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Identification of the state of a wet spouted bed through time‐frequency analysis of pressure fluctuation time series
Author(s) -
Oliveira W.P.,
Souza C.R.F.,
Lim C.J.,
Grace J.R.
Publication year - 2009
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.20159
Subject(s) - annulus (botany) , conical surface , body orifice , materials science , particle (ecology) , densitometer , analytical chemistry (journal) , mechanics , chemistry , composite material , chromatography , optics , geology , physics , oceanography , ecology , biology
The feasibility of detecting instability in wet spouted beds via pressure fluctuation (PF) time‐series analyses was investigated. Experiments were carried out in a cylindrical Plexiglas column of diameter 150 mm with a conical base of internal angle 60°, an inlet orifice diameter of 25 mm and glass beads of diameter 2.4 mm. Transducers at several axial positions measured PF time series with incremental addition of aqueous sucrose solutions of different concentrations. Liquid addition affected the spouted bed dynamics, causing irregular spouting, increased voidage in the annulus, increased fountain height, irregular annulus height, channelling, agglomeration, and adhesion of particles to the column walls. Autocorrelations indicated the appearance of periodicities in the PF signals with increasing sucrose addition. Dominant peaks in power‐spectral density developed at low frequencies with changing system dynamics. The results indicate that PF signals furnish relevant information on system dynamics, useful for monitoring and control of spouted bed operations such as particle coating and drying of paste‐like materials.