Experimental and Theoretical Studies on the Start-Up Operation of a Multivessel Batch Distillation Column

Abstract

Multivessel batch distillation is a promising alternative to conventional batch distillation. Earlier studies proved the feasibility of temperature control in a closed operation mode, that is, when no product is removed until the end of the process. In this article, the influence of the reflux strategy during the initial start-up period is investigated in detail. This is a very important task in terms of the development of automation procedures in an industrial realization. The work is divided into three main parts. First, a rigorous dynamic model is introduced to describe the behavior of a multivessel batch distillation during start-up. Then, two experiments carried out on a laboratory scale column were chosen to validate the model. Finally, a sensitivity study is presented observing composition response while changing the reflux strategy. The results show that the process can be improved by applying a high reflux ratio and establishing the hydraulics as soon as possible.

Closed Operation of Multivessel Batch Reactive Distillation Processes

“…The column configuration (only conventional batch distillation column) or the implementation of reaction in the column is restricted for these developed simulators which limits the investigation of multivessel batch reactive distillation. Some researchers have built models in a programming language, such as MATLAB, , FORTRAN, Aspen Custom Moldeler, , or gPROMS. , However, building a process model in a programming language can be very time-consuming, especially when a rigorous model is desired. Therefore, different levels of simplifying assumptions are usually made for the model.…”

“…Later on, the feasibility of a temperature control was also investigated experimentally . A wide variety of optimal operation problems (reflux ratio, initial feed distribution, product withdrawal rate, and reboiler duty) of multivessel batch distillation were investigated by Furlonge et al A rigorous model validated by experiments was used to study the behavior of the column during startup for closed operation by Grützmann and co-workers. , They provided process insights and general guidelines to improve industrial application. On the basis of the understanding of the startup period, the optimization of an open-loop control structure was also investigated .…”

Design and Operation of Batch Distillation

“…The set point for each controller is set to the arithmetic mean value of the boiling temperatures of the two key components to be separated in that column section. Gruetzmann et al [32] considered the same control strategy but also took into account startup of the column.…”

Time requirements in closed and open batch distillation arrangements for separation of a binary mixture

“…In most cases, the term is used for processes with at least four product vessels including the reboiler and the distillate receiver. Moreover, the main reason for using the arrangement is that it usually requires less energy or shorter batch time for a given heat input than a regular batch distillation column [23][24][25][26][27][28][29][30][31] . To the best of our knowledge, there is still no result for separating a binary zeotropic mixture by the multivessel column.…”