Anti-surge problems in centrifugal compressors
Thread Content
I have just started learning about *centrifugal compressors, and specifically the large-scale centrifugal compressors used in ammonia synthesis production (for example, Model 103). I don’t have a thorough understanding of the function and principle of the anti-surge pipeline in aircraft model 105. Could someone please explain it to me? Thank you.
It is necessary to ensure that the fan has a certain flow rate.
103J: Syngas compressor, 105J: Ammonia compressor (also known as an ice machine). In simple terms, surge in a centrifugal compressor occurs when there is backpressure at the compressor outlet (the pressure in the outlet pipeline or container is higher than the pressure at the compressor outlet), or when there is a blockage; it also happens when the inlet flow rate to the compressor suddenly decreases or stops. At this point, the compressor will experience surge. Each compressor is equipped with a compressor surge curve at the time of leaving the factory. When the compressor is in operation, surge occurs when parameters such as pressure, flow rate, temperature, and the nature of the medium fall within the surge curve. To prevent surge, return pipes (for pressure reduction) are installed at the second, third, fourth, or other stages of the compressor leading to the inlet of the first stage, in order to maintain the flow rate at the compressor inlet. This prevents the compressor from experiencing surge.
Assuming there is no anti-surge line, when you close the outlet valve of the centrifugal compressor, the gas flow rate will gradually decrease; once it reaches a certain level, a whistling sound can be heard and the unit vibrates intensely – this is surge. But with an anti-surge line in place, during backflow or venting, the valve opens under the automatic control of the system (anti-surge control), thereby maintaining a minimum flow rate and preventing surge from occurring at that pressure level~~