Specialty chemicals company Evonik is expanding its business in high-selectivity membranes for efficient gas separation and organic solvent nanofiltration.

The Germany-based company has developed a membrane technology for separation of volatile organic compounds (VOCs) and is launching this on the market under the brand name PuraMem VOC. With PuraMem VOC, Evonik offers a polymer-based membrane technology for efficient separation of long-chain hydrocarbons from a natural gas or nitrogen mixture, a statement said.

The spiral-wound membrane module has been optimised 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,” emphasised 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.”

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.