(52a) Design of Robust, Energy Efficient, Packed (Dividing-Wall) Column Line-Ups

It has long been known that Dividing Wall Columns (DWCs) can provide chemical process plants with more energy efficient separation trains while simultaneously reducing the capital cost. Until now, however, there existed no easy-to-use complete design process that made it straightforward to find the best, balanced, and robust DWC configurations. In this paper we outline a step-by-step methodology that leads to robust distillation column designs for regular as well as dividing wall applications with packing. Our approach considers many factors normally not part in conceptual design but that *do* influence actual hardware design and operation:

1. Thermal (in)stability
2. Variations in the feed composition (and state)
3. Pressure drop
4. Maldistribution
5. Marangoni effects
6. Liquid de-wetting
7. Foaming
8. Proper calculation of the total annualized cost (TAC) of DWCs*

(* TAC calculation models in the literature invariably omit many factors that impact the true cost. These include unequal effective column section heights either side of a wall, empty space, flow (re) distributors, column swaging, and sloped walls.)

For DWCs we will show that wall position and bed configurations can easily be optimized by simple, fast and efficient parametric variations of the stage efficiency and liquid splits. We illustrate our comprehensive approach by considering several industrial processes. In this paper we briefly outline our parallel column model that undergirds the proposed methodology. Then we discuss important extensions that make possible this comprehensive design process.