Abstract

BENABITHE, Zulamita Zapata; VANEGAS, Diana; MONTOYA, Juan Camilo Rendón  and  VELASQUEZ, Jorge A.. Case study of ethanol-water distillation in continuous and discontinuous operation and its simulation with cubic equations of state and activity models. TecnoL. [online]. 2020, vol.23, n.49, pp.201-227. ISSN 0123-7799.  https://doi.org/10.22430/22565337.1638.

A simulation of a column distillation represents an interesting problem because of the complex dynamics of the system, thermodynamic interactions in each tray and interaction between internal and external currents. This work evaluates the operation and simulation of a continuous distillation tower (CDT) and discontinuous distillation tower (DDT). The simulation was performed using the McCabe-Thiele and rigorous methods and using the modified cubic state equation Forero-Velazquez-Huron-Vidal (FVHV) and the No-Random-Two-Liquid (NRTL) activity model. The simulation predicts the composition of distillate and of the bottoms, the number of trays and the feeding stage. The continuous distillation tower has 9 real equilibrium trays, for FVHV was 8 trays were calculated and for NRTL was 9 trays, with both models it was found that the optimal feeding trays was 7. In the case of DDT two trials were carried out, with pall type packaging and without packaging, although the equation FVHV has many advantages since all pure substances’ parameters are generalized in terms of the thermodynamic properties up to the critical point. The equation correlates fittingly substances polar and non-polar, the equation NRTL presented a better fit in the composition, but for the volume of the distillate any model represented the experimental trend. A complement with Ms Excel® called Homosolver was used for the solution of the system of equations, for the solution of the equations in instantaneous distillation the Euler's method was used as an iterative method.

Keywords : Cubic equation of state; Vapour-Liquid Equilibrium; Simulation; Distillation tower; ethanol-water.

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