Tubular air preheater capable of avoiding blockage of ammonium bisulfate

Abstract

The invention discloses a tubular air preheater capable of avoiding blockage of ammonium bisulfate. The tubular air preheater comprises a shell, a flue gas pipeline, a container and a movable cavity, the plurality of flue gas pipelines are arranged in the shell, and the bottoms of the flue gas pipelines are connected with a first branch pipeline and a second branch pipeline; a cleaning agent is contained in the container, and the movable cavity comprises a first movable cavity body and a second movable cavity body; the first moving cavity is connected into the first branch pipeline in a sliding manner; the second moving cavity is slidably connected to the interior of the second branch pipeline; the container is respectively communicated with the first moving cavity and the second moving cavity; when the first moving cavity is moved upwards, the second branch pipeline is closed, and flue gas is introduced into the first branch pipeline; and when the second moving cavity is moved upwards, the first branch pipeline is closed, and the flue gas is introduced into the first branch pipeline. According to the air preheater, blockages in the pipeline can be cleaned on line.

Description

Technical Field

[0001] This invention relates to the field of air preheater technology, and more specifically to a tubular air preheater that avoids clogging by ammonium bisulfate. Background Technology

[0002] A tubular air preheater is a heat exchange surface in a boiler where flue gas from the tail flue is preheated to a certain temperature by internal heat exchange fins before entering the boiler. It is a device used to improve the heat exchange performance of a boiler and reduce energy consumption. Using a tubular air preheater in a boiler system can improve boiler thermal efficiency, improve combustion conditions, reduce heat loss from incomplete combustion of fuel, and save on evaporative heating surface area while enhancing radiative heat transfer within the furnace.

[0003] Tubular air preheaters are a type of tube-and-tube heat transfer device where flue gas and air flow inside and outside the tubes, respectively, exchanging heat through the tube walls. They are available in vertical and horizontal configurations. However, with increasingly stringent environmental regulations and the implementation of SCR (Self-Resistant Container) systems, the problem of blockage in tubular air preheaters has become increasingly serious. Ammonium bisulfate deposition frequently leads to ash blockage on the cold-end heat storage elements, causing a continuous increase in flue gas-side resistance. In severe cases, high-pressure water flushing is required to passively remove the ash adhering to the surface of the heat storage elements. Furthermore, with the implementation of ultra-low emission standards for coal-fired units, nitrogen oxide emissions are strictly controlled to 50 mg / nm. 3 The problem of ash blockage in tubular air preheaters is becoming increasingly serious.

[0004] Various anti-ash-clogging technologies have been adopted domestically, such as using enamel-lined elements in the low-temperature section of the thermal storage elements in tubular air preheaters, strengthening the management of steam soot blowing in tubular air preheaters, burning coal with relatively low sulfur content, and limiting the ammonia escape rate in SCR denitrification. However, these measures have not yet effectively solved the ash-clogging problem in tubular air preheaters. Furthermore, currently, dealing with ammonium bisulfate clogging in tubular air preheaters generally requires shutting down the boiler for cleaning, which affects the preheater's operating efficiency.

[0005] Therefore, developing a tubular air preheater that can clean blockages in pipelines online is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] In view of this, the present invention provides a tubular air preheater that can clean blockages in pipelines online.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A tubular air preheater that avoids ammonium bisulfate clogging, comprising:

[0009] case,

[0010] A flue gas pipeline, wherein multiple flue gas pipelines are arranged within the housing, and the bottom of each flue gas pipeline is connected to a first branch pipeline and a second branch pipeline; the first branch pipeline and the second branch pipeline are independent of each other;

[0011] A container containing a cleaning agent;

[0012] The movable cavity includes a first movable cavity and a second movable cavity; the first movable cavity is slidably connected to the first branch pipe; the second movable cavity is slidably connected to the inside of the second branch pipe; the container is connected to the first movable cavity and the second movable cavity respectively; when the first movable cavity is moved upward, the second branch pipe is closed, and flue gas is introduced into the first branch pipe; when the second movable cavity is moved upward, the first branch pipe is closed, and flue gas is introduced into the first branch pipe.

[0013] The beneficial effect of adopting the above technical solution is that the present invention realizes the alternation of flue gas heat exchange and pipeline cleaning, and can remove ammonium bisulfate blockage online without shutting down the furnace, thus maintaining the continuous and efficient operation of the preheater.

[0014] Preferably, the flue gas passages within the housing are arranged in multiple rows side-by-side, and baffles are provided between adjacent rows of flue gas passages. The baffles prevent mutual interference between adjacent flue gas passages.

[0015] Preferably, the bottom end of the side wall of the housing is provided with multiple louvers, and the multiple louvers correspond to the positions of the first branch pipe and the second branch pipe. Heat exchange between flue gas and air can be achieved by opening and closing the corresponding louvers.

[0016] Preferably, an annular rubber ring is provided on the side wall of the outlet of the first branch pipe and the second branch pipe. The rubber ring is placed below the first moving cavity or the second moving cavity. The top of the first moving cavity and the second moving cavity are open and the bottom is hinged with an outlet plate. When the first moving cavity or the second moving cavity is closed, the outlet plate presses against the rubber ring.

[0017] Preferably, the bottom of both the first and second movable cavities is provided with a limiting plate to limit the outlet plate, and the rubber ring is provided with a notch at the position corresponding to the limiting plate.

[0018] Preferably, the container is covered with an insulation board on its exterior; and the container is provided with a solution inlet on its side wall.

[0019] Preferably, the first branch pipe and the second branch pipe have exhaust ports on their top sidewalls.

[0020] Preferably, a level gauge is provided on the surface of the container.

[0021] Preferably, the outlet of the container is connected to a flexible hose, which passes through a first branch pipe and a second branch pipe and is connected to the first movable cavity and the second movable cavity, respectively. A valve is provided on the flexible hose.

[0022] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a tubular air preheater that avoids ammonium bisulfate blockage, the beneficial effects of which are:

[0023] (1) By dividing the cold end of the tubular air preheater into two parts, opening the first branch pipe and the second branch pipe and opening the louvers according to a certain cycle, heat exchange between flue gas and air and online cleaning of the cold end of the pipe can be achieved.

[0024] (2) The cleaning agent is sodium hydroxide solution, and the solution does not react with the first and second moving cavities made of iron sheet, so it will not corrode the pipes; and this type of tubular air preheater has a simple structure, is easy to manufacture, and reduces the resistance of the tubular air preheater and the maintenance and operation costs of coal-fired units. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0026] Figure 1 A schematic diagram of the structure of the air preheater provided by the present invention;

[0027] Figure 2 A side view of the air preheater provided by the present invention;

[0028] Figure 3 This is a schematic diagram of the connection between the first branch pipeline and the second branch pipeline provided by the present invention.

[0029] In the figure,

[0030] 1-Shell; 2-Flue gas pipeline; 3-First branch pipeline; 4-Second branch pipeline; 5-Container; 6-First movable cavity; 7-Baffle; 8-Louvre; 9-Rubber ring; 10-Outlet plate; 11-Limiting plate; 12-Insulation plate; 13-Solution inlet; 14-Exhaust port; 15-Level gauge; 16-Flue gas outlet; 17-Flue gas inlet. Detailed Implementation

[0031] 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.

[0032] This invention discloses a tubular air preheater that avoids clogging by ammonium bisulfate, comprising:

[0033] Casing 1,

[0034] Flue gas duct 2, multiple flue gas ducts 2 are arranged inside the shell 1, and the bottom of the flue gas duct 2 is connected to a first branch duct 3 and a second branch duct 4; the first branch duct 3 and the second branch duct 4 are independent of each other;

[0035] Container 5 contains cleaning agent;

[0036] The movable cavity includes a first movable cavity 6 and a second movable cavity. The first movable cavity 6 is slidably connected to the first branch pipe 3. The second movable cavity is slidably connected to the inside of the second branch pipe 4. The container 5 is connected to the first movable cavity 6 and the second movable cavity respectively. When the first movable cavity 6 is moved upward, the second branch pipe 4 is closed, and flue gas enters the first branch pipe 3, which operates normally. At this time, the second branch pipe 4 is closed, and the container 5 introduces cleaning agent into the second movable cavity to clean the inner wall of the second movable cavity. After the second movable cavity is cleaned, the first movable cavity 6 is moved downward and the second movable cavity is moved upward. At this time, the flue gas passes through the second movable cavity. The cleaning agent in the container 5 is introduced into the first movable cavity 6 to clean the first movable cavity 6, which can achieve heat exchange between the flue gas and the air while cleaning the inside of the pipe.

[0037] In one embodiment, multiple rows of flue gas passages 2 are arranged side by side within the housing 1, and baffles 7 are provided between adjacent rows of flue gas passages 2. The baffles 7 can block adjacent flue gas passages 2. The louvers 8 correspond one-to-one with the first branch pipe 3 or the second branch pipe 4. Heat exchange is carried out on the pipes through which the flue gas enters through the louvers 8. The baffles 7 can prevent interference between adjacent flue gas passages 2 during heat exchange.

[0038] In one embodiment, since the cleaning process is infrequent and requires intervals, the first moving cavity 6 and the second moving cavity do not need to move frequently. Therefore, the movement can be manually adjusted. Taking the first moving cavity 6 as an example: a moving rod can be provided outside the first branch pipe 3, passing through the first branch pipe 3 and connecting to the first moving cavity 6. This moving rod can be used to move and adjust the first moving cavity 6. A groove or a fixed component can also be provided on the outside of the first branch pipe 3 for the moving rod to move. Other manual adjustment methods are also possible and are not unique.

[0039] In one embodiment, a plurality of louvers 8 are provided at the bottom end of the side wall of the housing 1, and the louvers 8 correspond to the positions of the first branch pipe 3 and the second branch pipe 4. When flue gas is introduced into the corresponding branch pipe, the louvers 8 at the corresponding positions are opened to facilitate heat exchange between the flue gas and the air.

[0040] In one embodiment, an annular rubber ring 9 is provided on the side wall of the outlet of the first branch pipe 3 and the second branch pipe 4. The rubber ring 9 is positioned below the first movable cavity 6 or the second movable cavity. The top of the first movable cavity 6 and the second movable cavity are open, and the bottom is hinged to an outlet plate 10. When the first movable cavity 6 or the second movable cavity is closed, the outlet plate 10 presses against the rubber ring 9. When the first movable cavity 6 or the second movable cavity moves upward, the outlet plate 10 automatically falls under the action of gravity, and the bottom outlet of the first movable cavity 6 or the second movable cavity opens. When the first movable cavity 6 or the second movable cavity moves downward, the outlet plate 10 is lifted after contacting the rubber ring 9. When the outlet plate 10 is fully pressed against the rubber ring 9, the outlet of the first movable cavity 6 or the second movable cavity closes.

[0041] In one embodiment, both the first movable cavity 6 and the second movable cavity are provided with limiting plates 11 at their bottoms to restrict the exit plate 10. A notch is provided at the position corresponding to the rubber ring 9 and the limiting plate 11. When the exit plate 10 is in the open state, the limiting plate 11 supports the exit plate 10, causing it to tilt, thus facilitating its closure. The notch prevents the rubber ring 9 from affecting the limiting plate 11 during the up-and-down movement of the first movable cavity 6 or the second movable cavity. The rubber ring 9 is made of butyl rubber, and the first movable cavity 6 and the second movable cavity are made of sheet metal.

[0042] In one embodiment, the exterior of container 5 is covered with an insulation board 12; a solution inlet 13 is provided on the side wall of container 5. The insulation board 12 can reduce the impact of flue gas temperature on the cleaning agent. The insulation board 12 is a rock wool board.

[0043] In one embodiment, the first branch pipe 3 and the second branch pipe 4 have exhaust ports 14 on their top sidewalls. The exhaust ports 14 ensure that the cleaning agent can smoothly enter the first or second movable cavity 6 when it is closed. When cleaning is not required, the exhaust ports 14 can be blocked to prevent the exhaust of fumes.

[0044] In one embodiment, a level gauge 15 is provided on the surface of container 5. The level gauge 15 can measure the liquid level inside container 5, and when the cleaning agent is low, the cleaning agent can be introduced through solution inlet 13.

[0045] In one embodiment, the outlet of container 5 is connected to a hose, which passes through the first branch pipe 3 and the second branch pipe 4 and is connected to the first movable cavity 6 and the second movable cavity respectively. A valve 16 is provided on the hose.

[0046] In one embodiment, a controller may also be included. The louver 8 may be an electric louver, and the valve 16 may be a solenoid valve. The controller can control the opening or closing of the louvers. Since electric louvers and solenoid valves are only commonly used in the market, their working principles and the control process of the controller are well known and will not be described in detail here.

[0047] Working principle:

[0048] Normal heat exchange: The first moving chamber 6 moves upward, its outlet plate 10 falls and opens, and the flue gas enters the preheater through the first branch pipe 3; the second moving chamber moves downward, the outlet plate 10 presses the rubber ring 9, and the second branch pipe 4 is closed.

[0049] Online cleaning: Open the valve, and sodium hydroxide solution enters the closed second moving chamber, reacting with and dissolving the ammonium bisulfate adhering to the inner wall of the pipe, and carrying away the ammonium bisulfate ash; after cleaning, the first moving chamber 6 moves down, the first branch pipe closes, the second moving chamber moves up, the first branch pipe opens, flue gas is introduced, and cleaning agent is introduced into the first moving chamber 6 to clean the first moving chamber 6.

[0050] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0051] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A tubular air preheater that avoids clogging by ammonium bisulfate, characterized in that, include: case, A flue gas pipeline, wherein multiple flue gas pipelines are arranged inside the housing, and the bottom of the flue gas pipeline is connected to a first branch pipeline and a second branch pipeline; The first branch pipeline and the second branch pipeline are independent of each other; A container containing a cleaning agent; The movable cavity includes a first movable cavity and a second movable cavity; the first movable cavity is slidably connected to the first branch pipe; the second movable cavity is slidably connected to the inside of the second branch pipe; the container is connected to the first movable cavity and the second movable cavity respectively; when the first movable cavity is moved upward, the second branch pipe is closed, and flue gas is introduced into the first branch pipe; when the second movable cavity is moved upward, the first branch pipe is closed, and flue gas is introduced into the first branch pipe.

2. A tubular air preheater for avoiding ammonium bisulfate blockage according to claim 1, characterized in that, The flue gas passages inside the housing are arranged in multiple rows side by side, and baffles are provided between adjacent rows of flue gas passages.

3. A tubular air preheater for avoiding ammonium bisulfate blockage according to claim 1, characterized in that, The bottom of the side wall of the housing is provided with multiple louvers, and the multiple louvers correspond to the positions of the first branch pipe and the second branch pipe.

4. A tubular air preheater for avoiding ammonium bisulfate blockage according to claim 1, characterized in that, An annular rubber ring is provided on the side wall of the outlet of the first branch pipe and the second branch pipe. The rubber ring is placed below the first moving cavity or the second moving cavity. The top of the first moving cavity and the second moving cavity are open and the bottom is hinged with an outlet plate. When the first moving cavity or the second moving cavity is closed, the outlet plate presses against the rubber ring.

5. A tubular air preheater for avoiding ammonium bisulfate blockage according to claim 4, characterized in that, The bottom of both the first and second movable cavities is provided with a limiting plate to limit the position of the outlet plate, and the rubber ring is provided with a notch at the position corresponding to the limiting plate.

6. A tubular air preheater for avoiding ammonium bisulfate blockage according to claim 1, characterized in that, The container is covered with an insulation board on its exterior; the container has a solution inlet on its side wall.

7. A tubular air preheater for avoiding ammonium bisulfate blockage according to claim 6, characterized in that, The first branch pipe and the second branch pipe have exhaust ports on the side walls at the top.

8. A tubular air preheater for avoiding ammonium bisulfate blockage according to claim 1, characterized in that, A level gauge is installed on the surface of the container.

9. A tubular air preheater for avoiding ammonium bisulfate blockage according to claim 1, characterized in that, The container's outlet is connected to a flexible hose, which passes through a first branch pipe and a second branch pipe and is connected to the first movable cavity and the second movable cavity, respectively. A valve is installed on the flexible hose.

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