(109g) Recent Advances in Pressure Swing Adsorption Technology

Pressure swing adsorption (PSA) has been around for over half a century. Although it was commercialized for air drying in the late 1950’s, the original Skarstrom patents mention many additional applications including air separation for the production of oxygen, air separation for the production of nitrogen, and even bulk vapor separation. These applications have all been commercialized.

PSA easily separates oxygen from air, nitrogen from air, and water vapor from ethanol vapor. One of the best success stories for PSA is its use in hydrogen purification from steam methane reforming. However, lesser known applications have also been commercialized, including  gasoline vapor recovery, solvent vapor recovery, methane purification from natural gas wells, methane upgrading from landfill gas, and even carbon dioxide and water vapor removal from cabin air. The list seems to go on and on, with new separations or purifications being studied or even commercialized, like ethylene recovery from polyethylene production, as a more recent example.

Some of these PSA processes are based on equilibrium separation. Others are based on kinetic separation. Many of them utilize some type of aluminosilicate zeolite, while others utilize an activated carbon, and yet others utilize a carbon molecular sieve. Some of these PSA processes effect separation with a simple 2-bed 4-step cycle sequence, much like the original Skarstrom cycle. Others are utilizing a much more complex 16-bed 13-step cycle sequence. And, just about all combinations of bed numbers between 2 and 16 and cycle step numbers between 4 and 13 are being utilized in commercial and developmental PSA processes.

This presentation will provide an overview of some of the more recent advances in PSA technology. This overview will be based on recent journal literature, recent patent literature, and even unpublished results. This overview will also have a bias towards recent projects Professor Ritter and his team have worked on recently, and on-going projects currently being carried out by Professor Ritter and his group. A desirable outcome of this presentation will be a rudimentary understanding of why complexity in a PSA process is needed for some separations but not for others.