Novel feed spacer design for brackish water RO membranes to be launched by LANXESS

Chemicals company Lanxess will be introducing an addition to its reverse osmosis (RO) elements from its Lewabrane product line at next week’s Membrane Technology Conference & Exposition...

Jan 29th, 2016
Content Dam Ww Online Articles 2016 01 Lanxess Membrane

Chemicals company Lanxess will be introducing an addition to its reverse osmosis (RO) elements from its Lewabrane product line at next week’s Membrane Technology Conference & Exposition.

Initially, two, new products are to be introduced: Lewabrane B400 LE ASD and Lewabrane B400 FR ASD.

Designed for applications in brackish water, these elements have standard geometries (length: 40 inches, diameter: eight inches).

According to Lanxess, the feed spacers incorporated in the membrane elements are multifunctional. They create space between the membrane surfaces for fast-flowing water, support the membrane in the process and cause turbulent water flow.

The company said: “Although turbulent flow helps to lower salt concentrations at the surface of the membrane, and to reduce the extent of concentrate polarization, it also causes an increased pressure drop compared, for instance, to laminar flow. The optimal design of the feed spacers therefore is of critical importance to the properties of the elements. Filaments or strands of different thickness are used for the novel feed spacers. The new product family is named after this alternating strand design (ASD).”

Computational fluid dynamic (CFD) simulations had previously indicated that RO elements with ASD feed spacers would indeed be capable of achieving higher performance levels.

Tests of prototypes later fabricated as part of the project confirmed these calculations. The prototypes were shown to have a significantly lower pressure drop than standard grades and competitor products, according to Lanxess. Furthermore, the tendency towards scaling in the element was reduced.

Dr. Carsten Schellenberg, head of Research and development at the membrane facility operated by the Liquid Purification Technologies (LPT) business unit in Bitterfeld, Germany, said: “With the new elements, we expect energy usage to decline and dwell times to be extended.”

Hosted by the American Membrane Technology Association (AMTA) and the American Water Works Association (AWWA), the conference and exposition are being held in San Antonio, Texas, from February 1 to 5, 2016.

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