Horizontal air preheater for circulating fluidized bed boiler for pure combustion of Zhundong coal

Abstract

The utility model discloses a horizontal air preheater for a circulating fluidized bed boiler for pure combustion of Zhundong coal, and relates to an air preheater. The utility model relates to a horizontal air preheater, and aims to solve the problems that dust is easily deposited on corroded pipes, the heat exchange efficiency is not high, the boiler efficiency is influenced and the fuel consumption is increased due to the fact that pipes of the conventional horizontal air preheater are arranged sparsely by adopting large pipes and connecting flues between pipe boxes are formed by adopting expansion joints and bent plates. The heat exchanger comprises a plurality of tube boxes and a plurality of communicating boxes, the tube boxes are sequentially arranged from top to bottom in the height direction, heat exchange tube sets are arranged in the tube boxes, the peripheries of the lower ends of the tube boxes are supported on supporting beams, and the air outlet end of the heat exchange tube set in the lower tube box is connected with the air inlet end of the heat exchange tube set in the upper tube box through the communicating boxes. The communication box is provided with an inspection door, and the inspection door is connected with the communication box through a connecting assembly and a plurality of locking assemblies. The utility model is used for the circulating fluidized bed boiler.

Description

Technical Field

[0001] The utility model relates to an air preheater, in particular to a horizontal air preheater for a circulating fluidized bed boiler burning pure Zhundong coal. Background Art

[0002] The continuous increase in coal consumption has placed tremendous pressure on the environment. To address the increasing shortage of conventional coal resources, the development of circulating fluidized-bed boiler technology for pure combustion of Zhundong coal has become an inevitable trend. The Zhundong Coalfield, located in the Zhundong Economic and Technological Development Zone in Xinjiang, boasts my country's largest fully integrated coalfield, with projected reserves of substantial magnitude and the potential for continued mining for many years. This resource advantage is of great significance to promoting regional economic development. The principle of burning Zhundong coal is that Zhundong coal and air are mixed and burned in a fluidized state within the furnace, exchanging heat with the heating surfaces. The flue gas within the furnace (carrying a large amount of unburned carbon particles) further burns and releases heat in the upper furnace. The flue gas, after combustion in the furnace, enters a cyclone separator at the furnace outlet. The flue gas, carrying a large amount of material, enters an adiabatic cyclone separator, where it is separated. The separated flue gas flows through a diversion duct and into an air preheater, thereby heating the air.

[0003] Air preheaters are commonly used to improve boiler heat exchange efficiency and are widely used in circulating fluidized bed boilers, waste heat boilers, dust collectors, and other fields. For circulating fluidized bed boilers, air preheaters are essential and important structures, and their heat exchange efficiency has a significant impact on boiler performance. Conventional horizontal air preheater tubes often use a sparse arrangement of large tubes, and the connecting flues between tube boxes often use expansion joints and bent plates. This is prone to tube corrosion and dust accumulation, resulting in low heat exchange efficiency, affecting boiler efficiency and increasing fuel consumption. Utility Model Content

[0004] In order to solve the problems that the existing horizontal air preheater tubes are often arranged sparsely with large tubes, the connecting flues between the tube boxes are often in the form of expansion joints plus bent plates, the tubes are corroded and easily accumulate dust, the heat exchange efficiency is low, the boiler efficiency is affected, and the fuel consumption is increased, the utility model proposes a horizontal air preheater for a circulating fluidized bed boiler that purely burns Zhundong coal.

[0005] The technical solution adopted by the utility model to solve the above technical problems is:

[0006] A horizontal air preheater for a circulating fluidized bed boiler that purely burns Zhundong coal includes multiple pipe boxes and multiple connecting boxes. The multiple pipe boxes are arranged in sequence from top to bottom along the height direction. Heat exchange tube groups are provided in the pipe boxes. The four sides of the lower end of the pipe boxes are supported on support beams. The air outlet end of the heat exchange tube group in the lower pipe box is connected to the air inlet end of the heat exchange tube group in the upper pipe box through a connecting box. An inspection door is provided on the connecting box, and the inspection door is connected to the connecting box through a connecting assembly and multiple locking assemblies.

[0007] Furthermore, the pipe box is fixedly connected via a fixing frame, and the support beam is fixedly connected to the fixing frame.

[0008] Furthermore, the air inlet ends and air outlet ends of two adjacent heat exchange tube groups are staggered.

[0009] Furthermore, the heat exchange tubes in the first to third rows from top to bottom in each heat exchange tube group and the first to third rows from bottom to top in the lowest heat exchange tube group are all thick-walled tubes.

[0010] Furthermore, the heat exchange tubes of the lowest-level heat exchange tube group are Cow-Ten steel heat exchange tubes.

[0011] Furthermore, the inspection door includes a door frame and a furnace door cover, an inspection port is opened on the box body of the connecting box, the door frame is fixed to the outer end of the inspection port, the furnace door cover is arranged at the outer end of the door frame, the connecting assembly is arranged on one side of the furnace door cover, the furnace door cover is rotatably connected to the door frame through the connecting assembly, and multiple locking assemblies are evenly distributed between the furnace door cover and the door frame along the circumferential direction.

[0012] Furthermore, the connecting assembly includes a fixed ear seat, a pin shaft and a connecting ear seat. The fixed ear seat is fixed to the outer wall of the door frame, and the connecting ear seat is fixed to one side of the furnace door cover. The connecting ear seat and the fixed ear seat are hinged by a pin shaft.

[0013] Furthermore, the locking assembly includes a bolt fixing seat, a locking bolt and a butterfly nut. The bolt fixing seat is fixed to the outer side wall of the door frame, and the locking bolt is fixed vertically outward to the bolt fixing seat. A locking ear plate is fixed to the outer side of the furnace door cover, and a slot is provided on the locking ear plate. The locking bolt is inserted into the slot, and the butterfly nut is threadedly connected to the locking bolt and is arranged at the outer end of the locking ear plate.

[0014] Furthermore, a group of tensioning tubes is provided between each two opposite box plates in the connecting box.

[0015] Furthermore, every two adjacent pipe boxes are connected by a folding plate.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The utility model provides a horizontal air preheater for a circulating fluidized bed boiler that burns purely Zhundong coal. This is designed to improve the heat exchange efficiency of existing air preheaters and address the issues of corrosion and pipe contamination in the air preheater when burning Zhundong coal. Because Zhundong coal contains relatively high levels of alkali metals, moisture, and sulfur, ash easily adheres to the pipes during combustion, and the resulting sulfides also corrode the pipes more easily. This structure reduces ash accumulation, prevents pipe corrosion, improves boiler efficiency, enhances structural stability, is more energy-efficient and environmentally friendly, better improves boiler fuel combustion conditions, facilitates maintenance, and increases fuel utilization, thereby further improving boiler efficiency and saving costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is the main view of the overall structure of the utility model;

[0019] Figure 2 yes Figure 1 AA view in the;

[0020] Figure 3 yes Figure 2 CC view after removing the connecting box;

[0021] Figure 4 yes Figure 1 The enlarged view of point I in FIG.

[0022] Figure 5 yes Figure 1 The enlarged view of point II in the figure;

[0023] Figure 6 yes Figure 1 The enlarged view of point III in FIG.

[0024] Figure 7 yes Figure 1 Enlarged view of IV in the figure;

[0025] Figure 8 yes Figure 3 Enlarged view of V in the figure;

[0026] Figure 9 It is a cross-sectional view of the inspection door;

[0027] Figure 10 yes Figure 9 Enlarged view of VI in the figure. DETAILED DESCRIPTION

[0028] Specific implementation method 1: Combination Figures 1 to 10To illustrate this embodiment, a horizontal air preheater for a circulating fluidized bed boiler purely burning Zhundong coal described in this embodiment includes a plurality of pipe boxes 1 and a plurality of connecting boxes 2. The plurality of pipe boxes 1 are arranged in sequence from top to bottom along the height direction. A heat exchange tube group 3 is provided in the pipe box 1. The four sides of the lower end of the pipe box 1 are supported on a support beam 4. The air outlet end of the heat exchange tube group 3 in the lower pipe box 1 is connected to the air inlet end of the heat exchange tube group 3 in the upper pipe box 1 through a connecting box 2. An inspection door 5 is provided on the connecting box 2, and the inspection door 5 is connected to the connecting box 2 through a connecting assembly and a plurality of locking assemblies.

[0029] The tubes in heat exchange tube group 3 are changed from the original φ51X2 and transverse pitch of 100mm to φ40X2 and transverse pitch of 70mm, which can reduce dust accumulation, improve heat exchange efficiency and save materials; the tubes protrude 2mm from the tube sheet and are welded flush with the steel plate during welding, making the tube box look more beautiful.

[0030] The connection between the pipe box and the connecting box 1 is connected by connecting angle steel 15 and connecting channel steel 16, which not only improves the stability of the structure, but also simplifies the production steps and saves costs.

[0031] Specific implementation method 2: Combination Figures 1 to 2 In this embodiment, the pipe box 1 is fixedly connected via a fixing frame, and the support beam 4 is fixedly connected to the fixing frame. Other components and connection methods are the same as those of the first embodiment.

[0032] The support beam 4 is added under the pipe box 1 to prevent the air preheater from shaking and to bear the load of the air preheater.

[0033] Specific implementation method three: Combination Figures 1 to 2 To illustrate this embodiment, the air inlet and air outlet ends of two adjacent heat exchange tube groups 3 are staggered. Other components and connection methods are the same as those of the first embodiment.

[0034] Specific implementation method four: Combination Figure 1 In this embodiment, the heat exchange tubes in the first to third rows from top to bottom of each heat exchange tube group 3 and the first to third rows from bottom to top of the lowest heat exchange tube group 3 are all thick-walled tubes. Other components and connection methods are the same as those in the first embodiment.

[0035] Specific implementation method five: Combination Figure 1 In this embodiment, the heat exchange tubes of the bottom heat exchange tube group 3 are made of Corten steel. Other components and connection methods are the same as those of the fourth embodiment.

[0036] Each pipe box 1 has one to three rows, and the three rows from the bottom to the top of the lowest level use thick-walled pipes of φ40X2.5. The lowest level uses Corten steel to effectively prevent corrosion of the pipes due to the high sulfur content of Zhundong coal. The thick-walled pipes can extend the service life of the pipes once corroded, reduce pipe replacement, and save maintenance costs caused by pipe replacement.

[0037] Specific implementation method six: combination Figures 1 to 2 and Figures 9 and 10 This embodiment describes the inspection door 5, which includes a door cover 51 and a furnace door cover 52. An inspection port is provided on the body of the communication box 2. The door cover 51 is fixedly attached to the outer end of the inspection port. The furnace door cover 52 is disposed on the outer end of the door cover 51. A connecting assembly is disposed on one side of the furnace door cover 52. The furnace door cover 52 is rotatably connected to the door cover 51 via the connecting assembly. Multiple locking assemblies are evenly distributed along the circumferential direction between the furnace door cover 52 and the door cover 51. Other components and connection methods are the same as those of the first embodiment.

[0038] The connecting box adopts a new inspection door 5 structure, which saves the step of removing screws when checking the connecting box 2, making it more convenient.

[0039] A sealing plate 17 is provided between the door cover 51 and the furnace door upper cover 52 to seal the gap between the door cover 51 and the furnace door upper cover 52 and effectively prevent air leakage.

[0040] A handle 53 is fixedly connected to the outer side of the furnace door upper cover 52.

[0041] Specific implementation method seven: combination Figures 1 to 2 and Figures 9 and 10 This embodiment describes a connection assembly comprising a fixed lug 6, a pin 7, and a connecting lug 8. The fixed lug 6 is fixed to the outer wall of the door cover 51, and the connecting lug 8 is fixed to one side of the furnace door upper cover 52. The connecting lug 8 is hingedly connected to the fixed lug 6 via the pin 7. Other components and connection methods are the same as those of the sixth embodiment.

[0042] Specific implementation method eight: combination Figures 1 to 2 and Figures 9 and 10 This embodiment describes the locking assembly, which includes a bolt fixing base 9, a locking bolt 10, and a butterfly nut 11. The bolt fixing base 9 is fixed to the outer wall of the door cover 51, and the locking bolt 10 is fixed vertically outward to the bolt fixing base 9. A locking lug 12 is fixed to the outer side of the furnace door cover 52. The locking lug 12 has a slot, and the locking bolt 10 is inserted into the slot. The butterfly nut 11 is threadedly connected to the locking bolt 10 and is installed on the outer end of the locking lug 12. The other components and connection methods are the same as those of the sixth embodiment.

[0043] Specific implementation method nine: combination Figure 1 and Figure 6To illustrate this embodiment, a set of bracing tubes 13 is provided between each two opposing box plates in the connecting box 2. Other components and connection methods are the same as those in the first embodiment.

[0044] The connecting box 2 is supported by φ51 tensioning tubes 13 between the plates to strengthen the connecting box 2 and improve the overall stability of the air preheater.

[0045] Specific implementation method ten: Combination Figure 1 and Figure 7 To illustrate this embodiment, every two adjacent pipe boxes 1 are connected by a folding plate 14. Other components and connection methods are the same as those in the first embodiment.

[0046] The joints between the pipe boxes 1 are connected by folding plates 14, which can effectively absorb expansion, make the boiler operation more stable, and simplify the production and installation steps.

[0047] The heat exchange tube group adopts small tubes with a diameter of φ40X2. The tube box and the connecting box are connected with steel sections. The connecting box is supported by pipes. Thick-walled tubes are used in special positions. The inspection door of the connecting box adopts new structural forms such as new furnace doors, which can better improve heat exchange efficiency and reduce corrosion, thereby providing better performance for coal-fired circulating fluidized bed boilers.

[0048] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It should be understood that many modifications may be made to the illustrative embodiments, and that other arrangements may be devised, without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in ways other than those described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be employed in conjunction with other described embodiments.

Claims

1. A horizontal air preheater for a circulating fluidized bed boiler burning pure Zhundong coal, characterized by: The invention comprises a plurality of pipe boxes (1) and a plurality of connecting boxes (2). The plurality of pipe boxes (1) are arranged in sequence from top to bottom along the height direction. A heat exchange tube group (3) is provided in the pipe box (1). The four sides of the lower end of the pipe box (1) are supported on a support beam (4). The air outlet end of the heat exchange tube group (3) in the lower pipe box (1) and the air inlet end of the heat exchange tube group (3) in the upper pipe box (1) are connected through the connecting box (2). An inspection door (5) is provided on the connecting box (2). The inspection door (5) is connected to the connecting box (2) through a connecting component and a plurality of locking components.

2. The horizontal air preheater for a circulating fluidized bed boiler burning pure Zhundong coal according to claim 1, characterized in that: The pipe box (1) is fixedly connected via a fixing frame, and the support beam (4) is fixedly connected to the fixing frame.

3. The horizontal air preheater for a circulating fluidized bed boiler burning pure Zhundong coal according to claim 1, characterized in that: The air inlet ends and air outlet ends of two adjacent heat exchange tube groups (3) are arranged alternately.

4. The horizontal air preheater for a circulating fluidized bed boiler burning pure Zhundong coal according to claim 1, characterized in that: The heat exchange tubes in the first to third rows from top to bottom in each heat exchange tube group (3) and the first to third rows from bottom to top in the lowest heat exchange tube group (3) are all thick-walled tubes.

5. The horizontal air preheater for a circulating fluidized bed boiler burning pure Zhundong coal according to claim 4, characterized in that: The heat exchange tubes of the lowest heat exchange tube group (3) are Cowden steel heat exchange tubes.

6. The horizontal air preheater for a circulating fluidized bed boiler burning pure Zhundong coal according to claim 1, characterized in that: The inspection door (5) comprises a door cover (51) and a furnace door upper cover (52); an inspection port is provided on the box body of the communication box (2); the door cover (51) is fixedly connected to the outer end of the inspection port; the furnace door upper cover (52) is arranged at the outer end of the door cover (51); a connecting assembly is arranged on one side of the furnace door upper cover (52); the furnace door upper cover (52) is rotatably connected to the door cover (51) through the connecting assembly; and a plurality of locking assemblies are evenly distributed along the circumferential direction between the furnace door upper cover (52) and the door cover (51).

7. The horizontal air preheater for a circulating fluidized bed boiler burning pure Zhundong coal according to claim 6, characterized in that: The connecting assembly comprises a fixed ear seat (6), a pin shaft (7) and a connecting ear seat (8); the fixed ear seat (6) is fixedly connected to the outer side wall of the door cover (51); the connecting ear seat (8) is fixedly connected to one side of the furnace door upper cover (52); and the connecting ear seat (8) and the fixed ear seat (6) are hinged via the pin shaft (7).

8. The horizontal air preheater for a circulating fluidized bed boiler burning pure Zhundong coal according to claim 6, characterized in that: The locking assembly comprises a bolt fixing seat (9), a locking bolt (10) and a butterfly nut (11); the bolt fixing seat (9) is fixed to the outer side wall of the door cover (51); the locking bolt (10) is fixed to the bolt fixing seat (9) vertically outward; a locking ear plate (12) is fixed to the outer side of the furnace door upper cover (52); a slot is provided on the locking ear plate (12); the locking bolt (10) is inserted into the slot; the butterfly nut (11) is threadedly connected to the locking bolt (10) and is arranged at the outer end of the locking ear plate (12).

9. The horizontal air preheater for a circulating fluidized bed boiler burning pure Zhundong coal according to claim 1, characterized in that: A group of tensioning tubes (13) is provided between each two opposing box plates in the connecting box (2).

10. The horizontal air preheater for a circulating fluidized bed boiler burning pure Zhundong coal according to claim 1, characterized in that: Every two adjacent pipe boxes (1) are connected via a folding plate (14).

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