Heat recovery system

Abstract

The present invention provides a heat recovery device that prevents damage to joints caused by thermal stress resulting from temperature differences in heat transfer tubes. [Solution] A heat recovery device 1 is 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, and comprises a support part 32 that supports the end 22 of the heat transfer tube group 20, a joint part 25 that joins and fixes the end 22 of the heat transfer tube group 20 to the support part 32, and a supply part 65 that supplies cooling fluid 7 to the support part 32, and the support part 32 is cooled by the cooling fluid 7 supplied from the supply part 65.

Description

Technical Field

[0001] This invention relates to an exhaust heat recovery device (recuperator).

Background Art

[0002] In heat equipment such as a heating furnace, an exhaust heat recovery device that heats a fluid to be heated using exhaust heat generated from the heating furnace or the like is used. The exhaust 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 performing heat exchange.

[0003] Patent Document 1 and Patent Document 2 disclose an exhaust 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 an exhaust heat recovery device that prevents damage to the joint due to thermal stress generated by the temperature difference of the heat transfer tubes.

Means for Solving the Problems

[0007] To solve the above problems, a waste heat recovery device according to one aspect of this invention is provided. A heat recovery device that includes a group of heat transfer tubes through which a heated fluid flows, located inside a flow passage through which exhaust gas flows, A support portion that supports the end of the heat transfer tube group, A joint for joining and fixing the end of the heat transfer tube group to the support part, It comprises a supply unit that supplies cooling fluid to the support unit, The support portion is cooled by the cooling fluid supplied from the supply unit. [Effects of the Invention]

[0008] According to this invention, since the support portion is cooled with a cooling fluid, thermal stress caused by the temperature difference between the heat transfer tubes is suppressed in the heat transfer tube group that is joined and fixed to the support portion at the joint, thus suppressing damage to the joint. [Brief explanation of the drawing]

[0009] [Figure 1] This figure schematically illustrates a waste heat recovery device according to one embodiment. [Figure 2] This figure schematically illustrates section A in the waste heat recovery device shown in Figure 1. [Figure 3] This is a schematic cross-sectional view of the main part shown in Figure 2, along the line III-III. [Modes for carrying out the invention]

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

[0011] [First Embodiment] A heat recovery device 1 according to one embodiment will be described with reference to Figures 1 to 3. Figure 1 is a schematic diagram illustrating the heat recovery device 1 according to one embodiment. Figure 2 is a schematic diagram illustrating part A in the heat recovery device 1 shown in Figure 1. Figure 3 is a schematic cross-sectional view of the main part shown in Figure 2 along the line III-III.

[0012] As shown in Figure 1, the waste heat recovery device 1 is equipped with a group of heat transfer tubes 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 comprises a housing 11 with a circular or rectangular cross-section, an inlet 12 into which exhaust gas 3 flows, an outlet 14 into which 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 with the horizontal direction as its longitudinal direction. For example, 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 or overhead via a base or support (not shown). The inner surface of the flow passage 10 is covered with an insulating material (not shown).

[0014] The waste heat recovery device 1 comprises a first joint 17, an inlet pipe 43, a support member 30, a heat transfer tube group 20, a joint 25, a second joint 45, a connecting duct 50, and an outlet pipe 47. In the waste heat recovery device 1 shown in Figure 1, the inlet pipe 43, support member 30, heat transfer tube group 20, support member 30, a connecting duct 50 located below, a support member 30, a heat transfer tube group 20, a support member 30, a connecting duct 50 located above, a support member 30, a heat transfer tube group 20, a support member 30, a connecting duct 50 located below, a support member 30, a heat transfer tube group 20, a support member 30, and an outlet pipe 47, all connected in that order.

[0015] The inlet pipe 43 is located downstream of the flow passage 10, and the outlet pipe 47 is located upstream of the flow passage 10. The fluid to be heated 5 introduced from the inlet pipe 43 flows sequentially through the support member 30, the heat transfer tube group 20, the connecting duct 50, etc., and is then discharged from the outlet pipe 47. However, as it flows through the heat transfer tube group 20, it is heated by receiving exhaust heat from the exhaust gas 3. The fluid to be heated 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 contacts the high-temperature exhaust gas 3 can be reduced. For example, the connecting duct 50 located above is supported by the duct support 52 so as to be displaceable, and the connecting duct 50 located below is supported by the 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] For example, a first joint 17 made of 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 has a hollow box shape (shown as circular in the figure), and its outside has a metal plate as the 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, for example, a welded portion formed by 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 measurement 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 heated fluid 5 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 being deformed.

[0025] A cooling space 73 is formed by the cooling housing 72 and the support portion 32. The cooling housing 72 is disposed at a gap of a certain size from the support portion 32, 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 measurement unit 77. The measurement 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 unit 32. The supply unit 65 is, for example, a mass flow controller and acts as a supply amount adjustment unit that adjusts the amount of 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 amount of 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 memory and performs various controls in the heat recovery device 1.

[0028] Based on the temperature of the support portion 32 measured by the measuring unit 77, the control unit 60 controls the supply unit 65 to control the amount of cooling fluid 7 supplied so that the support portion 32 is cooled to an appropriate temperature. As a result, the support portion 32 is adjusted to an appropriate temperature so that the joint portion 25 is not damaged by thermal stress.

[0029] Therefore, with the above configuration, the support portion 32 is cooled by the cooling fluid 7, which suppresses thermal stress caused by temperature differences in the heat transfer tube group 20 that is joined and fixed to the support portion 32 at the joint portion 25, thereby suppressing damage to the joint portion 25.

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

[0031] As an example of how to join the heat transfer tube group 20 to the support member 30, welding was used, but brazing, screw fastening, etc., can also be used.

[0032] This invention and its embodiments can be summarized as follows:

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

[0034] According to the above configuration, the support portion 32 is cooled by the cooling fluid 7, which suppresses thermal stress caused by temperature differences in the heat transfer tube group 20 that is joined and fixed to the support portion 32 at the joint portion 25, thereby suppressing damage to the joint portion 25.

[0035] Furthermore, in one embodiment of the waste heat recovery device 1, The system further includes a measuring unit 77 for measuring the temperature of the support unit 32, and a control unit 60 for controlling the amount of cooling fluid 7 supplied. The temperature of the support portion 32 is adjusted by the supply unit 65, the measuring 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] Furthermore, in one embodiment of the waste heat recovery device 1, The system further comprises a cooling housing 72 attached to the support portion 32 located around the joint portion 25, The cooling housing 72 is movably mounted 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] Furthermore, in one embodiment of the waste heat recovery device 1, The cooling enclosure 72 is configured to surround the heat transfer tube group 20 via a gap insulation material 76.

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

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

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

[0043] 1… Heat recovery device (recuperator) 3… Exhaust gas 5...Fluid to be heated 7…Cooling fluid 10... Distribution path 11…Cabinet 12...Inflow part 14…Outlet 16…Mounting opening 17…First joint 20…Heat transfer tube group 21…Through hole 22...end 24…Interior insulation 25…Joint part 30…Support member 32...Support part 43...Introduction pipe 45...Second joint 47...Discharge pipe 50... Connecting duct 52... Duct support 54... Duct support legs 60... Control Unit 65...Supply section 70... Cooling box 72…Cooling enclosure 73…Cooling space 74...Entrance 75...exit 76... Gap insulation 77... Measuring unit (thermocouple) L…Vertical direction

Claims

1. A heat recovery device that includes a group of heat transfer tubes through which a heated fluid flows, located inside a flow passage through which exhaust gas flows, A support portion that supports the end of the heat transfer tube group, A joint for joining and fixing the end of the heat transfer tube group to the support portion, It comprises a supply unit that supplies cooling fluid to the support unit, A heat recovery device in which the support portion is cooled by the cooling fluid supplied from the supply portion.

2. The system further comprises a measuring unit for measuring the temperature of the support portion and a control unit for controlling the amount of cooling fluid supplied, The waste heat recovery device according to claim 1, wherein the temperature of the support portion is adjusted by the supply unit, the measurement unit, and the control unit.

3. The cooling housing is further provided, which is attached to the support portion located around the joint portion, The heat recovery device according to claim 1, wherein the cooling housing is movably mounted with respect to the heat transfer tube group.

4. The heat recovery device according to claim 3, wherein the cooling enclosure is configured to surround the heat transfer tube group via a gap insulation material.

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

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