Copper-nickel (CuNi) or Cupronickel is a copper alloy with nickel and other strengthening elements, including iron and manganese. The copper content in copper-nickel alloys typically varies between 60 to 90 percent. (Monel is a term for a nickel-copper alloy that contains a minimum nickel content of 52 percent.)
Despite a higher copper content, cupronickel or copper nickel alloys are silver in color. Cupronickel offers excellent resistance to corrosion by salt water and is therefore used for heat exchangers, piping, and condensers in seawater systems, as well as for marine hardware. It is also used for the propellers, shafts, and hulls of high-quality boats. Other uses of copper-nickel alloys include military equipment and chemical, electrical industries, and petrochemical.Usage of Copper Nickel Alloys
Copper Nickel Alloys find their place in a host of sectors or fields, making manufacturing easier and more convenient. In addition to building machine parts and repairs, these alloys have long held the reputation of being corrosion resistant which makes them an ideal pick in outdoor environments.
Here are some of the applications of copper-nickel alloys.
Copper nickel alloys are used widely in multi-stage flash (MSF) and multiple effect distillation (MED) desalination plants. With usage in cost considerations, these alloys are preferred in corrosion conditions in the various sections or areas of the plant.
2. MSF Plant
An MSF plant uses a process that typically consists of a series of tube or plate heat exchangers that can target temperatures of 120oC in the brine heater while decreasing as the brine and distillate travel through the plant to heat recovery, followed by heat rejection sections.
Both the brine heater and heat recovery sections require long exposure to hot de-aerated seawater and brine. On the other hand, the heat rejection section uses natural seawater. The tubing exteriors manage water vapor and other non-condensable gases.
3. Offshore Oil and Gas
Copper-nickel alloys have found expansive applications on both platforms and FPSOs (Floating Production Storage and Offloading vessels) and are used in cooling, seawater, and firewater/deluge systems. They are most favored in warmer climates for their excellent resistance to chloride crevice corrosion and stress corrosion cracking.
4. Power Generation
Electricity generation – both in nuclear and fossil-fuelled power plants involves vital heat transfer processes; heat exchangers, coolers, steam generators, condensers, pipework, valves, tanks, and fittings. Copper-nickel alloys are well-suited for these kinds of applications, as they can be used successfully in a range of environments that include clean seawater with high-total dissolved solids, brackish water, freshwater, and cooling tower water.
5. Shipbuilding and Repair
The 90-10 and 70-30 copper-nickel alloys were developed for naval condensers and seawater pipings eons ago. It is a testament to their resilience in harsh conditions that they are still being used in many of the world’s vital navies. Also, they are used on FPSOs and commercial shipping.
Seawater is used for tank cleaning and heating, cooling, ballast, waste disposal, firefighting, and, through distillation, as a source of fresh water for boiler feed water and sanitary cold and hot water. All require piping systems that consist of pumps, pipes, valves, and fittings. For cooling systems, heat exchangers are also required. Applications for copper-nickel alloys include condensers, coolers and heat exchangers, onboard desalination seawater plants, systems for compressed air, sanitary systems, bilge, ballast water, brine, fuel oil, lube oil, fire mains and sprinklers, warm water heating, hydraulic lines, grey and black water, and tank heating.
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