A boiler structure with the heating surface above the surface
By adopting a 60° U-shaped bend in the boiler's structure above the heating surface, the leakage problem caused by stress concentration in the heating surface pipes of the waste heat boiler was solved, the strength and thermal expansion adaptability of the pipes were improved, and the reliability of the unit was enhanced.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHANGHAI HUADIAN FENGXIAN THERMAL POWER CO LTD
- Filing Date
- 2025-07-21
- Publication Date
- 2026-05-26
AI Technical Summary
In gas-fired combined cycle units, the waste heat boiler heating surface pipes frequently rupture due to overheating, corrosion, wear, fatigue, and other reasons, leading to leaks and affecting the reliability of the unit.
A boiler structure with the heating surface above the boiler surface is designed, using 60° U-shaped bends in the stress concentration area. The bending design reduces thermal expansion stress. The bends in the first and second tube panels are symmetrically arranged and distributed in the stress concentration area.
It effectively reduces the stress generated in the pipeline during thermal expansion, protects the pipe section from being torn apart, and improves the strength and flexibility of the pipeline to adapt to the needs of thermal expansion.
Smart Images
Figure CN224284575U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a boiler structure with the heating surface higher than the surface. Background Technology
[0002] The waste heat boilers of Units 5 and 6 at Fengxian Company are three-pressure, reheat, horizontal, non-supplementary combustion, self-deaerator, naturally circulating gas turbine waste heat boilers with a tight-fitting enclosed frame. Designed and manufactured by Hangzhou Boiler Group Co., Ltd., model NG-54000F-R, they are matched with Siemens SGT5-4000F gas turbines and are one of the main units in the gas-fired combined cycle power plant. Leakage in the four tubes of the waste heat boiler in a gas-fired combined cycle unit refers to the rupture and leakage of the evaporator, superheater, reheater, and economizer tubes due to overheating, corrosion, wear, fatigue, or other reasons, leading to tube failure and potentially boiler accidents. Recent incidents of boiler heating surface pipe leaks have resulted in decreased unit reliability. Utility Model Content
[0003] The purpose of this utility model is to provide a boiler structure with the heating surface higher than the boiler surface, so as to solve the above-mentioned technical problems.
[0004] To achieve the above objectives, this utility model provides the following technical solution:
[0005] A boiler structure with its heating surface above the wall includes a first tube screen and a second tube screen. The first tube screen and the second tube screen are connected to an inlet header and an outlet header, respectively, via connecting pipes. The first tube screen has two rows of first heating surfaces, and the second tube screen has two rows of second heating surfaces. Both the first and second heating surfaces include multiple straight tube rows and multiple bent tube rows. The bent tube rows of the first heating surface and the bent tube rows of the second heating surface are positioned opposite each other and are symmetrically bent.
[0006] In the boiler structure described above, the two rows of bends on the first heating surface of the first tube panel are U-shaped bends with a curvature of 60°.
[0007] In the aforementioned boiler structure where the heating surface is higher than the boiler surface, the two rows of bent tubes on the second heating surface of the second tube panel are all U-shaped bends with a curvature of 60°.
[0008] The boiler structure with the heating surface above the surface is described above, wherein the two rows of bent tubes of the first heating surface of the first tube screen are symmetrically bent with the two rows of bent tubes of the second heating surface of the second tube screen.
[0009] The boiler structure described above has a height above the heating surface, wherein the bent tube arrays of the first heating surface and the second heating surface are distributed at stress concentration points. Beneficial effects
[0010] 1. This utility model sets the stress concentration point as a U-shaped bend with a curvature of 60°. This design ensures the strength of the pipe while providing sufficient flexibility to accommodate thermal expansion. The 60° curvature of the U-shaped bend allows the pipe to expand along a predetermined path when heated, rather than being directly stretched or compressed, thus reducing stress on the pipe section. The U-shaped bend design also absorbs and alleviates the stress generated by thermal expansion, protecting the pipe section from breakage. Attached Figure Description
[0011] Appendix Figure 1 This is a schematic diagram of the structure of this utility model;
[0012] Appendix Figure 2 This is a side view of the present invention;
[0013] In the diagram: 1. Inlet header; 2. Straight pipe row; 3. Bend pipe row; 4. Second heating surface; 5. Outlet header; 6. Second tube panel; 7. Second tube panel; 8. First heating surface; 9. First header; 10. Second header; 31. Straight pipe section. Detailed Implementation
[0014] Reference Figures 1-2 A boiler structure with a height above the heating surface includes a first tube panel 7 and a second tube panel 6. The first tube panel and the second tube panel are connected to the inlet header 1 and the outlet header 5 respectively via connecting pipes. The first tube panel has two rows of first heating surfaces 8, and the second tube panel has two rows of second heating surfaces 4. Both the first and second heating surfaces include multiple straight tube rows 2 and multiple bent tube rows 3. The bent tube rows of the first heating surface and the bent tube rows of the second heating surface are positioned opposite each other and are symmetrically bent.
[0015] In the boiler structure described above, the two rows of bends on the first heating surface of the first tube panel are U-shaped bends with a curvature of 60°.
[0016] In the aforementioned boiler structure where the heating surface is higher than the boiler surface, the two rows of bent tubes on the second heating surface of the second tube panel are all U-shaped bends with a curvature of 60°.
[0017] The boiler structure with the heating surface above the surface is described above, wherein the two rows of bent tubes of the first heating surface of the first tube screen are symmetrically bent with the two rows of bent tubes of the second heating surface of the second tube screen.
[0018] The tops of the two rows of bent pipes on the first heating surface and the two rows of bent pipes on the second heating surface are located at a distance of 1295mm from the center of the header. The distance between the center of the vertical section of the outer bent pipe and the center of the header is 330.4mm, and the distance between the center of the outer straight pipe and the center of the header is 57.15mm.
[0019] The boiler structure described above has a height above the heating surface, wherein the bent tube arrays of the first heating surface and the second heating surface are distributed at stress concentration points.
[0020] Stress concentration points are addressed by using U-shaped bends with a 60° curvature. This design ensures pipe strength while providing sufficient flexibility to accommodate thermal expansion. The 60° curvature of the U-bend allows the pipe to expand along a predetermined path when heated, rather than being directly stretched or compressed, thus reducing stress on the pipe section. The U-bend design also absorbs and alleviates stress caused by thermal expansion, protecting the pipe section from breakage.
Claims
1. A boiler structure with the heating surface above the surface, comprising: The first tube screen and the second tube screen are connected to the inlet header and the outlet header respectively via connecting pipes. The first tube screen has two rows of first heating surfaces, and the second tube screen has two rows of second heating surfaces. Both the first heating surfaces and the second heating surfaces include multiple straight pipe rows and multiple bent pipe rows. The bent pipe rows of the first heating surfaces and the bent pipe rows of the second heating surfaces are positioned opposite each other and are symmetrically bent.
2. The boiler structure with the heating surface higher than the boiler surface according to claim 1, characterized in that: The two rows of bends on the first heating surface of the first tube screen are all U-shaped bends with a curvature of 60°.
3. The boiler structure with the heating surface above the boiler surface according to claim 2, characterized in that: The two rows of bends on the second heating surface of the second tube screen are all U-shaped bends with a curvature of 60°.
4. The boiler structure with the heating surface higher than the boiler surface according to claim 3, characterized in that: The two rows of bent tubes on the first heating surface of the first tube screen are symmetrically bent with the two rows of bent tubes on the second heating surface of the second tube screen.
5. A boiler structure with the heating surface higher than the boiler surface according to claim 4, characterized in that: The bent pipe arrays of the first and second heated surfaces are located at stress concentration points.