Operating Experience of a New Generation Reverse Osmosis Spiral-Wound Membrane Elements by Membranium at Power Industry Facilities

The task of increasing the efficiency of water treatment in the generation of electricity and steam is one of the driving forces for improving the separating and operational properties of reverse osmosis membranes and spiral-wound elements based on them. A significant role in solving this is played by increasing the rejection of membranes as a result of their modification and by using spacers of an optimized design to improve the characteristics of the spiral-wound elements. The new generation of reverse osmosis spiral-wound elements made by “RM Nanotech” JSC combines changes concerning both aspects. Modification of the selective layer of the membrane allowed improving its separating properties, and a change in the geometry of the spacer led to a decrease in the pressure drop across the element and an increase in the efficiency of CIP procedures. The new generation elements were installed at four sites and operated in parallel with elements of the previous type and with elements of two generally recognized world leaders. The results of operation are given in the form of normalized data for permeate salinity, pressure drop and efficiency. In this case, both surface and underground sources served as feed water. The degree of conversion (recovery) ranged from 67 to 78%. In order to obtain relevant values, the number of tested elements at different sites varied from 48 to 108 depending on the design of RO plant units, and the duration of testing was from 0.5 to 4 years.