Evonik develops membrane technology for separation of volatile organic compounds

With PuraMem® VOC, Evonik offers an innovative polymer-based membrane technology for efficient separation of long-chain hydrocarbons from a natural gas or nitrogen mixture. The spiral-wound membrane module has been optimized for specialty applications such as natural gas treatment, emission control in tank farms, and in the chemical and process industries. It is distinguished by consistently high selectivity over a long period under demanding operating conditions.

The new membrane technology functions on the basis of the different molecular sizes of the substances to be separated: The gas mixture streams through the membrane at a pressure of up to 80 bar; the larger VOC molecules pass through the membrane while the smaller gas molecules are retained. The specialty chemicals company can adjust this key separation property, the selectivity, already at the polymer level.

Evonik is the world’s only fully backward-integrated producer of high-selectivity separation membranes. “Backward integration is an important innovation driver,” emphasizes Dr. Goetz Baumgarten, head of the Membranes innovation growth field at Evonik. “Thanks to our many years of expertise in polymer chemistry, we are able to adjust the membrane properties already at the development stage of the base material—our high-performance polymer—to produce especially selective and robust membranes that can withstand extreme pressures and temperatures.”

The design of PuraMem® VOC has been specially conceived to allow the new membrane from Evonik to be incorporated flexibly into the existing infrastructure of the system. The standard dimension of an 8” diameter and the flexible gasket or integrated Kwik-Flange adapter make it possible to easily plug-in as well as drop in replacement of PuraMem® VOC modules into existing system installations.

“The market launch of PuraMem® VOC strengthens our position as an innovation driver for membrane-based separation technologies for volatile substances and fluids. With Evonik’s power to create, we have become a significant global player in membrane technologies within fewer than ten years and, with an ever increasing range of membranes, can offer our customers new product synergies from a single source,” says Dr. Iordanis Savvopoulos, head of the Fibres, Foams & Membranes Product Line at Evonik.

Evonik launched its first membrane product—SEPURAN® Green, for efficient upgrading of biogas—on the market in 2011, laying the foundations for future business in membranes. This was followed by further membrane products for nitrogen, helium, hydrogen, natural gas, and nanofiltration applications. The membranes, which are now being successfully used in more than 500 system installations worldwide, are produced at Evonik’s site in Schörfling, Austria. The high-performance polymer-based material is produced in neighboring Lenzing.