Seawater desalination

Application of special alloys in the field of seawater desalination

· The materials used in the seawater desalination process must have corrosion resistance. The selection and design principles of materials depend on the service environment of the materials. Stainless steel is an ideal material due to its corrosion resistance and durability, and is used in the engineering of various desalination methods.

· Since seawater contains a lot of corrosive substances, the shells, pumps, evaporators, and high-temperature pipelines required for the manufacture of desalination equipment are all parts that are in direct contact with high-concentration seawater, and must have strong corrosion resistance, so the general Carbon steel is not suitable for use. Super austenitic stainless steel, super duplex stainless steel and cold-rolled titanium have excellent seawater corrosion resistance, can meet the requirements of seawater desalination projects, and are ideal materials for multi-effect distillation and reverse osmosis seawater desalination plants.

· At present, China's seawater desalination equipment and supporting equipment manufacturing capacity is still relatively weak. The core materials and key equipment of reverse osmosis seawater desalination, such as seawater membrane modules, energy recovery devices, and high-pressure pumps, mainly rely on imports. According to the investment price ratio of engineering equipment, the localization rate is less than 50%; The seawater corrosion pipes, steam injection device (heat pump) heat transfer efficiency, etc. are still far behind the international advanced level. At the same time, China's enterprises engaged in the manufacture of desalination equipment and complete sets of engineering projects are generally small, the manufacturing base is weak, and the ability to transform technological achievements is weak, which seriously restricts the industrialization process of desalination technology; the industrial chain of desalination equipment manufacturing has not yet been formed Even if the production line is imported from abroad, most of the raw materials still need to be imported, and it is difficult to form a strong brand effect; a seawater desalination equipment manufacturing base and a professional leading enterprise or enterprise cluster with international competitiveness have not yet been formed. Nor does it have the ability to compete with foreign companies.

Commonly used in seawater treatment equipment, seawater heat exchangers, acid gas environment pipelines. Hydraulic, perfusion pipes, fasteners, etc. in marine engineering.

Special alloy materials commonly used in the field of seawater desalination:
· Stainless steel: 317L, 1.4529, 254SMO, 904L, AL-6XN, etc.
· Nickel-based alloys: Alloy 31, Alloy 926, Incoloy 926, Incoloy 825, Monel 400, etc.
· Corrosion resistant alloy: NS112
· Corrosion-resistant alloys: The equipment materials used in the desalination process of NS112 must have corrosion-resistant characteristics. The selection and design principles of materials depend on the service environment of the materials. Stainless steel is an ideal material due to its corrosion resistance and durability, and is used in the engineering of various desalination methods.