Reverse Osmosis Elements Multifunctional Membrane
Lanxess has introduced novel reverse osmosis elements from its Lewabrane product line. Novel feed spacer used in the membrane element allows low energy consumption and high fouling resistance.
Lanxess has introduced novel reverse osmosis elements from its Lewabrane product line. B400 LE ASD and B400 FR ASD are optimized for applications in brackish water. The elements are characterized by very low energy consumption (LE) and high fouling resistance (FR). 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. 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).
Lower energy consumption, longer dwell times
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. Furthermore, the tendency towards scaling in the element was reduced. “With the new elements, we expect energy usage to decline and dwell times to be extended,” said Schellenberg, summarizing the results.