Bed density and bubble void fraction variation in a fluidized bed stripper

•Beddensity, pressure fluctuation andbubble void fraction quantified for strippers.•Gratings gave higher bed density and allowed a wider range of operating conditions.•Onset of flooding was a sudden rather than gradual occurrence.•Increasing fines and addingholes to the disk and donut traysmitigatedflooding.•Radial bubble void fraction profiles were different between the two internal types.