Improving The Operation Mode Of Batch Azeotropic Distillation

Batch azeotropic distillation is used to separate azeotropic mixtures. Because it has both advantages of batch distillation and azeotropic distillation, batch azeotropic distillation has been becoming more and more important for the products of small scale and high extra value, such as the fine chemicals, pharmaceuticals and so on.In this paper, the operation mode of regular batch azeotropic distillation is promoted and entrainer is reflux at the bottom .One experiment for the separation of ethanol and water using hexane as entrainer in the promoted batch azeotropic distillation was discussed.The experimental data were compared with those under the same operation condition in regular batch azeotropic distillation. The effect of some key operation parameters such as the reflux ratio, the volume of entrainer consumed on the separation processes was discussed. The results show that there are, in new mode, more advantages such as easier control of the process, higher yield of the distillate ,etc. The promoted mode also overcomes some difficulties which meet in regular mode: the top reflux is hard to control in higher distillate tower.Besides, the nonlinear stiff differential equations of the equilibrium mode describing batch azeotropic distillation are well solved by the modified two-point implicit integration method. The simulated results and the above experimental data show good agreement.