Carbon dioxide trapping system

Abstract

The utility model discloses a carbon dioxide trapping system which comprises an absorption tower and a centrifugal demister, a gas inlet is formed in the bottom of the absorption tower, and flue gas enters the absorption tower through the gas inlet; a gas outlet pipe is arranged at the top of the absorption tower, the centrifugal demister is connected with the gas outlet pipe, purified gas enters the centrifugal demister through the gas outlet pipe, and the gas outlet pipe is intersected with a rotating shaft of the centrifugal demister. The centrifugal demister is arranged outside the absorption tower and connected with the absorption tower through the gas outlet pipe, purified gas enters the centrifugal demister through the gas outlet pipe, the speed is high, the control range is wide, and the system operation flexibility is high. The gas outlet pipe is intersected with the rotating shaft of the centrifugal demister, so that the purified gas tangentially enters the centrifugal demister at a high speed to drive the centrifugal demister to rotate to generate centrifugal force, organic amine liquid drops and aerosol entrained in the purified gas are conveniently thrown out, and the organic amine is effectively prevented from escaping.

Description

Technical Field

[0001] The utility model relates to the technical field of flue gas treatment, and more specifically, to a carbon dioxide capture system. Background Art

[0002] At present, chemical absorption carbon dioxide capture technology is widely used in flue gas carbon dioxide capture. However, during the carbon dioxide capture process, some organic amine absorbents and their degradation products are discharged with the flue gas, causing absorbent loss and also bringing a series of environmental problems.

[0003] Existing technologies typically install a water scrubber and demister at the top of the absorption tower. However, these methods are effective at controlling physically entrained larger droplets (particle size > 3 μm), but are inefficient at removing small aerosol particles. Alternatively, a cyclone is installed inside the absorption tower, but the cyclone blades have weak rotational power, resulting in low removal efficiency.

[0004] Therefore, there is an urgent need to provide a convenient and effective carbon dioxide capture system that prevents organic amines from escaping. Utility Model Content

[0005] The purpose of this utility model is to overcome the above-mentioned defects of the prior art and provide a carbon dioxide capture system, including an absorption tower and a centrifugal demister;

[0006] An air inlet is provided at the bottom of the absorption tower, and the flue gas enters the absorption tower through the air inlet;

[0007] An air outlet pipe is provided on the top of the absorption tower, the centrifugal demister is connected to the air outlet pipe, the purified gas enters the centrifugal demister through the air outlet pipe, and the air outlet pipe is arranged perpendicular to the rotating shaft of the centrifugal demister.

[0008] The implementation of the present invention will have the following beneficial effects:

[0009] In this embodiment, the centrifugal demister is installed outside the absorption tower and connected to the absorption tower via an outlet pipe. The purified gas enters the centrifugal demister through the outlet pipe at a high speed, with a wide control range, and high system operational flexibility. The outlet pipe intersects the centrifugal demister's rotational axis, allowing the purified gas to enter the centrifugal demister tangentially at high speed. This drives the centrifugal demister to rotate, generating centrifugal force that facilitates the removal of organic amine droplets and aerosols entrained in the purified gas, effectively preventing the organic amine from escaping. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0011] in:

[0012] Figure 1 A schematic diagram of the carbon dioxide capture system provided by the present invention;

[0013] Figure 2 for Figure 1 An enlarged schematic diagram of area A in the middle;

[0014] 1-absorption tower, 11-air inlet, 12-air outlet pipe, 121-embedded section, 13-first filler, 14-absorption liquid inlet, 15-rich liquid outlet, 16-second filler, 17-demister, 18-water washing liquid inlet, 101-carbon dioxide absorption section, 102-water washing section, 2-centrifugal demister, 21-rotating shaft, 22-blades, 23-guide hole. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0016] Reference Figure 1 , the utility model discloses a carbon dioxide capture system, comprising an absorption tower 1 and a centrifugal demister 2;

[0017] An air inlet 11 is provided at the bottom of the absorption tower 1, and the flue gas enters the absorption tower 1 through the air inlet 11;

[0018] An air outlet pipe 12 is provided at the top of the absorption tower 1 , and the centrifugal demister 2 is connected to the air outlet pipe 12 . The purified gas enters the centrifugal demister 2 through the air outlet pipe 12 . The air outlet pipe 12 is intersected with the rotating shaft 21 of the centrifugal demister 2 .

[0019] It should be noted that the pretreated flue gas enters the absorption tower 1 through the air inlet 11, and comes into countercurrent contact with the organic amine chemical absorption solution in the absorption tower 1. The carbon dioxide in the flue gas is absorbed to obtain purified gas. The purified gas rises radially along the absorption tower 1 and enters the centrifugal demister 2 through the outlet pipe 12.

[0020] In conventional demisters, such as tubular demisters, the air inlet and outlet directions are coaxial. However, the centrifugal demister 2 in this embodiment improves these two directions. The outlet pipe 12 is intersecting with the rotation axis of the centrifugal demister 2. Furthermore, the outlet pipe 12 is perpendicular to the rotation axis 21 of the centrifugal demister 2. The centrifugal demister 2 also has an outlet (not shown) through which the purified gas is discharged from the centrifugal demister 2 and collected. The inlet direction of the purified gas entering the centrifugal demister 2 intersects with the outlet direction of the gas leaving the centrifugal demister 2, facilitating the centrifugal demister 2 to remove organic amine droplets and aerosols entrained in the purified gas.

[0021] In this embodiment, centrifugal demister 2 is positioned outside absorption tower 1 and connected to absorption tower 1 via an outlet pipe 12. Purified gas enters centrifugal demister 2 through outlet pipe 12 at a high speed, with a wide control range, and high system operational flexibility. The outlet pipe 12 intersects with the rotating axis 21 of centrifugal demister 2, allowing purified gas to enter centrifugal demister 2 tangentially and at high speed. This rotation of centrifugal demister 2 generates centrifugal force, which facilitates the removal of organic amine droplets and aerosols entrained in the purified gas, effectively preventing the escape of the organic amine.

[0022] In one embodiment, referring to Figure 1 A first filler 13 is provided in the absorption tower 1 , an air inlet 11 is provided below the first filler 13 , and an absorption liquid inlet 14 is provided above the first filler 13 .

[0023] It should be noted that the absorption tower 1 includes a carbon dioxide absorption section 101, which includes a first filler 13. An organic amine chemical absorption solution enters the absorption tower 1 through an absorption liquid inlet 14, countercurrently contacts the flue gas within the absorption tower 1, and absorbs carbon dioxide from the flue gas, producing purified gas and rich liquid. The purified gas rises radially along the absorption tower 1.

[0024] Specifically, the organic amine chemical absorption solution can be one or more of primary amines, secondary amines, tertiary amines, and sterically hindered amines. The first filler 13 can be a random packing represented by Pall rings, other high-performance packing represented by saddle packing, ring-saddle packing, spherical packing, etc., or a structured packing represented by Stedman wire mesh or Mellapak corrugated mesh.

[0025] Furthermore, a rich liquid outlet 15 is provided at the bottom of the absorption tower 1, through which the rich liquid is discharged from the absorption tower 1. In this embodiment, the rich liquid is discharged from the absorption tower 1 and then enters a desorption tower (not shown in the figure). After the rich liquid is desorbed, a lean liquid is obtained, which is then returned to the absorption tower 1 through the absorption liquid inlet 14 for recycling.

[0026] In one embodiment, referring to Figure 1The absorption tower 1 includes a second filler 16 and a demister 17 arranged from top to bottom. The second filler 16 and the demister 17 are both arranged above the first filler 13; a water washing liquid inlet 18 is provided above the second filler 16.

[0027] It should be noted that the purified gas is obtained from the flue gas through the carbon dioxide absorption section 101, and the purified gas carries chemical absorption solution droplets. A demister 17 is set above the carbon dioxide absorption section 101. Most of the absorption solution droplets carried by the purified gas are intercepted by impact and gravitational inertia, and fall back to the carbon dioxide absorption section 101. The escape of organic amines is controlled for the first time, the probability of organic amine aerosol formation is reduced, and the amount of organic amine droplets and aerosols carried by the purified gas is reduced.

[0028] The absorption tower 1 also includes a water washing section 102, and the water washing section 102 includes a second filler 16. After passing through the demister 17, the purified gas enters the water washing section 102 at the top of the absorption tower 1, and the washing liquid enters the absorption tower 1 through the washing liquid inlet 18. The purified gas and the washing liquid are fully contacted under the action of the second filler 16, and the residual absorption solution in the purified gas is diluted by the washing liquid, thereby reducing the concentration of organic amine in the organic amine droplets and aerosols. The purified gas after water washing leaves the absorption tower 1 and enters the centrifugal demister 2. Specifically, the second filler 16 can also be a random packing represented by a ball ring, or other high-performance packing represented by a saddle packing, a ring-saddle packing, a spherical packing, etc., or a structured packing represented by a Stedman wire mesh, a Mellapak corrugated mesh, etc.

[0029] The second filler 16 is arranged above the demister 17 . The demister 17 intercepts most of the absorption solution droplets and then dilutes the absorption solution remaining in the purified gas with water washing liquid, thereby reducing the load of the water washing section 102 .

[0030] Furthermore, the demister 17 includes one or more of a wire mesh demister, a ridge demister, a cyclone demister, and a tubular demister.

[0031] Furthermore, the demister 17 is made of a hydrophobic material, and the material of the demister 17 includes polypropylene (PP) or polyethylene (PE).

[0032] In a specific embodiment, the diameter of the air outlet pipe 12 is 275 mm-375 mm.

[0033] It should be noted that in this embodiment, the amount of purified gas in the absorption tower 1 is about 10,000 cubic meters per hour, the diameter of the outlet pipe 12 is 275 mm-375 mm, and the flow rate of the purified gas in the outlet pipe 12 is controlled to be 25 m / s-50 m / s.

[0034] The flow rate of the purified gas is controlled by setting the diameter of the outlet pipe 12. When the amount of purified gas is constant, the smaller the diameter, the greater the flow rate. Conversely, the larger the diameter, the smaller the flow rate. In actual applications, the diameter of the outlet pipe 12 can be adjusted according to the actual amount of purified gas to ensure that the flow rate of the purified gas is between 25m / s and 50m / s.

[0035] It is understandable that if the diameter of the outlet pipe 12 is too large, the flow rate of the purified gas is low, and the centrifugal force is small, it is not convenient to throw out the organic amine droplets and aerosols entrained in the purified gas; if the diameter of the outlet pipe 12 is too small, the flow rate of the purified gas is too fast, and the residence time of the purified gas is short, the centrifugal demister 2 has no obvious effect on removing the organic amine droplets and aerosols entrained in the purified gas.

[0036] Further, refer to Figure 2 Outlet pipe 12 includes an embedded section 121 that extends into centrifugal demister 2. The length of embedded section 121 is 100 mm to 500 mm. The purified gas after water washing leaves absorber 1 through the outlet of absorber 1 and enters centrifugal demister 2 through outlet pipe 12. Outlet pipe 12 extends tangentially into centrifugal demister 2 by 100 mm to 500 mm.

[0037] In one embodiment, referring to Figure 1 The centrifugal demister 2 includes a plurality of blades 22, which are arranged around the rotating shaft 21. The blades 22 can be arranged in multiple layers along the extending direction of the rotating shaft 21; along the tangential direction of the rotating shaft 21, the angle between the blades 22 and the rotating shaft 21 is 15°-75°.

[0038] It should be noted that the blades 22 rotate under the power of the fast-flowing purified gas (the flow rate of the purified gas inside the centrifugal demister 2 is controlled between 10m / s-25m / s), driving the purified gas to rotate in the centrifugal demister 2. The centrifugal force generated by the rotation throws the droplets and aerosols entrained in the purified gas to the inner wall of the centrifugal demister 2, and gathers at the bottom of the centrifugal demister 2 under the action of gravity.

[0039] Furthermore, the blade 22 is made of a hydrophobic, lightweight plastic material such as PP or PE.

[0040] In one embodiment, referring to Figure 2 A guide hole 23 is provided at the bottom of the centrifugal demister 2 , and the guide hole 23 is connected to the absorption tower 1 .

[0041] Furthermore, the bottom of the centrifugal demister 2 is arranged at an angle, and the height of the centrifugal demister 2 away from the absorption tower 1 is greater than the height of the centrifugal demister 2 close to the absorption tower 1; the angle between the bottom of the centrifugal demister 2 and the horizontal direction can be 3°-10°, and the horizontal direction is a direction parallel to the ground, that is, the centrifugal demister 2 is arranged at an angle, which facilitates the introduction of organic amine droplets and aerosols trapped at the bottom of the centrifugal demister 2 into the absorption tower 1 through a pipeline. Specific embodiment:

[0043] Example 1:

[0044] After desulfurization, denitrification and dust removal, the coal-fired flue gas enters the absorption tower 1 after flue gas pretreatment, and comes into countercurrent contact with a 30% mass concentration of ethanolamine (MEA) solution. The carbon dioxide in the flue gas is absorbed to obtain purified gas. The purified gas rises along the radial direction of the absorption tower 1, entraining droplets of chemical absorption solution. A roof demister 17 is set above the carbon dioxide absorption layer. Most of the absorption solution droplets entrained by the purified gas are intercepted by impact and gravitational inertia, and fall back to the carbon dioxide absorption section 101.

[0045] After passing through the demister 17, the purified gas enters the water washing section 102 at the top of the absorption tower 1 and is fully contacted with the water washing liquid flowing down from the top of the water washing section 102 under the action of the second filler 16. The chemical absorption solution remaining in the purified gas is diluted by the water washing liquid, thereby reducing the concentration of organic amine in the organic amine droplets and aerosols.

[0046] After water washing, the purified gas enters the centrifugal demister 2 through the outlet pipe 12. The outlet pipe 12 extends 500 mm into the centrifugal demister 2 in a vertical and tangential direction. The flow rate of the purified gas in the outlet pipe 12 is 30 m / s. A layer of PP blades 22 is set inside the centrifugal demister 2. The blades 22 are concentric with the centrifugal demister 2 and are arranged at 45 degrees in the tangential direction. There are 8 blades 22 in total. The blades 22 rotate under the power of the fast-flowing purified gas, driving the purified gas to rotate in the centrifugal demister 2. The centrifugal force generated by the rotation throws the droplets and aerosols entrained in the purified gas onto the wall of the centrifugal demister 2. Under the action of gravity, they gather at the bottom of the centrifugal demister 2. The trapped droplets and aerosols are introduced into the absorption tower 1 through the pipe through the guide hole 23 at the bottom.

[0047] The amine escape in the purified gas was detected to be 15 ppm.

[0048] Example 2:

[0049] After water washing, the purified gas enters the centrifugal demister 2 through the outlet pipe 12. The outlet pipe 12 extends tangentially into the centrifugal demister 2 by 500 mm along the vertical direction. The purified gas in the outlet pipe 12 has a flow rate of 30 m / s. Three layers of PP blades 22 are installed inside the centrifugal demister 2. The blades 22 are concentric with the centrifugal demister 2, and the blades 22 of each layer are arranged at a 45-degree angle along the tangential direction, for a total of eight blades 22. The remaining steps are the same as those in Example 1 and are not further described here.

[0050] The amine escape in the purified gas was detected to be 6 ppm.

[0051] Example 3:

[0052] After water washing, the purified air enters centrifugal demister 2 through outlet pipe 12, which extends 500 mm vertically and tangentially into the interior of centrifugal demister 2. The purified air in outlet pipe 12 has a flow rate of 45 m / s. A layer of PP blades 22 is installed inside centrifugal demister 2. Blades 22 are concentric with centrifugal demister 2 and arranged tangentially at 45 degrees. There are eight blades 22 in total.

[0053] The amine escape in the purified gas was detected to be 8 ppm.

[0054] Comparative Example:

[0055] Compared with Example 1, the comparative example does not have a centrifugal demister, and the purified gas after water washing is directly discharged and collected.

[0056] The amine escape concentration in the purified gas was detected to be 35 ppm. Compared with the comparative example, the centrifugal demister 2 was provided in Examples 1-3, which significantly reduced the amine escape concentration in the purified gas.

[0057] The above-described embodiments merely represent several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements fall within the scope of protection of the present invention. Therefore, the scope of protection of the present utility model patent shall be determined by the appended claims.

Claims

1. A carbon dioxide capture system, characterized in that: Including absorption tower and centrifugal demister; An air inlet is provided at the bottom of the absorption tower, and the flue gas enters the absorption tower through the air inlet; An air outlet pipe is provided on the top of the absorption tower, the centrifugal demister is connected to the air outlet pipe, the purified gas enters the centrifugal demister through the air outlet pipe, and the air outlet pipe is arranged to intersect with the rotating shaft of the centrifugal demister.

2. The carbon dioxide capture system according to claim 1, characterized in that A first filler is provided in the absorption tower, the air inlet is arranged below the first filler, and an absorption liquid inlet is provided above the first filler.

3. The carbon dioxide capture system according to claim 2, characterized in that The absorption tower includes a second filler and a demister arranged from top to bottom, wherein the second filler and the demister are both arranged above the first filler; and a water washing liquid inlet is provided above the second filler.

4. The carbon dioxide capture system according to claim 3, characterized in that The demister includes one or more of a wire mesh demister, a ridge demister, a cyclone demister, and a tubular demister.

5. The carbon dioxide capture system according to claim 3, characterized in that The material of the demister includes polypropylene or polyethylene.

6. The carbon dioxide capture system according to claim 1, wherein: The centrifugal demister includes a plurality of blades, and the blades are arranged around the rotating shaft.

7. The carbon dioxide capture system according to claim 6, characterized in that Along the tangential direction of the rotation axis, the angle between the blade and the rotation axis is 15°-75°.

8. The carbon dioxide capture system according to claim 6, characterized in that The blade material includes polypropylene or polyethylene.

9. The carbon dioxide capture system according to claim 1, wherein: A guide hole is provided at the bottom of the centrifugal demister, and the guide hole is connected to the absorption tower.

10. The carbon dioxide capture system according to claim 9, characterized in that The bottom of the centrifugal demister is tilted, and the height of the centrifugal demister away from the absorption tower is greater than the height of the centrifugal demister close to the absorption tower.

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