Gas-gas high-temperature heat exchanger

Abstract

The present discloses a gas-gas high-temperature heat exchanger, including a shell (12), a tube sheet (5), a low-temperature gas inlet pipeline (6) and an outlet pipeline (7), and a high temperature gas outlet (8), the tube is divided into a first heat transfer zone (1) and a second heat transfer zone (2), a low temperature gas (4) flows in the tube, the tube includes a insert component (9) and an outer fin (10); a heat transfer tube in the second heat transfer zone (2) has a sleeve structure, a high-temperature gas (3) flows in the core tube (13), the low temperature gas (4) flows in an annular region between the core tube (13) and an outer tube (14), the high-temperature gas (3) flows out of the core tube (13) and flows into the shell-side area of the second heat transfer zone (2) again.

Claims

1. A gas-gas high-temperature heat exchanger, comprising a shell (12), a tube plate (5), a low-temperature gas inlet pipeline (6) and an outlet pipeline (7), and a high-temperature gas outlet (8), wherein the gas-gas high-temperature heat exchanger is divided into a first heat transfer zone (1) and a second heat transfer zone (2), a high-temperature gas (3) and a low-temperature gas (4) in the first heat transfer zone (1) are cross-flowing, a first-zone tube is disposed in the first heat transfer zone (1), the low-temperature gas (4) flows in the first-zone tube, the first-zone tube includes a first insert component (9) inside the first-zone tube and an outer fin (10) outside the first-zone tube; a sleeve structure is disposed in the second heat transfer zone (2), wherein the sleeve structure includes a core tube (13) and an outer tube (14) disposed outside the core tube (13), and an annular region is disposed between the core tube (13) and an outer tube (14), the high-temperature gas (3) flows in the core tube (13), the low-temperature gas (4) flows in the annular region, a flow direction of the high-temperature gas (3) flowing in the core tube (3) is opposite to a flow direction of the low-temperature gas (4) flowing in the annular region, the high-temperature gas (3) flows out of the core tube (13) and flows into a shell-side area of the second heat transfer zone (2), the high-temperature gas (3) in the shell-side area of the second heat transfer zone has a flow direction cross with that of the low-temperature gas (4), and the core tube (13) includes a second insert component (9), the annular area includes inner fins (11).

2. The gas-gas high-temperature heat exchanger according to claim 1, wherein the high-temperature gas (3) is high-temperature flue gas, the low-temperature gas (4) is air, the high-temperature gas (3) sequentially flows through the first heat transfer zone (1), the core tube (13), and the shell-side of the second heat transfer zone (2), and the low-temperature gas (4) flows through the annular region in the second heat transfer zone (2) and the first-zone tube in the first heat transfer zone (1).

3. The gas-gas high-temperature heat exchanger according to claim 1, wherein the outer tube (14) in the second heat transfer zone (2) includes fins outside the outer tube (14).

4. The gas-gas high-temperature heat exchanger according to claim 1, wherein the number of longitudinal corrugations on the inner fins (11) gradually increases along the flow direction of the low-temperature gas (4).

5. The gas-gas high-temperature heat exchanger according to claim 1, wherein a surface of the tube plate (5), and an inner wall of the shell (12) includes an insulation layer.

6. The gas-gas high-temperature heat exchanger according to claim 1, wherein the inner fins (11) have a corrugated shape or straight shape.

7. The gas-gas high-temperature heat exchanger according to claim 1, wherein the inner fins (11) includes a hole or a slit.

8. The gas-gas high-temperature heat exchanger according to claim 1, wherein the outer fin (10) is H-type fin, circular fin, or integrated fin.

9. The gas-gas high-temperature heat exchanger according to claim 1, wherein the outer fin (10) includes a hole, a slit, a longitudinal vortex generator, or shutter.

10. The gas-gas high-temperature heat exchanger according to claim 1, wherein the first insert component (9) and the second insert component (9) have a twisted tape shape, and are inserted in the first-zone tube and the core tube (13), respectively.

11. The gas-gas high-temperature heat exchanger according to claim 1, wherein the first insert component (9) and the second insert component (9) include a hole, a slit or an airfoil structure.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic diagram of the high-temperature heat exchanger of the present disclosure.

(2) FIG. 2 (a) is a schematic diagram of a heat transfer tube in the second heat transfer zone of the present disclosure.

(3) FIG. 2 (b) is a schematic diagram of a heat transfer tube in the first heat transfer zone of the present disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(4) The present disclosure is described in detail below with reference to the drawings and specific embodiments.

(5) A gas-gas high-temperature heat exchanger includes a shell, a tube sheet, a low-temperature gas inlet pipeline and an outlet pipeline, and a high-temperature gas outlet pipelines. The heat exchanger is divided into a first heat exchanger zone and the second heat transfer zone. The gas flowing direction on both sides of the first heat transfer zone is cross-flowing. The low temperature gas flows in the tube, the tube includes insert components, fins are installed outside the tube. The heat transfer tube in the second heat transfer zone has sleeve structure. High-temperature gas flows in the core tube, low-temperature gas flows in the annular area between the core tube and the outer tube. The high-temperature gas and low-temperature gas has opposite flow directions. The high-temperature gas flows out of the core tube and flows into the shell-side area of the second heat transfer zone. The high-temperature gas in the shell-side of the second heat transfer zone has a flow direction cross with that of the low-temperature gas. The core tube includes insert components. The fins at the front part of the annular area are sparse, and the fins at the back part of the annular area are dense. The high temperature gas flows into the heat exchanger from one side of the first heat transfer zone, and sequentially flow through the shell side of the first heat transfer zone, the tube side of the second heat transfer zone, and the shell side of the second heat transfer zone, then transfers heat to the low temperature gas.

(6) The present disclosure can utilize the heat efficiently, improve the heat transfer efficiency of the heat exchanger, significantly reduce the wall surface temperature of the heat exchanger, improve the high temperature resistance performance of the heat exchanger, reduce the manufacturing cost of the high temperature heat exchanger, and be used in high temperature environments.

(7) As shown in FIG. 1, a gas-gas high-temperature heat exchanger includes a shell structure 12. A tube plate 5, a low-temperature gas inlet pipeline 6 and an outlet pipeline 7, and a high temperature gas outlet 8 are connected to the shell 12. The heat exchanger is divided into a first heat transfer zone 1 and a second heat transfer zone 2. The high temperature gas 3 is high-temperature flue gas as the heat source in the heat exchanger. The high temperature gas 3 flows sequentially through the shell side of the first heat transfer zone 1, the tube side of the second heat transfer zone 2, and the shell side of the second heat transfer zone 2, then flows out of the heat exchanger from the outlet pipeline 8. The low-temperature gas 4 is air, flows sequentially through the tube side of the second heat transfer zone 2 and the tube side of the first heat transfer zone 1, and then flows out of the heat exchanger from the outlet pipeline 7. The flow direction of the fluid on both sides of the first heat transfer zone 1 is cross-flowing.

(8) The tube includes insert components 9. Fins 10 are installed outside the tube. The insert component 9 has high thermal stability. The insert components 9 are used to replace the inner fins in the traditional inner and outer finned tube, thereby avoiding the hazards caused by the high temperature welding of the inner fins, and overcoming the disadvantage of high flow resistance in the tube. The enhanced heat transfer of the two sides of the heat transfer tubes in the first heat transfer zone 1 significantly reduces the temperature of the high-temperature gas 3 flowing through, thereby reducing the wall surface temperature of the heat transfer tube in the second heat transfer zone 2.

(9) The heat transfer tube in the second heat transfer zone 2 has a sleeve structure. The high-temperature gas 3 flows in the core tube 13, and the low-temperature gas 4 flows in the annular area between the core tube 13 and the outer tube 14. The high-temperature gas and low-temperature gas has opposite flow directions. The core tube 13 of the heat transfer tube includes insert components 9. The inner fins 11 are installed in the annular area between the core tube 13 and the outer tube. The inner fins 11 can significantly increase the heat transfer area and enhance the fluid disturbance.

(10) The heat is transferred from the high-temperature gas 3 to the low-temperature gas 4 through the enhanced heat transfer on both sides. The high temperature gas 1 flows out from the core tube 13, flows into the second heat transfer zone 2 again to heat the low-temperature gas 4. The high-temperature gas in the second heat transfer zone has a flow direction cross with that of the low-temperature gas 4. The heat transfer tubes in the second heat transfer zone 2 do not have fins on the outer side, which can significantly reduce the wall temperature, and increase the life of the inner fins 13 and the heat exchanger.

(11) When the temperature of the wall surface of the heat transfer tube in the heat transfer zone 2 is far lower than the critical temperature for welding the inner fins 11, outer fins may be installed outside the heat transfer tube in the second heat transfer zone 2, so as to further improve the heat transfer efficiency of the heat exchanger. The number of longitudinal corrugations on the inner fin 11 gradually increases along the flow direction of the low temperature gas 4, so that the temperature of the core tube wall can be reduced by adjusting the thermal resistance ratios of the inner side of the core tube to the outer side of the core tube in different regions. In this way, the difficulty and the cost for welding the fins 11 are greatly reduced, thereby ensuring the safety for welding the inner fin 11.

(12) When the temperature of the high-temperature gas 3 is low or the heat transfer requirement is weak, the first heat transfer zone 1 only needs one tube pass to complete the heat transfer task. When the temperature of the high-temperature gas 3 is high or the heat transfer requirement is strong, the first heat transfer zone 1 needs more than one tube passes to fully utilize the heat of the high temperature flue gas, and improve the heat transfer efficiency of the heat exchanger.

(13) The heat transfer tubes, outer fins 10, and insert components 9 in the first heat transfer zone 1 are made of high-temperature resistant materials. The outer tubes 14, core tubes 13, inner fins 11, and insert components 9 in the second heat transfer zone are made of common materials, so as to reduce costs. Heat insulation layers are disposed on the surface of the tube sheet 5, and the inner wall of the shell structure 12 to avoid heat dissipation and consumption.

(14) As shown in FIG. 2 (a), the heat transfer tube has a sleeve structure. The core tube 13 is sleeved inside the outer tube 14. The core tube 13 includes insert components 9. The insert components 9 are welded to the core tube 13 at both ends of the tube. The part of the insert component 9 in the tube is not connected to the core tube 13. The annular region between the core tube 13 and the outer tube 14 has longitudinal corrugated inner fin 11. The inner fin 11 is welded to the inner wall of the outer tube 14 and is not connected to the outer wall of the tube 13. The number of longitudinal corrugations of the inner fin 11 gradually increases along the flow direction of the fluid. The inner fin 11 and the insert component 9 may have holes or slits to further enhance heat transfer.

(15) As shown in FIG. 2 (b), the H-type outer fins 10 are symmetrically and uniformly fixed on the outer wall of the smooth tube. An empty groove 15 is disposed between two fins on the same tube in the flowing direction. A gap 16 is disposed between the fins on the adjacent tube. The inner fin 11 may have holes, slits, longitudinal vortex generators, or shutters to further enhance heat transfer.

INDUSTRIAL PRACTICABILITY

(16) The gas-gas high-temperature heat exchanger of the present disclosure can be manufactured or used in industry, thus has industrial practicability.