Vertical and horizontal composite arrangement tubular air pre-heater

Abstract

The utility model discloses a vertical and horizontal composite arrangement tubular air pre-heater, which relates to the technical field of boilers, and comprises an upper-stage vertical staggered tube box, a middle-stage vertical staggered tube box and a lower-stage horizontal sequential tube box, the upper-stage vertical staggered tube box is connected with the middle-stage vertical staggered tube box, the middle-stage vertical staggered tube box is connected with the lower-stage horizontal sequential tube box, and the lower-stage vertical staggered tube box is connected with the lower-stage horizontal sequential tube box. The lower-stage horizontal type in-line tube box is connected with an air feeder, a lower-stage flue is arranged at the bottom of the middle-stage vertical staggered tube box, and the lower-stage horizontal type in-line tube box is connected with the lower-stage flue through an expansion bent plate. The operation and maintenance convenience of the air pre-heater can be integrally improved, the service life of the air pre-heater can be integrally prolonged, and the operation safety level and economical efficiency of a boiler are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of boilers, in particular to a vertical and horizontal composite arrangement tubular air preheater. Background Art

[0002] Air preheater is the full name of air preheater, which is one of the necessary parts of power station boilers; this preheating equipment can improve the heat exchange performance of the boiler and reduce heat loss. The air preheater transfers the heat carried by the flue gas at the tail of the boiler to the air required for combustion in the furnace through steel pipes, increases the temperature of the hot air required for combustion in the furnace, improves the combustion conditions in the furnace, reduces incomplete combustion losses, and thus improves the thermal efficiency of the boiler.

[0003] The types of air preheaters for power station boilers can be generally divided into tubular air preheaters and rotary air preheaters. Compared with rotary air preheaters, tubular air preheaters have simpler structures, better tightness, better heat transfer performance, lower investment costs, and are easy to install and maintain; they are widely used in medium and small power station boilers.

[0004] Tubular air preheaters are divided into vertical and horizontal types according to the arrangement direction of the tube box. In vertical air preheaters, the flue gas flows longitudinally inside the tube, and the air flows transversely outside the tube to flush the tube. The tube box often adopts a staggered arrangement of the pipes, which has a high space utilization rate; in horizontal air preheaters, the flue gas flushes the tube longitudinally outside the tube, and the air flows transversely inside the tube. The tube box often adopts a sequential arrangement of the pipes, which occupies more space. Due to the direct flushing of the flue gas, the wall temperature of the horizontal tube is higher than that of the vertical one, which is more beneficial to prevent low-temperature corrosion.

[0005] The existing air preheater pipe boxes are generally divided into upper, middle and lower pipe boxes for hierarchical arrangement. The cold air is transported through the air blower to the low temperature section of the lower pipe box via the connecting air duct, and then transported into the pipe process of the tubular air preheater to exchange heat with the flue gas outside the tubular air preheater pipe, so that the temperature of the flue gas decreases; when the flue gas temperature is lower than the acid dew point, it provides conditions for low temperature corrosion to occur.

[0006] When the sodium, nitrogen and sulfur content in the fuel is too high, excessive sulfur trioxide will be produced in the flue gas, which will increase the flue gas dew point and aggravate the low-temperature corrosion of the pipe wall. Due to the migration of sodium in the fuel, a large amount of slag will be produced on the pipe wall. In addition, the ammonia escape caused by desulfurization and denitrification will form ammonium bisulfate with sulfur trioxide in the flue gas in the tail flue. When the exhaust temperature drops to 145-205℃, ammonium bisulfate is in liquid state and has high viscosity. Ammonium bisulfate will adhere to the fly ash in the air and adhere to the surface of the air preheater, forming a large amount of ash accumulation and blockage. In the vertical pipe box, it is even more difficult to clean.

[0007] Under existing technical conditions, vertical tube box air preheaters are mostly used due to space limitations. The lower tube box is made of corrosion-resistant materials, which increases costs and is not easy to remove slag and clean. When there is no space limit, a horizontal tube box air preheater is used. In order to facilitate slag removal and cleaning, the pipelines are arranged in series; to solve the corrosion problem, the lower tube box pipelines use enameled tubes. Enameled tubes are a composite material made by evenly coating the outer surface of a low-carbon steel base tube with porcelain enamel slurry or porcelain enamel powder and baking at high temperature. The surface of the enameled tube is smooth, and the air preheater made of it is resistant to corrosion, flue gas erosion, and fly ash wear. It has a long service life, which is about three times that of an ordinary steel tube preheater. The horizontal tube box occupies more space than the vertical one, and the heat exchange efficiency is relatively lower. Based on this, a vertical and horizontal composite arrangement tubular air preheater is designed, which has a simple structure, small space occupation, and high heat exchange efficiency. Utility Model Content

[0008] The utility model aims to overcome the deficiencies of the prior art and provide a vertical and horizontal composite tubular air preheater. The upper vertical staggered tube box and the middle vertical staggered tube box adopt a vertical ordinary carbon steel tube staggered arrangement to ensure the simple structure of the air preheater, small space occupation and high heat exchange efficiency. The lower horizontal sequential tube box is replaced from a conventional vertical arrangement to a horizontal enamel tube box, which increases the tube wall temperature and increases the corrosion resistance of the air preheater equipment. The sequential arrangement of the tubes of the lower horizontal sequential tube box is convenient for cleaning the slag and dust accumulation between the last stage tubes and is easy to replace the pipeline.

[0009] The purpose of the utility model is achieved through the following technical scheme: a vertical and horizontal composite arrangement tubular air preheater, the tubular air preheater includes an upper vertical staggered tube box, an intermediate vertical staggered tube box and a lower horizontal sequential tube box, the upper vertical staggered tube box is connected to the intermediate vertical staggered tube box, the intermediate vertical staggered tube box is connected to the lower horizontal sequential tube box, the lower horizontal sequential tube box is connected to the blower, a lower flue is provided at the bottom of the intermediate vertical staggered tube box, and the lower horizontal sequential tube box is connected to the lower flue through an expansion bent plate.

[0010] The upper vertical staggered tube box includes an upper tube box cavity for air flow and an upper heat exchange tube for smoke flow arranged in a staggered manner; the intermediate vertical staggered tube box includes an intermediate tube box cavity for air flow and an intermediate heat exchange tube for smoke flow arranged in a staggered manner; the lower horizontal sequential tube box includes a lower tube box cavity for smoke flow and horizontal tubes for air flow arranged in a sequential manner.

[0011] A double-stage metal expansion joint for hot flue gas flow is arranged on the top of the upper vertical staggered pipe box, and the double-stage metal expansion joint is connected to the upper heat exchange pipe. An upper flue is arranged on the bottom of the upper vertical staggered pipe box, and the upper heat exchange pipe is connected to the upper flue, and the upper flue is connected to the intermediate heat exchange pipe of the intermediate vertical staggered pipe box.

[0012] The upper flue is connected to the intermediate heat exchange tube of the intermediate vertical staggered tube box through a single-stage metal expansion joint.

[0013] The upper-level pipe box cavity of the upper-level vertical staggered pipe box and the middle-level pipe box cavity of the middle-level vertical staggered pipe box are connected through an upper-level connecting box.

[0014] The intermediate pipe box cavity of the intermediate vertical staggered pipe box is connected to the horizontal pipes of the lower horizontal sequential pipe box through a lower connecting box.

[0015] The bottoms of the upper vertical staggered pipe box, the middle vertical staggered pipe box and the lower horizontal straight pipe box are respectively provided with through beams.

[0016] The upper and lower ends of the expansion bent plate are respectively welded and sealed with the inner edges of the lower-level flue and the lower-level horizontal in-line pipe box.

[0017] The upper vertical staggered pipe box and the intermediate vertical staggered pipe box are both made of ordinary carbon steel pipes.

[0018] The lower-level horizontal in-line pipe box is made of enamel pipe material.

[0019] The beneficial effects of the utility model are:

[0020] 1. The utility model can improve the corrosion resistance of the lower pipe box of the air preheater, the convenience of cleaning slag and dust accumulation, and the convenience of later pipeline replacement while maintaining the simple structure of the air preheater, small space occupation, and a small increase in cost. It can improve the convenience and service life of air preheater operation and maintenance as a whole, and improve the safety level and economy of boiler operation.

[0021] 2. After the lower-level pipe box is changed from a conventional vertical pipe box to a horizontal pipe box, the upper end of the lower-level horizontal in-line pipe box is a cavity. At this time, it is impossible to use a metal expansion joint to connect it to the lower-level flue, so an expansion bent plate is used instead. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of the utility model;

[0023] Figure 2 This is a schematic diagram of the flue gas and air flow of a tubular air preheater;

[0024] Figure 3 It is a structural schematic diagram of an expansion bent plate;

[0025] Figure 4 for Figure 3 Left view of

[0026] In the figure: 1-upper level vertical staggered pipe box, 2-middle level vertical staggered pipe box, 3-lower level horizontal in-line pipe box, 4-lower level connecting box, 5-double-stage metal expansion joint, 6-upper level flue, 7-single-stage metal expansion joint, 8-upper level connecting box, 9-lower level flue, 10-expansion bent plate, 11-through beam. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the embodiment of the utility model clearer, the technical scheme in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, rather than all the embodiments. The components of the embodiment of the utility model generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiment of the utility model provided in the drawings is not intended to limit the scope of the utility model for protection, but merely represents the selected embodiment of the utility model. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the utility model.

[0028] The utility model will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0029] Embodiment 1:

[0030] like Figures 1 to 4 As shown, a tubular air preheater with a vertical and horizontal composite arrangement comprises an upper vertical staggered tube box 1, an intermediate vertical staggered tube box 2 and a lower horizontal sequential tube box 3. The upper vertical staggered tube box 1 is connected to the intermediate vertical staggered tube box 2, the intermediate vertical staggered tube box 2 is connected to the lower horizontal sequential tube box 3, the low-temperature end interface of the lower horizontal sequential tube box 3 is connected to the air supply fan through a first flue, a lower flue 9 is provided at the bottom of the intermediate vertical staggered tube box 2, and the lower horizontal sequential tube box 3 is connected to the lower flue 9 through an expansion bent plate 10.

[0031] The upper vertical staggered pipe box 1 includes an upper pipe box cavity for the lateral flow of air and an upper heat exchange tube arranged in a staggered manner for the vertical flow of flue gas. The intermediate vertical staggered pipe box 2 includes an intermediate pipe box cavity for the lateral flow of air and an intermediate heat exchange tube arranged in a staggered manner for the vertical flow of flue gas. The lower horizontal sequential pipe box 3 includes a lower pipe box cavity for the vertical flow of flue gas and a horizontal tube arranged in a sequential manner for the lateral flow of air.

[0032] A double-stage metal expansion joint 5 for hot flue gas flow is arranged on the top of the upper vertical staggered pipe box 1, and the double-stage metal expansion joint 5 is connected to the upper heat exchange pipe. An upper flue 6 is arranged on the bottom of the upper vertical staggered pipe box 1, and the upper heat exchange pipe is connected to the upper flue 6, and the upper flue 6 is connected to the intermediate heat exchange pipe of the intermediate vertical staggered pipe box 2.

[0033] The upper flue 6 is connected to the intermediate heat exchange tube of the intermediate vertical staggered tube box 2 through a single-stage metal expansion joint 7. The hot flue gas passes through the double-stage metal expansion joint 5, enters the upper heat exchange tube from the inlet pipe end of the upper vertical staggered tube box 1, flows downward in the vertically placed upper heat exchange tube, completes the heat exchange with the air in the upper tube box cavity, and then enters the upper flue 6 through the outlet end of the upper vertical staggered tube box 1, passes through the single-stage metal expansion joint 7, enters the intermediate heat exchange tube of the intermediate vertical staggered tube box 2, flows downward in the vertically placed intermediate heat exchange tube, completes the heat exchange with the air in the intermediate tube box cavity, and then enters the lower flue 9, passes through the expansion bend 10, enters the lower tube box cavity of the lower horizontal sequential tube box 3, flows vertically downward along the lower tube box cavity and completes the heat exchange with the air in the horizontal tube, and then is led out from the lower end of the lower horizontal sequential tube box 3 to the tail second flue.

[0034] Embodiment 2:

[0035] On the basis of Example 1, this example makes improvements to each pipe box, and the upper pipe box cavity of the upper vertical staggered pipe box 1 is connected with the middle pipe box cavity of the middle vertical staggered pipe box 2 through an upper connecting box 8.

[0036] The intermediate tube box cavity of the intermediate vertical staggered tube box 2 is connected to the horizontal tube of the lower horizontal sequential tube box 3 through the lower connecting box 4. The cold air enters the tube row inlet end of the lower horizontal sequential tube box 3 through the flue from the blower. Under the distribution of the tube sheet at the inlet end, the cold air evenly enters each horizontal sequential pipe, and exchanges heat with the flue gas in the cavity of the lower tube box in the horizontal tube. The preheated air is guided into the intermediate vertical staggered tube box 2 through the lower connecting box 4. The air flows in the intermediate tube box cavity and exchanges heat with the intermediate heat exchange tube placed vertically downward in the intermediate tube box cavity. The air preheated by the intermediate vertical staggered tube box 2 is guided into the upper vertical staggered tube box 1 through the upper connecting box 8. The air flows in the upper tube box cavity and exchanges heat with the upper heat exchange tube placed vertically downward in the upper tube box cavity. The air after the three-stage preheating is led out through the outlet of the upper vertical staggered pipe box 1.

[0037] The bottom of the upper vertical staggered pipe box 1, the middle vertical staggered pipe box 2 and the lower horizontal straight pipe box 3 are respectively provided with through beams 11. The weight of the upper vertical staggered pipe box 1, the middle vertical staggered pipe box 2 and the lower horizontal straight pipe box 3 are all borne on the through beams 11, and they expand vertically upward freely after being heated with the upper surface of each beam as the base point.

[0038] The upper and lower ends of the expansion bent plate 10 are welded and sealed to the lower flue 9 and the inner edges of the lower horizontal in-line pipe box 3 respectively.

[0039] Embodiment 3:

[0040] On the basis of Embodiments 1-2, this embodiment makes improvements to the material of each pipe box, and the upper vertical staggered pipe box 1 and the middle vertical staggered pipe box 2 are both made of ordinary carbon steel pipes.

[0041] The lower horizontal in-line pipe box 3 is made of enamel pipe material.

[0042] The above is only a preferred embodiment of the utility model. It should be understood that the utility model is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not deviate from the spirit and scope of the utility model, and should be within the scope of protection of the claims attached to the utility model.

Claims

1. A vertical and horizontal composite tubular air preheater, characterized in that: The invention comprises an upper vertical staggered pipe box (1), an intermediate vertical staggered pipe box (2) and a lower horizontal sequential pipe box (3); the upper vertical staggered pipe box (1) is connected to the intermediate vertical staggered pipe box (2); the intermediate vertical staggered pipe box (2) is connected to the lower horizontal sequential pipe box (3); the lower horizontal sequential pipe box (3) is connected to a blower; a lower flue (9) is arranged at the bottom of the intermediate vertical staggered pipe box (2); the lower horizontal sequential pipe box (3) is connected to the lower flue (9) via an expansion bent plate (10).

2. The vertical and horizontal composite tubular air preheater according to claim 1 is characterized in that: The upper vertical staggered pipe box (1) comprises an upper pipe box cavity for air flow and an upper heat exchange tube for smoke flow arranged in a staggered manner; the intermediate vertical staggered pipe box (2) comprises an intermediate pipe box cavity for air flow and an intermediate heat exchange tube for smoke flow arranged in a staggered manner; and the lower horizontal sequential pipe box (3) comprises a lower pipe box cavity for smoke flow and a horizontal tube for air flow arranged in a sequential manner.

3. The vertical and horizontal composite tubular air preheater according to claim 2 is characterized in that: A double-stage metal expansion joint (5) for hot flue gas flow is arranged at the top of the upper vertical staggered pipe box (1), and the double-stage metal expansion joint (5) is connected to an upper heat exchange pipe. An upper flue (6) is arranged at the bottom of the upper vertical staggered pipe box (1), and the upper heat exchange pipe is connected to the upper flue (6). The upper flue (6) is connected to an intermediate heat exchange pipe of the intermediate vertical staggered pipe box (2).

4. The vertical and horizontal composite tubular air preheater according to claim 3 is characterized in that: The upper flue (6) is connected to the intermediate heat exchange tube of the intermediate vertical staggered tube box (2) via a single-stage metal expansion joint (7).

5. A vertical and horizontal composite tubular air preheater according to any one of claims 2 to 4, characterized in that: The upper-level pipe box cavity of the upper-level vertical staggered pipe box (1) and the middle-level pipe box cavity of the middle-level vertical staggered pipe box (2) are connected via an upper-level connecting box (8).

6. A vertical and horizontal composite tubular air preheater according to any one of claims 2 to 4, characterized in that: The intermediate pipe box cavity of the intermediate vertical staggered pipe box (2) is connected to the horizontal pipes of the lower horizontal sequential pipe box (3) via a lower connecting box (4).

7. The vertical and horizontal composite tubular air preheater according to claim 6 is characterized in that: The bottoms of the upper vertical staggered pipe box (1), the middle vertical staggered pipe box (2) and the lower horizontal sequential pipe box (3) are respectively provided with through beams (11).

8. The vertical and horizontal composite tubular air preheater according to claim 7 is characterized in that: The upper and lower ends of the expansion curved plate (10) are welded and sealed to the lower flue (9) and the inner edges of the lower horizontal in-line pipe box (3).

9. The vertical and horizontal composite tubular air preheater according to claim 1, characterized in that: The upper vertical staggered pipe box (1) and the intermediate vertical staggered pipe box (2) are both made of ordinary carbon steel pipe material.

10. The vertical and horizontal composite tubular air preheater according to claim 1, characterized in that: The lower level horizontal in-line pipe box (3) is made of enamel pipe material.

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