Frequency analysis of pressure fluctuation in fluidized bed plenum and itsconfidence limit for detection of various modes of fluidization

Pressure fluctuations were measured in a fluidized bed plenum and power spe ctral density functions obtained by fast Fourier transform (FFT) analysis o f the pressure fluctuation and its confidence limit for the diagnosis of fl uidization were investigated. Various species of fluidized beds, which cons ist of Groups A. B or D particles of Geldart's classification and their mix tures, were used. Species of fluidizing particles, weight fraction of parti cles in bed and bed height strongly influenced the mode of fluidization. Th ey were also significantly reflected on the power spectral density function . From experimental results, it is concluded that frequency analysis of pre ssure fluctuation is useful to obtain information about fluidization and to diagnose the fluidized bed, while it has a limit for its ability for detec tion of the fluidization mode.