Thermal start-up control method of steam turbine in trough solar thermal power station

Abstract

This application relates to the technical field of start-up control of steam turbines, in particular to a method for temperature-state start-up control of steam turbines in trough-type solar thermal power plants, which includes: when the shaft seal is put into operation, delay the start-up time of the shaft plus fan, and when the low-pressure cylinder When the pressure of the shaft seal rises to 5KPa, start the shaft adding fan; the temperature of the steam supplied to the shaft seal is controlled to be 20-25°C higher than the temperature of the high-pressure cylinder to ensure the superheat of the steam supplied to the shaft seal; The compressed air source of the oil gear is withdrawn, and it is re-introduced after the steam turbine is connected to the grid; when the warm state is started, the temperature of the shaft seal behind the high-pressure cylinder is controlled at 160-175°C; When controlled below ‑0.2mm. This application has the effect of being able to solve the temperature start-up stability of the new unit of the domestic trough-type photothermal power station, ensure the smooth start-up of the new-type steam turbine, and meet the use requirements of the new-type steam turbine of the trough-type photothermal power station.

Description

technical field [0001] The present application relates to the technical field of start-up control of steam turbines, and in particular, to a method for controlling the temperature-state start-up of steam turbines in trough solar thermal power plants. Background technique [0002] CGN Delingha 50MW trough CSP plant is the first one in China. The steam turbine is the first model in China with two cylinders, two speeds, high pressure, medium temperature, and axial exhaust. At present, the domestic conventional steam turbine warm-up technology is relatively mature. , but there are many problems to be solved in the warm start-up of the first new type of unit in China. [0003] When the new-type steam turbine is in the warm state, the vibration of the rear bearing of the high-pressure cylinder reaches the shutdown value when it exceeds the critical speed region, and the new-type steam turbine cannot be started normally in the warm state. The high-pressure cylinder vibration shutd...

AI Technical Summary

Problems solved by technology

[0003] When the new steam turbine is in a warm state, the vibration of the rear bearing of the high-pressure cylinder reaches the shutdown value when it passes the critical speed zone, and the new steam turbine cannot start normally in the warm state

The fixed value of the high-pressure cylinder vibration shutdown is 125 μm. When the new steam turbine is started in a warm state, the vibration of the rear bearing of the high-pressure cylinder of the steam turbine is 2265 rpm, and the vibration of the rear bearing of the high-pressure cylinder reaches 132 μm. The vibration protection action of the steam turbine cannot be started in a warm state

[0004] The steam leakage of the shaft seal system of the steam turbine of CGN Delingha 50MW trough solar thermal power station is collected into one main pipe, causing the leakage of steam from the high pressure side to the low pressure side, which disturbs and cools the shaft seal of the low pressure side; the main steam The pressure of steam leaking from the valve stem on the low-pressure side of the valve and the speed-regulating valve is much higher than the steam supply pressure of the shaft seal, and the temperature of the leaking steam on the low-pressure side of the main valve and the speed-regulating valve passes through under the action of heat dissipation The temperature is lower than the steam supply temperature of the shaft seal, and a common shaft seal leakage steam main pipe will disturb the temperature of the shaft seal at the initial stage of the unit's temperature start-up, resulting in temperature fluctuations of the shaft seal and affecting the expansion of the shaft system; resulting in a new type of steam turbine. The vibration of the cylinder side of the high-pressure cylinder exhaust exceeds the limit during start-up, which makes the warm-state start-up of the new steam turbine impossible