Stainless steels for desalination plants

Stainless steel grades commonly used are, together with more modern grades, evaluated and commented with reference to different types of desalination processes including seawater reverse osmosis and distillation. The possibility to use solid stainless steel as an alternative to clad steel for evaporator vessels in distillation plants is discussed and also the possibility to use austenitic-ferritic or duplex steels instead of grades from the ASTM 300-series. The use of 316L (EN 1.4404) and 317L (EN 1.4438) is conservative in the sense of based on old-fashioned thinking without considering the far more reliable and cost effective concept with modern high strength and highly corrosion resistant duplex grades. Poor experiences from the use of conventional grades as well as installations of modern grades in different processes and process steps are described.