The Effects of Using Multiple Tubes On Effective Diffusivity and Separation Quality In An Oscillating Flow Separation Scheme

Pulsating or oscillating flow is a novel gas separation technique that has been considered as an alternative to membranes. The logic behind this consideration is that as membranes age, they tend to foul, which impairs separation.  Oscillating flow through a single tube has been well developed; however, it is useful to develop a greater understanding of the impact of varying the number of tubes in a bank system rather than varying the characteristics of a single tube.  This presentation covers an experimental study that compares the effect of a single tube versus multiple tubes on separation quality and species effective diffusivity in a separation scheme that utilizes oscillating flow in wavy-walled tubes.  This study shows that while separation quality is largely unaffected by adding additional tubes, the species effective diffusivity or flow is affected in a non-linear manner.  The gas mixtures used in the study were propylene/nitrogen mixtures that are typical of those seen in the degassing stage of polypropylene manufacturing plants.