Comprehensive experimental study of membrane cascades type of “continuous membrane column” for gases high-purification

Abstract

The gases high purification efficiency of a novel membrane cascade, a type of "continuous membrane column" configuration comprising of three counter-current radial membrane modules, has been evaluated experimentally in two regimes and compared with the membrane column configuration proposed by Hwang. The process of high-permeable impurity removal from low-permeable target component is studied using three model gas mixtures of high, medium and low selectivities for a commercially available silicone membrane: carbon dioxide/methane (2.5), nitrous oxide/nitrogen (15.7), and acetylene/nitrogen (94.3) respectively. A total reflux operation has been considered and the influence of the enrichment section on the performance of the stripping section has been evaluated. It has been shown that a novel configuration of the cascade comprising of one membrane module in the stripping section and two membrane modules in the enrichment section demonstrates higher separation efficiency compared to other considered configurations. Achieved product purity was 99.997 vol% for methane with a 1 vol% content of carbon dioxide, 99.99998 vol% for nitrogen with a 1 vol% content of nitrous oxide, and 99.999995 vol% for nitrogen with a 2 vol% content of the acetylene at product recovery equal to 15%, 30% and 50%, rescpectively, under the experimental conditions.