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Phase 2-A and Phase 2-B of the Al-Jubail multistage flash (MSF) evaporation plants were commissioned in 1982. The two phases consist of 40 desalination units and were designed and built by different contractors. A wide variety of materials was used in the construction of different components of the evaporators, namely, flash chambers (carbon steel, AISI 316L cladded carbon steel), heat transfer tubes (90/10 Cu/Ni, Ti), water boxes (AISI 316L cladded carbon steel, Al bronze cladded carbon steel), tube sheet [90/10 Cu/Ni, AISI 316L cladded carbon steel) and tube support (carbon steel and 316L cladded carbon steel). The role of design of the flash chamber and venting system on corrosion behavior of the evaporator construction materials was studied. Based on the corrosion rates of the materials at different locations of the desalination units and type and nature of the failures that occurred, the performance of the materials after years in service has been evaluated. The root cause of material failure has also been investigated. The results of the studies indicate that during 20 years operation, the desalination units encountered many corrosion problems. It has been concluded that a good ventilation design will minimize the corrosion in flash chambers. Good operation and maintenance would prolong the lifetime of the flash chambers.

The chemically aggressive environment generated in some parts of equipment at multi-stage fl ash (MSF) desalination plants can cause corrosion problems. The proper selection of materials with higher resistance to corrosion is considered as one of the most prospective approaches for smooth and effi cient running of the plants. Because of this, the study of the corrosion behavior of selected materials is an important issue in the realm of desalination technology. This paper reviews the performance of materials used in different MSF desalination plants. The corrosion behavior of materials in different sections of plants, under surrounding environmental conditions, is discussed. Various types or forms of corrosion occurring in different units of plant are described and the strong role of local attack is emphasized. Case histories dealing with failure of components in different plants are cited. The criteria for the selection of materials, which depend upon the nature of environment and operating conditions, are exemplifi ed. The merits and demerits of materials currently employed are highlighted and introduction of new materials either in existing plants as the possible replacements or in future plants are discussed.