Backflow heating system and method for high-pressure cylinder of cold-state steam turbine

Abstract

The invention discloses a backflow heating system for a high-pressure cylinder of a cold-state steam turbine. The system mainly comprises a steam-jet air extractor, an oil-water separator, a steam-water separator, an air heater and a hot air header; the hot air header is connected with an exhaust pipe of the high-pressure cylinder of the steam turbine; a suction opening of the steam-jet air extractor is connected with a pipeline between a high-pressure cylinder adjusting valve of the steam turbine and a main steam valve of the steam turbine. According to the characteristics that some steam turbine units are light in rotor, prone to rolling and the like, the backflow heating manner is adopted, the purpose of effective heating of a steam cylinder can be achieved, and the influence on normalstarting of the unit can be avoided; the steam-jet air extractor is adopted, so that the power consumption of the air heater can be reduced, and the starting running cost of the unit can be reduced; and the temperature of the high-pressure cylinder of the steam turbine can be increased quickly, and the system is beneficial to normal starting of the steam turbine unit. The invention further provides a backflow heating method for the high-pressure cylinder of the cold-state steam turbine. The method has the characteristics that the cost is saved through cold-state starting of a power generator set, the loss is reduced, the method quickly adapts to power grid power adjustment and dispatching and the like.

Description

technical field [0001] The invention relates to the technical field of steam turbines, in particular to a backflow heating system and method for a high-pressure cylinder of a cold steam turbine. Background technique [0002] During the cold start-up process of the steam turbine generator set, it is necessary to adjust the steam passing through the cylinder for heating through the regulating valve. Due to the thickness of the cylinder wall of the steam turbine for power generation, it takes a long time to heat up. At the same time, considering that the steam turbine rotor and the cylinder are heated and expanded out of sync, when the unit starts During high-speed rotation, dynamic and static friction will occur, so the steam intake of the steam turbine cannot be too large, and low flow rate is required for slow heating. This makes the start-up time of the unit too long, and the boiler supplying steam to the steam turbine runs at low load for a long time. The combustion of the...

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Problems solved by technology

This makes the start-up time of the unit too long, and the boiler supplying steam for the steam turbine runs at low load for a long time, and the combustion of the boiler operating at low load is very unstable, and it needs to be operated with oil or plasma, resulting in high cost of cold-state start-up of the unit.

For some steam turbine units, the rotor is light and easy to spin. During the heating process of the high-pressure cylinder, the rotor rotates at a low and medium speed. When the oil film on the shaft of the steam turbine is not formed, the flow parts of the steam turbine are worn, which is likely to affect the normal start of the unit.

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