Pipeline material for concentrated nitric acid
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Regarding the material for pipes used with concentrated nitric acid, what material is suitable for pipes in which high-temperature concentrated nitric acid flows, with water used for cooling both inside and outside the pipe? Aluminum pipes cannot withstand high temperatures, while high-silicon cast iron pipes cannot tolerate temperature changes. ? ? ?
At present, the most suitable option is also high-silicon ferroalloy
Can’t stainless steel be used? It has strong corrosion resistance after passivation
Application areas of duplex stainless steel 2205: equipment in the paper industry, processing equipment in the food industry, flue gas desulfurization equipment in thermal power plants, offshore oil platforms (heat exchanger tubes, water treatment and supply systems, fire protection systems, **systems, water stabilization systems), desalination equipment (high-pressure tubes in RO devices, seawater pipes) and other equipment for specialized chemical environments, oil field pipelines and equipment, and others chemical processing equipment. Heat exchangers, coolers, and devices resistant to seawater, high temperatures, and concentrated nitric acid, used in industries such as oil refining, fertilizer production, papermaking, the petroleum industry, and the chemical industry.
C4 steel/C276 steel pipes can be used
No matter what the temperature, it is better to use aluminum pipes
C276 is too expensive; aluminum will do
Duplex stainless steel, alloy 20, and Inconel alloys are all good choices； Try to use Ni-Cr-based alloys
When the temperature is below 45 degrees, high-purity aluminum is sufficient for pipes used with concentrated nitric acid; if pressure requirements exist, carbon steel pipes lined with high-purity aluminum can be used.
Neither 304 nor 316 stainless steel works; concentrated nitric acid is a highly oxidizing acid
For the material selection in the concentrated nitric acid section, according to the \"Corrosion Manual\", pure aluminum is used when the nitric acid concentration is greater than 98%; ordinary stainless steel is employed when the nitric acid concentration is less than 40% and the operating temperature ranges from 20 to 100°C; high-silicon cast iron is used when the nitric acid concentration is greater than 50% and the operating temperature is below 200°C. There’s also C4, and the upgraded version C8.