Causes of excessive vibration of debutanizer bottom pump and countermeasures

The causes of repeated off-specification vibration of the debutanizer bottom pump of hydrocracker were analyzed. The analysis results indicated that the vibration of pump was caused by the changes of ratio between the outlet flow of hot low-pressure oil separator bottom and outlet flow of cold low-pressure segregator bottom,i. e. the variation of effluent reaction depth. Effective measures were taken to control the reaction depth to ensure the ratio of bottom outlet flow of hot low-pressure separator to that of cold high-pressure separator within the range of 0. 45 ~ 0. 53 and the vibration of the pump at about 5 mm / s so as to restore the vibration of pump to normal design conditions and ensure the smooth operation of the unit.