Late in February 2006, KSB received an order for the delivery of pumps and valves worth some € 4m for the intake station of the Al Hidd seawater desalination plant in Bahrain. The order includes 600 seawater-resistant butterfly valves of different types and sizes, the largest of which will measure 3000 mm in diameter. The seawater intake section will be equipped with three tubular casing pumps type SEZN, each with a 4150 kW drive rating. Each pump is capable of handling 39,000 cubic meters of seawater per hour. With an 88 percent efficiency, the pumps will be very economical in terms of energy usage. The inlet conditions for the pumps are of vital importance for the smooth operation and reliability of the station as a whole. The intake chambers have to be carefully designed and built to ensure steady, vortex-free seawater flow to the impellers. To verify this, KSB’s hydraulics experts checked the inlet conditions and, hence, the future reliability of the station, using a series of model tests as well as a CFD (computational fluid dynamics) program. They simulated extreme inlet conditions, such as the lowest possible water level, and its effects on the operating characteristics of the pump units. The model tests showed that the design of the existing intake structure would ensure a satisfactory approach flow to the pumps even under difficult conditions, and thus warrant low life cycle costs of the pumps.
