Optimal energy cost in ideal internal thermally coupled distillation columns

Internal thermally coupled distillation column (ITCDIC) is the frontier of energy saving distillation research. In the paper, an evaluation method on operating cost and its saving in the ITCDIC processes of ideal mixtures is presented. A mathematical model for optimization is first derived. The benzene-toluene system is studied as an illustrative example. The optimization results show that the energy cost saving potential is close to 40% and annual energy cost saving is about 0.3 million dollars compared with the operating cost of a conventional distillation column operated at the minimum reflux ratio. The process analysis is also carried out. The optimal operating conditions and some useful results are obtained. These pave the way for the smooth operation and the further optimal design of ideal ITCDIC processes.