A triangular multi-channel SCR static mixer

Abstract

The present invention relates to a triangular multi-channel SCR static mixer, comprising a mixer body and a guide plate, wherein the mixer body comprises a triangular partition plate, an angle plate, and an inlet connector, wherein the partition plate is arranged up and down to form a flue gas channel, wherein the three sides of the triangular partition plate form a first and a second flue gas inlet and a flue gas outlet, and are located on one side of the first / second flue gas inlet, and the angle plate seals the first / second flue gas inlet of the odd / even layers on the side; the guide plate is arranged upstream of the flue gas inlet, and the inlet connector is arranged in the flue gas channel at the intersection of the first and second flue gas inlets, and the inlet connector is in a triangular cone shape, and the inlet connector connects the angle plates on both sides. The present invention can reduce the relative standard deviation of the NOx concentration distribution at the inlet of the ammonia injection grid by more than 60%, greatly reduce the influence of the unit load, grinding combination and combustion adjustment on the NOx concentration distribution at the SCR inlet, and fundamentally improve the adaptability of the SCR denitrification device to variable working conditions.

Description

Technical Field

[0001] The invention relates to the technical field of SCR denitration, and in particular to a triangular multi-channel SCR static mixer. Background Art

[0002] Under the current situation of ultra-low NOx emissions, NOx emissions from coal-fired power plants must be reduced to 50mg / m 3 Below, the SCR denitrification efficiency needs to be increased to about 90%. In order to control the ammonia escape concentration and ensure the safe operation of the unit, it is necessary not only to increase the catalyst volume in sufficient quantity, but also to put forward higher requirements for the uniformity of the NH3 / NO molar ratio distribution at the catalyst inlet of the top layer of the SCR reactor. The NOx concentration and distribution at the SCR inlet are directly related to the combustion conditions in the furnace. Changes in the combustion conditions in the furnace caused by unit load, mill combination changes and combustion adjustments will lead to significant changes in the NOx concentration distribution at the SCR inlet, the uniformity of the NH3 / NO molar ratio distribution at the catalyst inlet will deteriorate, and the ammonia escape at the denitrification outlet will increase.

[0003] In order to meet the demand for ultra-low NOx emissions, it is urgent to develop a new type of SCR static mixer to reduce the impact of unit load, grinding combination and combustion adjustment on the NOx concentration distribution at the SCR inlet, fundamentally improve the adaptability of the SCR denitrification device to variable operating conditions, and reduce ammonia slip.

[0004] In order to improve the uniformity of the NH3 / NOx molar ratio distribution at the SCR catalyst inlet, AIG nozzles and static mixers are usually arranged in an array on the SCR inlet cross section to enhance the mixing of the reducing agent ammonia gas at the nozzle outlet and the local flue gas. These SCR static mixers have a small mixing range (≤3m) and can only adapt to the changes in the NOx concentration field and flow field in the upstream flue gas by adjusting the AIG branch flow. When the NOx concentration distribution upstream of the AIG changes greatly under different unit loads and coal mill combinations, the conventional ammonia injection mixing device operating conditions cannot adapt to the catalyst inlet NH3 / NOx mixing uniformity.

[0005] See the patent with publication number CN106731827A, which discloses a large-scale self-mixing device for flue gas upstream of AIG. A diamond-shaped partition is set in the middle of the inlet of the device, and straight plates or folded plates are used on both sides to guide the flow, and no bypass element is set at the outlet. Due to the limitations of the inlet and outlet structure of the device, the relative standard deviation of the NOx concentration distribution at the inlet of the ammonia injection grid can only be reduced by 20% to 40%, and the performance still needs to be further improved. Summary of the invention

[0006] The object of the present invention is to provide a triangular multi-channel SCR static mixer.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] A triangular multi-channel SCR static mixer comprises a mixer body and a plurality of guide plates, wherein:

[0009] The mixer body includes a plurality of triangular partition plates and a plurality of angle plates. The partition plates are arranged up and down, and a smoke channel is formed between two adjacent partition plates. The first side of the triangular partition plate forms a first smoke inlet, the second side forms a second smoke inlet, and the third side forms a smoke outlet. The angle plate located on the side of the first smoke inlet closes the first smoke inlet of the odd-numbered layers on that side, and the angle plate located on the side of the second smoke inlet closes the second smoke inlet of the even-numbered layers on that side. A plurality of guide plates are arranged upstream of the first smoke inlet and the second smoke inlet. The mixer body also includes an inlet connector arranged in the smoke channel at the intersection of the first smoke inlet and the second smoke inlet. The inlet connector is in the shape of a triangular cone, and the inlet connector connects the angle plates on both sides.

[0010] Preferably, the mixer body further comprises a spoiler, and the spoiler is arranged on the side of the partition plate located on the side of the smoke outlet.

[0011] Further preferably, a plurality of spoilers are arranged along the side of the partition plate, and among two adjacent spoilers, one spoiler extends toward one side of the surface where the partition plate is located, and the other spoiler extends toward the other side of the surface where the partition plate is located.

[0012] Further preferably, the positions and extension directions of the spoilers on two adjacent partition plates are the same, and the adjacent two spoilers on two adjacent partition plates are connected.

[0013] Further preferably, the spoiler is trapezoidal in shape, and the long sides of the trapezoidal spoiler are connected to the side edges of the partition plate.

[0014] Preferably, the guide plate is arc-shaped, and the bending directions of the guide plates on both sides of the inlet connector are opposite to each other, so as to achieve cross-mixing of smoke on both sides and reduce resistance.

[0015] Preferably, guide plates arranged on both sides close to the inlet connector are connected to the inlet connector.

[0016] Preferably, the number of the guide plates is an even number and is ≥6.

[0017] Preferably, the number of the partition plates is an odd number and they are arranged in parallel, and the distance between two adjacent partition plates is 0.4-1.5 m.

[0018] Preferably, the cross-section of the corner plate is V-shaped with an angle ≤ 90°.

[0019] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0020] The present invention can reduce the relative standard deviation of NOx concentration distribution at the ammonia injection grid inlet by more than 60%, greatly reducing the influence of unit load, mill combination and combustion adjustment on the NOx concentration distribution at the SCR inlet, and fundamentally improving the adaptability of the SCR denitrification device to variable operating conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Attached Figure 1 It is the front view of this embodiment;

[0022] Attached Figure 2 is a side view of this embodiment;

[0023] Attached Figure 3 is a top view of this embodiment;

[0024] Attached Figure 4 This is the CFD simulation result diagram of NOx mixing effect when there is no mixer;

[0025] Attached Figure 5 This is a CFD simulation result diagram of the NOx mixing effect when the mixer of this embodiment is set up.

[0026] In the above attached figure:

[0027] 10. Partition plate; 100. First smoke inlet; 101. Second smoke inlet; 102. Smoke outlet; 11. Corner plate; 12. Smoke channel; 13. Inlet connector; 14. Spoiler; 2. Guide plate. DETAILED DESCRIPTION

[0028] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0030] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] like Figure 1-3 The triangular multi-channel SCR static mixer shown includes a mixer body and a plurality of guide plates 2. Specifically:

[0032] The mixer body includes a plurality of triangular partition plates 10 and a plurality of angle plates 11. The partition plates 10 are arranged in parallel up and down, and a smoke channel 12 is formed between two adjacent partition plates 10. The partition plates 10 are arranged in odd layers, and the partition plates 10 in odd layers divide the entire smoke channel into even layers of smoke channels 12 in the depth direction. The spacing between two adjacent partition plates 10 is 0.4-1.5m. The cross section of the angle plate 11 is V-shaped with an angle of ≤90°.

[0033] The first side of the triangular partition plate 10 forms a first smoke inlet 100, the second side forms a second smoke inlet 101, and the third side forms a smoke outlet 102. Located on one side of the first smoke inlet 100, the corner plate 11 closes the first smoke inlet 100 of the odd-numbered layers on that side, and located on one side of the second smoke inlet 101, the corner plate 11 closes the second smoke inlet 101 of the even-numbered layers on that side, that is, the left side or right side of each layer of the smoke channel 12 is sealed on one side by the corner plate 11, and the corner plates 11 of the smoke inlets on two adjacent layers of the smoke channel 12 are not on the same side.

[0034] The mixer body also includes an inlet connector 13 disposed in the smoke channel 12 at the intersection of the first smoke inlet 100 and the second smoke inlet 101. The inlet connector 13 is in a triangular pyramid shape and connects the two side angle plates 11. The inlet connector 13 can be formed by connecting three triangular plates, and preferably the connection between the three triangular plates is an arc transition.

[0035] The mixer body also includes a spoiler 14, which is arranged on the side of the partition plate 10 on the side of the smoke outlet 102. In this embodiment: the spoiler 14 is trapezoidal, and the long side of the trapezoidal spoiler 14 is connected to the side of the partition plate 10. A plurality of spoilers 14 are arranged along the side of the partition plate 10. Among two adjacent spoilers 14, one spoiler 14 extends toward one side of the surface where the partition plate 10 is located, and the other spoiler 14 extends toward the other side of the surface where the partition plate 10 is located, that is, the extension directions extend to both sides of the surface where the partition plate 10 is located, respectively, and are V-shaped when viewed from the side; the positions and extension directions of the spoilers 14 on the two adjacent partition plates 10 are the same, and the two adjacent spoilers 14 on the two adjacent partition plates 10 are point-connected to reduce the vibration generated when the smoke passes through the mixer, and are W-shaped when viewed from the side.

[0036] A plurality of guide plates 2 are arranged upstream of the first smoke inlet 100 and the second smoke inlet 101, and are distributed along both sides of the first smoke inlet 100 and the second smoke inlet 101. The number of guide plates 2 is an even number, and is ≥ 6. In this embodiment: the guide plates 2 are arc-shaped, and the bending directions of the guide plates 2 on both sides of the inlet connector 13 face each other to achieve cross-mixing of smoke on both sides and reduce resistance. The guide plates 2 arranged on both sides near the inlet connector 13 are connected to the inlet connector 13, such as the left and right guide plates 2 near the inlet connector 13 are connected to the inlet connector 13.

[0037] When the smoke passes through the mixer: the smoke entering the smoke channel 12 from the first smoke inlet 100 flows and diffuses to the entire width section through the even-numbered layers of smoke channels 12 in the depth direction, and the smoke entering the smoke channel 12 from the second smoke inlet 101 flows and diffuses to the entire width section through the odd-numbered layers of smoke channels 12 in the depth direction. At the smoke outlet 102, the smoke of the two connected layers of smoke outlets 102 is mixed with each other under the action of the bypass plate 14. Through the cross-flow of the smoke stratification on the left and right sides and the mixing between the outlet layers, a large-scale mixing over the entire width section is achieved.

[0038] Example:

[0039] The triangular multi-channel SCR static mixer of this embodiment is used to optimize the inlet flow field design and transformation of the SCR denitration device of a 660MW coal-fired power generation unit. The triangular multi-channel SCR static mixer is 16.2m wide, 8.5m long, and 3.2m high. 14 guide plates 2 are arranged at the inlet, 3 layers of triangular partition plates 10 are arranged in the height direction, and 4 corner plates 11 with an angle of 60° are arranged on both sides. The spacing between the partition plates 10 is 0.8m, and 42 trapezoidal flow-around plates 14 are arranged on each layer of the partition plates 10.

[0040] The CFD simulation results show that after the installation of the triangular multi-channel static mixer, the relative standard deviation (CV value) of the NOx concentration distribution at the AIG inlet is reduced from 17.5% to 6.6%, a decrease of 62%. Figure 4 , 5 shown.

[0041] This embodiment illustrates that the triangular multi-channel SCR static mixer proposed in this embodiment reduces the relative standard deviation of NOx concentration distribution at the ammonia injection grid inlet by more than 60%, greatly reducing the impact of unit load, mill combination and combustion adjustment on the NOx concentration distribution at the SCR inlet.

[0042] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A triangular multi-channel SCR static mixer, comprising a mixer body and a plurality of guide plates, wherein: The mixer body comprises a plurality of triangular partition plates and a plurality of angle plates, the partition plates are arranged up and down, a smoke channel is formed between two adjacent partition plates, a first side of the triangular partition plate forms a first smoke inlet, a second side forms a second smoke inlet, and a third side forms a smoke outlet, the angle plate located on the side of the first smoke inlet closes the first smoke inlet of the odd-numbered layers on that side, and the angle plate located on the side of the second smoke inlet closes the second smoke inlet of the even-numbered layers on that side; a plurality of guide plates are arranged upstream of the first smoke inlet and the second smoke inlet, characterized in that: the mixer body also comprises a smoke channel inner wall arranged at the intersection of the first smoke inlet and the second smoke inlet The inlet connector is in a triangular cone shape, and the inlet connector connects the angle plates on both sides. The cross-section of the angle plates is V-shaped with an angle of ≤90°. The mixer body also includes a spoiler, and the spoiler is arranged on the side of the partition plate located on the side of the smoke outlet. A plurality of spoilers are arranged along the side of the partition plate. Among two adjacent spoilers, one spoiler extends toward one side of the surface where the partition plate is located, and the other spoiler extends toward the other side of the surface where the partition plate is located. The positions and extension directions of the spoilers on the two adjacent partition plates are the same, and the two adjacent spoilers on the two adjacent partition plates are connected.

2. The triangular multi-channel SCR static mixer according to claim 1, characterized in that: The spoiler is in a trapezoidal shape, and the long side of the trapezoidal spoiler is connected to the side of the partition plate.

3. The triangular multi-channel SCR static mixer according to claim 1, characterized in that: The guide plate is arc-shaped, and the bending directions of the guide plates on both sides of the inlet connector are opposite to each other.

4. The triangular multi-channel SCR static mixer according to claim 1, characterized in that: The guide plates arranged on both sides close to the inlet connector are connected to the inlet connector.

5. The triangular multi-channel SCR static mixer according to claim 1, characterized in that: The number of the guide plates is an even number and is ≥6.

6. The triangular multi-channel SCR static mixer according to claim 1, characterized in that: The number of the partition plates is an odd number and they are arranged in parallel, and the distance between two adjacent partition plates is 0.4-1.5m.

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