In this paper, we propose a new procedure for fast evaluation of the potential of periodic operations in trickle-bed reactors, based on empirical modeling. Step response experiments, with different input amplitudes, were performed on a laboratory trickle-bed reactor, in order to derive a simple nonlinear dynamic model. a-methylstyrene (AMS) hydrogenation was used as a test reaction and the feed AMS concentration was used as the modulated input. An empirical nonlinear model was postulated and used for simulation of periodic operations. The simulation of a periodic operation with sinusoidal modulation of the inlet AMS concentration with 40 % amplitude resulted up to 35% higher time-averaged conversion than the corresponding steady-state one. (C) 2010 Elsevier Ltd. All rights reserved.