Residue curves are graphical tools used to understand the behavior of a mixture in a separation process and are often calculated assuming equilibrium between liquid and vapor phases. However, equilibrium assumption can lead to misleading conclusions about mixture behavior. Here the sensibility of residue curves is analyzed when efficiency values are applied to correct the equilibrium model. Efficiency values were calculated using the Barros and Wolf correlations. Results showed that residue curves are sensitive to the applied model, but singular points did not change. Residue curves did not cross distillation boundaries, since residue curves and distillation boundaries were calculated using the same model. Thus, the observed results confirm that residue curves are forbidden to cross distillation boundaries Ver menos