Coaxial flue gas air pre-heater

Abstract

The utility model aims to disclose a coaxial flue gas air pre-heater, which is composed of coaxial stainless steel round pipes with different radiuses, a flue gas flow channel and an air flow channel are formed between adjacent stainless steel round pipes, the flue gas flow channel is provided with straight ribs with uniform sections, and the air flow channel is provided with round pin ribs, so that the turbulent flow is enhanced, the heat exchange efficiency is improved, and the heat exchange efficiency is improved. The effects of supporting the flow channel and preventing the air pre-heater from deforming under the action of pressure difference are achieved; the device is compact in structure, can be directly and coaxially connected with an on-site flue gas pipeline according to on-site heat exchange working conditions, is easy to mount and dismount, and does not occupy extra space size; smoke and air are in a countercurrent flow heat exchange mode, the end difference of the air pre-heater can be reduced, the smoke exhaust temperature is further reduced, and the boiler efficiency is improved; and a full-welding sealing mode is adopted, so that zero air leakage can be realized, and the aim of the utility model is fulfilled.

Description

Technical Field

[0001] The utility model relates to an air heat exchanger device, in particular to a coaxial flue gas air preheater. Background Art

[0002] In my country's industrial production, in addition to heavy industrial boilers used in power generation, chemical and metallurgical industries, there are also a large number of small, medium and micro boilers used in light industries such as food, tobacco and papermaking. The heat loss of these boilers is mainly flue gas loss. In order to recover flue gas waste heat and improve boiler efficiency, a large number of boilers are equipped with flue gas air preheaters.

[0003] The exhaust temperature of small and medium-sized boilers is low, the flue gas flow rate is small, and the space size is generally limited. This puts forward new requirements for the heat exchange performance and size parameters of the flue gas air preheater. The corrugated plate air preheater that is currently widely used is large in size, has high pressure loss, and mostly adopts cross-flow heat exchange, which reduces the heat exchange efficiency.

[0004] Therefore, a coaxial flue gas air preheater is particularly needed to solve the above-mentioned existing problems. Utility Model Content

[0005] The utility model aims to provide a coaxial flue gas air preheater, which is suitable for waste heat recovery of flue gas from small and medium-sized boilers, and has the advantages of compact structure, small flow resistance, high heat transfer efficiency and easy installation, in view of the shortcomings of the prior art.

[0006] The technical problem solved by the present invention can be achieved by adopting the following technical solutions:

[0007] A coaxial flue gas air preheater comprises a coaxial heat exchange core, which is composed of coaxial stainless steel circular tubes of different diameters, and adjacent stainless steel circular tubes form flue gas flow channels and air flow channels, and the flue gas flow channels and the air flow channels are arranged in a staggered manner along the radial direction; the flue gas flow channels are arranged with straight ribs of equal cross-section for supporting the flow channels, and the air flow channels are arranged with circular needle ribs for supporting the flow channels, which play a role in increasing the heat exchange area, enhancing turbulence, and improving the heat exchange efficiency of the air preheater; annularly arranged air inlet branch pipe openings and air outlet branch pipe openings are arranged at the upper and lower edge positions of the stainless steel circular tubes, and annular steel sheets for sealing the air flow channels are welded on the upper and lower planes of the air flow channels; the air inlet joint and the air outlet joint are respectively connected to the air inlet branch pipe opening and the air outlet branch pipe opening, and the flue gas inlet joint and the smoke gas outlet joint are respectively connected to the upper plane and the lower plane of the coaxial heat exchange core, and the flue gas and air are in a countercurrent heat exchange manner.

[0008] In a preferred embodiment of the present invention, the distance between the flue gas flow channel and the air flow channel is 2mm-10mm.

[0009] In a preferred embodiment of the present invention, the width of the straight ribs with equal cross-section is 0.5 mm-1 mm.

[0010] In a preferred embodiment of the present invention, the diameter of the circular needle fin is 0.4 mm-1 mm.

[0011] Compared with the prior art, the coaxial flue gas air preheater of the utility model is composed of coaxial stainless steel circular tubes of different radii, and flue gas flow channels and air flow channels are formed between adjacent stainless steel circular tubes. The flue gas flow channel is arranged with straight ribs of equal cross-section, and the air flow channel is arranged with circular needle ribs, which not only enhance the turbulence and improve the heat exchange efficiency, but also support the flow channel and prevent the air preheater from deforming under the action of pressure difference; the structure is compact, and can be directly coaxially connected with the on-site flue gas pipeline according to the on-site heat exchange conditions, easy to install and disassemble, and does not occupy additional space; the flue gas and air are in a countercurrent heat exchange mode, which can reduce the end difference of the air preheater, further reduce the exhaust temperature, and improve the boiler efficiency; the full-welded sealing method is adopted to achieve zero air leakage, thereby achieving the purpose of the utility model.

[0012] The features of the present invention can be clearly understood by referring to the drawings and the following detailed description of the preferred embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the overall structure of the coaxial flue gas air preheater of the utility model;

[0014] Figure 2 It is a structural schematic diagram of the coaxial heat exchange core of the utility model;

[0015] Figure 3 It is a schematic diagram of an inclined cross section of a coaxial heat exchange core of the utility model;

[0016] Figure 4 It is a schematic diagram of an axial cross section of the coaxial heat exchange core of the utility model.

[0017] Description of the drawings: 1-coaxial heat exchange core, 2-smoke inlet joint, 3-smoke outlet joint, 4-air inlet joint, 5-air outlet joint, 11-stainless steel round tube, 12-air inlet branch pipe opening, 13-air outlet branch pipe opening, 14-annular steel sheet, 15-uniform cross-section straight ribs, 16-circular needle ribs. DETAILED DESCRIPTION

[0018] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below with reference to specific illustrations.

[0019] Example

[0020] like Figures 1 to 4As shown, the coaxial flue gas air preheater of the utility model is composed of a coaxial heat exchange core 1, a flue gas inlet joint 2, a flue gas outlet joint 3, an air inlet joint 4 and an air outlet joint 5.

[0021] The coaxial heat exchange core 1 is composed of coaxial stainless steel circular tubes 11 of different diameters, and flue gas flow channels and air flow channels are formed between adjacent stainless steel circular tubes 11, and the flue gas flow channels and the air flow channels are arranged in a staggered manner along the radial direction; wherein, the flue gas flow channel is arranged with straight ribs 15 of equal cross-section for supporting the flow channel, and the air flow channel is arranged with circular needle ribs 16 for supporting the flow channel, and all rib structures play a role in increasing the heat exchange area, enhancing turbulence, and improving the heat exchange efficiency of the air preheater; annularly arranged air inlet branch pipe openings 12 and air outlet branch pipe openings 13 are arranged at the upper and lower edge positions of the stainless steel circular tubes 11, and annular steel sheets 14 for sealing the air flow channel are welded on the upper and lower planes of the air flow channel; the air inlet joint 4 and the air outlet joint 5 are respectively connected to the air inlet branch pipe opening 12 and the air outlet branch pipe opening 13, and the flue gas inlet joint 2 and the flue gas outlet joint 3 are connected to the upper and lower planes of the coaxial heat exchange core 1, and the flue gas and air are in a countercurrent heat exchange manner.

[0022] Reference Figure 1 and Figure 2 High-temperature flue gas enters from the flue gas inlet joint 2, and its temperature decreases after heat exchange in the coaxial heat exchange core 1, and flows out from the flue gas outlet joint 3. Low-temperature air enters from the air inlet joint 4, and then enters the coaxial heat exchange core 1 through the air inlet branch pipe opening 12. After heat exchange in the coaxial heat exchange core 1, its temperature increases, and it flows out of the coaxial heat exchange core 1 through the air outlet branch pipe opening 13, and finally is discharged through the air outlet joint 5. The presence of the annular steel sheet 14 plays a role in sealing the air flow channel, ensuring that the flue gas does not enter the air flow channel.

[0023] Reference Figure 3 The straight ribs 15 of equal cross-section play a role in supporting the flue gas flow channel, and the circular needle ribs 16 play a role in supporting the air flow channel. The existence of the ribs ensures that the air preheater will not be deformed due to the existence of pressure difference.

[0024] The coaxial flue gas air preheater of the utility model has a compact structure and a cylindrical appearance. It can be directly coaxially connected to the on-site flue gas pipeline according to the on-site heat exchange conditions. It is easy to install and disassemble and does not occupy additional space. The flue gas flow channel adopts straight ribs with equal cross-section, and the flue gas flow resistance is small. The air flow channel adopts circular needle ribs, which greatly improves the heat exchange efficiency. The flue gas side is generally slightly negative pressure, and the air side is positive pressure. The presence of the ribs can resist deformation caused by the pressure difference. The flue gas and air are in a countercurrent heat exchange mode, which can reduce the end difference of the air preheater, further reduce the exhaust temperature, and improve the boiler efficiency.

[0025] The coaxial flue gas air preheater of the utility model adopts a fully welded sealing method, and can achieve zero air leakage.

[0026] The above shows and describes the basic principle and main features of the utility model and the advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principle of the utility model. Without departing from the spirit and scope of the utility model, the utility model may have various changes and improvements, which fall within the scope of the utility model to be protected, and the scope of protection of the utility model is defined by the attached claims and their equivalents.

Claims

1. A coaxial flue gas air preheater, characterized in that: It comprises a coaxial heat exchange core, which is composed of coaxial stainless steel circular tubes of different diameters, and adjacent stainless steel circular tubes form flue gas flow channels and air flow channels, and the flue gas flow channels and the air flow channels are arranged in a staggered manner along the radial direction; the flue gas flow channels are arranged with straight ribs of equal cross-section for supporting the flow channels, and the air flow channels are arranged with circular needle ribs for supporting the flow channels; annularly arranged air inlet branch pipe openings and air outlet branch pipe openings are arranged at the upper and lower edge positions of the stainless steel circular tubes, and annular steel sheets for sealing the air flow channels are welded on the upper and lower planes of the air flow channels; the air inlet joint and the air outlet joint are respectively connected to the air inlet branch pipe opening and the air outlet branch pipe opening, and the smoke inlet joint and the smoke outlet joint are respectively connected to the upper plane and the lower plane of the coaxial heat exchange core, and the smoke and air are in a countercurrent heat exchange manner.

2. The coaxial flue gas air preheater according to claim 1, characterized in that: The distance between the flue gas flow channel and the air flow channel is 2mm-10mm.

3. The coaxial flue gas air preheater according to claim 1, characterized in that: The width of the straight ribs with equal cross-section is 0.5 mm to 1 mm.

4. The coaxial flue gas air preheater according to claim 1, characterized in that: The diameter of the circular needle fin is 0.4 mm-1 mm.

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