The application of various types of structured packings to separate styrene monomer/ethyl benzene in packed columns is presented. The investigation was conducted over a wide range of operating conditions such as packing type, pressure, and reflux ratio. Several structured packings were used for separation of styrene monomer/ethyl benzene and the optimum conditions were determined for each of them. The proper condition of separation process and appropriate parameters for achieving better efficiency was discussed. The calculated results were compared with those obtained in industrial scale. It was shown that Mellapak-Plus 252Y and 452Y packings can provide the maximum capacity with an acceptable level of efficiency over a wide range of operating conditions.