Field Test of Superheater Pipes Vibration Caused by Sound Energy in the 235 MW_e Circulating Fluidized Bed Boiler

Abstract

This paper presents the results of measurements of vibrations of the pipes of the steam superheater installed in the convection pass of the 235 MWe Circulating Fluidized Bed boiler (CFB) induced using sonic soot blowers of the Nirafon NI-100 type. The measurements were made using two ICP Triaxial 356A16 accelerometers allowing the analysis of accelerations in the maximum range of ±490 m/s2. Simultaneously with vibration measurements, the sound pressure level was recorded using the G.R.A.S. 40BH high-pressure microphone. The measurements and spectral analysis of the recorded signals showed that the acoustic wave of 148 dB is safe for the steam superheater pipes causing vibrations of maximum amplitude not exceeding 1 mm. The field tests confirmed the supposition that the dominant mechanism for cleaning the surfaces of the superheater’s heating pipes are not pipe vibrations, but the breakage of cohesion forces between dust particles.

Keywords

• sonic soot blowers
• ash deposits
• superheaters
• circulating fluidized bed
• vibration