Bypass flue structure and SCR flue gas denitration system

Abstract

The utility model discloses a bypass flue structure and SCR flue gas denitration system, wherein, bypass flue structure includes compressed gas source, flue body and be used for closing flue body's flue baffle, flue baffle includes two groups of openable and closable baffle door, and compressed gas source is communicated with the area between two groups of baffle door in flue body through openable and closable gas pipeline, the utility model discloses bypass flue structure has at least the following beneficial effects: compressed air produced by compressed gas source is used as sealing gas, and the positive pressure produced by sealing gas is used between two groups of baffle door, avoids the seepage of flue gas along bypass flue, compared with the continuous sealing air pressure produced by using sealing fan, the bypass flue structure in the application reduces the configuration and electric energy consumption of fan, motor, switch board and other equipment, and avoids the influence of cold air suction on flue gas temperature, and also not easy to produce noise, also has the advantages of saving manpower and maintenance cost and high equipment reliability.

Description

Technical Field

[0001] This utility model relates to the field of flue gas denitrification technology, specifically to a bypass flue structure and an SCR flue gas denitrification system. Background Technology

[0002] To meet environmental emission requirements, modern thermal power units are generally equipped with SCR denitrification systems. SCR catalysts need to operate within a specific temperature window (usually 280℃-400℃) to maintain high activity and avoid byproducts (such as ammonium bisulfate) clogging the downstream air preheater. Therefore, units are generally equipped with denitrification bypass flues. By adjusting the opening of the flue gas dampers on the bypass, the temperature of the flue gas mixed to the SCR inlet is controlled to protect the catalyst. To ensure that high-temperature, high-dust, and corrosive flue gas does not leak when the bypass dampers are closed, thus affecting maintenance safety or polluting the environment, traditional designs use independent sealed fan systems.

[0003] Currently, the existing technology involves installing a sealing fan to provide sealing air to the baffle, maintaining the sealing effect by continuously generating air pressure acting on the baffle. However, this method has the following significant drawbacks: 1. High energy consumption: Sealing fans are high-power electrical equipment that operates continuously, increasing power consumption.

[0004] Second, the equipment is complex and costly: it requires additional configuration of fans, motors, power distribution cabinets, air ducts, etc., resulting in large initial investment and a lot of space occupation.

[0005] Third, the maintenance workload is large and there are reliability risks: the fan and its auxiliary equipment (such as bearings and filters) require regular inspection, lubrication and maintenance, and the failure rate is relatively high.

[0006] IV. Noise and Heat Loss: The operation of the fan generates noise, and the cold air drawn in will reduce the temperature of the local flue to some extent.

[0007] Therefore, there is an urgent need for a simpler, more energy-efficient, and more reliable alternative to solve the sealing problem of the denitrification bypass baffle. Utility Model Content

[0008] The purpose of this invention is to overcome the shortcomings mentioned in the background art and to provide a bypass flue structure and an SCR flue gas denitrification system.

[0009] The objective of this utility model is achieved through the following technical solution: On the one hand, this utility model provides a bypass flue structure, including a flue body and a flue baffle for sealing the flue body, and also includes a set of compressed air sources; The flue damper includes two sets of openable and closable damper doors. The compressed air source is connected to the area between the two sets of damper doors in the flue body through an openable and closable air supply pipe.

[0010] The bypass flue structure of this utility model has at least the following beneficial effects: This patent uses compressed air generated by a compressed air source as the sealing gas. The positive pressure generated by the sealing gas acts between two sets of baffle doors to prevent flue gas from seeping out along the bypass flue. Compared with using a sealing fan to continuously generate sealing air pressure, the bypass flue structure in this application reduces the configuration of equipment such as fans, motors, and power distribution cabinets, as well as the power consumption. It also avoids the intake of cold air from affecting the flue gas temperature and is less likely to generate noise. In addition, it has the advantages of saving manpower and maintenance costs and high equipment reliability.

[0011] Furthermore, the gas transmission pipeline is equipped with a manual shut-off valve and a pressure reducing valve in sequence from upstream to downstream.

[0012] With the above settings, the bypass flue structure can be turned on and off by manual shut-off valve. When turned on, the pressure is controlled and stabilized by pressure reducing valve.

[0013] Furthermore, a pressure gauge is installed on the gas pipeline downstream of the pressure reducing valve to facilitate timely monitoring of the gas pressure.

[0014] Furthermore, the compressed air source includes a compressed air storage tank, which directly stores positive pressure gas, thereby further reducing the number of compressed air source devices.

[0015] In some preferred embodiments, a compressed air main pipe can be connected upstream of the compressed air storage tank. In this case, the compressed air storage tank can act as a pressure buffer and stabilizing device to ensure a continuous supply of air during short-term fluctuations in the compressed air system.

[0016] Furthermore, the gas pipeline is also connected to a switchable backup gas source, which is connected in parallel with the compressed air storage tank. When the compressed air pressure output by the compressed air storage tank is too low and unstable, the backup gas source can be connected to the gas pipeline for pressure compensation.

[0017] Furthermore, the gas pipeline is made of galvanized steel.

[0018] Furthermore, a precision filter is installed on the gas pipeline upstream of the pressure reducing valve to filter impurities and moisture in the compressed air, ensuring the purity of the sealed gas and reducing pollution and corrosion to the gas pipeline and bypass flue structure.

[0019] Furthermore, the gas pipeline is also equipped with an overflow valve located downstream of the manual shut-off valve, which can further stabilize the sealing gas pressure.

[0020] On the other hand, this utility model also provides an SCR flue gas denitrification system, which is equipped with the aforementioned bypass flue structure, and the bypass flue structure is connected in parallel with the denitrification main circuit in the SCR flue gas denitrification system. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the bypass flue structure provided in Embodiment 1 of this utility model; Figure 2 This is a schematic diagram of the bypass flue structure provided in Embodiment 2 of this utility model; Figure 3 This is a schematic diagram of the bypass flue structure provided in Embodiment 3 of this utility model; The attached diagram lists the components represented by each number as follows: 1. Flue body; 10. Baffle door; 2. Compressed air source; 20. Compressed air storage tank; 21. Gas pipeline; 210. Manual shut-off valve; 211. Pressure reducing valve; 212. Pressure gauge; 22. Compressed air main pipe; 220. Air source connector; 23. Backup air source. Detailed Implementation

[0022] The principles and features of this utility model are described below. The examples given are only for explaining this utility model and are not intended to limit the scope of this utility model.

[0023] Example 1: Reference Figure 1 This embodiment provides a bypass flue structure, including a flue body 1, a compressed air source 2, and a flue baffle for sealing the flue body 1.

[0024] The flue damper includes two sets of openable and closable damper doors 10, which enhance the sealing performance of the bypass flue through the double-layer damper door 10 structure.

[0025] As needed, the two sets of damper doors 10 can be opened and closed independently or in conjunction within the flue body 1. The flow rate of flue gas through the bypass flue can also be adjusted by the opening size of the two sets of damper doors 10.

[0026] Reference Figure 1 The compressed air source 2 is connected to the area between the two sets of baffle doors 10 in the flue body 1 through the openable and closable air supply pipe 21. That is, the compressed air source 2 generates positive pressure between the two sets of baffle doors 10, which can prevent the flue gas outside the two sets of baffle doors 10 from seeping in, thereby blocking the flow of flue gas in the bypass flue.

[0027] This solution forms a sealed cavity structure between two sets of baffle gates 10, and generates a gas pressure environment greater than the flue gas pressure in the sealed cavity through the compressed air source 2, providing a continuous and stable sealing environment. Compared with the traditional sealing fan that directly outputs airflow with a certain air pressure to the baffle gate 10 for sealing, the bypass flue structure in this application reduces the configuration of equipment such as fans, motors, and power distribution cabinets, as well as the power consumption.

[0028] In addition, compared to traditional sealed fans that continuously blow outside air into the baffle door 10, which also generates some noise, this solution avoids the intake of cold air from affecting the flue gas temperature and is less likely to generate noise.

[0029] The bypass flue structure in this solution has the advantages of saving manpower and material maintenance costs and high equipment reliability.

[0030] Reference Figure 1 In the gas pipeline 21, a manual shut-off valve 210 and a pressure reducing valve 211 are installed sequentially from upstream to downstream. The manual shut-off valve 210 can control the opening and closing of the bypass flue structure. In addition, when in use, the pressure reducing valve 211 can control and stabilize the gas pressure between the two sets of baffle gates 10, so that the output gas pressure is always within a reasonable range and the waste of compressed gas is avoided.

[0031] In addition, in some embodiments, a pressure gauge 212 is provided on the gas pipeline 21 downstream of the pressure reducing valve 211 to facilitate timely observation of the gas pressure output after passing through the pressure reducing valve 211.

[0032] In some embodiments, the compressed air source 2 can be an existing compressed air main pipe 22 in the factory, so as to save the cost of the compressed air preparation equipment required in this solution.

[0033] Alternatively, in this embodiment, the compressed air source 2 includes a compressed air storage tank 20, which directly stores positive pressure gas, further reducing the number of devices in the compressed air source 2. Only compressed air needs to be replenished to the compressed air storage tank 20 periodically.

[0034] For example, compressed gas can be periodically replenished to the compressed air storage tank 20 using an air compressor.

[0035] In addition, it is easy to understand that the compressed air storage tank 20 should be equipped with a pressure gauge and an overflow valve.

[0036] Example 2: Reference Figure 2 As a further extension of the first embodiment, in this embodiment, the upstream of the compressed air storage tank 20 can also be connected to the compressed air main pipe 22 via the air source connector 220.

[0037] The compressed air header 22 can be continuously connected to the compressed air storage tank 20. In this case, the compressed air storage tank 20 can act as a pressure buffer and stabilizing device to ensure that the compressed air system can continue to supply air even when there are short-term fluctuations.

[0038] Alternatively, the compressed air main pipe 22 can be indirectly connected to the compressed air storage tank 20, such as by installing a PLC control or manual shut-off valve on the air source connector 220 to periodically replenish compressed air to the compressed air storage tank 20.

[0039] Example 3: Based on Embodiment 1 or Embodiment 2, this embodiment can also connect an on / off standby gas source 23 to the gas pipeline 21.

[0040] Reference Figure 3 For example, based on the bypass flue structure in Embodiment 2, this embodiment... The backup air source 23 is connected in parallel with the compressed air storage tank 20. When the compressed air pressure output by the compressed air storage tank 20 is too low, unstable or malfunctions, the backup air source 23 can be connected to the air transmission pipeline 21 for pressure compensation or replacement, so that the bypass flue structure can always maintain normal sealing pressure.

[0041] In some of the above embodiments, the gas transmission pipeline 21 may be made of galvanized steel pipe.

[0042] In addition, in some embodiments, a precision filter (not shown) is provided on the gas pipeline 21 upstream of the pressure reducing valve 211 to filter impurities and water vapor in the compressed air, ensuring the purity of the sealing gas and reducing pollution and corrosion to the gas pipeline 21 and the bypass flue structure as a whole.

[0043] In addition, in some embodiments, the gas pipeline 21 is also provided with an overflow valve located downstream of the manual shut-off valve 210, which can further stabilize the sealing gas pressure and reduce fluctuations in the output gas pressure.

[0044] For example, in the above embodiments, the output pressure of the gas through the gas pipeline 21 can be set to 4.0 kPa, which maintains a positive pressure margin of about 0.5-1.0 kPa compared to the flue gas.

[0045] Example 4: This embodiment provides an SCR flue gas denitrification system, which has the bypass flue structure described in Embodiment 1, Embodiment 2 or Embodiment 3 above, and the bypass flue structure is connected in parallel with the denitrification main circuit in the SCR flue gas denitrification system.

[0046] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0047] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0048] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0049] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0050] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A bypass flue structure, comprising a flue body and a flue baffle for sealing the flue body, characterized in that, It also includes a set of compressed air sources; The flue damper includes two sets of openable and closable damper doors, and the compressed air source is connected to the area located between the two sets of damper doors in the flue body through an openable and closable air supply pipe.

2. The bypass flue structure according to claim 1, characterized in that, The gas pipeline is equipped with a manual shut-off valve and a pressure reducing valve in sequence from upstream to downstream.

3. The bypass flue structure according to claim 2, characterized in that, The gas pipeline is also equipped with a pressure gauge located downstream of the pressure reducing valve.

4. The bypass flue structure according to claim 1, characterized in that, The compressed air source includes a compressed air storage tank.

5. The bypass flue structure according to claim 4, characterized in that, The compressed air storage tank is connected to a compressed air header upstream.

6. The bypass flue structure according to claim 5, characterized in that, The gas pipeline is also connected to a switchable backup gas source, which is connected in parallel with the compressed air storage tank.

7. The bypass flue structure according to claim 1, characterized in that, The gas pipeline is a galvanized steel pipe.

8. The bypass flue structure according to claim 2, characterized in that, The gas pipeline is also equipped with a precision filter located upstream of the pressure reducing valve.

9. The bypass flue structure according to claim 2, characterized in that, The gas pipeline is also equipped with an overflow valve located downstream of the manual shut-off valve.

10. An SCR flue gas denitrification system, characterized in that, The SCR flue gas denitrification system is provided with a bypass flue structure as described in any one of claims 1 to 9, and the bypass flue structure is connected in parallel with the denitrification main circuit in the SCR flue gas denitrification system.

Images