Synthesis And Design Of Double Dividing Wall Reactive Distillation Column

Reactive distillation is an effective theory to simplify the process flow.Reactive distillation column has drawn lessons from the idea of process intensification in structure,and its development also caters to the current situation of increasingly severe energy shortage.However,for some reacting mixtures,reactive distillation column can not show its superiority.When the ranking of relative volatilities of the system is the most unfavourable,the two conventional reactive distillation sequences(CRDS)have their own structural defects.In this paper,the structures of the two CRDS have been improved.For the conventional triple-column reactive distillation sequence(CRDS-TC),the serious backmixing was solved by the traditional heat exchanger coupling method.Aiming at the double-column side product reactive distillation sequence(CRDS-DCSP),a coupling method was proposed to introduce the mass transfer between the interlinking flows in order to improve the concentration of the lightest reactant on the side product tray.The two coupling methods are different about the operation,but same about the result,which developed the double dividing-wall reactive distillation column(DD-RDC).Taking the separation of ideal quaternary reversible reacting mixtures as an example,the steady-state performance of the proposed DD-RDC was studied.The results show that the steady-state performance of the DD-RDC is better than that of the two CRDS.In this paper,the liquid composition profile,the temperature profile and the reaction rate profile of all structures were analyzed and the conclusions were drawn as follows.The two CRDS have different defects which share the same essence.The two coupling methods have different operations which also share the same essence.They have increased the degree of adjustment of some parts.In this paper,the steady-state performance of the DD-RDC was further analyzed with reference to the chemical equilibrium constant and product purity.The robustness of the steady-state performance of the DD-RDC has been proved by this.As a part of the simple design,the proposed new structure can provide a new idea for the separation of the quaternary reacting mixtures with the most unfavorable ranking of relative volatilities.And the new coupling method and the new analysis method for the degree of freedom can also provide a good reference for the design of the reactive distillation system.