Analysis And Study Of Distillation Sequences Containing Dividing Wall Column

Distillation is one of the most widely applicated and significant separation methods in chemical industry.Due to its considerable energy consumption,researches have been concentrated on energy efficient distillations.Both energy consumption and equipment cost can be reduced by Dividing wall column(DWC),which attracts much attention both in industry and academia.To separate multi-component mixtures,distillation is conducted sequentially in chemical industry.The energy consumption in the chemical process can also be effectively reduced by choosing a better sequence.When including DWC,the number of columns in each distillation sequence can be reduced.However,at the meantime,the number of separation subproblem and feasible sequences will increase rapidly.In this thesis,comparing with existing conclusions regarding simple columns,inferential deduction method has been used to explore the number of separation subproblems,subgroups and distillation sequences for multi-component sharp splits.General term formulas are obtained and discussed under different assumptions.The complexity of structure makes it difficult to establish the exact DWC model.In this work,a short-cut method is adopted first,and then rigorous DWC model is established in Aspen software for the initial design.With these simulation results,DWC is then simulated and optimized by gPROMS software based on equation-oriented method.With dynamic programming method,the optimal distillation sequence with DWC in different system or with various mixture contents can be efficiently identified respectively.Intermolecular forces are calculated,their impact on the optimal sequence has been discussed based on existing results,which could be a reference for choosing the position of DWC in the feasible distillation sequence.It is instructive in reducing the computation load in the optimization of distillation sequence in other separation system by eliminating several chioces from the searching space.