Large temperature difference treatment device for cylinder of supercritical steam turbine
By adding a heating system at the interlayer of high-pressure cylinder and medium-pressure cylinder, high-temperature steam is introduced into heat by using the steam seal leakage between the high-pressure cylinder and medium-pressure cylinder to introduce high-temperature steam, the problem of excessive temperature difference between high-pressure inner cylinder is solved and the operation of the turbine is improved Safety and efficiency reduce production costs.
Patent Information
- Application Number
- CN202420604542.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-27
- Publication Date
- 2024-12-27
- Estimated Expiration
- 2034-03-27
AI Technical Summary
The temperature difference between the inner and outer walls of the medium and high pressure inner cylinder of the supercritical turbine is too large, resulting in deformation, exceeding the perpendicularity of the flange bolt hole, low temperature in the steam inlet chamber and reduced return water heating efficiency, affecting the safe operation and efficiency of the unit.
An annular heating pipe and nozzle group are added to the interlayer of the high-pressure cylinder and the medium-pressure cylinder. High-temperature steam is introduced through the steam seal leakage between the high-pressure cylinder and the medium-pressure cylinder to heat it to reduce the temperature difference and prevent the cylinder from deforming.
It effectively reduces the temperature difference between the inner and outer walls of the high-pressure inner cylinder, extends the maintenance period, reduces spare parts costs, improves power generation efficiency, and saves production costs.
Smart Images
Figure CN222254092U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of steam turbines in power plants, in particular to a device for controlling large temperature differences in cylinders of supercritical steam turbines. Background Art
[0002] The supercritical units currently installed were put into operation in 2003 and are generally operating well, but there are also some problems. Specifically:
[0003] 1) The temperature difference between the inner and outer walls of the high and medium pressure inner cylinders of the steam turbine is large. The operating parameters show that the temperature difference between the inner and outer walls of the high pressure inner cylinder of the steam turbine is generally 90-120℃, and the temperature difference between the inner and outer walls of the steam inlet chamber of the medium pressure cylinder is also above 80℃, which obviously exceeds the 50℃ standard requirement.
[0004] 2) Deformation of high and medium pressure inner cylinders. After the overhaul of the unit, it was found that there was a large gap in the middle dividing surface of the high and medium pressure inner cylinders, and there was steam leakage at the joint surface of the cylinder high pressure nozzle.
[0005] 3) Cylinder deformation causes the verticality of the inner cylinder flange bolt hole to exceed the standard, and the bolts are prone to die or crack and become scrapped.
[0006] 4) The high and medium pressure steam chamber inlet temperatures and the third extraction temperatures are too low and do not reach the design values.
[0007] A comprehensive analysis of the reasons leading to the above problems is as follows:
[0008] Due to the large gap between the insulation ring of the high and medium pressure inner cylinders and the inner wall of the outer cylinder, the low-temperature steam (designed to be 316.2 ℃) discharged from the high and medium pressure cylinders passes through the cylinder interlayer and merges with the three-stage steam extraction port of the medium pressure cylinder, causing uneven cooling of the high and medium pressure cylinders, increasing the temperature difference between the inner and outer walls, and causing the internal opening to exceed the standard. Long-term operation causes permanent deformation of the cylinder.
[0009] This will have the following effects: 1) Affecting the expansion of the unit, in severe cases, causing the local dynamic and static clearance to become smaller and form friction, threatening the safe operation of the unit; 2) If the cylinder opening exceeds the standard, it will cause the flange joint surface to erode and leak steam, affecting the thermal efficiency of the cylinder; 3) The flow of low-temperature steam in the interlayer will cause the temperature of the high and medium pressure steam inlet chamber to drop, affecting the efficiency of the unit; 4) The reduction of the three-stage steam extraction temperature will affect the return water heating efficiency. 5) Cylinder deformation will also extend the maintenance period and increase the cost of spare parts.
[0010] In order to solve the above problems, people have been seeking an ideal technical solution. Summary of the invention
[0011] The utility model aims to address the deficiencies of the prior art and thus provide a supercritical steam turbine cylinder temperature difference control device which can reduce the temperature difference between the inner and outer walls of the high and medium pressure inner cylinder of the steam turbine and prevent the cylinder body from deforming.
[0012] In order to achieve the above-mentioned purpose, the technical solution adopted by the utility model is: a supercritical steam turbine cylinder temperature difference treatment device, comprising a high-pressure cylinder inner cylinder, a medium-pressure cylinder inner cylinder, a high-pressure cylinder interlayer heating component and a medium-pressure cylinder interlayer heating component, wherein the high-pressure cylinder inner cylinder is connected to the inside of the medium-pressure cylinder inner cylinder;
[0013] The high-pressure cylinder interlayer heating assembly is distributed along the circumference of the high-pressure cylinder inner cylinder and is used to heat the interlayer of the high-pressure cylinder inner cylinder;
[0014] The intermediate pressure cylinder interlayer heating assembly is distributed along the circumference of the inner cylinder of the intermediate pressure cylinder and is used to heat the interlayer of the inner cylinder of the intermediate pressure cylinder.
[0015] Based on the above, the high-pressure cylinder interlayer heating assembly includes a first annular heating tube and a first nozzle group. The first nozzle group is distributed in an annular manner on the first annular heating tube. The inner cylinder of the high-pressure cylinder is provided with a circle of first mounting holes from the outside to the inside. The nozzles in the first nozzle group are respectively installed in each first mounting hole. The outlets of the nozzles in the first nozzle group are connected to the interlayer space of the inner cylinder of the high-pressure cylinder.
[0016] Based on the above, the medium-pressure cylinder interlayer heating assembly includes a second annular heating tube and a second nozzle group, the second nozzle group is distributed in an annular manner on the second annular heating tube, the medium-pressure cylinder inner cylinder is provided with a circle of second mounting holes from the outside to the inside, the nozzles in the second nozzle group are respectively installed in each second mounting hole, and the outlets of the nozzles in the second nozzle group are connected to the interlayer space of the medium-pressure cylinder inner cylinder.
[0017] Based on the above, the incoming steam pressure in the high-pressure cylinder interlayer heating assembly and the medium-pressure cylinder interlayer heating assembly is ≥9MPa, and the temperature is ≥500°C.
[0018] Based on the above, the number of the first mounting holes and the second mounting holes is at least four.
[0019] Based on the above, the incoming steam in the high-pressure cylinder interlayer heating assembly and the medium-pressure cylinder interlayer heating assembly is connected to the steam seal leakage between the high-pressure cylinder and the medium-pressure cylinder through a pipeline.
[0020] The utility model has substantial characteristics and progress compared with the prior art. Specifically, the utility model has the following advantages:
[0021] Add an interlayer heating system to the high and medium pressure cylinders. That is, add annular heating pipes and nozzle groups to the interlayers of the high and medium pressure cylinders respectively, introduce relatively high-temperature steam from the bridge steam seal to block the high-exhaust low-temperature incoming steam, and the temperature difference between the inner and outer walls of the high-pressure inner cylinder can be effectively reduced, with obvious improvement effects.
[0022] The steam comes from the leakage of the steam seal between the high-pressure cylinder and the medium-pressure cylinder, and no additional air source is required. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 It is a structural principle diagram of a device for treating large temperature difference in a supercritical steam turbine cylinder in the utility model.
[0024] Figure 2 It is a cross-sectional view of the inner cylinder of the medium and high pressure cylinder of the utility model.
[0025] Figure 3 It is a structural schematic diagram of a medium and high pressure cylinder interlayer heating component of the utility model.
[0026] In the figure: 1. High-pressure cylinder inner cylinder; 2. First mounting hole; 3. First annular heating tube; 4. First nozzle group; 5. Interlayer. DETAILED DESCRIPTION
[0027] The technical solution of the utility model is further described in detail below through specific implementation methods.
[0028] like Figure 1-Figure 3 As shown, a device for controlling large temperature difference of supercritical steam turbine cylinders includes a high-pressure cylinder inner cylinder 1, an intermediate-pressure cylinder inner cylinder, a high-pressure cylinder interlayer heating component and an intermediate-pressure cylinder interlayer heating component, wherein the high-pressure cylinder inner cylinder 1 is connected through the inside of the intermediate-pressure cylinder inner cylinder; the high-pressure cylinder interlayer heating component is distributed along the circumference of the high-pressure cylinder inner cylinder and is used to heat the interlayer 5 of the high-pressure cylinder inner cylinder; the intermediate-pressure cylinder interlayer heating component is distributed along the circumference of the intermediate-pressure cylinder inner cylinder and is used to heat the interlayer of the intermediate-pressure cylinder inner cylinder.
[0029] The high-pressure cylinder interlayer heating assembly includes a first annular heating tube 3 and a first nozzle group 4, the first nozzle group 4 is annularly distributed on the first annular heating tube 3, the high-pressure cylinder inner cylinder 1 is provided with a circle of first mounting holes 2 from the outside to the inside, the nozzles in the first nozzle group 4 are respectively installed in each first mounting hole 2, and the outlets of the nozzles in the first nozzle group 4 are connected to the interlayer space of the high-pressure cylinder inner cylinder 1. The medium-pressure cylinder interlayer heating assembly includes a second annular heating tube and a second nozzle group, the second nozzle group is annularly distributed on the second annular heating tube, the medium-pressure cylinder inner cylinder is provided with a circle of second mounting holes from the outside to the inside, the nozzles in the second nozzle group are respectively installed in each mounting hole, and the outlets of the nozzles in the second nozzle group are connected to the interlayer space of the medium-pressure cylinder inner cylinder, and the number of the first mounting holes and the second mounting holes is at least 4.
[0030] The incoming steam pressure in the high-pressure cylinder interlayer heating assembly and the medium-pressure cylinder interlayer heating assembly is ≥9MPa, and the temperature is ≥500°C; the incoming steam in the high-pressure cylinder interlayer heating assembly and the medium-pressure cylinder interlayer heating assembly is connected to the steam seal leakage between the high-pressure cylinder and the medium-pressure cylinder through a pipeline.
[0031] Example 1
[0032] The 600MW steam turbine is one of the main power generating units in China. It has a long maintenance cycle and affects power generation. The large temperature difference in the cylinders not only directly threatens the safe operation of the unit, but also causes low operating efficiency of the steam turbine and increases the heat consumption of the unit.
[0033] Taking advantage of the opportunity of minor repairs, special drilling machines are used to drill holes in the corresponding parts of the high and medium pressure outer cylinders (4 holes in each high and medium pressure cylinder), and special alloy steel heat-resistant devices are installed respectively. During operation, the steam from the bridge steam seal (pressure of about 9MPa and temperature of 500℃ under rated load) is input into the medium pressure cylinder interlayer through the regulating station, and the high exhaust steam is blocked with a relatively high temperature steam source. In order to prevent uneven inlet steam temperature in the upper and lower cylinders, temperature measuring points are installed in the upper and lower cylinder interlayers.
[0034] The steam source is taken from the leakage of steam seals between high and medium pressure rooms, with a temperature of about 500℃ and a pressure of about 9MPa. The system is simple and easy to arrange.
[0035] After this solution was applied in Tianyi #3 unit, the temperature difference between the inner and outer walls of the high-pressure inner cylinder could be controlled within 60°C, and the temperature difference between the medium-pressure inner cylinder was within 40°C, with obvious improvement effects.
[0036] It takes about 5 days to drill the cylinder holes and install the heat-insulating device, and about 5 days to connect and lay the pipelines, for a total of 10 days.
[0037] According to the test, the use of interlayer heating under THA conditions can generally reduce the unit's heat consumption by about 40kj / kwh compared to the condition without it. Based on the annual power generation of 3.5 billion kwh of a single 600MW unit, it can save nearly 5,000 tons of standard coal and more than 5 million yuan in production costs throughout the year, with considerable safety and economic benefits.
[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the utility model can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the utility model, which should be included in the scope of the technical solution for protection of the utility model.
Claims
1. A device for treating large temperature difference in the cylinder of a supercritical steam turbine, characterized in that: It includes a high-pressure cylinder inner cylinder, a medium-pressure cylinder inner cylinder, a high-pressure cylinder interlayer heating component and a medium-pressure cylinder interlayer heating component, and the high-pressure cylinder inner cylinder is connected to the inside of the medium-pressure cylinder inner cylinder; The high-pressure cylinder interlayer heating assembly is distributed along the circumference of the high-pressure cylinder inner cylinder and is used to heat the interlayer of the high-pressure cylinder inner cylinder; The medium-pressure cylinder interlayer heating assembly is distributed along the circumference of the medium-pressure cylinder inner cylinder, and is used to heat the interlayer of the medium-pressure cylinder inner cylinder; the high-pressure cylinder interlayer heating assembly includes a first annular heating tube and a first nozzle group, the first nozzle group is distributed in an annular manner on the first annular heating tube, and the high-pressure cylinder inner cylinder is provided with a circle of first mounting holes from the outside to the inside, and the nozzles in the first nozzle group are respectively installed in each first mounting hole, and the outlets of the nozzles in the first nozzle group are connected to the interlayer space of the high-pressure cylinder inner cylinder.
2. The device for treating large temperature difference in the cylinder of a supercritical steam turbine according to claim 1, characterized in that: The medium-pressure cylinder interlayer heating assembly includes a second annular heating tube and a second nozzle group, the second nozzle group is distributed in an annular manner on the second annular heating tube, the medium-pressure cylinder inner cylinder is provided with a circle of second mounting holes from the outside to the inside, the nozzles in the second nozzle group are respectively installed in each second mounting hole, and the outlets of the nozzles in the second nozzle group are connected to the interlayer space of the medium-pressure cylinder inner cylinder.
3. The device for treating large temperature difference in the cylinder of a supercritical steam turbine according to claim 2, characterized in that: The incoming steam pressure in the high-pressure cylinder interlayer heating assembly and the medium-pressure cylinder interlayer heating assembly is ≥9MPa, and the temperature is ≥500°C.
4. The device for treating large temperature difference in supercritical steam turbine cylinders according to claim 3 is characterized in that: The number of the first mounting holes and the second mounting holes is at least four.
5. The device for treating large temperature difference in supercritical steam turbine cylinders according to claim 4 is characterized in that: The incoming steam in the high-pressure cylinder interlayer heating assembly and the medium-pressure cylinder interlayer heating assembly is connected to the steam seal leakage between the high-pressure cylinder and the medium-pressure cylinder through pipelines.