阅读说明：本技术 一种防止烟气泄漏的低温省煤器结构 (Low-temperature economizer structure for preventing flue gas leakage ) 是由 张知翔 薛宁 赵锋 徐党旗 姬海民 魏铜生 张广才 于 2021-09-17 设计创作，主要内容包括：本发明公开了一种防止烟气泄漏的低温省煤器结构,包括入口过渡段、出口过渡段及低温省煤器本体；低温省煤器本体中的套管与中间管板之间满焊,低温省煤器本体中的套管与支撑圆管之间填充有密封材料,低温省煤器本体中的换热管与集箱侧管板之间满焊,低温省煤器本体中的换热管与弯头侧管板之间满焊,入口过渡段与低温省煤器本体的入口相连通,出口过渡段与低温省煤器本体的出口相连通,该结构能够防止烟气漏入弯头处,提高低温省煤器的安全性和经济性。(The invention 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 outlet transition section; 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.)

1. A low-temperature economizer structure for preventing flue gas leakage is characterized by comprising an inlet transition section (1), an outlet transition section (2) and a low-temperature economizer body;

the full-welding connection structure of the low-temperature economizer comprises a low-temperature economizer body, wherein a sleeve (8) and a middle tube plate (11) are fully welded, a sealing material (12) is filled between the sleeve (8) and a supporting circular tube (3) in the low-temperature economizer body, a heat exchange tube (7) and a header side tube plate (9) in the low-temperature economizer body are fully welded, the heat exchange tube (7) and a elbow side tube plate (4) in the low-temperature economizer body are fully welded, an inlet transition section (1) is communicated with an inlet of the low-temperature economizer body, and an outlet transition section (2) is communicated with an outlet of the low-temperature economizer body.

2. The low-temperature economizer structure for preventing flue gas leakage according to claim 1, further comprising two expansion joints (6), wherein the inlet transition section (1) is communicated with the inlet of the low-temperature economizer body through a first expansion joint (6), and the outlet transition section (2) is communicated with the outlet of the low-temperature economizer body 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), heat exchange tubes (7), sleeves (8), elbows (5), support round tubes (3) and tube plates, and the tube plates comprise header side tube plates (9), middle tube plates (11) and elbow side tube plates (4);

the middle tube plate (11) is positioned between the header side tube plate (9) and the elbow side tube plate (4), the sleeve (8) is sleeved in the middle of the support circular tube (3), the sleeve (8) is connected with the middle tube plate (11), and the support circular tube (3) is fixed between the header side tube plate (9) and the elbow side tube plate (4);

the lower side of each heat exchange tube (7) is fully welded with the header side tube plate (9), the upper side of each heat exchange tube (7) is fully welded with the elbow side tube plate (4), the middle part of each heat exchange tube (7) penetrates through the middle tube plate (11), the end parts of the adjacent heat exchange tubes (7) are communicated through the elbow (5), and the header (10) is communicated with the first heat exchange tube (7) and the last heat exchange tube (7).

4. The low-temperature economizer structure for preventing flue gas leakage according to claim 1, wherein the diameter D of the sleeve (8) and the diameter D of the support circular tube (3) have the following relation: D-D is less than or equal to 2 mm.

5. The low-temperature economizer structure for preventing flue gas leakage according to claim 1, wherein the round supporting tube (3) is cut at the middle tube plate (11) and has a distance δ after cutting, the maximum expansion of the heat exchange tube (7) is L1, and the maximum expansion of the round supporting tube (3) is L2, so δ is 1.5 (L2-L1).

6. The low temperature economizer structure for preventing flue gas leakage according to claim 1, wherein the installation process of the sleeve (8) is: in a factory, fully welding the supporting circular tube (3) and the middle tube plate (11), breaking the supporting circular tube (3) at the middle tube plate (11) after the low-temperature economizer body is installed, welding the two semicircular sleeves at the port parts on the supporting circular tube (3), filling a gap between the sleeve (8) and the supporting circular tube (3) with a sealing material (12), and compacting.

Technical Field

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

Background

The low-temperature economizer can reduce the temperature of the flue gas, and the absorbed heat is used for heating condensed water to reduce the coal consumption of the unit; the low-temperature economizer is arranged at the inlet of the dust remover and can reduce the temperature of the flue gas entering the dust remover, thereby improving the dust removal efficiency, and simultaneously the temperature of the flue gas is reduced to be below the acid dew point, and the SO can be removed₃And various types of metal contaminants; the exhaust gas waste heat absorbed by the low-temperature economizer can also be used for heating a hot water air heater, so that the inlet air temperature and the outlet smoke temperature of the air preheater are greatly improved, and low-temperature corrosion and ammonium bisulfate ash blockage are effectively relieved, so that the low-temperature economizer technology is widely applied domestically. However, the domestic coal quality is variable, the coal quality is poor, the received basic sulfur content, the ash content and the water content are high, ammonia escape in tail flue gas exceeds the standard, and the flue gas corrosion is high, so that the problems of corrosion, abrasion and leakage of the elbow of the low-temperature economizer occur after the low-temperature economizer operates for a period of time.

The low-temperature economizer is arranged in a flue, in order to prevent the expansion of the heat exchange tube and the expansion of the flue from being uneven, a tube plate and the heat exchange tube at the elbow of the heat exchange tube adopt a perforation mode and are not welded, so that a small amount of flue gas leaks into the elbow, and because cooling water flows into the elbow and the flow rate of the flue gas is low, the temperature of the flue gas is reduced to be lower than 80 ℃, and viscous ash blockage and low-temperature corrosion are caused.

The existing method for preventing leakage at the elbow is to increase a sealing sleeve at the pipe hole to reduce the leakage of smoke, but the diameter of the sleeve is about 1mm larger than that of a heat exchange pipe, and a small amount of smoke still leaks into the elbow, so that the problem cannot be effectively solved.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a low-temperature economizer structure for preventing flue gas from leaking, which can prevent the flue gas from leaking into an elbow and improve the safety and the economical efficiency of the low-temperature economizer.

In order to achieve the purpose, the low-temperature economizer structure for preventing the flue gas from leaking comprises an inlet transition section, an outlet transition section and a low-temperature economizer body;

the sleeve and the middle tube plate in the low-temperature economizer body are fully welded, a sealing material is filled between the sleeve and the supporting circular tube in the low-temperature economizer body, a heat exchange tube in the low-temperature economizer body and a header side tube plate are fully welded, the heat exchange tube in the low-temperature economizer body and an elbow side tube plate are fully welded, an inlet transition section is communicated with an inlet of the low-temperature economizer body, and an outlet transition section is communicated with an outlet of the low-temperature economizer body.

The low-temperature economizer comprises a low-temperature economizer body and is characterized by further comprising two expansion joints, wherein the inlet transition section is communicated with an inlet of the low-temperature economizer body through a first expansion joint, and the outlet transition section is communicated with an outlet of the low-temperature economizer body through a second expansion joint.

The low-temperature economizer body comprises a header, a heat exchange tube, a sleeve, an elbow, a support circular tube and tube plates, wherein the tube plates comprise a header side tube plate, a middle tube plate and an elbow side tube plate;

the middle tube plate is positioned between the header side tube plate and the elbow side tube plate, the sleeve is sleeved in the middle of the supporting circular tube, the sleeve is connected with the middle tube plate, and the supporting circular tube is fixed between the header side tube plate and the elbow side tube plate;

the lower side of each heat exchange tube is fully welded with the tube plate at the side of the header, the upper side of each heat exchange tube is fully welded with the tube plate at the side of the elbow, the middle part of each heat exchange tube penetrates through the middle tube plate, the end parts of the adjacent heat exchange tubes are communicated through the elbows, and the header is communicated with the first heat exchange tube and the last heat exchange tube.

The diameter D of the sleeve and the diameter D of the supporting circular tube have the following relationship: D-D is less than or equal to 2 mm.

The supporting round pipe is disconnected at the middle pipe plate, the distance is delta after disconnection, the maximum expansion amount of the heat exchange pipe is L1, the maximum expansion amount of the supporting round pipe is L2, and delta is 1.5 (L2-L1);

the installation process of the sleeve is as follows: in a factory, fully welding the supporting circular tube and the middle tube plate, breaking the supporting circular tube at the middle tube plate after the low-temperature economizer body is installed, welding the two semicircular sleeves at the end openings of the supporting circular tube, and filling and compacting a sealing material in a gap between the sleeves and the supporting circular tube.

The invention has the following beneficial effects:

when the low-temperature economizer structure for preventing the flue gas leakage is in specific operation, 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 in the low-temperature economizer body is in full-welding with the header side tube plate, and the heat exchange tube is in full-welding with the elbow side tube plate, so that the flue gas is ensured not to leak into the elbow, and the corrosion and the abrasion of the elbow are avoided. The invention can ensure that the elbow is not leaked by flue gas, and meanwhile, the expansion of the heat exchange tube is independent of the flue, the supporting round tube and the tube plate, so that the safety and the economical efficiency of the device are higher.

Drawings

FIG. 1 is a front view of a low-temperature economizer body according to the present invention;

FIG. 2 is a top view of the low-temperature economizer body according to the present invention;

FIG. 3 is a side view of the low-temperature economizer body of the present invention;

fig. 4 is a schematic view of a sleeve 8 according to the present invention.

Wherein, 1 is an inlet transition section, 2 is an outlet transition section, 3 is a supporting round tube, 4 is an elbow side tube plate, 5 is an elbow, 6 is an expansion joint, 7 is a heat exchange tube, 8 is a sleeve, 9 is a header side tube plate, 10 is a header, 11 is a middle tube plate, 12 is a sealing material, 13 is an upper sealing plate, and 14 is a lower sealing plate.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described 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 present disclosure. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present disclosure. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

There is shown in the drawings a schematic block diagram of a disclosed embodiment in accordance with the invention. The figures are not drawn to scale, wherein certain details are exaggerated and possibly omitted for clarity of presentation. The shapes of various regions, layers and their relative sizes and positional relationships shown in the drawings are merely exemplary, and deviations may occur in practice due to manufacturing tolerances or technical limitations, and a person skilled in the art may additionally design regions/layers having different shapes, sizes, relative positions, according to actual needs.

Referring to fig. 1, 2, 3 and 4, the low-temperature economizer structure 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, wherein the inlet transition section 1 is communicated with an inlet of the low-temperature economizer body, an outlet of the low-temperature economizer body is communicated with the outlet transition section 2, the inlet transition section 1 is communicated with the low-temperature economizer body through a first expansion joint 6, and the low-temperature economizer body is communicated with the outlet transition section 2 through a second expansion joint 6.

The low-temperature economizer body comprises a header 10, a heat exchange tube 7, a sleeve 8, an elbow 5, a supporting circular tube 3 and tube plates, wherein the tube plates comprise a header side tube plate 9, a middle tube plate 11 and an elbow side tube plate 4, the sleeve 8 is sleeved on the supporting circular tube 3, the sleeve 8 is connected with the middle tube plate 11, the sleeve 8 and the supporting circular tube 3 are sealed through a sealing material 12, the lower side of the heat exchange tube 7 is welded with the header side tube plate 9, the upper side of the heat exchange tube 7 is welded with the elbow side tube plate 4, the middle of the heat exchange tube 7 penetrates through the middle tube plate 11, in addition, an upper sealing plate 13 in the low-temperature economizer body is connected with the header side tube plate 9, the upper sealing plate 13 is welded with the elbow side tube plate 4, a 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.

The diameter D of the sleeve 8 and the diameter D of the support circular tube 3 are in the following relation: D-D is less than or equal to 2 mm.

The supporting round tube 3 is broken at the middle tube plate 11, the distance is delta after the breaking, the maximum expansion amount of the heat exchange tube 7 is L1, the maximum expansion amount of the supporting round tube 3 is L2, and delta is 1.5 (L2-L1).

In addition, when the length of the sleeve 8 is determined, the sleeve 8 is required to meet the stress strength when the heat exchange module is lifted.

The installation process of the sleeve 8 is as follows:

the support circular tube 3 is fully welded with the middle tube plate 11 when leaving the factory, after the low-temperature economizer body is installed, the middle tube plate 11 is disconnected, the two semicircular sleeves are welded at the fracture of the support circular tube 3, and after welding is completed, the gap between the sleeve 8 and the support circular tube 3 is filled with the sealing material 12.

The specific working process of the invention is as follows:

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 is continuously reduced, so that the expansion amounts of the inlet transition section 1, the low-temperature economizer body and the outlet transition section 2 are different, and therefore expansion joints 6 are arranged at the inlet and the outlet of the low-temperature economizer body, the thermal stress at two sides is eliminated, and the low-temperature economizer body and the flues at two sides are prevented from being cracked. The outer portion of a heat exchange tube 7 in the low-temperature economizer body is high-temperature flue gas, low-temperature working medium water is arranged in the heat exchange tube 7, the heat exchange coefficient of the working medium water is two levels higher than that of the flue gas, so that the wall temperature of the heat exchange tube 7 is close to that of the working medium water, no working medium water exists in the supporting circular tube 3, the temperature of the supporting circular tube 3 is close to that of the flue gas, expansion of the heat exchange tube 7 is different from that of the supporting circular tube 3, and internal stress on the supporting circular tube 3 is eliminated through a sleeve 8 structure. The temperature of the upper sealing plate 13 and the lower sealing plate 14 is always equal to the flue gas temperature, but the upper sealing plate 13 and the lower sealing plate 14 are flue steel plates with the thickness of about 6mm, the elasticity is large, the thermal stress can be automatically absorbed, and by the structure, the flue gas is ensured not to leak into the elbow 5 while various thermal stresses in the low-temperature economizer body are eliminated, and the safety of the elbow 5 is ensured.