In this paper results are presented of our investigations on the use of fluidised beds as turbulence promotors in tubular membrane systems. The fluidised bed will be compared with other types of turbulence promotors like static mixers and spiral wires. Attention will be given to mass transfer, to possible damage of the membrane surface and to the energy-efficiency of the fluidised bed. Mass transfer is favourably effected at superficial velocities as low as 1 cm/sec. Damage of the membrane surface could not be observed for glass particles equal to or smaller than 0,7 mm diameter. For a fluidised bed the same mass transfer coefficient as in the empty tube can be reached with only about 5% of the circulation energy.