In celebration of the memory of Dr. Shivaji Sircar
- PDF / 456,643 Bytes
- 3 Pages / 595.276 x 790.866 pts Page_size
- 46 Downloads / 149 Views
EDITORIAL
In celebration of the memory of Dr. Shivaji Sircar Alan L. Myers1
© Springer Science+Business Media, LLC, part of Springer Nature 2020
I am fortunate to have known Shivaji Sircar for 55 years. He was a splendid man, and his life is worthy of special recognition and celebration (Fig. 1). I first met Shivaji Sircar in 1965 when he came to the University of Pennsylvania from Jadavpur University in West Bengal. Shivaji completed his Ph.D. in 1970 and stayed on an additional two years as a post-doc, before joining Air Products & Chemicals Company in Allentown, Pennsylvania. Although his primary allegiance was always with Air Products, during the last three decades of the 20th century he and I published joint papers on the thermodynamics of adsorption—and in the process we became close friends and colleagues. Shivaji’s Ph.D. thesis was about adsorption from liquid mixtures—a noteworthy focus because most adsorption processes are concerned with adsorption from gaseous mixtures. In adsorption from liquid mixtures, physical experimentation is key. What you can measure experimentally is the change in the composition of the liquid mixture before and after contact with an adsorbent. That change in composition is proportional to the “surface excess” of components in the adsorbed phase. The same considerations about surface excess apply to the adsorption of gases on solid adsorbents—but in this case
the excess adsorption of a single gas is measured experimentally, either volumetrically or gravimetrically. The manipulated variable for the adsorbed phase is known as the spreading pressure (for a flat surface) or the grand potential (for a microporous adsorbent). With these two concepts in hand, Gibbs surface excess and grand potential, the adsorbed and gas phases can be treated just like liquid and gas phases for phase equilibrium calculations. Shivaji adopted this thermodynamic approach and incorporated it into novel new designs of adsorptive separations. One of Shivaji’s major research interests was the production of oxygen from air. One method to accomplish this is by cryogenic distillation, a process that is very efficient in terms of operating costs but quite capital intensive. Shivaji focused, instead, on a manufacturing method with a dramatically lower capital cost: pressure swing adsorption (PSA). Shivaji worked on designing portable PSA oxygenators. Before PSA design, supplemental medical oxygen came from heavy and bulky pressurized steel cylinders. Today, you can buy a 5-pound portable Inogen oxygenator that delivers continuous 90% oxygen for $2300. Shivaji’s design work was fortuitous, as he depended on supplementary oyygen for the last 20 years of his life.
* Alan L. Myers [email protected] 1
Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
13
Vol.:(0123456789)
Adsorption
Fig. 1 Dr. Sircar receiving the AIChE Professional Progress Award in 1988. The picture has been reproduced with the permission of Dr. Sircar’s family
One of our most successfu
Data Loading...
