A fluidized catalyst stripping unit for displacing entrained gas from catalyst particles comprising: a vessel housing a two stage cyclonic separation section which comprises one or more primary cyclonic separation devices and one or more secondary cyclones; a stripping section which comprises internals; and an inlet in fluid communication with a catalytic reactor to feed a particulate-fluid suspension to the two stage cyclonic separation section; wherein each primary cyclonic separation device comprises an internal cylindrical surface to separate a major fraction of the particulates from the suspension and form a vortex of reduced particulate content; a particulate discharge outlet from each secondary cyclone to the stripping section; wherein the particulate discharge outlet of the secondary cyclone is submerged in a catalyst bed located above the stripper internals, and wherein the stripping section comprises one or more bubble breaking grids within the catalyst bed and above the stripping internals is provided.