Study On The Nonideal Multicomponent System Distillation

This dissertation is focused on the theory and experiment of mass transfer in nonideal multicomponent distillation. The mass transfer and separation process is an important part of the chemical industry. Most of the systems that the industry dealt with is nonideal system and distillation is the most important and normally separation unit. So, the research on the nonideal multicomponent system distillation is significant in the theory and application.In this article the theory of multicomponent system mass transfer process is researched. There has great difference between the multicomponent system and two components system, the former is more complex. For the mass transfer efficiency, the point efficiency of each component is unequal in the multicomponent system. Some of the efficiency may be less than zero or more than one, even infinite. The reason why the curious phenomena happened is the interaction of the component in the multicomponent mass transfer process. The basic equations which describe the multicomponent system mass transfer process are Maxwell-Stefan equations and the general Fick law. The theory of multicomponent mass transfer process derived from these equations could explain the curious phenomena.The second part of the dissertation is the simulation of the mass transfer process of nonideal multicomponent system. For the importance of distillation process simulation, the research work on distillation process simulation has been taken on for a long time. Normally, the simulation is carried out using an equilibrium stage model, which is based on the assumption that thermodynamic equilibrium exists on each tray in the column. To deal with the departures from thermodynamic equilibrium, the common practice is to specify a efficiency, which is the same for all components on all stages. But, in fact, the efficiencies are not equal in multicomponent systems.In this dissertation, a nonequilibrium model for the distillation columns is described. The nonequilibrium model incorporates the equation of mass balance, energy balance, mass transfer, heat transfer rate and interface phase equilibrium, and then establish a general mathematical model. Later, the model is applied to the distillation process. The mathematical model of multicomponent distillation process is solved by the rigorous arithmetic.