A steam turbine, also called a steam turbine engine, is a rotary steam power device. High-temperature and high-pressure steam passes through a fixed nozzle to become an accelerated airflow and then sprays onto the blades, which rotates the rotor with blade rows while doing external work. Steam turbines are the main equipment of modern thermal power plants and are also used in the metallurgical industry, chemical industry, and ship power plants.
The steam turbine vacuum system is mainly composed of a condenser, a circulating water pump, a condensate pump, and an air extractor.
1.The role of the condenser is to reduce the exhaust pressure of the steam turbine to form a high degree of vacuum to increase the ideal enthalpy drop of the steam in the steam turbine; the exhaust steam of the cooling turbine becomes condensed water, which recovers the working fluid and part of the heat; The drain is recovered during shutdown; the condensate and condenser make-up water are subjected to one-stage vacuum deaeration.
2.The air extractor has two functions: one is to extract the air in the condenser during the start and stop of the unit to establish a starting vacuum; the other is to continuously extract the leaking in the condenser during the operation of the unit Air and other non-condensable gases and steam maintain the vacuum in the condenser to ensure the working efficiency of the condenser and improve the economy of the unit.
3.The function of the circulating water pump is to continuously provide a certain pressure and flow of cooling water to the condenser and other coolers (air cooler, oil cooler), etc., to ensure their work needs.
4.The role of the condensate pump is to continuously transport the condensate in the condenser and send it to the deaerator as boiler feed water to recover the working fluid.
Advantages of water ring vacuum pump for steam turbine application
1.It can solve the problem that the unit cannot run at full load due to low vacuum, especially in summer. The pumping rate of the water ring vacuum pump is extremely high, and the pumping volume is large. The vacuum degree can reach more than 0.09Mpa during normal summer operation, which far meets the needs of summer operation.
2.It can reduce the unit steam consumption of power generation unit and greatly improve the efficiency of power generation. The vacuum of the steam turbine drops during operation, especially in summer, the condenser vacuum has a greater impact on the economics of the steam turbine operation. If other conditions remain unchanged, for every 1% change in the vacuum degree, the steam turbine’s steam consumption rate changes by 1%~2% on average. The coal consumption changes by about 1% to 1.5%, and the power output changes by about 1%, which will be a benefit of several million yuan per year.
3.Good safety operation. In the design of the vacuum pump, effective measures are taken to prevent the atmosphere from being poured into the condenser when the equipment is out of service or failure to destroy the vacuum. Backflow, it has good sensitivity and tightness. In case of failure, the check valve installed at the inlet quickly disconnects the vacuum pump from the system; then the butterfly valve is closed to ensure the sealing of the system. In addition, the vacuum pump has the characteristics of extremely low maintenance and extremely low failure rate. Another advantage is that the high vacuum reduces the steam consumption and reduces the axial thrust of the steam turbine to avoid threatening the safety of the unit.
4.Great progress has been made in energy conservation and environmental protection. The application of the water ring vacuum pump can make the water jet extraction system can be dismantled, such as removing the jet pump, jet extraction device, jet pool, pipeline, etc. Can save a large area ofspace, can reduce a lot of water consumption. Because the noise of the water ring vacuum pump is low, this can improve the working environment of the staff.
The most common vacuum pump used in steam turbine applications is the 2BE series single-stage water ring pump, which has a wide range of air volume and good performance, which can meet the requirements of most steam turbines. The DLV series two-stage water ring pump can also be used when the working vacuum is relatively high. If you have any questions or needs, please contact the Shanghai EVP sales team.
Copyright: EVP Vacuum Solutions
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