Determination of Actual First-order Critical Speed Value of Centrifugal Compressor

The Residue Desulfurization(RDS) unit of Sichuan petrochemical had 2 sets of centrifugal compressor, found that in single machine start-up, when speed is lower than the first- order critical speed, VIA8220 and VIA8221 vibration increase obviously.Through the analysis, it was found that compressor in the critical region and the first order critical speed is lower than 4369 RPM, so it is necessary to find out the true first-order critical value of the centrifugal compressor through experiment in order to make the centrifugal compressor quickly across the critical region to avoid vibration increase and the damage of equipment.