Centrifugal compressor is widely used in petrochemical, metallurgy and other industries because of its large exhaust volume, high operating efficiency, simple structure, small area coverage, stable operation and no pulsation of compressed air.
Compressor surge refers to the periodic oscillation of air flow generated by the whole compressor pipe network system, which is an abnormal and unstable working state of compressor performance. When the compressor surge occurs, not only the compressor performance deteriorates, but also the air flow parameters, pressure and flow produce a large range of pulsation, and it will produce the same surge noise as that of the asthmatic patient, and aggravate the vibration of the whole unit.
When the compressor is surging, the strong reciprocating pulse generated by the air flow will make the rotor and stator and other parts of the compressor suffer from alternating dynamic stress, and the interstage pressure imbalance will cause strong vibration, resulting in seal and bearing damage, rotor centering damage, gas leakage and even explosion and other vicious accidents.
The causes of compressor surge include: insufficient air supply to the compressor, no supplementary air supply; gas pressure in the pipe network system is greater than the corresponding maximum pressure at a certain speed; mechanical parts are damaged and fall off; during operation, the speed increase and pressure rise are too fast, and there is no pressure reduction before the speed decrease; before changing the working conditions, the characteristic curve is not checked, so that the compressor operation point falls into the surge area, etc.
The key to anti surge is to ensure that the suction flow of the compressor is larger than the surge flow no matter how large the compression ratio of the air compressor is, so as to ensure the normal operation of the compressor. In addition, by adjusting the opening of the inlet guide vane and anti surge valve, it is used to control the gas flow and pressure through the compressor and carry out anti surge control.
Surge is the inherent characteristic of centrifugal compressor, which has great harm. Equipment operators must attach great importance to it. It should be combined with production practice, control the main influencing factors of surge, take effective anti surge measures to improve the anti surge performance and operation reliability of centrifugal compressor.
