Simulation of Distillation Process in the Bioethanol Production Using Nonequilibrium Stage Model

Most models available for simulation of multicomponent separation processes are based on the idealized concept of equilibrium or theoretical stages. However, accuracy of the predictions can be highly enhanced if a nonequilibrium stage model is taken into account. In this work, hydrous bioethanol production process was simulated using Aspen Plus(R) considering three calculation methods: equilibrium, equilibrium with constant plate efficiency and nonequilibrium stage models. Comparison of nonequilibrium and equilibrium model simulations, assuming the same number of stages, showed that energy consumption calculated is much larger when nonequilibrium model is considered and that column specifications have to be adapted in order to achieve bioethanol specification. Equilibrium model with efficiency of 70% presented a satisfactory agreement with nonequilibrium model.