Spectral analysis: A Contribution to Control Strategy in Spouted Bed

Abstract

The stability of fluid dynamics regime is one of the most desired objectives to ensure the good performance of processes in spouted bed equipment. However, the major problem in these processes is the lack of a control variable with fast response and easy acquisition towards a control strategy in closed loop that could guarantee operation under a condition of stable spouting. The aim of this work was to study and evaluate the behaviour of pressure fluctuation signals and their power spectra in spouted bed as a control and monitor variable. The spectral alterations caused by the change in the mechanics and kinetics of particles were compared with visual observations to identify different phenomena that occur in each fluid dynamic regime. Three variables were monitored: dominant frequency, dominant amplitude and standard deviation of pressure fluctuation signals. Glass beads were used as inert particles and air 343 K as the spouting gas. This paper showed that the dominant frequency, dominant amplitude and standard deviation of pressure fluctuation were variables that show operation range well defined to stable spouted, internal spouted and fixed bed regimes. The three variables demonstrated to be useful to identify the transition regimes or as control variables for maintaining the system in stable spout operation.