Study On Reflux Modes Of Entrainer In Heterogeneous Batch Azeotropic Distillation

Compared with homogeneous batch azeotropic distillation,heterogeneous batchazeotropic distillation can separate multi- component mixture with a single distillationcolumn.It is universally used. Heterogeneous batch azeotropic distillation candecrease the dosage of entrainer because the liquid rich of entrainer refluxs at thetop.These advantages make heterogeneous batch azeotropic distillation widely used inindustry.This paper studies on the reflux modes of entrainer in heterogeneous batchazeotropic distillation operation.The internal diameter of column filled withθ-ring is30mm and the height of column is 0.8m.Isopropanol-water is selected to do theexperiment with cyclohexane as entrainer.The research includes internal reflux ofentrainer at the top and in the bottom with different ratios(IRETB) and external refluxof entrainer both at the top and in the bottom with different ratios(ERETB).This paper compared the reflux modes of entrainer. The yield and timeconsumption of the above reflux modes were compared.The result showed that, withthe same specified product purity, if the yield of product of ERETB is the same as theyield of product of IRETB,the time consumption of ERETB is less than of IRETB; ifthe time consumption of ERETB is the same as the time consumption of IRETB,theyield of product of ERETB is higher than of IRETB.Otherwise, the nonlinear stiff differential equations of the equilibrium modedescribing batch azeotropic distillation are well solved by two-point implicitintegration method and Newton Raphson method.As an example ofisopropanol-water-cyclohexane system,the simulation calculation result inosculateswith the experimental result. The simulation calculation can reflect actual course.