Multi-effect distillation applied to an industrial case study

An industrial separation system consisting of four pressure-staged distillation columns has been studied to see if multi-effect integration can be applied to any two columns in the sequence. Shortcut equations and Vmin-diagrams have been used for screening purposes to find the columns with the highest potential for energy savings. The most promising case has then been further studied using rigorous simulation tools to verify the results from the shortcut approach. Three cases have been simulated: a non-integrated base case (existing), a multi-effect indirect split arrangement (ISF) and a multi-effect prefractionator arrangement (PF). The results showed that when considering the existing number of stages available the ISF arrangement was the best, however when considering infinite number of stages the PF arrangement was the best (as expected).