Pervaporation process has a great potential for separation of liquid mixtures especially for azeotropic ones, due to its independence of vapor-liquid thermodynamic equilibrium. In this research, trans-membrane flux model and also modeling of the flow in the pervaporation modules have been investigated. It considers the trans-membrane flux as a function of feed temperature and concentration. Initially, by considering four sets of different published experimental data and also making comparison between the proposed model and three of the most recent models, the virtues of applying the developed flux model has been detected and also it was validated. According to the simulation results of the trans-membrane flux, the developed model reduced relative error value by 99.9% compared to model (1) in which only the temperature dependency of the flux is assumed. A reduction in relative errors of 35.4% for model (2) by considering both the temperature and the transferred component concentration dependency of the flux. This issue for model (3) which has used the same model as model (2) but with a different structure, was 62%. The validated developed flux model was applied for designing of pervaporation process based on a proposed algorithm. The flow model has been developed based on conservative law of mass and energy, with ignoring of the pressure drop. This model was used for simulation of pervaporation process on separation of an azeotropic mixture of isopropanol-water. It was solved under isotherm and adiabatic conditions by numerical method. Under specific feed conditions, the effect of temperature on the process performance under isotherm condition have been studied and it was shown that the required membrane areas could be reduced 34% by 10?C increasing in the feed temperature. Other hand, the temperature reduction was calculated 55?C less than the inlet feed temperature under adiabatic condition. Thus, neglecting of this temperature drop and assuming isotherm condition, results in 98% errors in evaluating of the required membrane areas in the process design. To attain the purpose of reducing the necessary membrane area, an alternative of multi-stage process with interstage heating was considered to compensate the temperature drop. Two different methods for designing of multistage pervaporation systems have been investigated and compared. By defining a specific conditions for both inlet and outlet streams, a multistage pervaporation system has been designed in two different methods. The first is a 10 stages system with equal membrane areas of 30 m 2 per each stage. The second one is an 8 stages system with equal temperature drop of 5?C per stage. The required membrane areas for these structures were reduced respectively 97.64% and 97.66% compared to the single stage. The solution of the model equations and the simulation of the process were performed through MATLAB environment. Key Words Pervaporation, Water/Isopropanol separation, Interstage heating, Flow model, Trans-membrane flux model, Simulation.
