Evonik Industries has developed a new hollow-fiber membrane for the separation of nitrogen from air.
Essen/Germany –With Sepuran N2 Evionik offers a new Nitorgen separation technology based on hollow-fiber membranes. Goetz Baumgarten, who is responsible for global Sepuran business in Evonik’s Resource Efficiency Segment, says: “Compared with other conventional membrane systems the new technology requires fewer modules and less air. Its smaller compressor reduces investment costs as well as energy consumption and the modular structure means that the system can be used flexibly".
The hollow-fiber membranes consists of polyimide, a high-performance polymer that is highly chemically and thermally stable, and is produced by Evonik at its Lenzing site in Austria. 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. Air has two main components, consisting of up to 78 % nitrogen and 21 % oxygen. 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 resulting Nitrogen with a purity of 95 to 98 % makes the Sepuran N2 suitable for applications in many industry sectors such as the food industry or in the aerospace industry to inert the fuel tanks of planes and create a flame-resistant atmosphere.
This technology can be combined with existing systems, for example to meet peak demand, or directly connected to compressed air systems to supply nitrogen.