Double-tube-plate finned tube air heater

Abstract

This utility model belongs to the technical field of pulp and paper making, and discloses a double-tube-plate finned tube air heater, which consists of a shell-side air heating side and a tube-side steam side that are interconnected. The tube-side steam side includes a steam inlet header, a condensate outlet header, and finned tubes located between the steam inlet header and the condensate outlet header. A steam diversion plate is arranged in the steam inlet header. The upper end of the finned tube is welded to a fixed tube sheet, and its lower end is welded to a floating tube sheet. The condensate outlet header and the floating tube sheet are confined inside a U-shaped space enclosed by a sealing plate. A condensate outlet pipe is connected to the bottom of the condensate outlet header, and the condensate outlet pipe is connected to the sealing plate through a condensate outlet sealing device. This utility model can solve the problems of water hammer phenomenon caused by poor drainage of condensate in the tubes during the operation of traditional air heaters, which ultimately leads to heat exchanger leakage, and the problem of weld tearing between the heat exchange tubes and the tube sheet due to thermal expansion in traditional air heaters.

Description

Technical Field

[0001] This utility model belongs to the technical field of pulp and paper making, and particularly relates to a double-tube plate finned tube air heater. Background Technology

[0002] Currently, in the pulp and paper grade chemical industry, alkali recovery technology plays a role in protecting the environment and recovering resources. It is an indispensable and important part of the pulp and paper process. Through processes such as evaporation, combustion, and causticization, it recovers alkali resources from pulp black liquor on the one hand, and converts the organic matter in pulp black liquor into energy on the other hand, avoiding pollution of the environment by wastewater discharge.

[0003] In order to maintain the temperature of the carbon bed in the alkali furnace and ensure that the black liquor is fully combusted, the primary air, secondary air and tertiary air of the alkali furnace need to be heated to a specific temperature before being put into the furnace to assist combustion and improve the efficiency of thermal energy utilization.

[0004] Traditional air heaters experience water hammer during operation due to poor drainage of condensate inside the tubes, ultimately leading to heat exchanger leaks. Furthermore, thermal expansion can cause tearing of the welds between the heat exchange tubes and the tube sheet. Additionally, thermal shock from the inlet steam can easily cause vibration in the air heater. Utility Model Content

[0005] Based on the shortcomings of the existing technology, the technical problem solved by this utility model is to provide a double tube sheet finned tube air heater, which can reduce the vibration of the air heater and solve the problems of water hammer phenomenon caused by poor drainage of condensate in the tubes during the operation of traditional air heaters, which ultimately leads to heat exchanger leakage, and the problem of the weld between the heat exchange tube and the tube sheet tearing due to thermal expansion of traditional air heaters.

[0006] To solve the above-mentioned technical problems, this utility model provides a double-tube sheet finned tube air heater, which consists of a shell-side air heating side and a tube-side steam side that are interconnected. The tube-side steam side includes a steam inlet header, a condensate outlet header, and finned tubes located between the steam inlet header and the condensate outlet header. A steam diversion plate is arranged in the steam inlet header. A fixed tube sheet is welded to the steam inlet header. The upper end of the finned tube is welded to the fixed tube sheet, and its lower end is welded to the floating tube sheet. A support device is provided between the finned tubes. The condensate outlet header and the floating tube sheet are confined inside a U-shaped space enclosed by a sealing plate. A condensate outlet pipe is connected to the bottom of the condensate outlet header, and the condensate outlet pipe is connected to the sealing plate through a condensate outlet sealing device.

[0007] Furthermore, the condensate outlet sealing device includes a fixing plate welded to the bottom of the sealing plate, a connecting plate fixed to the fixing plate by means of hexagon socket head cap screws, and a sealing fiber rope wound between the fixing plate and the connecting plate.

[0008] Furthermore, the support device consists of a corrugated support plate and a buckle, used to hold the finned tube in place, and a support device is provided at intervals of length.

[0009] Preferably, the two sides of the sealing plate are welded to the first side plate.

[0010] Optionally, the shell-side air heating side includes second side plates located on the left and right sides of the windward side of the air heater, and a bent plate welded to the fixed tube sheet. The second side plates are welded to the bent plate and the first side plates.

[0011] Furthermore, a steam inlet pipe and a steam inlet flange are welded onto the steam inlet header, and a condensate outlet pipe and a condensate outlet flange are welded onto the condensate outlet header.

[0012] Optionally, the steam inlet header, fixed tube sheet, and upper end plate are sealed and welded together, and the condensate outlet header, floating tube sheet, and lower end plate are sealed and welded together.

[0013] Therefore, the double-tube sheet finned tube air heater of this utility model has at least the following beneficial effects:

[0014] 1. The primary, secondary, and tertiary air from the primary, secondary, and tertiary air fans are sent to the air heater via air ducts. After heat exchange and temperature increase, the air is finally sent to the alkali furnace for combustion support. Low-pressure steam is used as the heating medium in the low-pressure section, and medium-pressure steam is used in the medium-pressure section. Condensate is recycled.

[0015] 2. This utility model solves the problem of water hammer caused by poor drainage of condensate in the pipes during the operation of traditional air heaters, which ultimately leads to heat exchanger leakage.

[0016] 3. The condensate outlet pipe and the condensate outlet header are connected by a stuffing box seal. When the air heater is running, the floating tube sheet can float up and down according to the actual expansion without being torn or damaged. This solves the problem of the weld seam between the heat exchange tube and the tube sheet being torn due to thermal expansion in traditional air heaters.

[0017] 4. The steam inlet and condensate outlet adopt a header design to reduce air resistance, and the steam inlet is equipped with a steam diversion plate to avoid vibration of the air heater caused by thermal shock. The primary, secondary, and tertiary air of the alkali furnace need to be heated to specific temperatures before being put into the furnace for combustion, which facilitates achieving the required heating temperatures for the primary, secondary, and tertiary air.

[0018] 5. The finned tubes are made of stainless steel-aluminum bimetallic composite finned tubes or stainless steel-aluminum bimetallic composite finned tubes. These finned tubes have the characteristics of tight bonding, low thermal resistance, good heat transfer performance, high strength, and strong corrosion resistance.

[0019] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the invention more apparent and understandable, the following detailed description is provided in conjunction with preferred embodiments and accompanying drawings. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings of the embodiments will be briefly described below.

[0021] Figure 1 This is a front view of the double-tube sheet finned tube air heater of this utility model;

[0022] Figure 2 This is a side view of the double-tube sheet finned tube air heater of this utility model;

[0023] Figure 3 This is a top view of the double-tube sheet finned tube air heater of this utility model;

[0024] Figure 4 This is a schematic diagram of the fixed tube sheet of this utility model;

[0025] Figure 5 This is a schematic diagram of the steam diversion plate of this utility model;

[0026] Figure 6 This is a schematic diagram of the floating tube sheet of this utility model;

[0027] Figure 7 This is a schematic diagram of the support device of this utility model;

[0028] Figure 8 This is a schematic diagram of the structure of the condensate outlet sealing device of this utility model;

[0029] Figure 9 This is a schematic diagram of the structure of the fixing plate of this utility model;

[0030] Figure 10 This is a schematic diagram of the connecting plate of this utility model.

[0031] In the diagram: 1-Steam inlet pipe; 2-Steam inlet header; 3-Steam distributor plate; 4-Fixed tube sheet; 5-Finned tube; 6-Support device; 7-Floating tube sheet; 8-Condensate outlet header; 9-Sealing plate; 10-Condensate outlet sealing device; 11-Condensate outlet pipe; 12-Lower end plate; 13-First side plate; 14-Second side plate; 15-Upper end plate; 16-Bending plate; 17-Crossbeam; 18-Fixed plate; 19-Connecting plate; 20-Sealing fiber rope; 21-Hex socket head cap screw. Detailed Implementation

[0032] The specific embodiments of this utility model are described in detail below with reference to the accompanying drawings, which form part of this specification. These embodiments illustrate the principles of the invention, and other aspects, features, and advantages of this utility model will become apparent from this detailed description. In the accompanying drawings, the same or similar parts in different figures are indicated by the same reference numerals.

[0033] like Figures 1 to 10 As shown, the double tube sheet finned tube air heater of this utility model includes a shell-side air heating side and a tube-side steam side, which are interconnected to form a double tube sheet finned tube air heater.

[0034] The tube-side steam side includes a steam inlet header 2 and a condensate outlet header 8. A steam diverter plate 3 is arranged in the steam inlet header 2. A fixed tube sheet 4 is welded to the steam inlet header 2. The upper end of the finned tube 5 is welded to the fixed tube sheet 4, and the lower end of the finned tube 5 is welded to the floating tube sheet 7. A support device 6 is provided between the finned tubes 5. The condensate outlet header 8 and the floating tube sheet 7 are confined within a U-shaped space enclosed by a sealing plate 9, and finally welded to the sealing plate 9 by a first side plate 13. The shell-side air-heating side includes second side plates 14 located on the left and right sides of the air heater's windward side, and bent plates 16 welded to the fixed tube sheet 4. The second side plates 14 are welded to the bent plates 16 and the first side plates 13. The second side plates 14 are also welded to the first side plates 13. The function of the first side plates 13 is to seal the left and right sides of the sealing plate 9, and the function of the second side plates 14 is to seal the left and right sides of the air heater's windward side.

[0035] After entering through the steam inlet header 2, the steam first passes through the steam distribution plate 3 to distribute the steam evenly in the cavity, and then enters each finned tube 5 at a uniform speed. This helps to protect the weld between the end of the finned tube 5 and the fixed tube sheet 4, and also reduces the vibration of the heater.

[0036] Steam inlet header 2, fixed tube sheet 4, and upper end plate 15 are sealed and welded together. Condensate outlet header 8, floating tube sheet 7, and lower end plate 12 are sealed and welded together.

[0037] Furthermore, the finned tube 5 is stably supported by the support device 6, which consists of a support corrugated plate and a buckle to hold the finned tube 5 in place. A support device 6 needs to be installed at intervals of length.

[0038] Furthermore, the lower part of the finned tube 5 is welded to the floating tube sheet 7. To facilitate the air heater's free up-and-down movement during operation due to thermal expansion, the floating tube sheet 7 is located inside the lower sealing plate 9. See the detailed structure below. Figure 8When the heater is running, the finned tube 5 expands due to heat, and the floating tube sheet 7, the condensate outlet header 8, and the condensate outlet pipe 11 float up and down together to eliminate the thermal stress generated during the operation of the heater.

[0039] The finned tube 5 of this utility model adopts a stainless steel-aluminum bimetallic composite finned tube or a stainless steel-aluminum bimetallic composite finned tube.

[0040] A condensate outlet manifold 8 is connected to the bottom of a condensate outlet pipe 11, which is connected to the sealing plate 9 via a condensate outlet sealing device 10. The condensate outlet sealing device 10 includes a fixing plate 18 welded to the bottom of the sealing plate 9, a connecting plate 19 fixed to the fixing plate 18 by hexagonal head screws 21, and a sealing fiber rope 20 wound between the fixing plate 18 and the connecting plate 19. The condensate outlet pipe 11 passes through the sealing plate 9 and is sealed by the fixing plate 18, the connecting plate 19, and the sealing fiber rope 20. The sealing fiber rope 20, wound between the fixing plate 18 and the connecting plate 19, serves as a seal.

[0041] Furthermore, the floating tube sheet 7 is fully welded to the condensate outlet header 8, and the condensate outlet pipe 11 extends all the way to the condensate outlet header 8 and is welded thereon, ensuring that the condensate can be smoothly discharged from the condensate outlet header 8 (lower header).

[0042] Furthermore, after the first side plate 13 and the second side plate 14 are welded together, the on-site air duct is welded and fixed to the second side plate 14.

[0043] Steam inlet pipe 1 and steam inlet flange are welded onto steam inlet header 2 (upper header), and condensate outlet pipe 11 and condensate outlet flange are welded onto condensate outlet header 8 (lower header).

[0044] The fixed tube sheet 4 is welded to the bending plate 16, and the bending plate 16 is fixed to the second side plate 14; the finned tubes 5 at both ends are fixed to the fixed tube sheet 4 and the floating tube sheet 7, and the middle finned tube 5 is fixed by the bending plate and the crossbeam 17.

[0045] Below, refer to Figures 1 to 10 Based on the above description of structural features, the usage steps of the double-tube sheet finned tube air heater of this utility model are briefly described as follows:

[0046] The product is connected to the on-site inlet air duct, inlet steam pipe, condensate outlet pipe and outlet air duct. The air enters from the left side of the air heater. The steam enters from the steam inlet header 2 and first passes through the steam diverter plate 3 for full mixing before entering the finned tube 5 at a uniform speed to heat the air. The condensate from the condensate outlet header 8 is discharged from the bottom. After the air is heated to the required temperature, it enters the outlet air duct from the right side and is put into the furnace for combustion.

[0047] This utility model is assembled and welded from a double tube sheet (fixed tube sheet 4 and floating tube sheet 7), a steam inlet, a steam outlet, finned tubes 5, and a support device 6. Air flows outside the tubes to increase heat exchange efficiency, while steam flows inside. To maintain the temperature of the carbon bed in the alkali furnace and ensure complete combustion of the black liquor, the primary, secondary, and tertiary air of the alkali furnace needs to be heated to specific temperatures before being introduced into the furnace for combustion. This utility model provides a convenient way to achieve the required heating temperatures for the primary, secondary, and tertiary air. The purpose of using a double tube sheet (fixed tube sheet 4 and floating tube sheet 7) is to allow the finned tubes 5 to float freely after thermal expansion.

[0048] The above description is merely a preferred embodiment of the present invention and should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A double-tube sheet finned tube air heater, comprising a shell-side air heating side and a tube-side steam side interconnected, characterized in that, The tube-side steam side includes a steam inlet header (2), a condensate outlet header (8), and a finned tube (5) located between the steam inlet header (2) and the condensate outlet header (8). A steam diversion plate (3) is arranged in the steam inlet header (2), a fixed tube sheet (4) is welded to the steam inlet header (2), the upper tube end of the finned tube (5) is welded to the fixed tube sheet (4), and its lower tube end is welded to the floating tube sheet (7). A support device (6) is provided between the finned tubes (5). The condensate outlet header (8) and the floating tube sheet (7) are confined inside the U-shaped space enclosed by the sealing plate (9). The bottom of the condensate outlet header (8) is connected to a condensate outlet pipe (11), which is connected to the sealing plate (9) through a condensate outlet sealing device (10).

2. The dual-tube sheet finned tube air heater as described in claim 1, characterized in that, The condensate outlet sealing device (10) includes a fixing plate (18) welded to the bottom of the sealing plate (9), a connecting plate (19) connected and fixed to the fixing plate (18) by an internal hexagon head screw (21), and a sealing fiber rope (20) wrapped between the fixing plate (18) and the connecting plate (19).

3. The dual-tube sheet finned tube air heater as described in claim 1, characterized in that, The support device (6) consists of a support corrugated plate and a buckle, used to hold the finned tube (5) in place, and a support device (6) is provided at intervals of length.

4. The double-tube sheet finned tube air heater as described in claim 1, characterized in that, The sealing plate (9) is welded to the first side plate (13) on both sides.

5. The double-tube sheet finned tube air heater as described in claim 4, characterized in that, The shell-side air heating side includes a second side plate (14) located on the left and right sides of the windward side of the air heater, and a bent plate (16) welded to the fixed tube sheet (4). The second side plate (14) is welded to the bent plate (16) and the first side plate (13).

6. The dual-tube sheet finned tube air heater as described in claim 1, characterized in that, The steam inlet header (2) is welded with a steam inlet pipe (1) and a steam inlet flange, and the condensate outlet header (8) is welded with a condensate outlet pipe (11) and a condensate outlet flange.

7. The double-tube sheet finned tube air heater as described in claim 1, characterized in that, The steam inlet header (2), fixed tube sheet (4) and upper end plate (15) are sealed and welded together, and the condensate outlet header (8), floating tube sheet (7) and lower end plate (12) are sealed and welded together.

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