A Novel Mapping Method for Assessing the Applicability of Reactive Distillation to Quaternary Reaction Systems

  • Rahma Muthia

Student thesis: Phd


Reactive distillation is a process intensification technology that promises significant improvements in the chemical industry by allowing the integration of reaction and separation to takes place simultaneously in a single apparatus. This integration, unfortunately, causes a complex interplay between mass transfer, chemical reaction and hydrodynamics within the column. As a consequence, the commercialisation of reactive distillation applications is hindered by challenges and difficulties in understanding, screening and designing the process. Many previous studies have developed different approaches for assessing the operability of reactive distillation during the conceptual design. Those methods provide a good basis for initialising the column design; however, their capability to generate reactive distillation design parameters, such as reflux ratio and the number of theoretical stages, tends to be limited to a single set of solutions. Furthermore, the assessment of the operability of reactive distillation has been reported to be lengthy and complicated mainly because of multi-nonlinear equations involved. Driven by the current limitations, this research proposes a new conceptual method that can simplify the assessment of the applicability of reactive distillation at the conceptual design by reducing computational effort. This novel approach, which is called a mapping method, is developed for quaternary reaction systems that are frequently encountered in industrial reactive distillation applications. This method visualises the applicability of reactive distillation in a plot of reflux ratio vs the number of theoretical stages that is called an applicability graph. The applicability of reactive distillation is assessed by employing hypothetical generic cases with two or three process characteristics, namely relative volatilities, chemical equilibrium constant and, in case of kinetically controlled reactions, the Damkohler number. To begin with, the method is introduced and developed for (near-) ideal reaction systems with both reactants as mid-boiling compounds, Tb,C < Tb,A < Tb,B < Tb,D. With this order of boiling points, an ease of products separation is anticipated as product C is predominantly present at the top and product D is largely present at the bottom part of reactive distillation columns. Next, the development of the mapping method is extended for (near-) ideal systems with other boiling point orders of compounds. And finally, the mapping method is developed for non-ideal reaction systems containing homogeneous and/or heterogeneous azeotropes. The development of the mapping method gives rise to the synthesis of a new framework that offers an aid for process engineers to make a go-/no-go decision about the application of reactive distillation before performing any rigorous simulations of RD processes. The proposed method is validated by either performing rigorous simulations for case studies or comparing the results of this work with those reported in previous studies using different approaches. The validation using case studies aims to demonstrate the advantages proposed by the mapping method, along with its limitation. This assessment is carried out by comparing the predicted applicability graph from pre-generated applicability graphs of generic cases and the actual applicability graph generated from rigorous simulations for case studies. The validation referring to previous studies aim to seek a possible agreement between the results generated in this work by employing generic cases and those obtained by previous studies by performing detailed computations for real reaction systems. This thesis demonstrates the potential usefulness of the mapping method to assess the applicability of reactive distillation for both near-ideal quaternary reaction systems that are not hindered by the formation of azeotropes and non-ideal quaternary reaction systems involving the existence of homogeneous and/or heterogeneous azeotrope
Date of Award1 Aug 2020
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorMegan Jobson (Supervisor) & Anton Kiss (Supervisor)


  • Reactive distillation
  • Mapping method
  • Applicability assessment
  • Process intensification
  • Conceptual design

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