OPTIMIZING CONTROL OF PETLYUK DISTILLATION - UNDERSTANDING THE STEADY-STATE BEHAVIOR

The ''Petlyuk'' or ''dividing-wall'' or ''fully thermally coupled'' di stillation column is an interesting alternative to the conventional ca scaded binary columns for separation of multi-component mixtures. The industrial use has been very limited, and difficulties in control has been reported as one reason. Since we have more manipulated variables than controlled variables, the column is a candidate for on-line optim ization. We show that the steady-state optimal solution surface is qui te narrow, and depend strongly on disturbances and design parameters. Thus it seems difficult to achieve the potential energy savings compar ed to traditional approaches without a good control strategy.