A new graphical feasibility method is developed to investigate batch reactive distillation processes in middle vessel column. The suggested methodology can deal with fully reactive, nonreactive, and complex column configuration. A new formulation is suggested to describe the composition profiles in the reactive sections. Its application has made possible to develop a generic feasibility methodology containing the same model equations independently of the presence or absence of reaction. By combining the reactive and nonreactive models, not only the fully reactive and fully nonreactive but also hybrid configurations can be studied. Feasibility criteria related to the hybrid configurations are also presented. Application of the new methodology is demonstrated on the production of ethyl acetate in batch reactive distillation. Five configurations are found feasible; pure EtOAc is produced as distillate, and pure H 2 O is produced at the bottom. In each case, continuous feeding of AcOH is necessary. V V C 2009 American Institute of Chemical Engineers AIChE J, 55: 1185AIChE J, 55: -1199AIChE J, 55: , 2009 Keywords: separation, reactive distillation, design, feasibility study, hybrid column
IntroductionApplying reactive distillation is one of the most important options for process intensification. 1,2 In traditional processes, the reaction itself and the separation of the reaction products are carried out in subsequent operations, and in separate devices. Total conversion cannot be reached if the reaction is equilibrium limited, and the nonreacted components must be recycled to the reactor. This recycling increases the investment and the energy demand, as well. In addition, transportation of the compounds between the equipment units makes the production more hazardous.In reactive distillation, on the other hand, the reaction and the separation are carried out in one operation, in the same unit ( Figure 1). The investment costs are decreased because of the decreasing number of operation units. The operation costs, the hazards related to the process, and the amount of by-products are also decreased because no external recycling is applied.In spite of the numerous advantages, the number of industrial applications is yet small. One of the reasons of this reluctance may be the lack of well-known design and control Correspondence concerning this article should be addressed to C. Stéger at stegercsaba@googlemail.com. methodology. Hence, the thorough investigation and deep understanding of this integrated process is a really important task.Preliminary design methodologies are normally applied to find a feasible configuration accompanied by a suggested value or range of the most important operation parameters. These methods usually rely on some simplified model with thermodynamic approach, 3 namely they neglect such technical parameters such as the hold-up, the pressure drop, the height and the diameter of the column, and so forth. Most of the preliminary methods work in graphical mode; this eases their understanding but, at t...