Stage extent of separation in ideal countercurrent recycle membrane cascades

摘要

Rony's extent of separation ξ is useful to characterize the quality of separation of a binary feed that occurs in membrane stages, membrane modules and cascades. The stage extent of separation ξ_i, has a maximum value for a specified stage separation factor, α_i. The ideal cascade design requires a minimum total interstage flow compressor duty, and membrane area to make a specified overall separation. It is shown that ξ_i has the maximum value at each stage in an ideal membrane cascade composed of ideal perfect-mix stages. This is aldo true in a "properly designed" no-mix cascade composed of crossflow stages. This suggests that ξ is a basic separation index.