Water. Desalination + reuse
Issue link: https://fhpublishing.uberflip.com/i/107143
PROJECTS Figure 2. An artistic view of the Sorek desalination plant. greatest impact on plant capacity and operating costs are: l Pressure Center concept l Large diameter (16 in) membrane elements l Pipejacking methodology l Self-generating energy-supply system PRESSuRE CEnTER COnCEPT Having proved its benefits in IDE's Ashkelon and Hadera plants, the Pressure Center concept was adopted for Sorek due to its economy of scale, simplification of erection and the superior operational flexibility, reliability and availability that it affords. The Pressure Center includes the RO membrane segment and the feedpumping center. Water to be desalinated is supplied to the RO section by the feedpumping center, which comprises both the highpressure (HP) pumps and the advanced energyrecovery systems (ERS). The HP pumping and ERS centers, which supply the HP feed to the RO banks via common feed lines, can been optimized by the selection of a minimal number of large HP pumps and ERS units working at the highest efficiency rates and best operation conditions. A key advantage of the Pressure Center design is that it allows the plant to vary production rates during the day, resulting in the high level of flexibility needed to maximize efficiency. Since it allows increasing/decreasing the feed pressure to the RO trains, all RO trains remain operational during stages of decreased production, thereby decreasing system recovery without increasing the total feed to the plant. This feature reflects the Pressure Center concept's ability to produce at low recovery yields, resulting in lower osmotic pressures and furthermore producing at lower permeate fluxes through the entire available membrane area. This model is identical to those deployed successfully in the Ashkelon and Hadera plants, which have demonstrated increased availability and reliability, higher efficiencies and flexibility under variable operational modes and lower Capex/Opex costs. LaRgE diamETER (16 in) mEmbRanE ELEmEnTS Great emphasis has been placed on the optimization of the RO banks' configuration by utilizing a unique IDE patent-pending design that includes the use of a minimal number of independent trains fed by both feed pumping centers. The present design adopts the use of 16-in membrane elements installed in vertical pressure vessels. The behavior of the 16-in membrane element, as confirmed by the installation and successful continuous operation of vertical 16-in pressure vessels in IDE's Larnaca plant in Cyprus, is identical to that of the 8-in membrane, resulting in identical salt-rejection performance and a correspondingly 4.3 times larger flow rate at the same feed pressure and operation conditions. The combination of the proven 16-in membrane technology and the long-term operation of various size industrial RO systems installed in vertical pressure vessels results in an optimized design that is expected to result in a significant reduction in membrane handling for maintenance purposes. This approach allows a significant reduction in plant footprint, shorter HP pipe headers and an improved membrane loading method. In addition, due to the larger volumes of feed water, there is a lower tendency for membrane fouling and polarization in the second stage. If required, the same configuration can produce larger quantities of permeate by operating at the high production regime for longer periods and increasing the flux through the membrane elements within the limits of manufacturer recommendations. PiPEJaCking mEThOdOLOgy To minimize the plant's environmental impact (air, land and marine), the feed and brine pipelines are being installed using the pipejacking method, a proven environmentally-superior tunneling method for the installation of underground pipelines. Pipejacking is used for at least 1,100 m from Figure 3. Sorek under construction showing the 16-in vertical membranes arrangement. | 18 | Desalination & Water Reuse | August-September 2012