Efficient separation of acetaldehyde from glyoxal (CAS number: 107-22-2) reaction mixture using a gas stripping (GS) technique is investigated experimentally. A non-equilibrium model for describing the GS process is proposed and solved with a Newton-homotopy method. The steady-state performances of the GS column are investigated by a non-equilibrium model. The effects of liquid-gas ratio, feeding temperature and theoretical plate number on the residue acetaldehyde concentration are examined in detail. The simulating results are closed to the experimental data. According to the simulation results, liquid-gas ratio 1.6, feeding temperature 313 K and theoretical Plate 12 are the optimum operation condition for getting an acetaldehyde concentration of below 0.5 wt%. (C) 2011 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.