Study On The Drain System Vibration Of The Air Heater Of A 350MW Unit

Pipeline vibration occurred after the remodeling of the heater’s drain system of a350 MW unit,which caused serious safety risks and endangered the safe operation of the power plant.In order to solve the problem,the vibration signal test and analysis were performed on the main vibration parts of the heater’s hydrophobic system.Added pressure and temperature measurement points and data collection at the heater’s drain outlet,in front of the warm tong drain line check valve,and at the outlet of the heat-trapping drain line.Thermal check calculations,analysis and analysis of the cause of the system’s pipeline vibration.Based on this,two solutions are provided: a porous pressure reducer for the drain line of the secondary air heater and a bypass drain pump.And numerical simulation of the porous decompression device using ANSYS software,Provide the model and manufacturer of the pump.The main research results show that: 1)One of the causes of the vibration of the heater drainage system pipe is as follows: Excessive steam pressure at the steam inlet of the secondary air heater directly causes the pipe vibration of the drainage system,which is the main cause of vibration 2)The second reason for the vibration of the drainage system pipeline is as follows: When the pressure of the system’s trap box is greater than the pressure before the warm tong drain pipeline check valve,the warm tong drain check induces water hammer in the warm tong drain pipeline and becomes the main source of severe vibration of the system pipeline;3)The pressure drop design value of the porous pressure reducer designed by numerical simulation method is ≥0.2MPa.Setting it in front of the inlet of the steam side of the secondary air heater can reduce the pressure of the trap and also relieve the hydraulic imbalance of the primary air heater.4)It can be expected: The two vibration reduction schemes have complementary effects.The addition of a bypass pump in the warm tong drainage pipeline can eliminate the main source of severe vibration of the system pipeline.