Recovery of butyl acetate in wastewater of penicillin plant by solvent sublation II. Theoretical modeling

In recent years, pilot-scale solvent sublation has been explored in the treatment of industrial wastewater containing dilute organics. In the present work, a mathematical model is proposed to describe the experimental results of semibatch sublation for recovering butyl acetate (BA) in the wastewater from solvent extraction of penicillin. Different from other models in recent literatures, our model took account of the variation of the volume of solvent, v(o) in the sublation. The model parameters of the sublation of BA in the wastewater are calculated. Calculation results show the volume of solvent could increase by more than 30% in 180min under optimal conditions. Calculation results with different operation parameters show that increasing the gas flow rate, Q(a) could improve the sublation efficiency, E-ss, which would be more than 70% under optimal conditions. Decreasing the bubble size, a, would increase the rate of the sublation. The initial solvent volume, v(oi), may affect the sublation weakly when initial ratio of water to solvent used is in the range from 50 to 70. Calculation results also show that the loss of butyl acetate to the atmosphere, E-ls, is minimal, though with high gas flow rate. The simulated results are in good agreement with experimental results.