In many parts of the world, fresh water is an urgent need. Desalination – the process of obtaining freshwater from the earth’s vast reserves of seawater – is the obvious answer. But desalination is both complex and costly, a combination that can discourage investment in new facilities.
Few processes can top desalination for a harsh project environment. Awash in highly corrosive salt water, desalination plants face unique challenges in life cycle costs.
Multi Stage Flash (MSF) desalination is the most commonly used desalination method today. Seawater is heated in a thermal process, flashed into steam in a series of evaporation chambers and then condensed.
When Fisia Italimpianti of Italy – a leader in MSF desalination – committed to expansion of three existing desalination plants decade ago, the company turned to Outokumpu. As a supplier of stainless steel to the majority of desalination plant contractors, Outokumpu meets the demands of an uncommonly challenging process.
Life cycle approach
In previous desalination installations, steel for mildly corrosive environment was used. When Outokumpu introduced its Forta dual duplex construction, Fisia gained a solution with improved corrosion resistance and strength. The evaporation chambers of three desalination plant extensions use a combination of the more corrosion resistant Forta DX 2205 and Forta LDX 2101 in less corrosive sections. By using duplex stainless steel, evaporation chambers can be built with thinner plates. That means less material, less need for welding and easier handling. Containing less nickel, Forta LDX 2101 has better price stability than high-nickel stainless steels. The solution represents advanced MSF technology and translates into increasingly affordable desalination plant investments and, as a result, can make fresh water increasingly available where it is most needed. For the evaporation chambers in the Fisia Italimpianti projects, Outokumpu delivered 4,000 tonnes of hot rolled plate, much of it Outokumpu’s proprietary Forta LDX 2101duplex stainless steel.