Evonik Industries introduces Sepuran N2, a new hollow-fiber membrane for efficient separation of nitrogen from air. The technology offers greater flexibility than classical cryogenic air separation and current membrane processes, according to the company. It can be combined with existing systems to meet peak demand or directly connected to compressed air systems to supply nitrogen. Evonik’s Sepuran N2 membranes reportedly offer a lower-cost solution due to the high capacity and low air requirement. ,
The Sepuran N2 hollow-fiber membrane consists of polyimide, a high-performance polymer that is highly chemically and thermally stable, and is produced by Evonik at its Lenzing (Austria) site. The hollow fibers, which resemble long and very thin tubes of pasta, are bundled together, embedded in a resin developed specially for the purpose, and enclosed in a stainless steel module. The membrane module, approximately 1.3 m long, contains several tens of thousands of these fine tubes, each of diameter 0.5 mm.
For separation of nitrogen, compressed air is fed into the hollow-fiber membranes. Due to their smaller size, oxygen molecules can pass through the membrane more easily than nitrogen molecules. This leads to enrichment of nitrogen to the desired purity inside the hollow fibers, while an O2-rich airstream is generated on the outside. The purity of the N2 can be regulated via the flow rate of the incoming air; the lower this flow rate, the higher is the quality of the nitrogen.
Compared with other conventional membrane systems, the new technology requires fewer modules and less air, according to the company. A smaller compressor reduces costs and energy consumption and the modular structure offers flexibility.