An optimal control method for the shaft seal and door lever steam leakage system of a power station steam turbine unit

Abstract

The invention discloses an optimization control method for the shaft seal and door lever steam leakage system of a steam turbine unit in a power station, comprising: at the initial stage of unit start-up, the shaft seal steam is supplied by auxiliary steam, and the inlet temperature is automatically adjusted and controlled through the shaft seal steam supply electric heater, The shaft seal steam supply regulating valve automatically controls the pressure of the shaft seal main pipe to maintain at 3.5kPa; the first pneumatic door and the fourth pneumatic door are opened, the third electric door is closed, the pneumatic steam trap is opened, and the shaft seal overflow regulating valve automatically tracks the shaft seal Main pipe pressure; when the unit is connected to the grid with a load of 20% THA, and the fifth-stage extraction pressure is greater than 0.04MPa, the third electric door starts to open automatically, while keeping the pneumatic trap fully open; when the unit load gradually increases to When the THA is 70% and above, the shaft seal system is in a sealed state, the shaft seal steam supply regulating valve is automatically closed, and the shaft seal overflow regulating valve is automatically opened. This method can ensure that the shaft seal system and door lever leak steam when the unit is started and grid The whole process of operation and load shedding is safe, reliable and energy-efficient.

Description

Technical field [0001] The present invention belongs to the artifact of steam turbine shaft system and door leakage steam transformation optimization technology, and is relate to an optimization control method of a power station steam turbine unit shaft and door leakage steam system. Background technique [0002] Steam turbine shaft seals and door leakage vapor systems are an important part of a steam turbine. Its main function is to provide sealed steam to the shaft seal and main vapor valve of the steam turbine. The function of the shaft sealing system is to prevent steam from leaking to ensure high efficiency of steam to ensure that the steam turbine has high efficiency. In the low pressure cylinder area of ​​the steam turbine, the function of the bearing system is to prevent the outside air from entering the steam turbine to ensure that the steam turbine has as high as possible and the high efficiency of the steam turbine. The shaft sealing system is mainly composed of a seal...

AI Technical Summary

Problems solved by technology

However, in the actual operation of the unit, accidental tripping conditions cannot be avoided. After the unit trips, if the difference between the shaft seal steam supply temperature and the rotor temperature is too large, it may cause the risk of major shaft lockup.

In addition, the existence of the gap between the main steam valve and the door lever of the adjustment valve will inevitably cause some steam to leak out, and if the steam leakage of the door lever is not properly controlled during the recovery process, it will cause the erosion loss of the sealing surface of the door lever packing. Therefore, a new method is proposed. An effective and reliable control strategy of the shaft seal and door lever steam leakage system is very important to realize the safety and reliability of the steam turbine unit during the entire start-up operation stage

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