Urea injection device for boiler flue gas denitration

Abstract

The utility model provides a urea injection device for boiler flue gas denitration. The urea injection device comprises a pipe body, an auxiliary heating plate arranged in the pipe body and an injection mechanism arranged on the pipe body, the spraying mechanism comprises an auxiliary heating ring arranged on the pipe body and a spraying head arranged on the auxiliary heating ring, the auxiliary heating ring and the pipe body are coaxially arranged, the auxiliary heating plate is arranged corresponding to the middle of the auxiliary heating ring, and ventilation gaps communicated with the pipe body exist between the left side and the right side of the auxiliary heating plate and the auxiliary heating ring. At least two nozzles are uniformly arranged on the left side and the right side corresponding to the auxiliary heating plate; a containing cavity used for containing heat conduction liquid is formed in the auxiliary heating plate, an auxiliary hot runner communicated with the containing cavity is arranged in the auxiliary heating ring, and a connecting pipe used for installing a spray head is arranged at the position, corresponding to the auxiliary hot runner, of the auxiliary heating ring. The urea injection device for boiler flue gas denitration has the advantages of being high in integration level, stable, reliable, easy to use and maintain and suitable for boiler flue gas denitration operation.

Description

Technical Field

[0001] The utility model belongs to the technical field of boiler denitration equipment, in particular to a urea injection device for boiler flue gas denitration. Background Art

[0002] Under the influence of exhaust gas temperature and airflow, urea rapidly decomposes to release ammonia, reducing NOx to nitrogen, achieving the desired NOx reduction effect. Urea-based aqueous solutions have gained widespread adoption due to their stable performance, simple chemical reaction, and relatively low reductant requirements. SNCR devices are a crucial component of power plant boiler flue gas denitrification. By adjusting the urea pump flow rate, they can alter NOx emissions to accommodate unit startup and shutdown, load fluctuations, and coal type variations, meeting the grid's needs for unit downtime and frequency regulation, and improving the economic efficiency, safety, and reliability of variable-mode operation. However, when boilers operate at low temperatures, the flue gas temperature is relatively low, making the urea spray liquid prone to crystallization. Urea crystals within the denitrification urea spray gun can cause blockage, directly impacting denitrification operations. Therefore, heating and dissolving the urea solution during the spray process is essential. However, existing urea spray guns require external heating piping or electrical heating. Installing multiple urea spray guns in a pipeline complicates the piping connections of the spray system, hindering its sustained and stable operation. Utility Model Content

[0003] In view of this, the present invention aims to provide a urea injection device for boiler flue gas denitrification to solve the problem that when the existing injection device is equipped with multiple urea spray guns, the pipeline structure is relatively complex, which affects the reliability of the injection device.

[0004] In order to achieve the above-mentioned purpose, the technical solution of the utility model is achieved as follows:

[0005] A urea injection device for boiler flue gas denitrification comprises a pipe body, an auxiliary heating plate arranged in the pipe body, and an injection mechanism arranged on the pipe body; the injection mechanism comprises an auxiliary heating ring arranged on the pipe body, and a nozzle arranged on the auxiliary heating ring, the auxiliary heating ring is coaxially arranged with the pipe body, the auxiliary heating plate is arranged corresponding to the middle part of the auxiliary heating ring, there is a ventilation gap connected with the pipe body between the left and right sides of the auxiliary heating plate and the auxiliary heating ring, and at least two nozzles are evenly arranged corresponding to the left and right sides of the auxiliary heating plate; a accommodating cavity for accommodating heat-conducting liquid is provided in the auxiliary heating plate, an auxiliary heat flow channel connected with the accommodating cavity is provided in the auxiliary heating ring, a connecting pipe for installing the nozzle is provided at a position corresponding to the auxiliary heat flow channel on the auxiliary heating ring, one end of the connecting pipe extends into the auxiliary heat flow channel and is connected with the pipe body, and the other end extends out of the pipe body.

[0006] Furthermore, a driving component for driving the flow of the heat transfer fluid is provided at a position on the tube body corresponding to the auxiliary heating plate accommodating cavity.

[0007] Further, the position corresponding to the auxiliary heating plate accommodating cavity on the pipe body is provided with a heating element, one end of the heating element extends into the accommodating cavity, and the other end is detachably mounted on the pipe body.

[0008] Further, the left and right sides of the auxiliary heating plate are correspondingly provided with a plurality of heat-conducting fins, each heat-conducting fin is provided on the auxiliary heating plate at one end and is provided obliquely downward at the other end.

[0009] Further, the connecting pipe is provided with a heat-conducting element, and the length direction of the heat-conducting element is the same as the length direction of the connecting pipe.

[0010] Further, the auxiliary heating ring is arranged on the inner side of the pipe body, and the end of the auxiliary heating ring is provided with a bevel portion facilitating gas flow.

[0011] Further, the auxiliary heating ring or the auxiliary heating plate is provided with a liquid inlet pipe, one end of the liquid inlet pipe is in communication with the auxiliary heating flow channel or the accommodating cavity, the other end of the liquid inlet pipe extends out of the pipe body, and the end of the liquid inlet pipe extending out of the pipe body is provided with a detachable sealing cover.

[0012] Compared with the prior art, the urea injection device for boiler flue gas denitrification has the following advantages:

[0013] The urea injection device for boiler flue gas denitrification has the advantages of high integration, stability, reliability, easy use and maintenance, and can be suitable for boiler flue gas denitrification operation and has good denitrification effect on high-temperature and low-temperature flue gas. By arranging the auxiliary heating plate in the pipe body, the auxiliary heating plate can efficiently absorb heat in the flue gas and heat the heat-conducting liquid in the accommodating cavity. At the same time, by connecting the auxiliary heating flow channel in the auxiliary heating ring with the accommodating cavity in the auxiliary heating plate, the heated heat-conducting liquid can flow into the auxiliary heating ring and heat the connecting pipe on the auxiliary heating ring, so that the urea in the connecting pipe is prevented from crystallizing, the nozzle can continuously and stably inject urea into the pipe body, and the denitrification effect of urea on the flue gas passing through the pipe body is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0014] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application and are incorporated herein for illustration only. The embodiments of the present application and the description thereof are presented for the purpose of enabling one of ordinary skill in the art to make and use the application and to comprehend it. In the drawings:

[0015] Figure 1 The structure schematic view of the urea injection device for boiler flue gas denitrification is shown in the drawings.

[0016] Figure 2 The structure schematic view of the auxiliary heating ring in the urea injection device for boiler flue gas denitrification is shown in the drawings.

[0017] Figure 3The utility model discloses a kind of urea injection devices for boiler flue gas denitration of connecting pipe's internal structure schematic view for the embodiment described in the utility model.

[0018] Mark explanation:

[0019] 1, pipe body;2, auxiliary heating plate;3, connecting pipe;4, liquid inlet pipe;5, sealing cover;6, heating piece;7, heat conduction fin;8, driving assembly;9, auxiliary heating ring;10, auxiliary heating runner;11, containing cavity;12, spray head;13, ventilation gap;14, inclined surface part;15, heat conduction piece. Specific implementation

[0020] It should be noted that the embodiments in the utility model and the features in the embodiments can be combined with each other without conflict.

[0021] In the description of the utility model, it needs to be understood that the orientation or position relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is the orientation or position relationship based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the utility model and simplifying the description, and therefore cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the utility model. In addition, the terms "first", "second" and the like are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" and the like can explicitly or implicitly include one or more of the features. In the description of the utility model, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0022] In the description of the utility model, it needs to be explained that, unless otherwise specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected;It can be mechanical connection, or electrical connection;It can be directly connected, or indirectly connected through intermediate medium, or the communication inside two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood through specific circumstances.

[0023] The utility model will be described in detail below with reference to the drawings and in combination with embodiments.

[0024] A kind of urea injection device for boiler flue gas denitration, such as Figures 1 to 3As shown, it comprises a pipe body 1, a secondary heating plate 2 arranged in the pipe body 1, and a spraying mechanism arranged on the pipe body 1; the spraying mechanism comprises a secondary heating ring 9 arranged on the pipe body 1 and a spray head 12 arranged on the secondary heating ring 9, the secondary heating ring 9 is coaxially arranged with the pipe body 1, the secondary heating plate 2 is arranged at the middle part of the secondary heating ring 9, and there is a ventilation gap 13 communicating with the pipe body 1 between the left and right sides of the secondary heating plate 2 and the secondary heating ring 9, and the spray head 12 is evenly arranged at least on both sides of the secondary heating plate 2; the secondary heating plate 2 is provided with a containing cavity 11 for containing heat-conducting liquid, the secondary heating ring 9 is provided with a secondary heating flow channel 10 communicating with the containing cavity 11, and the secondary heating ring 9 is provided with a connecting pipe 3 for mounting the spray head 12 at the position corresponding to the secondary heating flow channel 10, one end of the connecting pipe 3 extending into the secondary heating flow channel 10 communicates with the pipe body 1, and the other end extends out of the pipe body 1.

[0025] For example, the secondary heating plate 2 and the secondary heating ring 9 are fixed on the pipe body 1 and are fixedly connected between them. In addition, those skilled in the art can also select other ways to connect the above-mentioned components according to actual needs to achieve stable connection, which will not be described here. In actual use, the connecting pipe 3 can be connected with an external urea supply device to realize the spraying of urea at the spray head 12, and those skilled in the art can select as needed, which will not be described here.

[0026] In actual application, the heat-conducting liquid can be heat-conducting oil, by arranging the secondary heating plate 2 in the pipe body 1, the secondary heating plate 2 can efficiently absorb the heat in the flue gas and heat the heat-conducting liquid in the containing cavity 11. At the same time, by connecting the secondary heating flow channel 10 in the secondary heating ring 9 with the containing cavity 11 in the secondary heating plate 2, the heated heat-conducting liquid can flow into the secondary heating ring 9 and heat the connecting pipe 3 on the secondary heating ring 9, thereby avoiding the crystallization of urea in the connecting pipe 3, ensuring that the spray head 12 can continuously and stably spray urea into the pipe body 1, and ensuring the denitration effect of urea on the flue gas passing through the pipe body 1.

[0027] Preferably, the pipe body 1 is provided with a driving assembly 8 for driving the flow of heat-conducting liquid at the position corresponding to the containing cavity 11 of the secondary heating plate 2. For example, the driving assembly 8 is arranged below the pipe body 1, and the heating element 6 is arranged above the pipe body 1 to realize the circulating flow of the heat-conducting liquid.

[0028] Specifically, the drive assembly 8 may include a paddle and a drive motor for driving the paddle to rotate. The paddle is disposed in the accommodating cavity 11. The fixed end of the drive motor is mounted and fixed on the tube body 1. The output end passes through the tube body 1 and the auxiliary heat plate 2 and is connected to the paddle to drive the paddle to rotate, thereby driving the heat transfer fluid in the accommodating cavity 11 to circulate between the accommodating cavity 11 and the auxiliary heat flow channel 10, which is beneficial to improving the heating effect of the heated heat transfer fluid on the connecting pipe 3 in the auxiliary heat ring 9, further reducing the possibility of urea solution crystallization. In addition, it seems that those skilled in the art can also select other suitable drive assemblies 8 and corresponding installation methods according to actual needs, such as a circulation pump, etc., to achieve the purpose of driving the flow of the heat transfer fluid, and no further details will be given here.

[0029] In actual application, a threaded connection can be adopted between the connecting pipe 3 and the nozzle 12. Two, four or more nozzles 12 can be provided accordingly. The nozzles 12 can also be provided on the side wall and the top of the tube body 1 as needed to improve the denitrification effect of urea on the flue gas passing through the tube body 1. Specifically, when multiple nozzles 12 are provided, multiple nozzle 12 mounting positions can be provided on the connecting pipe 3, for example, multiple threaded holes are provided on the connecting pipe 3, or multiple threaded pipes connected to the connecting pipe 3 are fixed. The skilled person in the art can also choose other ways to install the nozzle 12 according to actual needs to achieve a detachable connection between the nozzle 12 and the connecting pipe 3, which will not be described in detail here.

[0030] Optionally, the connecting pipe 3 is fixed on the auxiliary heating ring 9, and a through hole is provided on the tube body 1 for the connecting pipe 3 to extend out. Those skilled in the art can also choose other ways to install the connecting pipe 3 according to actual needs, which will not be described here. By adopting a detachable manner to install the nozzle 12, it is convenient for operators to replace and maintain the nozzle 12. At the same time, by using the connecting pipe 3 to install the nozzle 12 and setting the connecting pipe 3 in the auxiliary heating flow channel 10, the urea solution can be continuously heated after entering the connecting pipe 3, which can not only avoid urea crystallization, but also avoid the pipeline being exposed on the outside of the tube body 1, which is conducive to reducing the possibility of pipeline damage and improving the reliability and stability of this injection device during operation.

[0031] Preferably, a heating element 6 is provided on the pipe body 1 at a position corresponding to the accommodating cavity 11 of the auxiliary heating plate 2. One end of the heating element 6 extends into the accommodating cavity 11, and the other end is detachably mounted on the pipe body 1. Exemplarily, the heating element 6 can be an electric heating rod, which can be fixed to the pipe body 1 by screws. The pipe body 1 is provided with a through hole for facilitating the passage of the electric heating rod, and the through hole is in communication with the accommodating cavity 11.

[0032] In actual use, by providing the heating element 6, when the flue gas temperature is low, the operator can turn on the heating element 6 to heat the thermal fluid in the accommodating chamber 11, and use the drive assembly 8 to drive the thermal fluid to flow to the auxiliary heat ring 9, thereby heating the urea solution in the connecting pipe 3. When the flue gas temperature rises, the operator can turn off the heating element 6 and use the drive assembly 8 to drive the thermal fluid flow, or turn off both the heating element 6 and the drive assembly 8, so that only the thermal conduction effect of the thermal fluid itself can continue to heat the connecting pipe 3. This helps reduce the energy consumption of this injection device and is energy-saving and environmentally friendly.

[0033] Preferably, a plurality of heat-conducting fins 7 are provided on the left and right sides of the auxiliary heat plate 2, and each heat-conducting fin 7 has one end disposed on the auxiliary heat plate 2 and the other end disposed obliquely downward. For example, two, four, six, or more heat-conducting fins 7 may be provided at intervals along the length of the auxiliary heat plate 2, and each heat-conducting fin 7 is fixed to the auxiliary heat plate 2. Providing heat-conducting fins 7 on the auxiliary heat plate 2 is beneficial for increasing the heat absorption area of ​​the auxiliary heat plate 2, and improving the heating effect of the flue gas on the auxiliary heat plate 2 and the heat-conducting liquid in the auxiliary heat plate 2. Furthermore, by disposing the heat-conducting fins 7 obliquely downward, urea solution and dust can be prevented from remaining on the heat-conducting fins 7, which is beneficial for ensuring the reliability and heat-conducting effect of the heat-conducting fins 7. When the flue gas temperature is low, when the operator turns on the heater 6 to heat the heat-conducting liquid, the heat-conducting fins 7 can also be used to dissipate heat, thereby increasing the flue gas temperature at the auxiliary heat ring 9, which is beneficial for further reducing the probability of urea crystallization and improving the denitrification effect of the flue gas.

[0034] Preferably, a heat conductor 15 is provided on the connecting tube 3, and the length direction of the heat conductor 15 is the same as the length direction of the connecting tube 3. For example, two, four, or more heat conductors can be evenly arranged along the circumference of the connecting tube 3, and each heat conductor 15 is fixed to the inner wall or outer wall of the connecting tube 3. Under the premise of ensuring the flow efficiency of urea contained in the connecting tube 3, the heat conductor 15 on the connecting tube 3 can increase the contact area between the connecting tube 3, the urea solution, and the heat transfer fluid, thereby ensuring the heat transfer effect and ensuring that the heat transfer fluid can better heat the urea solution flowing in the connecting tube 3.

[0035] In actual application, the heat conductor 15 is a cross-shaped structural member and is arranged in the connecting pipe 3 to increase the contact area between the urea solution and the connecting pipe 3 and reduce the difficulty of installing the connecting pipe 3. Those skilled in the art can also select heat conductors 15 of other structures according to actual needs to achieve rapid heat conduction, which will not be repeated here.

[0036] Preferably, the auxiliary heating ring 9 is arranged on the inner side of the tube body 1, and the end of the auxiliary heating ring 9 is provided with a bevel portion 14 to facilitate gas flow. In actual use, by arranging the auxiliary heating ring 9 on the inner side of the tube body 1, heat dissipation can be avoided, ensuring that the heat of the flue gas and the heat transfer fluid can better heat the urea solution in the connecting pipe 3. At the same time, the tube body 1 can also provide good protection for the internal auxiliary heating ring 9, auxiliary heating plate 2 and other structures, which is conducive to further improving the reliability and service life of this injection device.

[0037] Preferably, the auxiliary heating ring 9 or the auxiliary heating plate 2 is provided with a liquid inlet pipe 4, one end of which is in communication with the auxiliary heating channel 10 or the accommodating chamber 11, and the other end extends out of the tube body 1. The end of the liquid inlet pipe 4 extending out of the tube body 1 is provided with a detachable sealing cover 5. Exemplarily, the liquid inlet pipe 4 can be fixed to the auxiliary heating ring 9 or the auxiliary heating plate 2, or fixed to the tube body 1, and in communication with the auxiliary heating channel 10 or the accommodating chamber 11. The sealing cover 5 and the liquid inlet pipe 4 can be connected by threads or flanges. Those skilled in the art can also choose other methods to install the liquid inlet pipe 4 and the sealing cover 5 according to actual needs, which will not be described in detail here.

[0038] In actual application, by providing a detachable sealing cover 5 on the liquid inlet pipe 4, the operator can open the sealing cover 5 and use the liquid inlet pipe 4 to add heat transfer liquid to the accommodating cavity 11 or the auxiliary heat flow channel 10 to ensure that the heat transfer liquid can fill the accommodating cavity 11 and the auxiliary heat flow channel 10, which is conducive to reducing the difficulty of use and maintenance of this injection device.

[0039] The utility model discloses a urea injection device for boiler flue gas denitrification, which has the advantages of high integration, stability, reliability, and ease of use and maintenance. It is applicable to boiler flue gas denitrification operations and has a good denitrification effect on both high-temperature and low-temperature flue gases. By arranging an auxiliary heating plate in the pipe body, the auxiliary heating plate can efficiently absorb the heat in the flue gas and heat the heat transfer liquid in the accommodating cavity. At the same time, by connecting the auxiliary heating flow channel in the auxiliary heating ring with the accommodating cavity in the auxiliary heating plate, the heated heat transfer liquid can flow into the auxiliary heating ring and heat the connecting pipe on the auxiliary heating ring, thereby avoiding urea crystallization in the connecting pipe, ensuring that the nozzle can continuously and stably spray urea into the pipe body, and ensuring the denitrification effect of urea on the flue gas passing through the pipe body.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A urea injection device for boiler flue gas denitrification, characterized by: The invention comprises a tube body (1), an auxiliary heating plate (2) arranged in the tube body (1), and a spray mechanism arranged on the tube body (1); the spray mechanism comprises an auxiliary heating ring (9) arranged on the tube body (1), and a spray head (12) arranged on the auxiliary heating ring (9); the auxiliary heating ring (9) and the tube body (1) are coaxially arranged; the auxiliary heating plate (2) is arranged corresponding to the middle of the auxiliary heating ring (9); there is a ventilation gap (13) between the left and right sides of the auxiliary heating plate (2) and the auxiliary heating ring (9) and the nozzle (12) connected to the tube body (1); At least two heads (12) are evenly arranged on the left and right sides of the auxiliary heating plate (2); a receiving cavity (11) for receiving heat-conducting liquid is provided in the auxiliary heating plate (2); an auxiliary heating channel (10) communicating with the receiving cavity (11) is provided in the auxiliary heating ring (9); a connecting pipe (3) for installing the nozzle (12) is provided at a position corresponding to the auxiliary heating channel (10) on the auxiliary heating ring (9); one end of the connecting pipe (3) extends into the auxiliary heating channel (10) and communicates with the pipe body (1), and the other end extends out of the pipe body (1).

2. The urea injection device for boiler flue gas denitrification according to claim 1, characterized in that: A driving component (8) for driving the flow of heat-conducting fluid is provided at a position on the tube body (1) corresponding to the accommodating cavity (11) of the auxiliary heat plate (2).

3. A urea injection device for boiler flue gas denitrification according to claim 1 or 2, characterized in that: A heating element (6) is provided on the tube body (1) at a position corresponding to the auxiliary heating plate (2) accommodating cavity (11); one end of the heating element (6) extends into the accommodating cavity (11), and the other end is detachably mounted on the tube body (1).

4. The urea injection device for boiler flue gas denitrification according to claim 1, characterized in that: A plurality of heat-conducting fins (7) are correspondingly provided on the left and right sides of the auxiliary heat plate (2), and one end of each heat-conducting fin (7) is arranged on the auxiliary heat plate (2) and the other end is arranged obliquely downward.

5. The urea injection device for boiler flue gas denitrification according to claim 1, characterized in that: A heat conducting member (15) is provided on the connecting pipe (3), and the length direction of the heat conducting member (15) is the same as the length direction of the connecting pipe (3).

6. The urea injection device for boiler flue gas denitrification according to claim 1, characterized in that: The auxiliary heat ring (9) is arranged corresponding to the inner side of the tube body (1), and the end of the auxiliary heat ring (9) is provided with an inclined portion (14) for facilitating gas flow.

7. The urea injection device for boiler flue gas denitrification according to claim 1, characterized in that: The auxiliary heating ring (9) or the auxiliary heating plate (2) is provided with a liquid inlet pipe (4), one end of which is connected to the auxiliary heating channel (10) or the accommodating cavity (11), and the other end of which extends out of the tube body (1), and the end of the liquid inlet pipe (4) extending out of the tube body (1) is provided with a detachable sealing cover (5).

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