The characteristics of vibration displacement signals of graphite tube in vapor-liquid-solid (V-L-S) external circulating fluidized bed evaporator were investigated by means of accelerometers and a system of measurement and analysis of dynamic vibration signals using signal analysis tools of the standard deviation

power spectrum and wavelet transformation. Main results were as follows. The original and global vibration displacement signal with multi-scale behavior can be decomposed into low and middle vibration displacement signal (LFS/MFS) and high frequency vibration displacement signal (HFS). The standard deviation of the original signal (under V-L-S boiling flow) and its LFS/MFS by wavelet transformation increased at first and then a stable trend with increasing steam pressure

and its HFS by wavelet transformation showed a slight increasing trend. The addition of solid particles can weaken the vibration intensity of LFS/MFS and enhance the vibration intensity of HFS. The standard deviation of HFS represented an apparent increasing trend with the solid holdup. The standard deviation of three vibration signals (original

LFS/MFS

HFS) indicated a weak enhancement with solid particle diameter. The vibration behavior of graphite tube at different axial positions was also investigated. Two correlations of vibration intensity for vapor-liquid and V-L-S boiling flows were provided.