Flexible retrofit design of multiproduct batch plants

R. Fletcher, J. A.J. Hall, W. R. Johns*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


We treat the addition of new equipment to an existing multiproduct batch plant for which new production targets and selling profits have been specified. This optimal retrofit design problem has been considered by Vaselenak et al. (Ind. Engng Chem. Res. 26, 718-728, 1987). Their constraint that new units must be used in the same manner for all products places a restriction on the design which could readily be overcome in practice. We present a mixed-integer nonlinear programming (MINLP) formulation which eliminates this constraint. A series of examples is presented which demonstrate greater profitability for plants designed with our formulation. The examples also bring to fight a further unwanted constraint in the Vaselenak, Grossmann and Westerberg formulation. In their formulation they limit batch size to the smallest unit at a stage, even when that unit is not needed. It is noted that, at the expense of some additional mathematical complexity, our formulation could be enhanced to allow reconnexion of existing units and alternate use of multiple additional units.

Original languageEnglish
Pages (from-to)843-852
Number of pages10
JournalComputers and Chemical Engineering
Issue number12
Publication statusPublished - Dec 1991


Dive into the research topics of 'Flexible retrofit design of multiproduct batch plants'. Together they form a unique fingerprint.

Cite this