(49c) Hot-Gas Pressure Swing Adsorption for Isopropanol Dehydration

Many processes can be used to dehydrate the azeotropic mixture of water and isopropanol.  Membrane pervaporation, vapor permeation, and azeotrope and extractive distillations can all be used for this purpose.   But both membrane separation and distillation are limited by their ability and/or cost to produce isopropanol with less than 1.5 wt-% water.  Hot-gas pressure swing adsorption (HGPSA) is ultimately capable of delivering water concentrations less than 10 ppm if required and is generally less energy and less capital intensive compared to extractive distillation and membrane technology. 

 A HGPSA process was designed and implemented in a Dow process to dry isopropanol. Experimental studies were first performed to evaluate the feasibility and validate a HGPSA mathematical model. The dynamic model was then used to design the HGPSAS process. Aspen ADSORPTION® was used to improve the design of the process. In this presentation, both experimental and mathematical modeling results will be discussed. The implemented HGPSA process, which is able to remove water from isopropanol to non-detectable levels, will also be presented.