How to Decide When and How Much to Use Reactive Distillation

Process design deals with synthesis and optimization tasks, where process synthesis means to conceive a set of processing units and the interconnections between these units which will fulfill the performance target of the process, and optimization means the evaluation of the best set of parameter values of the system. The intensive use of modular simulators, e.g. ASPEN PLUS or numerical solver tools as gPROMS has hugely increased our ability of optimizing process structures; thus finding the set of alternatives solutions structures has become the key factor in the process design task. Frey et al. [1] showed how knowledge of reactive distillations lines and potential reactive azeotropes can be used for the systematic design of reactive distillation processes. Hauan et al. [2] demonstrates how phenomena vectors may be used in the early stage of the design of reactive distillation columns for graphical determination of stationary points (reactive azeotropy) as possible boundaries of the feasible regions. They further showed how to use the length of phenomena vectors for preliminary design of complex hybrid process. However in this paper we use simple thermodynamics features given VLE data and preliminary kinetics considerations to show on practical ground the power of thermodynamics insights for the determination of the structure(s) in the early stage of process synthesis. Our interest in this paper is a quick and systematic geometric procedure for establishing whether reactive distillation is advantageous or not with regard to a particular system. The aim of the presented approach is to reduce the complexity of the combined process in order to enable simple structure solutions to be recognized quickly. We consider a case study to illustrate the approach.