Development of a software for simulating separation processes using a nonequilibrium stage model

This paper is concerned with the computational aspects of countercurrent multicomponent separation processes using a nonequilibrium stage model. The developed program solves the component material and energy balance relations for each phase together with mass and energy transfer rate equations and equilibrium equations for the interface. The program is formulated in such a way as to make the describing equations and the method of solving them independent of the methods used to predict the vapor and liquid multicomponent mass transfer coefficients and heat transfer coefficients as well as physical properties like density, viscosity, binary diffusion coefficients, component specific heats and thermal conductivity, and the thermodynamic properties of the system. The composition and temperature profiles predicted by the program during the multicomponent distillation in bubble-cap-tray columns can be compared with the profiles given by the simulation using a conventional equilibrium stage model. The comparison permits the deduction of a methodology to predict more realistic stage efficiencies which can allow the utilization of the equilibrium stage model. A first attempt is being made using a new procedure based on the O'Connell correlation.