Air pre-heater with anti-blocking function

Abstract

The utility model relates to the technical field of anti-blocking of boiler air pre-heaters, in particular to an air pre-heater with an anti-blocking function. The air pre-heater comprises an air pre-heater main body air side which is communicated with the air duct, and an air pre-heater main body smoke side which is communicated with the flue; the air pre-heater channel partition plates are installed in the air pre-heater body and divide the air side of the air pre-heater body into a plurality of independent small channels. The air duct partition plate is installed in the air duct and used for dividing an inlet air duct of the air pre-heater body into a plurality of independent small air ducts, and each independent small air duct communicates with one independent small channel; and the baffle door is mounted on the inlet air duct of the air pre-heater main body and is used for closing or opening the independent small air duct. According to the air pre-heater, cold air is stopped from being supplied to the local area of the air pre-heater, then the temperature of the local area of the air pre-heater body is increased to the proper temperature, ammonium bisulfate condensed on the heat exchange face of the air pre-heater is decomposed into ammonia, hydrogen sulfide and water to be discharged along with flue gas, and therefore the problem that the air pre-heater is blocked is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of boiler air preheater anti-blocking, in particular to an air preheater with an anti-blocking function. Background Art

[0002] Sulfur dioxide (SO2) and nitrogen oxides (NOx) are two major air pollutants emitted from flue gas from coal-fired boilers, which have multiple hazards to the environment and human health. With the large-scale use of SCR (selective catalytic reduction) denitrification devices, the NOx emissions in flue gas from coal-fired boilers have been well controlled. The SCR reactor uses a vanadium-based catalyst. While removing nitrogen oxides (NOx) from flue gas, the catalyst also oxidizes part of the sulfur dioxide (SO2) in the flue gas into sulfur trioxide (SO3). Sulfur trioxide (SO3) reacts chemically with escaped ammonia (NH3) that does not participate in the denitrification reduction reaction to form ammonium bisulfate (ABS). Ammonium bisulfate (ABS) is a viscous solid in a melted state between 147 and 235°C, with the characteristics of strong viscosity, easy adsorption of fly ash, and strong hygroscopicity. When ammonium bisulfate (ABS) condenses on the heat exchange surface of the low-temperature section of the air preheater in the pipeline, the moisture and fly ash particles in the flue gas will be collected, eventually leading to dust accumulation, blockage and low-temperature corrosion of the air preheater, thus affecting the safe, stable and economical operation of the boiler unit. In the case where the flue gas flow field, NOx concentration field and denitrification agent injection entering the SCR reactor are uneven, or the flue gas temperature entering the SCR reactor is lower than the working temperature of the catalyst denitrification when the boiler is under low load, in order to meet environmental protection requirements, the relevant technology will inevitably inject excessive amino denitrification agent, resulting in an increase in the concentration of escaping ammonia at the outlet of the SCR reactor, thereby increasing the amount of ammonium bisulfate generated, and further exacerbating the dust accumulation, blockage and low-temperature corrosion of the air preheater. Utility Model Content

[0003] In the related technology, the concentration of ammonia escaping from the outlet of the SCR reactor is too high, which leads to an increase in the generation of ammonium bisulfate. Ammonium bisulfate (ABS) condenses on the heat exchange surface of the low-temperature section of the air preheater in the pipeline, thereby aggravating the dust accumulation, blockage and low-temperature corrosion problems of the air preheater.

[0004] The present application provides an air preheater with an anti-blocking function, comprising:

[0005] An air preheater body, comprising an air side and a flue gas side, wherein the air side is communicated with the air duct, and the flue gas side is communicated with the flue;

[0006] An air preheater tube box partition plate is installed inside the air preheater body, and the air preheater tube box partition plate divides the air side of the air preheater body into a plurality of independent small channels;

[0007] An air duct dividing plate is installed in the air duct, and the air duct dividing plate divides part of the air duct into a plurality of independent small air ducts, and each of the independent small air ducts is connected to one of the independent small channels;

[0008] A baffle door is installed on the air duct, and the baffle door is used to cut off or open the independent small air duct.

[0009] In combination with the first aspect, in one implementation, the air preheater further includes:

[0010] An outlet pressure sensor is installed at the outlet flue of the air preheater body, and is used to detect the pressure parameters at the outlet flue of the air preheater body;

[0011] An inlet pressure sensor is installed at the inlet flue of the air preheater body, and is used to detect pressure parameters at the inlet flue of the air preheater body.

[0012] In combination with the first aspect, in one embodiment, 1 to 3 outlet pressure sensors are provided at the outlet flue of the air preheater body, and an inlet pressure sensor is provided at the inlet flue of the air preheater body.

[0013] In combination with the first aspect, in one embodiment, a plurality of air preheater tube box partition plates are provided in the air preheater body;

[0014] A plurality of the air duct partition plates are arranged in the air duct, the number of the air duct partition plates is equal to the number of the air preheater tube box partition plates, and each of the air duct partition plates is connected to one of the air preheater tube box partition plates.

[0015] In combination with the first aspect, in one embodiment, a plurality of baffle doors are provided in the air duct, a plurality of air duct partition plates are provided between the baffle doors and the air preheater body, the number of the baffle doors is equal to the number of the air duct partition plates, and each baffle door is connected to one of the air duct partition plates.

[0016] In combination with the first aspect, in one embodiment, the air preheater body includes a high-temperature section pipe box, a medium-temperature section pipe box and a low-temperature section pipe box, a connecting flue is provided between the high-temperature section pipe box, the medium-temperature section pipe box and the low-temperature section pipe box, and the air preheater pipe box partition plate is provided in the medium-temperature section pipe box and the low-temperature section pipe box.

[0017] In combination with the first aspect, in one embodiment, the number of the air preheater tube box partition plates and the air duct partition plates in the medium temperature section tube box and the low temperature section tube box is equal, and each of the air duct partition plates is connected to one of the air preheater tube box partition plates.

[0018] In combination with the first aspect, in one embodiment, a flue partition plate is provided in the connecting flue between the medium-temperature section pipe box and the low-temperature section pipe box, and the flue partition plate divides the connecting flue between the medium-temperature section pipe box and the low-temperature section pipe box into multiple small flues, and the number of the small flues is equal to the independent small channels in the air side of the air preheater body, and the positions correspond one to one.

[0019] In combination with the first aspect, in one embodiment, a thermocouple is provided at the flue outlet of the air preheater body, and the thermocouple is used to detect the flue gas temperature at the flue outlet of the air preheater body.

[0020] In combination with the first aspect, in one embodiment, a plurality of the thermocouples are provided at the flue outlet of the air preheater body, the plurality of thermocouples are all located in the same cross-section of the flue outlet of the air preheater body, and the plurality of thermocouples correspond one-to-one to the independent small channels of the air preheater body.

[0021] The beneficial effects brought by the technical solution provided by the embodiment of the present application include at least:

[0022] The present application divides the air duct in the air preheater body into multiple independent small channels by using a partition plate, and uses a controllable baffle door to stop the supply of cold air to a local area of ​​the air preheater. Then the temperature of the local area of ​​the air preheater body is raised above a suitable temperature, so that the ammonium bisulfate condensed on the heat exchange surface of the air preheater is decomposed into ammonia (NH3), hydrogen sulfide (H2S) and water (H2O) and discharged with the flue gas, thereby solving the problem of ammonium bisulfate blockage in the air preheater. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 This is a schematic diagram of an air preheater with an anti-blocking function in an embodiment of the present application;

[0025] Figure 2 For this application Figure 1 Cross-sectional view of the air preheater from the AA perspective.

[0026] In the figure: 1. Flue gas duct; 2. Air duct; 3. Air preheater body; 31. Low temperature section pipe box; 4. Baffle door; 5. Thermocouple; 6. Outlet pressure sensor; 7. Inlet pressure sensor; 8. Air preheater pipe box partition plate; 9. Air duct partition plate. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0028] In the related technology, the concentration of ammonia escaping from the outlet of the SCR reactor is too high, which leads to an increase in the generation of ammonium bisulfate. Ammonium bisulfate (ABS) condenses on the heat exchange surface of the low-temperature section of the air preheater in the pipeline, thereby aggravating the dust accumulation, blockage and low-temperature corrosion problems of the air preheater.

[0029] First, as Figure 1 and Figure 2 As shown, the present application discloses an air preheater with anti-blocking function, which comprises: a flue 1, an air duct 2, an air preheater body 3, an air preheater tube box partition plate 8, an air duct partition plate 9 and a baffle door 4; wherein,

[0030] An air preheater body 3, which includes an air side and a flue gas side, the air side is connected to the air duct 2, and the flue gas side is connected to the flue 1; an air preheater tube box partition plate 8, which is installed inside the air preheater body 3, and the air preheater tube box partition plate 8 divides the air side of the air preheater body 3 into a number of independent small channels; an air duct partition plate 9, which is installed in the air duct 2, and the air duct partition plate 9 divides part of the air duct 2 into a number of independent small air ducts, and each of the independent small air ducts is connected to one of the independent small channels; a baffle door 4, which is installed on the air duct 2, and the baffle door 4 is used to cut off or conduct the independent small air duct.

[0031] It is worth noting that the flue 1 is the exhaust channel at the tail of the boiler and is connected to the flue gas side of the air preheater body 3. The air duct 2 is the air supply channel of the boiler combustion system and is connected to the air side of the air preheater body 3. The air preheater body 3 is a hot air heating device for the boiler combustion system. The air preheater body 3 is divided into a high-temperature section pipe box, a medium-temperature section pipe box and a low-temperature section pipe box 31 according to the working temperature. The three are arranged in series from high to low temperature in the vertical flue at the outlet of the boiler economizer. Furthermore, the baffle door 4 can be pneumatically or electrically driven to achieve conduction to the independent small air duct, so as to stop supplying cold air to the local area of ​​the air preheater, and to increase the temperature of the local area of ​​the air preheater pipe box to above 235°C, thereby solving the problem of ammonium bisulfate blockage in the air preheater.

[0032] In some specific embodiments, the air preheater further includes: an outlet pressure sensor 6 and an inlet pressure sensor 7; wherein,

[0033] An outlet pressure sensor 6 is installed at the outlet flue of the air preheater body 3, and is used to detect the pressure parameters at the outlet flue of the air preheater body 3; an inlet pressure sensor 7 is installed at the flue gas inlet flue of the air preheater body 3, and is used to detect the pressure parameters at the inlet flue of the air preheater body 3. Optionally, 1-3 outlet pressure sensors 6 are provided at the outlet flue of the air preheater body 3, and 1-3 inlet pressure sensors 7 are provided at the flue gas inlet flue of the air preheater body 3.

[0034] It should be noted that the outlet pressure sensor 6 and the inlet pressure sensor 7 are used to detect the air preheater inlet and outlet pressure difference. The outlet pressure difference can be used to obtain the air preheater inlet and outlet flue gas resistance, and then accurately determine the switch state of the damper door 4.

[0035] Furthermore, a plurality of the air preheater tube box partition plates 8 are provided in the air preheater main body 3; a plurality of the air duct partition plates 9 are provided in the air duct 2, the number of the air duct partition plates 9 is equal to the number of the air preheater tube box partition plates 8, and each of the air duct partition plates 9 is connected to one of the air preheater tube box partition plates 8.

[0036] It should be noted that the air duct partition plate 9 corresponds to the air preheater tube box partition plate 8 one by one, and the two are closely connected.

[0037] In some preferred embodiments, a plurality of baffle doors 4 are provided in the air duct 2, a plurality of air duct partition plates 9 are provided between the baffle doors 4 and the air preheater body 3, the number of the baffle doors 4 is equal to the number of the air duct partition plates 9, and each baffle door 4 is connected to one air duct partition plate 9.

[0038] It is worth noting that during the operation of the boiler, the damper door 4 should remain open and not affect the normal operation of the air preheater. When the air preheater needs to perform the anti-blocking function, only one damper door 4 is allowed to be closed at most in the same period to cut off the independent small air duct, and the time limit shall not exceed a certain period.

[0039] In some optional embodiments, as described above, the air preheater body 3 includes a high-temperature section pipe box, a medium-temperature section pipe box and a low-temperature section pipe box 31, and a connecting flue is provided between the high-temperature section pipe box, the medium-temperature section pipe box and the low-temperature section pipe box 31, and the air preheater pipe box partition plate 8 is provided in the medium-temperature section pipe box and the low-temperature section pipe box 31. Further, a plurality of the air duct partition plates 9 extend from the outlet of the low-temperature section pipe box 31 to the inlet of the medium-temperature section pipe box, and each of the air duct partition plates 9 is connected to one of the air preheater pipe box partition plates 8 in the medium-temperature section pipe box and the low-temperature section pipe box 31.

[0040] It can be understood that in the above embodiment, the air duct partition plate 9 is connected to the air preheater tube box partition plate 8 in the medium temperature section tube box and the low temperature section tube box 31, so that the air side in the medium temperature section tube box and the low temperature section tube box 31 are divided into several independent small channels.

[0041] Furthermore, a flue partition plate is provided in the connecting flue between the medium-temperature section pipe box and the low-temperature section pipe box 31, and the flue partition plate divides the connecting flue between the medium-temperature section pipe box and the low-temperature section pipe box 31 into a plurality of small flues, and the number of the small flues is equal to the number of independent small channels in the air side of the air preheater body 3, and the positions correspond one to one.

[0042] In some preferred embodiments, a thermocouple 5 is provided at the outlet flue of the air preheater body 3, and the thermocouple 5 is used to detect the flue gas temperature at the outlet flue of the air preheater body 3. Further, a plurality of the thermocouples 5 are provided at the outlet flue of the air preheater body 3, and the plurality of the thermocouples 5 are all located in the same cross section of the outlet flue of the air preheater body 3, and the plurality of the thermocouples 5 correspond one to one to the independent small channels of the air preheater body 3.

[0043] It should be noted that when the air preheater of the present application performs the anti-blocking function, the local temperature of the medium-temperature section pipe box or the low-temperature section pipe box can be raised to above 235°C by closing one of the baffle doors 4, thereby reducing the impact of the increased flue gas temperature on the desulfurization and dust removal system.

[0044] Furthermore, when the air preheater performs the anti-blocking function, when it is determined that the anti-blocking function needs to be performed according to the inlet and outlet pressure difference of the air preheater body 3, the damper door 4 can be driven to perform the preset process. The preset process includes closing the damper door 4 to block the passage for a certain period of time, and then opening the damper door 4 again. It should be noted that only one damper door 4 is allowed to be in a closed state at the same time period.

[0045] In summary, the embodiment of the present application adds several electric (pneumatic) damper doors 4 at the entrance of the air duct of the low-temperature section of the air preheater tube box, and divides the air side inside the air preheater into several independent small channels, and at the same time divides the connecting electric (pneumatic) damper door and the tubular air preheater air duct into several independent small ducts. The number of the above-mentioned electric (pneumatic) damper doors 4, the independent small channels inside the air preheater, and the independent small ducts are equal and one-to-one corresponding. During the operation of the boiler, the electric (pneumatic) damper door is closed at a fixed time or according to the resistance of the flue gas at the inlet and outlet of the air preheater. By stopping the supply of cold air to the local area of ​​the air preheater, the temperature of the local area of ​​the air preheater tube box is raised to above 235°C, so that the ammonium bisulfate condensed on the heat exchange surface of the air preheater is decomposed into ammonia (NH3), hydrogen sulfide (H2S) and water (H2O) and discharged with the flue gas, thereby solving the problem of ammonium bisulfate blockage in the air preheater.

[0046] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application 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 a limitation on the present application. 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 an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0047] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0048] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. An air preheater with anti-blocking function, characterized in that: include: Flue (1); Air duct (2); An air preheater body (3), comprising an air side and a flue gas side, wherein the air side is in communication with the air duct (2), and the flue gas side is in communication with the flue (1); An air preheater pipe box partition plate (8) is installed inside the air preheater body (3), and the air preheater pipe box partition plate (8) divides the air side of the air preheater body (3) into a plurality of independent small channels; An air duct partition plate (9) is installed in the air duct (2), and the air duct partition plate (9) divides part of the air duct (2) into a plurality of independent small air ducts, and each of the independent small air ducts is connected to one of the independent small channels; A baffle door (4) is installed on the air duct (2), and the baffle door (4) is used to cut off or open the independent small air duct.

2. The air preheater according to claim 1, characterized in that: The air preheater also includes: An outlet pressure sensor (6) is installed at the outlet flue of the air preheater body (3), and the outlet pressure sensor (6) is used to detect the pressure parameters at the outlet flue of the air preheater body (3); An inlet pressure sensor (7) is installed at the inlet flue of the air preheater body (3), and the inlet pressure sensor (7) is used to detect the pressure parameters at the inlet flue of the air preheater body (3).

3. The air preheater according to claim 1, characterized in that: One to three outlet pressure sensors (6) are provided at the outlet flue of the air preheater body (3), and an inlet pressure sensor (7) is provided at the inlet flue of the air preheater body (3).

4. The air preheater according to claim 1, characterized in that: A plurality of air preheater tube box partition plates (8) are provided in the air preheater body (3); A plurality of the air duct partition plates (9) are arranged in the air duct (2), the number of the air duct partition plates (9) is equal to the number of the air preheater tube box partition plates (8), and each of the air duct partition plates (9) is connected to one of the air preheater tube box partition plates (8).

5. The air preheater according to claim 4, characterized in that: A plurality of baffle doors (4) are provided in the air duct (2), a plurality of air duct partition plates (9) are provided between the baffle doors (4) and the air preheater body (3), the number of the baffle doors (4) and the air duct partition plates (9) are equal, and each baffle door (4) is connected to one air duct partition plate (9).

6. The air preheater with anti-blocking function according to claim 1, characterized in that: The air preheater body (3) comprises a high-temperature section pipe box, a medium-temperature section pipe box and a low-temperature section pipe box (31), a connecting flue is provided between the high-temperature section pipe box, the medium-temperature section pipe box and the low-temperature section pipe box (31), and the air preheater pipe box partition plate (8) is provided in both the medium-temperature section pipe box and the low-temperature section pipe box (31).

7. The air preheater with anti-blocking function as claimed in claim 6, characterized in that: The number of the air preheater tube box partition plates (8) and the air duct partition plates (9) in the medium-temperature section tube box and the low-temperature section tube box (31) is equal, and each of the air duct partition plates (9) is connected to one of the air preheater tube box partition plates (8).

8. The air preheater with anti-blocking function as claimed in claim 7, characterized in that: A flue partition plate is provided in the connecting flue between the medium-temperature section pipe box and the low-temperature section pipe box (31), and the flue partition plate divides the connecting flue between the medium-temperature section pipe box and the low-temperature section pipe box (31) into a plurality of small flues, wherein the number of the small flues is equal to the number of independent small channels in the air side of the air preheater body (3), and the positions correspond one to one.

9. The air preheater according to claim 8, characterized in that: A thermocouple (5) is provided at the flue outlet of the air preheater body (3), and the thermocouple (5) is used to detect the flue gas temperature at the flue outlet of the air preheater body (3).

10. The air preheater according to claim 9, characterized in that: A plurality of the thermocouples (5) are provided at the flue outlet of the air preheater body (3), the plurality of the thermocouples (5) are all located in the same cross section of the flue outlet of the air preheater body (3), and the plurality of the thermocouples (5) correspond one-to-one to the independent small channels of the air preheater body (3).

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