Obvious vibration existed on medium pressure feed-water pipeline no.1 of one 210 MW CFB boiler.Through survey measurement and analysis in the field

it is believed that the main causes resulting in the pipeline vibration are as follows:low stiffness along horizontal direction of the pipeline;shortage of the effective position-limiting constraint;and abnormal state of the support-and-hanger.On the basis of mode analysis and stress calculation for the tubulature

a vibration elimination scheme has been worked out.After implementation of the said scheme

pipeline vibration is substantially reduced

the primary and secondary stress being up to standard

the thrust and moment of force applied by the pipeline onto the end equipments all are within the allowable range

vibration elimination achieving the desired result.