Study On Heterogeneous Azeotropic Distillation For The System Acetic Acid-Water

The azeotropic distillation of the system acetic acid-water-azeotropic agent(isopropyl acetate and butyl acetate)is simulated.Due to the non-ideal behavior, NRTL-HOC and UNIQUAC-HOC model is used to depict vapor-liquid phase equilibrium behavior of this system.Concerning the liquid in the decanter,the stability is checked by tangent plane stability analysis,and the initialization of phase splitting calculation is produced. A good estimate of the phase fration is gotten by successive substitution with Newton's method,and every component of two phase is gotten by mass equilibrium equation.Finally,the solution of this equation is produced with successive substitution calcultion.The Naphtali-Sandholm method is used to simulation of azeotropic distillation.By virtue of this combined calculation method,the simulation is begun with operational data as basical data.The results of simulation accord with the operating data,which proved that the combined calculation method is credible.The optimum results are gotten by simulation of changing the value of some variable such as feed position, theoretical tray.The optimum value can be used to guide industrial design.Both isopropyl acetate and butyl acetate as azeotropic agent are contrast to each other according to operational data.Besides, liquid-liquid equilibrium still is designed by onself,and its credibility is checked by the experimental data of the system acetic acid water-isopropyl acetate at 24. 6 C is contrast to the literature data.The LLE data of the system measured at 40 C,which is correlated in virtue of NRTL or UNIQUAC equation. The correlated parameters are used to the simulation of azeotropic distillation process.In addition,the VLE data of the system acetic acid-water-n-butyl acetate at 1 atm from literature are correlated by virtue of NRTL-HOC and UNIQUAC-HOC model,and the parameters are also used to azeotropic distillation simulation.By tint of a kind of computer language MATLAB,the binary parameters is correlated,stability of original liquid is checked, liquid-phase splitting calculation and simulation of heterogeneous azeotropic distillation are performed.