Scale-up of Distillation Columns. In spite of remarkable advances in the development of computer programs for calculations on distillation columns, it is frequently still impossible to design them without experimental testing. Economic constraints demand use of miniaturised test plant, thus enhancing the importance of laboratory measurements. A system is presented for scale-up of separation which required information from laboratory experiments, includes data from reference columns. and takes account of models of fluid dynamics and mass transfer. The special feature of this approach lies in the free choise of internals; both in the laboratory and in the designed column.