Exhaust heat recovery device

Abstract

Provided is an exhaust heat recovery device that prevents damage to joints due to thermal stress generated by a temperature difference in a heat transfer tube. 【Solution means】An exhaust heat recovery device 1 provided with a heat transfer tube group 20 through which a heated fluid 5 flows inside a flow passage 10 through which exhaust gas 3 flows, including a support portion 32 that supports an end portion 22 of the heat transfer tube group 20, a joint portion 25 that joins and fixes the end portion 22 of the heat transfer tube group 20 to the support portion 32, and a supply portion 65 that supplies a cooling fluid 7 to the support portion 32. The support portion 32 is cooled by the cooling fluid 7 supplied from the supply portion 65.

Description

Technical Field

[0001] This invention relates to a waste heat recovery device (recuperator).

Background Art

[0002] In heat equipment such as a heating furnace, a waste heat recovery device that heats a fluid to be heated using waste heat generated from the heating furnace or the like is used. The waste heat recovery device can improve the energy efficiency of the heat equipment by heating a heat transfer tube group through which the fluid to be heated flows with the heat of exhaust gas and exchanging heat.

[0003] Patent Document 1 and Patent Document 2 disclose a waste heat recovery device in which a heat transfer tube group is disposed inside a flow passage through which exhaust gas flows.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The heat transfer tube group is joined and fixed to a support member by a joint formed by, for example, welding. In the above prior art, when heat exchange is performed, there is a problem that the joint is likely to be damaged due to thermal stress generated by the temperature difference in the heat transfer tube group heated to a high temperature.

[0006] Therefore, an object of this invention is to provide a waste heat recovery device that prevents damage to the joint due to thermal stress generated by the temperature difference of the heat transfer tube.

Means for Solving the Problems

[0007] To solve the above problems, a waste heat recovery device according to an aspect of the present invention includes: a waste heat recovery device including a heat transfer tube group through which a fluid to be heated flows inside a flow passage through which exhaust gas flows, a support portion that supports an end portion of the heat transfer tube group, a joint portion that joins and fixes the end portion of the heat transfer tube group to the support portion, and a supply portion that supplies a cooling fluid to the support portion, wherein the support portion is cooled by the cooling fluid supplied from the supply portion.

Advantages of the Invention

[0008] According to the present invention, since the support portion is cooled by the cooling fluid, in the heat transfer tube group joined and fixed to the support portion at the joint portion, thermal stress caused by the temperature difference of the heat transfer tube group is suppressed, so that damage to the joint portion can be suppressed.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0010] Hereinafter, an embodiment of a waste heat recovery device 1 according to the present invention will be described with reference to the drawings.

[0011] 〔First Embodiment〕 A waste heat recovery device 1 according to an embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is a diagram schematically explaining a waste heat recovery device 1 according to an embodiment. FIG. 2 is a diagram schematically explaining a part A in the figure in the waste heat recovery device 1 shown in FIG. 1. FIG. 3 is a schematic cross-sectional view taken along line III-III of the main part shown in FIG. 2.

[0012] As shown in FIG. 1, the waste heat recovery device 1 includes a heat transfer tube group 20 through which the heated fluid 5 flows inside a flow passage 10 through which the exhaust gas 3 flows.

[0013] The flow passage 10 has a housing 11 with a circular or rectangular cross-section, an inlet portion 12 through which the exhaust gas 3 flows in, an outlet portion 14 through which the exhaust gas 3 flows out, and a plurality of mounting openings 16 provided in the housing 11. The flow passage 10 is, for example, a flue extending in the horizontal direction as the longitudinal direction. For example, the exhaust gas 3 at 1200°C and 0.2 MPa flows inside the flow passage 10. The flow passage 10 is installed on the floor surface or overhead via a base or support columns (not shown). Also, the inner surface of the flow passage 10 is covered with a heat insulating material (not shown).

[0014] The waste heat recovery device 1 includes a first joint 17, an introduction pipe 43, a support member 30, a heat transfer tube group 20, a joint portion 25, a second joint 45, a connection duct 50, and a discharge pipe 47. In the waste heat recovery device 1 shown in FIG. 1, the introduction pipe 43, the support member 30, the heat transfer tube group 20, the support member 30, the connection duct 50 located below, the support member 30, the heat transfer tube group 20, the support member 30, the connection duct 50 located above, the support member 30, the heat transfer tube group 20, the support member 30, the connection duct 50 located below, the support member 30, the heat transfer tube group 20, the support member 30, and the discharge pipe 47 communicate in this order.

[0015] The introduction pipe 43 is located on the downstream side of the flow passage 10, and the discharge pipe 47 is located on the upstream side of the flow passage 10. The heated fluid 5 introduced from the introduction pipe 43 flows sequentially through the support member 30, the heat transfer tube group 20, the connection duct 50, etc., and is then discharged from the discharge pipe 47, but is heated by receiving waste heat from the exhaust gas 3 during the process of flowing through the heat transfer tube group 20. The heated fluid 5 is, for example, a combustion gas such as hydrogen gas.

[0016] The connecting duct 50 is disposed outside the flow passage 10. Thereby, the thermal stress generated due to the temperature difference of the connecting duct 50 when the connecting duct 50 comes into contact with the high-temperature exhaust gas 3 can be reduced. For example, the connecting duct 50 located above is supported by a duct support 52 so as to be displaceable, and the connecting duct 50 located below is supported by a duct support leg 54 so as to be displaceable.

[0017] The heat transfer tube group 20 extends in a direction (for example, the vertical direction L) intersecting the longitudinal direction of the flow passage 10. The heat transfer tube group 20 is arranged in multiple stages and multiple rows with a plurality of heat transfer tubes forming a group being spaced apart from each other. The heat transfer tubes are made of, for example, steel pipes with a circular cross-section. A gap through which the exhaust gas 3 flows is formed between the plurality of heat transfer tubes, and the exhaust heat from the exhaust gas 3 can be efficiently received.

[0018] A first joint 17 made of, for example, metal is attached to the attachment opening 16 provided in the housing 11, and a support member 30 is connected to the first joint 17. In other words, the first joint 17 is interposed between the housing 11 of the flow passage 10 and the support member 30.

[0019] A second joint 45 is interposed between the connecting duct 50 located above and the support member 30. Also, a second joint 45 is interposed between the connecting duct 50 located below and the support member 30.

[0020] The support member 30 is a member that supports each of the plurality of end portions 22 in the heat transfer tube group 20 and is a so-called header (manifold). The support member 30 is in the shape of a hollow box (shown as circular in the figure), and its outer side has a metal plate as a support portion 32. The support portion 32 has a through hole 21 for inserting the heat transfer tube group 20. An inner heat insulating material 24 is disposed on the inner surface of the support portion 32. The end portion 22 of the heat transfer tube group 20 protrudes into the support member 30 and is joined and fixed to the support portion 32 of the support member 30 by a joining portion 25. The joining portion 25 is a welded portion formed by, for example, welding. Thereby, the heat transfer tube group 20 is firmly fixed to the support portion 32 even at high temperatures.

[0021] However, since the heat transfer tube group 20 is firmly fixed to the support portion 32 by the joint portion 25, the thermal stress caused by the temperature difference of the heat transfer tube group 20 may damage the joint portion 25, so a structure for suppressing the thermal stress is required.

[0022] As shown in FIGS. 2 and 3, the waste heat recovery device 1 further includes a cooling box 70, a measuring unit 77, and a control unit 60.

[0023] The cooling box 70 is attached to the outer surface of the support portion 32 of the support member 30. The cooling box 70 has a cooling housing 72. The cooling housing 72 is attached to the support portion 32 located around the joint portion 25. The cooling housing 72 is configured to surround the heat transfer tube group 20 via a gap heat insulating material 76. Thereby, it is possible to prevent the temperature of the fluid 5 to be heated from dropping due to the heat transfer tube group 20 being cooled more than necessary.

[0024] The cooling housing 72 is not fixedly attached to the outer surface of the heat transfer tube group 20, but is movably attached to the heat transfer tube group 20. Thereby, even if the heat transfer tube group 20 expands due to thermal expansion, it is possible to suppress the cooling housing 72 from deforming.

[0025] A cooling space 73 is formed by the cooling housing 72 and the support portion 32. The cooling housing 72 is spaced apart from the support portion 32 by a certain size gap, and the cooling space 73 is, for example, an open space.

[0026] The cooling housing 72 has an inlet 74 and an outlet 75. The cooling fluid 7 is supplied through the inlet 74, and the cooling fluid 7 that has flowed through the cooling space 73 formed inside the cooling housing 72 is discharged through the outlet 75. In the process of the cooling fluid 7 flowing through the cooling space 73, the support portion 32 is cooled by the cooling fluid 7. The temperature of the support portion 32 is measured by the measuring unit 77. The measuring unit 77 is, for example, a thermocouple and is disposed so as to contact the support portion 32.

[0027] The cooling fluid 7 is, for example, air. The cooling fluid 7 is supplied from the supply unit 65 to the cooling box 70 to cool the support part 32. The supply unit 65 is, for example, a mass flow controller, and acts as a supply amount adjustment unit that adjusts the supply amount of the cooling fluid 7 supplied into the cooling housing 72 of the cooling box 70. The supply unit 65 is connected to the control unit 60. The supply amount of the cooling fluid 7 supplied from the supply unit 65 is controlled by the control unit 60. The control unit 60 includes at least a CPU (Central Processing Unit) and a memory, and performs various controls in the exhaust heat recovery device 1.

[0028] Based on the temperature of the support part 32 measured by the measurement unit 77, the control unit 60 controls the supply unit 65 to control the supply amount of the cooling fluid 7 so that the support part 32 is cooled to an appropriate temperature. Thereby, the support part 32 is adjusted to an appropriate temperature such that the joint part 25 is not damaged by thermal stress.

[0029] Therefore, according to the above configuration, since the support part 32 is cooled by the cooling fluid 7, in the heat transfer tube group 20 joined and fixed to the support part 32 at the joint part 25, the thermal stress caused by the temperature difference of the heat transfer tube group 20 is suppressed, so that damage to the joint part 25 can be suppressed.

[0030] Although specific embodiments and numerical values of the present invention have been described, the present invention is not limited to the above embodiments, and various modifications can be made and implemented within the scope of the present invention.

[0031] As an example of the joining method of the heat transfer tube group 20 to the support member 30, welding has been exemplified, but brazing, screw fixing, etc. can also be used.

[0032] Summarizing the present invention and the embodiments, it is as follows.

[0033] The exhaust heat recovery device 1 according to one aspect of the present invention is an exhaust heat recovery device 1 provided with a heat transfer tube group 20 through which the heated fluid 5 flows inside a flow passage 10 through which the exhaust gas 3 flows, A support portion 32 that supports an end portion 22 of the heat transfer tube group 20, A joint portion 25 that joins and fixes the end portion 22 of the heat transfer tube group 20 to the support portion 32, A supply portion 65 that supplies the cooling fluid 7 to the support portion 32, and is provided with, The support portion 32 is cooled by the cooling fluid 7 supplied from the supply portion 65.

[0034] According to the above configuration, since the support portion 32 is cooled by the cooling fluid 7, in the heat transfer tube group 20 joined and fixed to the support portion 32 at the joint portion 25, the thermal stress caused by the temperature difference of the heat transfer tube group 20 is suppressed, so that damage to the joint portion 25 can be suppressed.

[0035] Further, in the exhaust heat recovery device 1 of one embodiment, A measurement unit 77 that measures the temperature of the support portion 32 and a control unit 60 that controls the supply amount of the cooling fluid 7 are further provided, The temperature of the support portion 32 is adjusted by the supply portion 65, the measurement unit 77, and the control unit 60.

[0036] According to the above embodiment, the support portion 32 is adjusted to an appropriate temperature so that the joint portion 25 is not damaged by thermal stress.

[0037] Further, in the exhaust heat recovery device 1 of one embodiment, A cooling housing 72 attached to the support portion 32 located around the joint portion 25 is further provided, The cooling housing 72 is movably attached to the heat transfer tube group 20.

[0038] According to the above embodiment, even if the heat transfer tube group 20 expands due to thermal expansion, deformation of the cooling housing 72 can be suppressed.

[0039] Further, in the exhaust heat recovery device 1 of one embodiment, The cooling housing 72 is configured to surround the heat transfer tube group 20 via a gap heat insulating material 76.

[0040] According to the above embodiment, it is possible to prevent the temperature of the fluid to be heated 5 from dropping because the heat transfer tube group 20 is not cooled more than necessary.

[0041] Also, in the waste heat recovery device 1 of one embodiment, The joint portion 25 is a welded portion formed by welding.

[0042] According to the above embodiment, the heat transfer tube group 20 is firmly fixed to the support portion 32 even at high temperatures.

Explanation of reference numerals

[0043] 1…Waste heat recovery device (recuperator) 3…Exhaust gas 5…Fluid to be heated 7…Cooling fluid 10…Flow passage 11…Housing 12…Inlet portion 14…Outlet portion 16…Mounting opening 17…First joint 20…Heat transfer tube group 21…Through hole 22…End portion 24…Inner heat insulating material 25…Joint portion 30…Support member 32…Support portion 43…Introduction pipe 45…Second joint 47…Discharge pipe 50…Connection duct 52…Duct support 54…Duct support leg 60…Control portion 65…Supply portion 70…Cooling box 72…Cooling housing 73…Cooling space 74…Inlet 75…Outlet 76…Gap heat insulating material 77…Measurement portion (thermocouple) L…Vertical direction

Claims

1. An exhaust heat recovery device comprising a group of heat transfer tubes through which a fluid to be heated flows, provided inside a flow passage through which exhaust gas flows, a support portion that supports an end portion of the group of heat transfer tubes, a joint portion that joins and fixes the end portion of the group of heat transfer tubes to the support portion, a supply portion that supplies a cooling fluid to the support portion, and a cooling housing that is attached to the support portion located around the joint portion and through which the cooling fluid supplied from the supply portion passes, wherein the support portion is cooled by the cooling fluid supplied from the supply portion, and the cooling housing is movably attached to the group of heat transfer tubes. An exhaust heat recovery device.

2. The exhaust heat recovery device according to claim 1, further comprising a measurement unit that measures the temperature of the support portion and a control unit that controls the supply amount of the cooling fluid, wherein the temperature of the support portion is adjusted by the supply portion, the measurement unit, and the control unit.

3. The exhaust heat recovery device according to claim 1, wherein the cooling housing is configured to surround the group of heat transfer tubes via a gap heat insulating material.

4. The exhaust heat recovery device according to claim 1, wherein the joint portion is a welded portion formed by welding.

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