Desalination Plants are recognized to be very severe environments due to the high chloride, warm conditionsi. Before, austenitic stainless steels within the ASTM 300 series somewhat the material of in desalination plants. In the event through which even higher corrosion resistance may be needed, the standard material solution has been higher alloyed Austenitic grades built after dark 300 series, for example austenitic 6Mo grades (UNS NO 8367)ii. Lately, Duplex 2205 (UNS S32205/S31803) along with other duplex stainless steels emerged since the more optimal material in numerous situations.
Duplex 2205 along with other duplex stainless steels have gained in popularity from the desalination industry for several reasons. First, duplex stainless steels have good corrosion resistance and perhaps can be offered at a price savings within the comparable austenitic steel. As an example, Duplex 2205 has similar pitting and crevice corrosion properties to 904L (UNS NO8904), but is available better value mainly because what has chemical composition includes lower percentages of expensive metalsii. Furthermore, duplex stainless steels have high strength. Specifically, Duplex’s strength is almost double those of austenitic steels. Thus, less weight of cloth is typically needed resulted in further cost savings.
Duplex stainless steels have been successfully implemented in many applications within desalination plants, including evaporators, SWRO and BWRO high-pressure piping, and numerous components in connection with product water processingii. Here are a few specific examples.
Solid Duplex and DualDuplex Evaporators:
The breakthrough for duplex in the desalination industry occurred in 2003 when Duplex 2205 was selected to be installed in the Melittah MSF plant in Libya, built by REGGIANE of Italy. Duplex 2205 made it possible to build the evaporators with thinner plates, requiring less material and less welding compared to traditional evaporator materials, such as Austenitic 316L (UNS S31603). Additional benefits include easier handling and less overall environmental impacti. Both the Melittah plant in Libya and the Skikda plant in Algeria (constructed in 2004 and 2005) have successfully demonstrated the ability of Duplex 2205 to meet the needs of these environmentsiv.
SWRO High Pressure Piping:
Experience from numerous Seawater Ro (SWRO) plants already in service shows that you have a risky of corrosion if your wrong stainless steel is used inside the high-pressure piping necessary for this environment. The 316L (UNS S31600) and 317L (UNS 31603) grades do not possess sufficient corrosion resistance properties to endure this environmentiv. Consequently, highly alloyed austenitic steels, such as 254 SMO (UNS S31254), have been deemed approximately mandatory for yearsv. These days, however, super duplex stainless steel grades such as SAF 2507 (UNS S32750) are making strong headway into this area. SAF 2507 is often a desirable solution because of the fact that is has almost the identical potential to deal with pitting and crevice corrosion as 254 SMO, they have twice the strength, as well as the expense is far lowerv. The Singspring desalination plant in Singapore, which offers about 10% of Singapore’s freshwater needs, is a superb demonstration of SAF 2507s successful implementation. SAF 2507 can be used for the high-pressure piping that feeds the incoming seawater with the initial seawater ro (SWRO) pass for that plantiv. Singspring has been in operation since 2005 and the SAF 2507 has continued to do welliv.