New thermally coupled schemes for ternary distillation

The fully thermally coupled system of distillation columns for ternary separation has two, two-way connections between the columns. New: simplified (and easier to control) systems of columns for ternary separations, with a reduced number of connecting streams, are proposed The new systems contain one one-way and one two-way connection between the columns. Depending on which connection is located on top and which phase stream (liquid or vapor) is used hz the one-way connection, there are four possible configurations for these new systems. For certain feed compositions and relative volatilities of components, these new systems can replace the fully thermally coupled system of columns without ally increase in energy demand. The optimum system selected front the four proposed configurations consumes no more, and frequently much less, energy than the sine stripper or side rectifier configuration or than a system with a prefractionator.