CN216644185U - Low-temperature economizer structure for preventing flue gas leakage - Google Patents

Abstract

The utility model discloses a low-temperature economizer structure for preventing flue gas leakage, which comprises an inlet transition section, an outlet transition section and a low-temperature economizer body, wherein the inlet transition section is connected with the inlet of the low-temperature economizer; the sleeve and the middle tube plate in the low-temperature economizer body are fully welded, the sleeve and the supporting circular tube in the low-temperature economizer body are filled with sealing materials, the heat exchange tube in the low-temperature economizer body and the header side tube plate are fully welded, the heat exchange tube in the low-temperature economizer body and the elbow side tube plate are fully welded, the inlet transition section is communicated with the inlet of the low-temperature economizer body, the outlet transition section is communicated with the outlet of the low-temperature economizer body, smoke can be prevented from leaking into the elbow, and safety and economy of the low-temperature economizer are improved.

Description

A low-temperature economizer structure for preventing flue gas leakage

technical field

The utility model belongs to the technical field of heat exchangers, and relates to a low-temperature economizer structure for preventing flue gas leakage.

Background technique

The low temperature economizer can reduce the flue gas temperature, and the absorbed heat is used to heat the condensed water to reduce the coal consumption of the unit; the low temperature economizer is arranged at the inlet of the dust collector to reduce the temperature of the flue gas entering the dust collector, thereby improving the dust removal efficiency and reducing the flue gas temperature. It can also remove SO ₃ and various metal pollutants below the acid dew point; the waste heat of flue gas absorbed by the low temperature economizer can also be used to heat the hot water heater, greatly improving the inlet air temperature and outlet smoke temperature of the air preheater, effectively Alleviate low-temperature corrosion and ash blocking with ammonium hydrogen sulfate, so low-temperature economizer technology has been widely used in China. However, due to the changeable and poor quality of domestic coal, the sulfur content, ash content and water content of the received base are relatively high. At the same time, the escape of ammonia in the tail flue gas exceeds the standard, and the flue gas is highly corrosive, resulting in low-temperature economizers. After running for a period of time, there are problems of corrosion, wear and leakage at the elbow.

The low temperature economizer is arranged in the flue. In order to prevent the expansion of the heat exchange tube and the uneven expansion of the flue, the tube sheet and the heat exchange tube at the elbow of the heat exchange tube are perforated and not welded, which will cause a small amount of flue gas leakage. When entering the elbow, since the cooling water flows into the elbow and the flue gas flow rate is low, the flue gas temperature will drop to below 80°C, causing viscous ash blocking and low-temperature corrosion.

At present, the method to prevent leakage at the elbow is to add a sealing sleeve at the pipe hole to reduce the leakage of flue gas. However, the diameter of the casing is about 1mm larger than the diameter of the heat exchange tube, and there is still a small amount of flue gas leaking into the elbow. effectively solve the problem.

Utility model content

The purpose of the utility model is to overcome the shortcomings of the above-mentioned prior art, and provide a low-temperature economizer structure for preventing flue gas leakage. economical.

In order to achieve the above purpose, the structure of the low-temperature economizer for preventing flue gas leakage according to the present invention includes an inlet transition section, an outlet transition section and a low-temperature economizer body;

The sleeve in the low-temperature economizer body and the intermediate tube sheet are fully welded, the sleeve in the low-temperature economizer body and the supporting round tube are filled with sealing material, and the heat exchange tube in the low-temperature economizer body is connected to the collector. The tank side tube sheets are fully welded, the heat exchange tube in the low temperature economizer body and the elbow side tube sheet are fully welded, the inlet transition section is connected to the inlet of the low temperature economizer body, and the outlet transition section is connected to the low temperature economizer body. The outlet of the coal burner body is communicated.

It also includes two expansion joints, wherein the inlet transition section and the inlet of the low temperature economizer body are communicated through a first expansion joint, and the outlet transition section and the outlet of the low temperature economizer body are communicated through a second expansion joint .

The low-temperature economizer body includes a header, a heat exchange tube, a casing, an elbow, a supporting round tube and a tube sheet, and the tube sheet includes a header side tube sheet, an intermediate tube sheet and an elbow side tube sheet;

The middle tube sheet is located between the header side tube sheet and the elbow side tube sheet, the sleeve is sleeved in the middle of the supporting round pipe, the casing is connected with the middle tube sheet, and the supporting round pipe is fixed on the header side tube sheet and the elbow. Between the head side tube sheets;

The lower side of each heat exchange tube and the header side tube sheet are fully welded, the upper side of each heat exchange tube and the elbow side tube sheet are fully welded, and the middle part of each heat exchange tube passes through the middle tube sheet. The ends of the adjacent heat exchange tubes are communicated through elbows, and the header is communicated with the first heat exchange tube and the last heat exchange tube.

The relationship between the diameter D of the casing and the diameter d of the supporting circular tube is: D-d≤2mm.

The supporting round tube is broken at the middle tube sheet, and the distance after breaking is δ, the maximum expansion amount of the heat exchange tube is L1, and the maximum expansion amount of the supporting round tube is L2, then δ=1.5(L2-L1);

The installation process of the casing is as follows: in the factory, the supporting circular tube and the intermediate tube sheet are fully welded. When the low-temperature economizer body is installed, the supporting circular pipe is interrupted at the intermediate tube sheet, and then the two The semi-circular sleeve is welded to the port on the supporting round pipe, and then the sealing material is filled in the gap between the casing and the supporting round pipe and compacted.

The utility model has the following beneficial effects:

In the specific operation of the low-temperature economizer structure for preventing flue gas leakage, the flue gas enters the low-temperature economizer body from the inlet transition section, and flows out from the outlet transition section after heat exchange. The heat exchange tube and the header side tube sheet are fully welded, and the heat exchange tube and the elbow side tube sheet are fully welded to ensure that the flue gas does not leak into the elbow and avoid corrosion and wear at the elbow. The utility model can ensure that no flue gas leakage occurs at the elbow, and at the same time, the expansion of the heat exchange tube is independent of the flue, the supporting circular tube and the tube sheet, and the safety and economy of the equipment are high.

Description of drawings

Fig. 1 is the front view of the middle and low temperature economizer body of the utility model;

Fig. 2 is the top view of the middle and low temperature economizer body of the utility model;

Fig. 3 is the side view of the middle and low temperature economizer body of the utility model;

FIG. 4 is a schematic diagram of the sleeve 8 in the utility model.

Among them, 1 is the inlet transition section, 2 is the outlet transition section, 3 is the supporting circular tube, 4 is the elbow side tube sheet, 5 is the elbow, 6 is the expansion joint, 7 is the heat exchange tube, 8 is the casing, 9 It is the header side tube sheet, 10 is the header, 11 is the middle tube sheet, 12 is the sealing material, 13 is the upper sealing plate, and 14 is the lower sealing plate.

Detailed ways

In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described The embodiments are only a part of the embodiments of the present invention, not all of the embodiments, and are not intended to limit the scope of the disclosure of the present invention. Also, in the following description, descriptions of well-known structures and techniques are omitted to avoid unnecessarily obscuring the concepts disclosed in the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

The accompanying drawings show a schematic structural diagram of an embodiment according to the disclosure of the present invention. The figures are not to scale, some details have been exaggerated for clarity, and some details may have been omitted. The shapes of various regions and layers shown in the figures and their relative sizes and positional relationships are only exemplary, and in practice, there may be deviations due to manufacturing tolerances or technical limitations, and those skilled in the art should Regions/layers with different shapes, sizes, relative positions can be additionally designed as desired.

Referring to Figure 1, Figure 2, Figure 3 and Figure 4, the structure of the low temperature economizer for preventing flue gas leakage according to the present invention includes an inlet transition section 1, an outlet transition section 2, a low temperature economizer body and two expansion joints 6. The inlet transition section 1 is communicated with the inlet of the low temperature economizer body, the outlet of the low temperature economizer body is communicated with the outlet transition section 2, and the inlet transition section 1 and the low temperature economizer body pass through the first expansion joint 6 is connected, and the low-temperature economizer body and the outlet transition section 2 are connected through the second expansion joint 6 .

The low-temperature economizer body includes a header 10, a heat exchange tube 7, a sleeve 8, an elbow 5, a supporting round tube 3 and a tube sheet. The tube sheet includes a header side tube sheet 9, an intermediate tube sheet 11 and an elbow side tube The plate 4, the sleeve 8 is sleeved on the supporting circular tube 3, the sleeve 8 is connected with the intermediate tube plate 11, the sleeve 8 and the supporting circular tube 3 are sealed by the sealing material 12, and the lower side of the heat exchange tube 7 is connected to the middle tube plate 11. The header side tube sheet 9 is welded, the upper side of the heat exchange tube 7 is welded with the elbow side tube sheet 4, the middle part of the heat exchange tube 7 passes through the middle tube sheet 11, in addition, the upper sealing plate in the low temperature economizer body 13 is connected with the header side tube plate 9, the upper sealing plate 13 is welded with the elbow side tube plate 4, the lower sealing plate 14 is welded with the header side tube plate 9, and the lower sealing plate 14 is welded with the elbow side tube plate 4 phase welding.

The relationship between the diameter D of the sleeve 8 and the diameter d of the supporting circular tube 3 is: D-d≤2mm.

The supporting circular tube 3 is broken at the middle tube plate 11, and the distance after the disconnection is δ, the maximum expansion amount of the heat exchange tube 7 is L1, and the maximum expansion amount of the supporting circular tube 3 is L2, then δ=1.5 (L2- L1).

In addition, when determining the length of the sleeve 8, it is required that the sleeve 8 can meet the force strength when the heat exchange module is lifted.

The installation process of the casing 8 is as follows:

The supporting round tube 3 is fully welded with the middle tube plate 11 when it leaves the factory. When the low-temperature economizer body is installed, it is disconnected at the middle tube plate 11, and the two semicircular sleeves are welded on the supporting round tube 3. At the fracture, after the welding is completed, the gap between the sleeve 8 and the supporting round pipe 3 is filled with the sealing material 12 .

The concrete working process of the present utility model is:

When the flue gas flows through the inlet transition section 1, the low temperature economizer body and the outlet transition section 2, the temperature of the flue gas decreases continuously, resulting in different expansion amounts of the inlet transition section 1, the low temperature economizer body and the outlet transition section 2. Expansion joints 6 are installed at the inlet and outlet of the economizer body to eliminate thermal stress on both sides and ensure that the low temperature economizer body and the flue on both sides do not crack. The outside of the heat exchange tube 7 in the low temperature economizer body is high temperature flue gas, and the inside of the heat exchange tube 7 is low temperature working fluid water. Since the heat exchange coefficient of working fluid water is two grades higher than that of flue gas, heat exchange The wall temperature of the tube 7 is close to the temperature of the working fluid, but there is no working fluid in the supporting circular tube 3, so the temperature of the supporting circular tube 3 is close to the temperature of the flue gas, resulting in the expansion of the heat exchange tube 7 being different from that of the supporting circular tube 3 , through the structure of the casing 8, the internal stress on the supporting circular tube 3 is eliminated. The temperature of the upper sealing plate 13 and the lower sealing plate 14 is the same as the temperature of the flue gas, but the upper sealing plate 13 and the lower sealing plate 14 are both flue steel plates with a thickness of about 6 mm, which have high elasticity and can absorb thermal stress independently. , while eliminating various thermal stresses inside the low-temperature economizer body, ensuring that the flue gas does not leak into the elbow 5 and ensuring the safety of the elbow 5 .

Claims (5)

1. A low-temperature economizer structure for preventing flue gas leakage, characterized in that it comprises an inlet transition section (1), an outlet transition section (2) and a low-temperature economizer body; The sleeve (8) in the low-temperature economizer body and the intermediate tube sheet (11) are fully welded, and a sealing material ( 12), the heat exchange tube (7) in the low temperature economizer body and the header side tube sheet (9) are fully welded, and the heat exchange tube (7) in the low temperature economizer body and the elbow side tube sheet (9) are fully welded. 4) is fully welded, the inlet transition section (1) is communicated with the inlet of the low temperature economizer body, and the outlet transition section (2) is communicated with the outlet of the low temperature economizer body. 2. The low-temperature economizer structure for preventing flue gas leakage according to claim 1, characterized in that it further comprises two expansion joints (6), wherein the inlet transition section (1) and the inlet of the low-temperature economizer body They are communicated with each other through a first expansion joint (6), and the outlet transition section (2) and the outlet of the low-temperature economizer body are communicated through a second expansion joint (6). 3. The low-temperature economizer structure for preventing flue gas leakage according to claim 1, wherein the low-temperature economizer body comprises a header (10), a heat exchange tube (7), a sleeve (8), a bending The head (5), the supporting round pipe (3) and the tube sheet, the tube sheet includes the header side tube sheet (9), the middle tube sheet (11) and the elbow side tube sheet (4); The middle tube sheet (11) is located between the header side tube sheet (9) and the elbow side tube sheet (4). The middle tube sheets (11) are connected, and the supporting round tubes (3) are fixed between the header side tube sheets (9) and the elbow side tube sheets (4); The lower side of each heat exchange tube (7) and the header side tube sheet (9) are fully welded, and the upper side of each heat exchange tube (7) and the elbow side tube sheet (4) are fully welded. The middle parts of the heat pipes (7) all pass through the middle tube sheet (11), the ends of the adjacent heat exchange pipes (7) are connected through the elbows (5), and the header (10) is connected to the first heat exchange pipe (10). 7) is connected with the last heat exchange tube (7). 4. The low-temperature economizer structure for preventing flue gas leakage according to claim 1, wherein the relationship between the diameter D of the sleeve (8) and the diameter d of the supporting circular pipe (3) is: D-d≤2mm. 5. The low-temperature economizer structure for preventing flue gas leakage according to claim 1, characterized in that, the supporting circular pipe (3) is disconnected at the middle tube sheet (11), and the distance after the disconnection is δ, and the replacement The maximum expansion amount of the heat pipe (7) is L1, and the maximum expansion amount of the supporting circular pipe (3) is L2, so δ=1.5 (L2-L1).

Images