Strategy Study Of Saving Energy In Extractive Distillation Flowsheet Integration

Extractive distillation is a well-known technology for separating azeotropes and mixtures of components having close boiling point. And it is applied widely in petrochemistry areas. With the development of methods for searching extraction solvent, the improvement of tray configuration and process arrangement, extractive distillation has been applied more and more widely. When the solvent and the tray configuration can not be changed easily, the transformation of extractive distillation flowsheet is an effective way to reduce energy consumption. Heat-integration technology is a method for reducing the energy consumption by matching the quality of heat. But with the restriction of process background and the operating conditions, not all the distillation process can achieve the least energy consumption with only heat-integration in practical separation process. In extractive distillation process, complex column and heat-integration technology can make the whole process become an integrated system, and the flowsheet will become intensive and the energy consumption will be reduced greatly. The strategy of saving energy in extractive distillation process was studied on the view of flowsheet integration.Firstly, the features of extractive distillation process were analyzed explicitly, and a method to solve the mathematic model was put forward by combining Relaxation with N-R Method. This method used the virtues both the steady of Relaxation Method and fast convergence of N-R Method. The dealkynes column system of separating C₅ fraction with extractive distillation was simulated in this paper, and the results showed that this method was suitable for the system with strong nonideal property.