Hydrodynamics of a slot-rectangular spouted bed of biomass particles with simultaneous injection of spouting and pulsating air streams

A study was undertaken to evaluate the operation of a slot-rectangular spouted bed (SRSB) when pulsed air flow at different frequencies and static bed heights was used to spout biomass particles. A pulsed air stream injected at frequencies from 1 to 5 Hz was applied simultaneously with the main spouting air flow to fluidize millet particles of mean diameter 1.25 mm and particle density 1331 kg/m3. Nine static bed heights from 0.15 to 0.55 m were studied at room temperature and atmospheric pressure. Pressure fluctuations were recorded at a sampling frequency of 100 Hz. The results showed that, at constant average pulsation gas volumetric flow rate and bed depth, a pulsation frequency of 5 Hz required the least total air flow to achieve spouting. However, for low pulsation volumetric flow rate, the effect of the pulsation frequency became less evident for deep beds than for shallow ones.