Keywords: materials selection, stainless steel, duplex grades, corrosion resistance, desalination plants, sustainable water production, multi-stage flash, MSF, multi-effect distillation, reverse osmosis
Stainless steels within desalination for reliable water supply
To assure sustainable water production, the materials used in desalination plants need to perform for many decades without failures. During the last years, duplex - austenitic-ferritic - stainless steels have been selected for several desalination projects due to their unique combination of mechanical properties and corrosion resistance. Price stability of those grades, as a consequence of a rather low nickel content, has also encouraged the transition. However, material selection might appear even more complicated, when more grades are available. This paper addresses the subject of material selection and summarises experience of using stainless steels in MSF, MED and RO desalination plants. The families of duplex and austenitic grades are compared and a wide range of grades is discussed in terms of mechanical properties and corrosion resistance. Application areas are suggested for each grade, based on experience from existing installations, field and laboratory tests, and the overall property profile of the grade is described.