Development of Separation Processes and Applications using Hollow Fiber Membranes: Challenges and Opportunities

Membrane systems can offer an effective alternative to more conventional unit operations.  The fact that membranes work differently than older technologies can give them advantages in certain applications.  Understanding how and when to use membranes will lead to more productivity, and fewer failures.  To that end we will briefly look at three diverse membrane applications and understand the challenges and opportunities of each. 

The first application is that of waste water treatment with an anaerobic membrane bioreactor (AnMBR).   Membrane systems can handle higher strength waste water with a smaller footprint and a higher purity filtrate than conventional settling ponds.  In addition, anaerobic MBRs produce a useful byproduct.   The challenge is that sizing and pretreatment of the system must be done carefully to ensure a good outcome.  In addition, some waste streams are more suited for an AnMBR than others.  

The second application is that of beer filtration.  Membranes provide benefits vs diatomaceous earth filtration in terms of cutoff, contamination, and scalability.  Here the challenge is to understand the cleaning cycle and the transmembrane pressure during that cycle and operate these systems in a way to ensure longer periods of time between cleanings, leading to longer membrane life and higher productivity. 

The third application is quite different from the first two.  This involves a gas separation membrane used for drying compressed air or other gases.  In this case the opportunity presented by membranes over pressure swing adsorption or refrigerated dryers is that of smaller footprint, simpler operation, and scalability for point of use.  Membranes are not invulnerable, however, so care must be taken to avoid fouling or rupture.  In this use, differences in operation and pretreatment can mean the difference between years of productive output and a short, marginally productive life.