A general thermodynamic model is developed by combining organically the nonequilibrium thermodynamic analysis with the traditional METSH simulation of distillation processes. The model is capable of both simulating industrial distillation processes and analyzing energy consumptions of the processes. The benzene-toluene binary distillation is selected as the model system to test the theory, and the industrial-scale tray column is studied in this work. The simulation results show that the tray structure and operation parameters have significantly influenced the entropy generation rate (EGR). It is also found that the development of vapor and liquid flow patterns on the industrial-scale trays can enhance tray efficiency and result in evident reduction of the EGR. The model is suitable for tray, design, column performance analysis, and energy consumption evaluation of distillation processes. (c) 2006 American Institute of Chemical Engineers.