A method for processing thermal expansion anomaly of a steam turbine

Abstract

The application discloses a kind of steam turbine thermal expansion abnormality processing method, it is related to steam turbine equipment technical field, main purpose is to provide a kind of steam turbine thermal expansion abnormality processing method capable of processing the phenomenon of excessive thermal expansion of cylinder.The main technical scheme of the application is: a kind of steam turbine thermal expansion abnormality processing method, comprising the following steps: the valve operation of unit is switched to single valve operation, the opening of high-pressure regulating valve is controlled;Adjust the temperature rising rate of main steam temperature, and carry out phased temperature rising simultaneously, control the expansion difference of high-pressure cylinder does not exceed the allowable value;Adjust the back pressure of unit to make back pressure stable;Control the load increasing speed, and increase the warm-up time of steam turbine simultaneously;The heat of cylinder is disturbed by adjusting the steam admission of unit to increase or reduce unit load, so that the sealing part of cylinder is tightly fitted.The application is mainly used for processing steam turbine thermal expansion abnormality.

Description

Technical Field

[0001] This invention relates to the field of steam turbine equipment technology, and in particular to a method for handling abnormal thermal expansion of steam turbines. Background Technology

[0002] A steam turbine, also known as a steam engine, is a rotary steam power unit. High-temperature, high-pressure steam passes through a fixed nozzle, becomes an accelerated airflow, and is then injected onto blades, causing a rotor equipped with rows of blades to rotate and perform work. Steam turbines are the main equipment in modern thermal power plants and are also used in the metallurgical industry, chemical industry, and ship propulsion systems.

[0003] During start-up, shutdown, and operation, steam turbines expand due to temperature changes. To ensure the safe operation of the unit and guarantee the expansion of both moving and stationary components in a predetermined direction, a reasonable sliding pin system is designed. However, due to certain problems with the cylinder sealing components, large steam temperature changes can cause uneven expansion, creating gaps in the sealing parts. Some high-temperature steam leaks through these gaps into the high-pressure cylinder jacket, causing the cylinder to overheat and abnormally increase in thermal expansion, reaching alarm thresholds. This affects the unit's load capacity and threatens its safe operation. Summary of the Invention

[0004] In view of this, the present invention provides a method for handling abnormal thermal expansion of a steam turbine, the main purpose of which is to provide a method for handling abnormal thermal expansion of a steam turbine that can handle the phenomenon of excessive thermal expansion of the cylinder.

[0005] To achieve the above objectives, the present invention mainly provides the following technical solutions:

[0006] This invention provides a method for handling abnormal thermal expansion of a steam turbine, the method comprising the following steps:

[0007] Switch the unit's shunt valve operation to single valve operation to control the opening of the high-pressure regulating valve;

[0008] Adjust the heating rate of the main steam inlet temperature, and simultaneously carry out staged heating to control the expansion difference of the high-pressure and intermediate-pressure cylinders to not exceed the allowable value;

[0009] Adjust the unit back pressure to stabilize it;

[0010] Control the rate of load application while increasing the turbine warm-up time;

[0011] By adjusting the steam intake of the unit by increasing or decreasing the unit load, the heating of the cylinder is disturbed, ensuring that the sealing parts of the cylinder are tightly sealed.

[0012] Furthermore, the opening degree of the high-pressure regulating valve is 40% to 50%.

[0013] Furthermore, the heating rate for adjusting the main steam inlet temperature is 0.5 to 1.5 °C / min.

[0014] Furthermore, for every 5°C increase in the main steam temperature during the phased heating process, the warm-up time increases by 30 to 40 minutes.

[0015] Furthermore, the controlled loading rate is 2 to 3 MW / min.

[0016] Furthermore, the warm-up time for the steam turbine is increased by 1 hour for every 10MW increase in load.

[0017] Furthermore, the temperature difference between the upper and lower inner walls of the high-pressure exhaust port is monitored in real time. When the difference increases, the main steam temperature and pressure are reduced.

[0018] Compared with the prior art, the present invention has the following technical effects:

[0019] First, by adjusting some parameters, the expansion of the cylinder can be controlled to return to normal, so that the expansion of the cylinder matches the expansion of the rotor, ensuring the clearance between the moving and stationary parts of the unit and ensuring the safe and stable operation of the unit.

[0020] Secondly, by restoring the unit load rate to over 90% in a relatively short time, the working efficiency of the steam turbine is improved, ensuring the thermal economy of the unit and reducing the production costs of the enterprise. Attached Figure Description

[0021] Figure 1 A flowchart illustrating a method for handling abnormal thermal expansion of a steam turbine, provided in an embodiment of the present invention;

[0022] Figure 2 A flowchart of another method for handling abnormal thermal expansion of a steam turbine provided in an embodiment of the present invention. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0024] like Figure 1 As shown in the figure, this embodiment of the invention provides a method for handling abnormal thermal expansion of a steam turbine, the method comprising the following steps:

[0025] 101. Switch the unit's shunt valve operation to single valve operation and control the opening degree of the high-pressure regulating valve.

[0026] During unit operation, "follow-valve operation" means that all main steam valves are fully open, while "single-valve operation" means that all regulating valves are fully open. The main steam valves are used to control the steam turbine's intake air volume. When starting or shutting down, it is necessary to switch from "follow-valve operation" to "single-valve operation" or maintain "single-valve operation". At the same time, it is necessary to control the opening of the high-pressure regulating valve to stabilize the unit.

[0027] 102. Adjust the heating rate of the main steam inlet temperature, and simultaneously carry out phased heating to control the expansion difference of the high-pressure and intermediate-pressure cylinders to not exceed the allowable value.

[0028] Then control the heating rate of the main steam valve inlet temperature, keeping the heating rate below 1.5℃ / min. At the same time, for every 5℃ increase in the main steam valve inlet temperature, warm up the engine for at least 30 minutes to ensure that the expansion difference between the intermediate and high-pressure cylinders does not exceed the allowable value, which is usually 25mm.

[0029] 103. Adjust the back pressure of the unit to stabilize the back pressure.

[0030] The back pressure of the unit is controlled by adjusting the frequency of the air-cooled fan. During normal operation, the back pressure is controlled at 14 kPa.

[0031] 104. Control the load application rate and increase the turbine warm-up time.

[0032] Then, the loading rate is controlled to correspond to the cylinder temperature. The loading rate is controlled to be less than 3MW / min. While increasing the loading rate, the turbine warm-up time is increased. The warm-up time is increased by 1 hour for every 10MW increase in load.

[0033] 105. By increasing or decreasing the unit load to adjust the steam intake of the unit, the heating of the cylinder is disturbed, so that the sealing parts of the cylinder are tightly sealed.

[0034] Then, by increasing or decreasing the unit load to adjust the steam intake of the unit, the heating of the cylinder is disturbed. The disturbance makes the sealing parts of the cylinder fit tightly, so that the sealing parts no longer have gaps, thereby cutting off the air source leaking into the cylinder jacket, and then the cylinder expansion returns to normal.

[0035] Compared with the prior art, the present invention has the following technical effects:

[0036] In the technical solution provided by this invention, the expansion difference of the high-pressure and intermediate-pressure cylinder is controlled by adjusting the heating rate, the warm-up time is adjusted by controlling the load increase rate, and the unit load is adjusted. The change in steam volume is used to disturb the heating of the cylinder, so that the sealing parts of the cylinder are tightly sealed. This not only effectively controls the normal expansion of the turbine body and ensures the high load rate of the unit, enabling the unit to operate safely and stably, but also reduces the power generation cost under high load conditions, thereby achieving the technical effect of improving the economic benefits of the enterprise.

[0037] Furthermore, as a response to Figure 1 A refinement and further extension of the method shown, another embodiment of the present invention also provides a method for handling abnormal thermal expansion of a steam turbine, such as... Figure 2 As shown, the method includes the following steps:

[0038] 201. Switch the unit from indirect valve operation to single valve operation, and control the opening of the high-pressure regulating valve to 40% to 50%.

[0039] The opening degree of the high-pressure regulating valve depends on the stability of the unit, and the opening degree can be 40%, 42%, 45%, 47% or 50%.

[0040] 202. Adjust the main steam temperature rise rate to 0.5 to 1.5℃ / min, and simultaneously carry out phased temperature rise. For every 5℃ increase in main steam temperature, increase the warm-up time by 30 minutes, and control the expansion difference of the high and medium pressure cylinders to not exceed the allowable value.

[0041] The heating rate of the main steam inlet temperature is related to the intake air volume. The heating rate is 0.5℃ / min, 1℃ / min, 1.2℃ / min or 1.5℃ / min. For every 5℃ increase in the main steam temperature, the warm-up time increases by more than 30 minutes. The warm-up time can also be 40 minutes, 50 minutes or 60 minutes, so that the temperature of the unit gradually rises.

[0042] 203. Adjust the back pressure of the unit to stabilize the back pressure.

[0043] The implementation method of this step is the same as Figure 1 The implementation method of step 103 is the same, so it will not be described again.

[0044] 204. Control the load increase rate to 2 to 3 MW / min, and at the same time increase the turbine warm-up time by 1 hour for every 10 MW increase in load.

[0045] By controlling the loading rate to correspond to the cylinder temperature, the loading rate is controlled at 2 to 3 MW / min, with loading rates of 2 MW / min, 2.3 MW / min, 2.5 MW / min, 2.8 MW / min, or 3 MW / min. While increasing the loading rate, the turbine warm-up time is also increased, with the warm-up time increasing by 1 hour for every 10 MW increase in load.

[0046] 205. By increasing or decreasing the unit load to adjust the steam intake of the unit, the heating of the cylinder is disturbed, so that the sealing parts of the cylinder are tightly sealed.

[0047] The implementation method of this step is the same as Figure 1 The implementation method of step 105 is the same, so it will not be described again.

[0048] 206. Monitor the temperature difference between the upper and lower inner walls of the high-pressure exhaust port in real time. When the difference increases, reduce the main steam temperature and pressure.

[0049] The temperature changes of the upper and lower inner walls of the high-pressure exhaust port are monitored in real time. When the temperature difference between the upper and lower inner walls increases, the exhaust temperature is reduced by lowering the main steam temperature and pressure, thereby reducing the cylinder temperature.

[0050] In the technical solution provided by this invention, the expansion difference of the high-pressure and intermediate-pressure cylinder is controlled by adjusting the heating rate. Then, the warm-up time is adjusted by controlling the load increase rate. Then, the unit load is adjusted, and the heating of the cylinder is disturbed by the change in steam volume, so that the sealing part of the cylinder is tightly sealed. Then, the temperature changes of the upper and lower inner walls of the high-pressure exhaust port are monitored in real time. This not only effectively controls the normal expansion of the turbine body and ensures the high load rate of the unit, enabling the unit to operate safely and stably, but also, by monitoring the temperature changes of the upper and lower inner walls of the high-pressure exhaust port in real time, when the temperature deviation increases, the cylinder temperature is reduced by lowering the main steam temperature and main steam pressure, thereby achieving the technical effect of real-time cylinder temperature regulation.

[0051] Through the above description of the embodiments, those skilled in the art can clearly understand that the present invention can be implemented by means of software plus necessary general-purpose hardware, and of course, it can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a readable storage medium, such as a computer floppy disk, hard disk, or optical disk, and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0052] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for handling abnormal thermal expansion of a steam turbine, characterized in that, Includes the following steps: Switch the unit from sequential valve operation to single valve operation, and control the opening of the high-pressure regulating valve, wherein the opening of the high-pressure regulating valve is 40% to 50%; Adjust the heating rate of the main steam inlet temperature and simultaneously perform staged heating to control the expansion difference of the high-pressure and intermediate-pressure cylinders to not exceed the allowable value. The heating rate of the main steam inlet temperature is 0.5 to 1.5℃ / min. For each 5℃ increase in the main steam temperature during the staged heating, the warm-up time is increased by 30 to 40 minutes. Adjust the unit back pressure to stabilize it; Control the load increase rate to 2 to 3 MW / min, and at the same time increase the turbine warm-up time by 1 hour for every 10 MW increase in load; By increasing or decreasing the unit load to adjust the steam intake of the unit, the heating of the cylinder is disturbed, so that the sealing parts of the cylinder are tightly sealed. The temperature difference between the upper and lower inner walls of the high-pressure exhaust port is monitored in real time. When the difference increases, the main steam temperature and pressure are reduced.

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