A device and method for realizing flue gas temperature equalization of a denitration catalyst

Abstract

The application discloses a device and method for realizing flue gas temperature equalization of a denitration catalyst, which comprises a grid air extraction device, a partitioned low-temperature air extraction mechanism, a partitioned high-temperature air supply mechanism, an infrared temperature detector and a grid air supply device, the lower end of the grid air extraction device is connected with the partitioned high-temperature air supply mechanism through an air conveying pipe, the partitioned low-temperature air extraction mechanism is arranged on the upper side of the partitioned high-temperature air supply mechanism, the infrared temperature detector is installed on the lower side of the partitioned high-temperature air supply mechanism, and the lower end of the partitioned low-temperature air extraction mechanism is connected with the grid air supply device through an air conveying pipe. The device and method for realizing flue gas temperature equalization of the denitration catalyst can convey the flue gas before a coal economizer to the position of the denitration catalyst area, and convey the flue gas before the denitration catalyst area to the position of an air preheater. Through the flow of the flue gas, the stability of the flue gas temperature can be maintained, and the flow of the flue gas is realized through pressure difference, so that the operation energy consumption is low.

Description

Technical Field

[0001] This invention relates to the field of flue gas denitrification technology, specifically to a device and method for achieving temperature equalization of flue gas in denitrification catalysts. Background Technology

[0002] Selective catalytic reduction (SCR) is a commonly used method for flue gas denitrification. Flue gas from, for example, a coal-fired boiler comes into contact with a catalyst, where nitrogen oxides are reduced to nitrogen and water. The reaction rate is closely related to the flue gas temperature. As temperature increases, nitrogen oxide removal initially increases and then decreases. Furthermore, as temperature increases, NH3 escape decreases, but SO2 conversion increases. Therefore, for the SCR process, the temperature cannot be too high or too low; maintaining flue gas temperature stability is crucial. However, due to the large cross-section of the inlet flue, even if the average temperature is within the required range, uniform temperature distribution within the flue cross-section cannot be guaranteed; some areas may be too hot, while others may be too cold. Currently, there is a lack of effective methods to regulate the uniformity of flue gas temperature in the flue, hindering further improvements in denitrification performance. Summary of the Invention

[0003] (a) Technical problems to be solved

[0004] To address the shortcomings of existing technologies, this invention provides an apparatus and method for achieving temperature equalization of flue gas from denitrification catalysts, thus solving the problem of the inability to guarantee the stability of flue gas temperature during flue gas treatment.

[0005] (II) Technical Solution

[0006] To achieve the above objectives, the present invention provides the following technical solution: a device for equalizing the temperature of flue gas from a denitrification catalyst, comprising a grid extraction device, a zoned low-temperature extraction mechanism, a zoned high-temperature gas delivery mechanism, an infrared thermometer, and a grid gas delivery device. The lower end of the grid extraction device is connected to the zoned high-temperature gas delivery mechanism via a gas delivery pipe. The zoned low-temperature extraction mechanism is located on the upper side of the zoned high-temperature gas delivery mechanism, and the infrared thermometer is installed on the lower side of the zoned high-temperature gas delivery mechanism. The lower end of the zoned low-temperature extraction mechanism is interconnected with the grid gas delivery device via a gas delivery pipe.

[0007] Preferably, the grid extraction device is located on the front side of the economizer, and the economizer and the boiler are connected to each other through a conveying pipe, with the grid extraction device located at the connection point between the conveying pipe and the economizer.

[0008] Preferably, the zoned high-temperature gas supply mechanism is located in front of the denitrification catalytic zone, and the denitrification catalytic zone and the economizer are connected to each other through a conveying pipe.

[0009] Preferably, the grid air supply device is located on the lower side of the air preheater, and the air preheater and the denitrification catalytic zone are connected to each other through a delivery pipe.

[0010] Preferably, the partitioned low-temperature air extraction mechanism is provided with partitioned low-temperature air extraction devices, and the number of partitioned low-temperature air extraction devices is 2-20, and the lower end of each partitioned low-temperature air extraction device is connected to the grid air supply device.

[0011] Preferably, the partitioned high-temperature gas supply mechanism is provided with partitioned high-temperature gas supply devices, and the number of partitioned high-temperature gas supply devices is 2-20, and the upper end of each partitioned high-temperature gas supply device is connected to a grid extraction device.

[0012] Preferably, a high-temperature valve is provided between the partitioned high-temperature gas supply mechanism and the grid extraction device, and a low-temperature valve is provided between the partitioned low-temperature gas extraction mechanism and the grid gas supply device.

[0013] A method for achieving temperature equalization of flue gas in denitrification catalysts, the method comprising the following steps:

[0014] a) The infrared thermometer will detect the temperature inside the device. When the temperature of a certain zone is low and below the average value DT;

[0015] b) Open the corresponding high-temperature valve, and use the grid extraction device to flow the flue gas from the economizer to the denitrification catalytic zone. Adjust the high-temperature valve to ensure that the flow rate Qh satisfies the following relationship:

[0016] Qh = Q(Ta-T) / (Th-Ta);

[0017] Where Q and T represent the flue gas flow rate and temperature of the zone;

[0018] Th represents the flue gas temperature before the economizer;

[0019] Ta represents the average temperature of all zones before the denitrification catalyst;

[0020] c) Open the corresponding cryogenic valve and use the zoned cryogenic extraction mechanism to flow the flue gas from the denitrification catalytic zone to the air preheater at a flow rate of Qc.

[0021] Preferably, methods b) and c) should satisfy Qh = Qc.

[0022] (III) Beneficial Effects

[0023] This invention provides an apparatus and method for achieving temperature equalization of flue gas from a denitrification catalyst. It has the following beneficial effects:

[0024] The device and method for achieving flue gas temperature equalization in denitrification catalysts utilizes a grid extraction device, a zoned low-temperature extraction mechanism, a zoned high-temperature gas delivery mechanism, and a grid gas delivery device. This allows the flue gas before the economizer to be transported to the denitrification catalytic zone, and the flue gas before the denitrification catalytic zone to be transported to the air preheater. Through the flow of the flue gas, the flue gas temperature can be maintained stably, and the flow of the flue gas is all achieved through pressure difference. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the flue gas equalization device of the present invention;

[0026] Figure 2 This is a schematic diagram of the conveying pipe and denitrification catalytic zone structure of the present invention;

[0027] Figure 3 This is a schematic diagram of the connection structure between the grid extraction device and the zoned high-temperature gas delivery mechanism of the present invention;

[0028] Figure 4 This is a schematic diagram of the connection structure between the partitioned low-temperature air extraction mechanism and the grid air delivery device of the present invention;

[0029] Figure 5 This is a schematic diagram of the structure of the partitioned low-temperature air extraction mechanism of the present invention;

[0030] Figure 6 This is a schematic diagram of the structure of the partitioned high-temperature gas supply mechanism of the present invention;

[0031] Figure 7 This is a flowchart of the flue gas equalization process of the present invention.

[0032] In the diagram: 1. Boiler; 2. Delivery pipe; 3. Grid extraction device; 4. Economizer; 5. Zoned low-temperature extraction mechanism; 6. Zoned high-temperature gas delivery mechanism; 7. Denitrification catalytic zone; 8. Infrared thermometer; 9. Air preheater; 10. Grid gas delivery device; 1101. High-temperature valve; 1102. Low-temperature valve. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] like Figure 1-6As shown, the present invention provides a technical solution: a device for achieving temperature equalization of flue gas from a denitrification catalyst, comprising a grid extraction device 3, a zoned low-temperature extraction mechanism 5, a zoned high-temperature gas delivery mechanism 6, an infrared thermometer 8, and a grid gas delivery device 10. The lower end of the grid extraction device 3 is connected to the zoned high-temperature gas delivery mechanism 6 via a gas delivery pipe. The zoned low-temperature extraction mechanism 5 is located on the upper side of the zoned high-temperature gas delivery mechanism 6. The infrared thermometer 8 is installed on the lower side of the zoned high-temperature gas delivery mechanism 6. The lower end of the zoned low-temperature extraction mechanism 5 is connected to the grid gas delivery device 10 via a gas delivery pipe.

[0035] The grid extraction device 3 is located on the front side of the economizer 4, and the economizer 4 and the boiler 1 are connected to each other through the conveying pipe 2. The grid extraction device 3 is located at the connection position between the conveying pipe 2 and the economizer 4.

[0036] The zoned high-temperature gas supply mechanism 6 is located in front of the denitrification catalytic zone 7, and the denitrification catalytic zone 7 and the economizer 4 are connected to each other through the delivery pipe 2;

[0037] The grid air supply device 10 is located on the lower side of the air preheater 9, and the air preheater 9 and the denitrification catalytic zone 7 are connected to each other through the delivery pipe 2;

[0038] The zoned low-temperature air extraction mechanism 5 is equipped with zoned low-temperature air extraction devices, and the number of zoned low-temperature air extraction devices is 2-20, and the lower end of each zoned low-temperature air extraction device is connected to the grid air supply device 10.

[0039] The zoned high-temperature gas supply mechanism 6 is equipped with a zoned high-temperature gas supply device, and the number of zoned high-temperature gas supply devices is 2-20, and the upper end of each zoned high-temperature gas supply device is connected to the grid extraction device 3.

[0040] A high-temperature valve 1101 is installed between the zoned high-temperature gas supply mechanism 6 and the grid extraction device 3, and a low-temperature valve 1102 is installed between the zoned low-temperature gas extraction mechanism 5 and the grid gas supply device 10.

[0041] A method for achieving temperature equalization of flue gas in denitrification catalysts, the method comprising the following steps:

[0042] a) The infrared thermometer 8 will detect the temperature inside the device. When the temperature of a certain zone is low and below the average value DT;

[0043] b) Open the corresponding high-temperature valve 1101, and use the grid extraction device 3 to direct the flue gas from the economizer 4 to the denitrification catalytic zone 7. Adjust the high-temperature valve 1101 to ensure that the flow rate Qh satisfies the following relationship:

[0044] Qh = Q(Ta-T) / (Th-Ta);

[0045] Where Q and T represent the flue gas flow rate and temperature of the zone;

[0046] Th represents the flue gas temperature before the economizer;

[0047] Ta represents the average temperature of all zones before the denitrification catalyst;

[0048] c) Open the corresponding cryogenic valve 1102, and use the zoned cryogenic extraction mechanism 5 to flow the flue gas from the denitrification catalytic zone 7 to the air preheater 9 at a flow rate of Qc.

[0049] Methods b) and c) should satisfy Qh = Qc.

[0050] In use, for example, when the temperatures of the four zones are 350℃, 350℃, 345℃, and 350℃ respectively, the temperature of the third zone is relatively low, so it needs to be increased by 5℃. To meet the temperature requirements, the following calculation formula is used: Qh*650+Q*345=Qh+Q350. That is, the high-temperature gas supply device 603 of the third zone needs to be turned on to a suitable opening degree so that Qh satisfies Qh / Q=1.67%, thereby increasing the flue gas temperature in the low-temperature area and making the temperature distribution in front of the denitrification catalyst more balanced. At the same time, all contents not described in detail in this specification are existing technologies known to those skilled in the art.

[0051] In summary, the device and method for achieving flue gas temperature equalization in the denitrification catalyst, through the use of the grid extraction device 3, the zoned low-temperature extraction mechanism 5, the zoned high-temperature gas delivery mechanism 6, and the grid delivery device 10, can transport the flue gas before the economizer 4 to the denitrification catalytic zone 7, and the flue gas before the denitrification catalytic zone 7 to the air preheater 9. Through the flow of flue gas, the stability of the flue gas temperature can be maintained, and the flow of flue gas is all based on pressure difference.

[0052] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0053] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A device for achieving temperature equalization of flue gas from a denitrification catalyst, comprising a grid extraction device (3), a zoned low-temperature extraction mechanism (5), a zoned high-temperature gas delivery mechanism (6), an infrared thermometer (8), and a grid gas delivery device (10), characterized in that: The lower end of the grid extraction device (3) is connected to the partition high temperature gas delivery mechanism (6) through a gas delivery pipe. The partition low temperature extraction mechanism (5) is set on the upper side of the partition high temperature gas delivery mechanism (6). The infrared thermometer (8) is installed on the lower side of the partition high temperature gas delivery mechanism (6). The lower end of the partition low temperature extraction mechanism (5) is connected to the grid gas delivery device (10) through a gas delivery pipe. The grid extraction device (3) is located on the front side of the economizer (4), and the economizer (4) and the boiler (1) are connected to each other through the conveying pipe (2), and the grid extraction device (3) is located at the connection position between the conveying pipe (2) and the economizer (4). The partitioned high-temperature gas supply mechanism (6) is located in front of the denitrification catalytic zone (7), and the denitrification catalytic zone (7) and the economizer (4) are connected to each other through the delivery pipe (2); The grid air delivery device (10) is located on the lower side of the air preheater (9), and the air preheater (9) and the denitrification catalytic zone (7) are connected to each other through the delivery pipe (2); The partitioned low-temperature air extraction mechanism (5) is equipped with partitioned low-temperature air extraction devices, and the number of partitioned low-temperature air extraction devices is 2-20, and the lower end of each partitioned low-temperature air extraction device is connected to the grid air delivery device (10). The partitioned high-temperature gas delivery mechanism (6) is equipped with partitioned high-temperature gas delivery devices, and the number of partitioned high-temperature gas delivery devices is 2-20, and the upper end of each partitioned high-temperature gas delivery device is connected to the grid extraction device (3). A high-temperature valve (1101) is provided between the partitioned high-temperature gas supply mechanism (6) and the grid gas extraction device (3), and a low-temperature valve (1102) is provided between the partitioned low-temperature gas extraction mechanism (5) and the grid gas supply device (10).

2. A method for achieving temperature equalization of flue gas from a denitrification catalyst, the method employing the apparatus for achieving temperature equalization of flue gas from a denitrification catalyst as described in claim 1, the method comprising the following steps: a) The infrared thermometer (8) will detect the temperature inside the device. When the temperature of a certain zone is low and below the average value DT; b) Open the corresponding high-temperature valve (1101), and use the grid extraction device (3) to flow the flue gas from the economizer (4) to the denitrification catalytic zone (7). Adjust the high-temperature valve (1101) so that the flow rate Qh satisfies the following relationship: Qh = Q(Ta-T) / (Th-Ta); Where Q and T represent the flue gas flow rate and temperature of the zone; Th represents the flue gas temperature before the economizer; Ta represents the average temperature of all zones before the denitrification catalyst; c) Open the corresponding cryogenic valve (1102) and use the zoned cryogenic extraction mechanism (5) to flow the flue gas from the denitrification catalytic zone (7) to the air preheater (9) at a flow rate of Qc.

3. The method for achieving flue gas temperature equalization in denitrification catalyst according to claim 2, wherein method b) and method c) shall satisfy Qh = Qc.

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