The distillation of a ternary BTX mixture was studied to evaluate three potential energy saving methods : optimal configuration structuring, heat integration and heat pumping. Ten heuristics, in two categories, were induced and arranged in order of priority.
Separation-technique heuristics : （1） Favor heat flux exchange between units by direct stream contact (thermal coupling). (2) Favor separations with initial splits between extremes in volatility (prefractionation). (3) Favor heat integration if flexibility and operability are satisfactory. (4) Favor operation under lower pressures if the cost involved is reasonable. (5) Favor heat pumping with a product stream as the working medium.
Separation-system heuristics : (1) Favor the PET configuration. (2) Favor the PF configuration if various feeds are anticipated. (3) Favor the SS configuration for very low concentrations of the most or least volatile components. (4) Favor the R heat integration form. (5) Favor the OHP heat pumping form.