Gas-separation membrane cascades utilizing limited numbers of compressors

A systematic procedure is presented to drawn n-compressor membrane cascades for gas-separation applications with n greater than or equal to 1. In this method, a parent cascade structure is created that contains the n-compressor cascades as substructures. These substructures are then revealed by systematically eliminating unwanted membrane stages and recycle compressors from the parent cascade. The procedure is illustrated by generating arrays of one- and two-compressor cascade schemes. It is found that these arrays contain the cascade schemes known from the literature and also lead to some new schemes. This procedure increases the likelihood of finding an economically viable membrane cascade for a given separation application.