Flow hydrodynamics and mass transport between the liq. and packing surface in a trickle-bed reactor were studied under conditions of a cyclic change (pulsation) of flow velocity in glass ball-packed lab. glass column rinsed with biphase systems consisting of N and H2O, aq. glycerol and aq. MeOH (N flow velocity 0, 14-0,27 m/s). Dynamic liq. holdup was detd. and correlated as dimensionless equation. The mass transfer (liq. to solid) coeffs. were also detd. as a function of liq. phase flow velocity.