to complete the CO2 adsorption process. Under the same working conditions, the same adsorbent type and after the device has been running for 24 hours, the degree of adsorption particle wear of the moving bed adsorption tower is at least 50% lower than that of the bubbling fluidized bed adsorption tower, and the degree of adsorption particle wear is at least 80% lower than that of the fast fluidized bed adsorption tower; the desorption and transportation of the adsorbent are completed in the desorption device, the cooling and lifting device and the cooling and conveying device. Because the adsorbent and the transport device are in a relatively static state, there is basically no wear of the adsorbent particles. Therefore, the system described in the present invention is used to adsorb and recover CO2 from flue gas, and the degree of adsorption of the adsorbent is greatly reduced.

[0086] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for recovering CO2 from flue gas by adsorption, characterized in that: The method is implemented in a system for adsorbing and recovering CO2 in flue gas; The method comprises the following steps: The flue gas to be treated is introduced into a moving bed adsorption tower (1), and is countercurrently contacted with an adsorbent having a particle size of 0.3-0.8 mm moving from top to bottom, and CO2 in the flue gas is removed by chemical adsorption. The operating temperature of the moving bed adsorption tower (1) is controlled to be 40-80°C by a built-in cooling coil (13), and the flue gas from which CO2 has been removed is discharged from the moving bed adsorption tower (1); the adsorbent after adsorbing CO2 is discharged from the bottom of the moving bed adsorption tower (1) by self-weight falling, and then enters the first conveyor belt (21) in the desorption device (2) from the inlet of the desorption device (2) to be heated, desorbed and conveyed at the same time, and the operating temperature of the desorption device (2) is controlled to be 100-300°C, and the generated CO2 gas is discharged from the CO2 outlet (24) of the desorption device (2). The adsorbent after desorption is conveyed to the outlet of the desorption device (2), and then is conveyed into the cooling and lifting device (3) from the lower inlet of the cooling and lifting device (3) for lifting and preliminary cooling at the same time. The adsorbent after preliminary cooling is lifted to the upper outlet of the cooling and lifting device (3) for discharge, and the temperature of the upper outlet is controlled to be 80-100° C. when the adsorbent is discharged. The preliminarily cooled adsorbent is then conveyed from the inlet of the cooling and conveying device (4) to the second conveyor belt (41) of the cooling and conveying device (4) for cooling and conveying at the same time. The cooled adsorbent is conveyed to the outlet of the cooling and conveying device (4) for discharge, and the temperature of the outlet is controlled to be 40-80° C. when the adsorbent is discharged, and then enters the moving bed adsorption tower (1) from the top inlet of the moving bed adsorption tower (1) for reuse. The adsorbent is selected from at least one of a solid amine-based adsorbent and an alkali metal-based adsorbent; The system comprises a moving bed adsorption tower (1), a desorption device (2), a cooling and lifting device (3) and a cooling and conveying device (4); the bottom outlet of the moving bed adsorption tower (1) is connected to the inlet of the desorption device (2), the outlet of the desorption device (2) is connected to the lower inlet of the cooling and lifting device (3), the upper outlet of the cooling and lifting device (3) is connected to the inlet of the cooling and conveying device (4), and the outlet of the cooling and conveying device (4) is connected to the top inlet of the moving bed adsorption tower (1); The desorption device (2) comprises a first shell (22) and a first conveyor belt (21) arranged inside the first shell, wherein the first conveyor belt (21) is used to convey the adsorbent from the bottom outlet of the moving bed adsorption tower (1) to the lower inlet of the cooling and lifting device (3); The cooling conveying device (4) comprises a second shell (42) and a second conveyor belt (41) arranged inside the second shell (42), wherein the second conveyor belt (41) is used to convey the adsorbent from the upper outlet of the cooling lifting device (3) to the top inlet of the moving bed adsorption tower (1); A surface heating coil (23) is provided on the surface of the first shell (22) of the desorption device (2); The cooling and lifting device (3) comprises a bucket elevator (31); the bucket elevator (31) is provided with a first cooling gas inlet (32) and a first cooling gas outlet (33), the first cooling gas inlet (32) and the first cooling gas outlet (33) are respectively used for introducing and discharging cooling gas; the cooling gas is nitrogen; The second shell (42) of the cooling conveyor (4) is provided with a second cooling gas outlet (44) and a second cooling gas inlet (43), wherein the second cooling gas inlet (43) and the second cooling gas outlet (44) are respectively used for introducing and discharging cooling gas; the cooling gas is nitrogen; A rotating sealing plate is provided between the bottom outlet of the moving bed adsorption tower (1) and the inlet of the desorption device (2), and a rotating sealing plate is provided between the bottom outlet of the desorption device (2) and the inlet of the cooling and lifting device (3).

2. The method according to claim 1, characterized in that The upper portion of the moving bed adsorption tower (1) is provided with a flue gas outlet (11), and the lower portion of the moving bed adsorption tower (1) is provided with a flue gas inlet (12).

3. The method according to claim 1, characterized in that A built-in cooling coil (13) is provided inside the moving bed adsorption tower (1).

4. The method according to claim 1 or 2, characterized in that: A temperature monitor is provided inside the moving bed adsorption tower (1) for monitoring the internal temperature of the moving bed adsorption tower (1) during operation.

5. The method according to claim 1, characterized in that A CO2 outlet (24) is provided on the first shell (22) of the desorption device (2), and the CO2 outlet (24) is used to discharge the CO2 generated by desorption in the desorption device (2).

6. The method according to claim 1, characterized in that The flue gas to be treated is the flue gas after purification and dehydration.

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