The optimal operation of CBD and IBD columns are evaluated
in terms of minimum batch time required for a given separation
task (defined in terms of the amount of lactic acid and its purity).
For CBD column, multiple intervals over the batch time is considered
and within these intervals piecewise constant reflux ratio are
assumed which are optimized together with the interval For IBD
column, single interval with piecewise constant reboil ratio over is
considered and both the reboil ratio and the interval length (batch
time) are optimized