Comprehensive experimental and modeling studies conducted recently with various types and sizes of Montz structured packing have revealed most performance-related secrets of this gasliquid contacting device. Compared with other established gas-liquid contacting devices, structured packings are generally known as having the lowest pressure drop per theoretical tray. Less known is the fact that only a small fraction of this low-pressure drop is used in masstransfer processes. Knowing this and using a model capable of describing realistically the relationship between geometric features and fluid mechanics, we have manipulated the geometry of the packed bed to develop configurations that allow a substantial increase in capacity without affecting efficiency adversely. The resulting configurations were tested experimentally and a joint experimental and modeling effort by the Delft University of Technology and J. Montz GmbH has led to increased capacity of well-established 45°corrugated sheet packings.

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Results are presented of the total reflux distillation experiments carried out with the newest generation of J. Montz corrugated sheet structured packings, including metal sheet packings (B1-250MN, B1-350MN, B1-500MN), expanded metal packings (BS-500MN), and wire gauze packings (A3-500M), using a 0.59 m i.d. column and chlorobenzene/ethylbenzene as a test system. It appears that by combining appropriately the dimensions and design of corrugations and the corrugation inclination angle, either efficiency or capacity, or occasionally even both, can be enhanced significantly, depending on the type of the packing. This allows leaner columns in new designs and more capacity and other benefits in retrofit situations. The Delft model, with appropriate enhancement of the turbulent vapor flow mass transfer coefficient and the flow direction change related pressure drop, proved to be capable of approaching closely measured efficiency and pressure drop both qualitatively and quantitatively. The exception in this respect is the pressure drop of B1-500MN, with a significant underprediction that is more pronounced at 1 bar than at 0.1 bar, while the trend as well as the predicted points of onset of loading are close to observed ones.

Results are presented of total reflux distillation experiments conducted with Montz-pak B1-250MN at Fractionation Research Inc. in a 1.22 m internal diameter column using a paraxylene/orthoxylene (p/o-xylene) system at 0.1 bar and a cyclohexane/n-heptane (C6/C7) system at 0.31 and 1.62 bar. The same efficiencies were obtained at vacuum and above atmospheric pressure with the C6/C7 system, and these were slightly lower compared to those measured with the close boiling, p/o-xylene system. The Delft model, which accounts for packing geometry modifications as employed in this case, proved to be capable of approaching the closely measured efficiency as well as the measured pressure drop both qualitatively and quantitatively.