Header structure and boiler

Abstract

A header structure and a boiler equipped with the same are provided. [Solution] A header structure 100 comprising a first header 110 through which a first fluid flows, a plurality of support fittings supporting the first header 110 from below, a support mechanism to which a plurality of support fittings are attached above and which supports the header 110 via the support fittings, a second header 120 arranged adjacent to the support mechanism and through which a second fluid having a higher temperature than the first fluid flows, and insulation that suppresses heat transfer from the second header 120 to the first header 110 attached to at least one of the outer surface of the first header 110, the support fittings, and the support mechanism, wherein heat transfer from the second header 120 to the first header 110 is suppressed in the first header 110 through which the first fluid flows and the second header 120 through which a second fluid having a higher temperature than the first fluid flows, thereby preventing the promotion of corrosion of the first header 110.

Description

[Technical Field]

[0001] The present disclosure relates to a header structure and a boiler. [Background technology]

[0002] Conventionally, pressure vessels or large-diameter piping for accommodating high-pressure fluids such as high-pressure steam and high-temperature water have been widely used in thermal power plants and the like. For example, a pressure vessel such as a header for accommodating high-pressure steam is used in a boiler. Small-diameter piping is connected to this pressure vessel, and steam is extracted through the small-diameter piping (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-14940 Summary of the Invention [Problem to be solved by the invention]

[0004] When damage such as thinning or cracks occurs in a header due to corrosion or the like, repair work is required, which involves cutting and removing the damaged portion and forming a new header in the removed area. Since such repair work requires the boiler to be shut down for an extended period of time, it is desirable to prevent damage to the header due to corrosion or the like. However, if a header contains corrosive components and is exposed to heat transfer from a heat source such as another header located adjacent to it, the fluid inside may be heated, accelerating corrosion due to the corrosive components.

[0005] The present disclosure has been made in consideration of the above circumstances, and aims to provide a header structure comprising a first header through which a first fluid flows and a second header through which a second fluid having a higher temperature than the first fluid flows, and a boiler comprising the same, in which heat transfer from the second header to the first header is suppressed to prevent the acceleration of corrosion of the first header. [Means for solving the problem]

[0006] In order to solve the above problems, a header structure according to one aspect of the present disclosure employs the following measures.

[0007] A header structure according to one embodiment of the present disclosure comprises a first header that extends cylindrically along an axis and through which a first fluid flows; a plurality of support fittings that support the first header from below at a plurality of support positions along the axis; a support mechanism to which a plurality of the support fittings are attached above and that supports the first header via the support fittings; a second header that is positioned below the support mechanism and through which a second fluid that is hotter than the first fluid flows; and insulation that suppresses heat transfer from the second header to the first header is attached to at least one of the outer surface of the first header, the support fittings, and the support mechanism. [Effects of the Invention]

[0008] According to the present disclosure, in a header structure comprising a first header through which a first fluid flows and a second header through which a second fluid having a higher temperature than the first fluid flows, and in a boiler comprising the same, heat transfer from the second header to the first header can be suppressed to prevent the promotion of corrosion of the first header. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram illustrating a flue of a boiler according to one embodiment of the present disclosure. [Figure 2] FIG. 1 is a plan view of a header structure according to one embodiment of the present disclosure, viewed from above. [Figure 3] 3 is a cross-sectional view of the header structure shown in FIG. 2 taken along the line AA. [Figure 4] FIG. 4 is a perspective view of the support metal fitting shown in FIG. 3. [Figure 5] FIG. 4 is a partial enlarged view of part B of the header structure shown in FIG. 3. [Figure 6] FIG. 6 is a cross-sectional view of the header structure shown in FIG. 5 taken along the arrow CC. [Figure 7]FIG. 6 is a cross-sectional view of the header structure shown in FIG. 5 taken along the arrow DD. DETAILED DESCRIPTION OF THE INVENTION

[0010] A header structure according to one embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 is a schematic diagram showing a flue 2 of a boiler 1 provided with a heat exchanger 10 including a header structure 100 according to one embodiment of the present disclosure. The flue 2 of the boiler 1 is provided with a plurality of heat exchangers, such as superheaters and reheaters.

[0011] The heat exchanger 10 is composed of a header structure 100 including a first header 110 and a second header 120, and a boiler tube group 200 connected to the header structure 100. High-temperature gas (e.g., combustion gas discharged from a gas turbine) introduced into the boiler 1 heats a fluid circulating within the boiler tube group 200 arranged in the flue 2. Steam, feedwater, etc. (fluids) supplied to or discharged from the boiler tube group 200 flow inside the first header 110 and the second header 120.

[0012] Although FIG. 1 shows a heat recovery boiler that recovers heat from gas turbine exhaust gas, the boiler on which the header structure 100 is installed is not limited to this, and the header structure 100 can also be applied to headers installed in other types of boilers, such as entrained bed boilers equipped with burners, fluidized bed boilers, and fixed bed boilers.

[0013] Fig. 2 is a plan view of a header structure 100 according to one embodiment of the present disclosure, viewed from above. Fig. 3 is a cross-sectional view of the header structure 100 shown in Fig. 2 taken along the line AA. In Figs. 2 and 3, a first header 110 is indicated by a dotted line. As shown in Figs. 2 and 3, the header structure 100 comprises the first header 110, a second header 120, a plurality of support fittings 130, and a support mechanism 140. The header structure 100 is disposed away from the flue 2 of the boiler 1, and is installed in an area where combustion gas hardly flows.

[0014] 2 and 3, the first header 110 is a cylindrical body that extends cylindrically along an axis X1 and through which a first fluid flows. For example, feedwater flows through the first header 110 for generating steam from high-temperature gas flowing through the flue 2. The first header 110 has a pipe stub (not shown) to which piping that supplies feedwater to the first header is connected, and a pipe stub (not shown) that supplies feedwater from the first header 110 to the piping that constitutes the boiler tube bank 200.

[0015] 2 and 3, the second header 120 is a cylindrical body that extends cylindrically along an axis X2 that is arranged parallel to the axis X1 and through which the second fluid flows. For example, superheated steam generated by heating with high-temperature gas flowing through the flue 2 flows through the second header 120.

[0016] The second fluid (e.g., superheated steam) flowing through the second header 120 has a higher temperature than the first fluid (e.g., feedwater) flowing through the first header 110. The second header 120 has a pipe stub (not shown) connected to the boiler tube group 200 and a pipe stub (not shown) that supplies superheated steam from the second header 120 to the pipes that constitute other boiler tube groups (not shown). A boiler tube group 201 (first pipe) that constitutes an evaporator and a boiler tube group 202 (second pipe) that constitutes a superheater are arranged in the flue 2 of the boiler 1. The combustion gas passing through the flue 2 of the boiler 1 heats the fluid passing through the boiler tube group 201 (first pipe) that constitutes the evaporator and the boiler tube group 202 (second pipe) that constitutes the superheater.

[0017] In the above description, an example of the first fluid is feedwater and an example of the second fluid is superheated steam, but other combinations are also possible. As long as the second fluid has a higher temperature than the first fluid during steady-state operation of the boiler 1, other combinations such as feedwater and steam, steam and superheated steam, etc. may be used.

[0018] As shown in Figure 3, the first header 110 is attached to the upper surface of the support mechanism 140. On the other hand, the second header 120 is attached to the lower surface of the support mechanism 140. In the header structure 100 of the present disclosure, when the heat insulating materials 151, 152, 153 (see Figures 5 to 7 described below) are not attached, the heat of the second header 120 heated by the heat of the second fluid flowing through the second header 120 is transferred to the first header 110 via the support mechanism 140.

[0019] The support hardware 130 is a metal member that supports the first header 110 from below at a plurality of support positions P1, P2, P3, and P4 along the axis X1. FIG. 4 is a perspective view of the support hardware 130 shown in FIG. 3. A portion of the first header 110 is omitted in FIG. 4. As shown in FIG. 4, the support hardware 130 has a pair of support portions 131, 132 that are arranged opposite each other across the axis X1. The pair of support portions 131, 132 support the weight of the first header 110 by contacting the lower side of the outer peripheral surface 110a of the first header 110. The support hardware 130 is attached to the support mechanism 140 by fastening a fastening bolt 133 to a fastening nut 134.

[0020] The support mechanism 140 has a plurality of support metal fittings 130 attached thereto and supports the first header 110 via the support metal fittings 130. As shown in Figs. 2 and 3, the support mechanism 140 has a pair of support beams 141, a plurality of connecting beams 142, a plurality of cross beams 143, an upper partition plate 144, and a lower partition plate 145. As shown in Fig. 2, the pair of support beams 141 are members arranged along the longitudinal direction LD parallel to the axis X1, and are formed, for example, from H-shaped steel.

[0021] The connecting beam 142 is a member that extends in a width direction WD perpendicular to the axis X1 and connects the pair of support beams 141. The cross beam 143 is a member that is arranged so as to intersect with both the width direction WD and the longitudinal direction LD along the axis X1 and connects the pair of support beams 141. The connecting beam 142 and the cross beam 143 are formed, for example, from H-shaped steel. The upper partition plate 144 and the lower partition plate 145 are each plate-shaped members made of metal. The upper partition plate 144 is attached above the support beam 141, connecting beam 142, and cross beam 143. The lower partition plate 145 is attached below the support beam 141, connecting beam 142, and cross beam 143.

[0022] Next, the heat insulating materials 151, 152, and 153 that suppress heat transfer from the second header 120 to the first header 110 will be described with reference to the drawings. Fig. 5 is a partially enlarged view of portion B of the header structure 100 shown in Fig. 3. Fig. 6 is a cross-sectional view taken along arrow CC of the header structure 100 shown in Fig. 5. Fig. 7 is a cross-sectional view taken along arrow DD of the header structure 100 shown in Fig. 5. The heat insulating materials 151, 152, and 153 are omitted from illustration in Figs. 2 to 4.

[0023] 5 and 6, a heat insulating material 151 that suppresses heat transfer from the second header 120 to the first header 110 is attached to the lower region of the outer peripheral surface of the first header 110 of the header structure 100. The heat insulating material 151 suppresses the transfer of heat of the second fluid to the first header 110, which is transferred in the following order: second header 120, support metal fittings 125 that support the second header 120 on the lower partition plate 145, lower partition plate 145, support beam 141, and upper partition plate 144.

[0024] 5, the heat insulating material 151 is attached only near the tip 110b of the first header 110, and is not attached to an area spaced apart from the tip 110b along the axis X1. This is because heat transfer from the second header 120 to the first header 110 via the support metal fittings 130 is significant, and therefore it is effective to attach the heat insulating material 151 near the support metal fittings 130.

[0025] As shown in Fig. 6, the thermal insulation material 151 is attached to the outer peripheral surface 110a of the first header 110 in an area other than the non-insulated area on the upper side (an area at an angle θ symmetrical with respect to the axis X1). The angle θ is preferably set, for example, in the range of 120 degrees or more and 240 degrees or less, centered on the lower end of the first header 110. The angle θ is set, for example, in the range of 180 degrees, centered on the lower end of the first header 110. By setting the angle θ in the range of 180 degrees, it is possible to minimize the installation area of ​​the thermal insulation material 151 while suitably suppressing the transfer of heat from the second fluid to the first header 110, thereby reducing installation costs and improving workability.

[0026] As shown in Figure 6, a heat insulating material 152 that suppresses heat transfer from the second header 120 to the first header 110 is attached to the underside of the upper partition plate 144 of the header structure 100. The heat insulating material 152 suppresses the transfer of heat from the second header 120, which is transferred in this order through the second header 120, the support metal fittings 125, the lower partition plate 145, and the space between the lower partition plate 145 and the upper partition plate 144, to the first header 110 via the upper partition plate 144.

[0027] In the header structure 100 shown in Fig. 6, the heat insulating material 152 is attached to the lower surface of the upper partition plate 144, but other configurations are also possible. For example, the header structure 100 may be configured so that the heat insulating material 152 is attached to the upper surface of the upper partition plate 144. Also, for example, the header structure 100 may be configured so that the heat insulating material 152 is attached to both the upper and lower surfaces of the upper partition plate 144.

[0028] As shown in Figure 7, a heat insulating material 153 is attached to the support metal fittings 130 of the header structure 100 so as to surround the support metal fittings 130. The heat insulating material 153 prevents the heat of the second fluid, which is transferred in the order of the second header 120, support metal fittings 125, lower partition plate 145, support beam 141, upper partition plate 144, and support metal fittings 130, from being transferred to the first fluid via the first header 110.

[0029] The insulating materials 151, 152, and 153 are formed, for example, from biosoluble fibers that have the property of dissolving in the body. Biosoluble fibers do not contain asbestos or ceramic fibers and dissolve in body fluids, which reduces health risks. Biosoluble fibers are mainly composed of inorganic glass containing silica, calcium, and magnesium, and are highly heat-resistant, making them effective as insulating materials.

[0030] The functions and effects of the header structure of this embodiment described above will now be described.

[0031] According to the header structure 100 of this embodiment, a plurality of support metal fittings 130 are attached above the support mechanism 140, and the first header 110 is supported via the support metal fittings 130. Meanwhile, the second header 120 is attached below the support mechanism 140. Because the second fluid has a higher temperature than the first fluid, unless some countermeasure is taken, the heat of the second fluid flowing through the second header 120 will be transferred to the first fluid flowing through the first header 110 via the support mechanism 140.

[0032] Therefore, in the header structure 100 of this embodiment, heat insulation materials 151, 152, 153 that suppress heat transfer from the second header 120 to the first header 110 are attached to at least one of the outer peripheral surface 110a of the first header 110, the support metal fittings 130, and the support mechanism 140, thereby suppressing the transfer of heat from the second fluid to the first fluid. This makes it possible to prevent the first header 110 from becoming corroded.

[0033] According to the header structure 100 of this embodiment, the insulating material 151 is attached to the entire area of ​​the outer peripheral surface 110a of the first header 110 except for the non-insulated area above, so that it is possible to prevent the heat of the second fluid flowing through the second header 120 located below the support mechanism 140 from being transferred to the first fluid flowing through the first header 110 located above the support mechanism 140. Furthermore, compared to when insulating material 151 is attached to the entire area of ​​the outer peripheral surface 110a of the first header 110, the amount of insulating material 151 used can be reduced, thereby reducing the manufacturing cost of the header structure 100.

[0034] According to the header structure 100 of this embodiment, the heat insulating material 153 is attached so as to surround the support metal fittings 130, thereby reducing the amount of heat transferred from the second fluid to the first fluid through the support metal fittings 130 that are in contact with the first header 110.

[0035] The header structures and boilers described in the above-described embodiments can be understood, for example, as follows.

[0036] The header structure according to the first aspect of the present disclosure comprises a first header (110) extending cylindrically along an axis (X1) and through which a first fluid flows, a plurality of support fittings (130) supporting the first header from below at a plurality of support positions (P1, P2, P3, P4) along the axis, a support mechanism (140) to which the plurality of support fittings are attached above and which supports the first header via the support fittings, a second header (120) arranged adjacent to the support mechanism and through which a second fluid having a higher temperature than the first fluid flows, and insulating materials (151, 152, 153) attached to at least one of the outer circumferential surface of the first header, the support fittings, and the support mechanism to suppress heat transfer from the second header to the first header.

[0037] In the header structure according to the first aspect of the present disclosure, a plurality of support metal fittings are attached above the support mechanism, and a first header is supported via the support metal fittings. Meanwhile, a second header is disposed adjacent to the support mechanism. Because the second fluid has a higher temperature than the first fluid, unless some countermeasure is taken, the heat of the second fluid flowing through the second header will be transferred to the first fluid flowing through the first header via the support mechanism.

[0038] Therefore, in the header structure according to the first aspect of the present disclosure, heat transfer from the second fluid to the first fluid is suppressed by attaching a heat insulating material to at least one of the outer circumferential surface of the first header, the support metal fittings, and the support mechanism, which suppresses heat transfer from the second header to the first header, thereby preventing the acceleration of corrosion of the first header.

[0039] The header structure according to the second aspect of the present disclosure is the same as that of the first aspect, and further includes the following configuration: the heat insulating material (151) is attached to the outer peripheral surface of the first header in a region other than the non-insulated region.

[0040] According to the header structure of the second aspect of the present disclosure, since the insulation material is attached to the outer peripheral surface of the first header in areas other than the non-insulated area, it is possible to suppress the heat of the second fluid flowing through the second header arranged adjacent to the support mechanism from being transferred to the first header. Furthermore, compared to when insulation material is attached to the entire outer peripheral surface of the first header, the amount of insulation material used can be reduced, thereby reducing the manufacturing cost of the header structure.

[0041] The header structure according to a third aspect of the present disclosure is the first or second aspect, further comprising the following configuration: the heat insulating material (153) is attached so as to surround the support metal fittings.

[0042] According to the header structure of the third aspect of the present disclosure, insulation is attached to surround the support metal, thereby reducing the amount of heat transferred from the second fluid to the first fluid through the support metal in contact with the first header.

[0043] The header structure according to a fourth aspect of the present disclosure is the header structure of any one of the first to third aspects, further comprising the following configuration: the support mechanism has a support plate (144) to which the support metal fittings are attached, and the heat insulating material is attached to the support plate.

[0044] According to the header structure of the fourth aspect of the present disclosure, since an insulating material is attached to the support plate to which the support hardware is attached, the amount of heat transferred from the second fluid to the first fluid via the support plate and the support hardware can be reduced.

[0045] A boiler according to a fifth aspect of the present disclosure comprises a header structure according to any one of the first to fourth aspects, wherein the first header circulates steam generated in an evaporator as the first fluid, and the second header circulates superheated steam generated in a superheater as the second fluid, and further comprises a flue (2) in which a first pipe constituting the evaporator and a second pipe constituting the superheater are disposed and which heats fluid passing through the first pipe and the second pipe with combustion gas.

[0046] According to the boiler according to the fifth aspect of the present disclosure, heat transfer from the second header to the first header can be suppressed, thereby preventing the acceleration of corrosion of the first header. [Explanation of symbols]

[0047] 1 boiler 2 Flue 10 Heat exchanger 100 Header structure 110 Headers No. 1 110a Outer surface 110b Tip 120 No. 2 Headers 125,130 Support hardware 131,132 Support part 133 Fastening bolt 134 Fastening nut 140 Support mechanism 141 Support beam 142 Connecting beam 143 Cross Beam 144 Upper partition plate 145 Lower partition plate 151,152,153 Insulation material 200 Boiler tube bank LD Longitudinal direction P1,P2,P3,P4 Support position WD Width direction X1,X2 axis θ angle

Claims

1. a first header extending cylindrically along an axis and through which a first fluid flows; a plurality of support fittings that support the first header from below at a plurality of support positions along the axis; a support mechanism having a plurality of support metal fittings attached thereto and supporting the first header via the support metal fittings; a second header disposed adjacent to the support mechanism and through which a second fluid having a temperature higher than that of the first fluid flows; A header structure in which an insulating material for suppressing heat transfer from the second header to the first header is attached to at least one of the outer peripheral surface of the first header, the support metal fittings, and the support mechanism.

2. 2. The header structure according to claim 1, wherein the heat insulating material is attached to the outer peripheral surface of the first header in an area other than the non-insulated area.

3. 3. The header structure according to claim 1, wherein the heat insulating material is attached so as to surround the support metal.

4. the support mechanism has a support plate to which the support metal fitting is attached, 3. The header structure according to claim 1, wherein the heat insulating material is attached to the support plate.

5. A header structure according to claim 1 or 2, the first header allows feedwater to be supplied to an evaporator to flow as the first fluid; the second header allows superheated steam generated in the superheater to flow as the second fluid; A boiler in which a first pipe constituting the evaporator and a second pipe constituting the superheater are disposed, and further comprising a flue for heating a fluid passing through the first pipe and the second pipe with combustion gas.

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