Trio of RO membranes for strong-fouling water

Three new types of Lewabrane membrane separation elements for reverse osmosis (RO) were announced on 1 February 2013 by German specialty chemicals company Lanxess for waters with strong fouling potential.

The new membranes have a surface area of 37.2, 34.4, and 8.4 m² (equivalent to 400, 370, and 90 ft²). Lewabrane RO B400 FR and Lewabrane RO B370 FR have a diameter of 201 mm (8 in), while Lewabrane RO B090 FR 4040 has a diameter of 101 mm (4 in).

All Lewabrane products comprise a polyamide composite membrane, wound in several layers to form a spiral wound element. A special feed spacer has been incorporated in the newly developed FR types.

“Our membrane separation elements are characterized by a high degree of polymerization and a low surface charge, which in itself reduces the accumulation of dissolved solids at the membrane surface,” says Alan Sharpe, head of the RO Membrane Strategic Project at Lanxess’ Ion Exchange (IX) Resins business unit. “The new membrane elements were designed to generate greater turbulence in the feedwater channel, meaning that less solids accumulate on the membrane surface.”

The separation elements, manufactured at Lanxess ‘ Bitterfeld site, were engineered specifically for industrial water treatment. The fields of application include the desalination of brackish and low-salinity water with a high potential for organic or biological fouling.

· The IX Resins business unit has also expanded its design tool for industrial water treatment. Using LewaPlus, complete systems can now be designed, for example, employing different separation processes.

Dr Jens Lipnizki, membrane applications manager, explains: “Until now, LewaPlus was only capable of engineering RO and IX systems separately. With the expanded version, an RO process can now be engineered with a downstream IX and, if necessary, even with an intermediate degasification system.”

This is a typical application for water treatment in power plants.