How to choose pipe materials
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The temperature of the atmospheric tower residual oil outlet pipe is 360°C, the liquid contains 1.5% sulfur, low acid, and the design pressure is 2.54MPa. What pipe material should be selected? This post was last edited by dongdong1 on 2009-2-6 17:20 ]
Seamless pipes can be used, medium-pressure ones are sufficient, and they comply with GB/T8163 standards.
Temperature is an important basis for deciding the material. If it is low temperature, ss304 may be OK, but if it is high temperature, I want ss316.
What's the temperature? Tower top or side line? Be clear.
Just choose seamless steel pipe made of 0Cr18Ni9 material
Forgot to mention this, it is the atmospheric tower residual oil outlet pipe, the temperature is 360°C.
For atmospheric pressure residual oil pipelines, according to what was said above, the medium temperature is 360 degrees, the sulfur content is 1.5%, and the acid is low. At present, most refineries use 1Cr5Mo material or 1Cr9Mo material that is resistant to high-temperature sulfur corrosion corrosion. In contrast, 1Cr5Mo material can meet the requirements of the working conditions you mentioned with a suitable corrosion margin. 1Cr9Mo has higher high-temperature sulfur corrosion resistance than 1Cr5Mo. When the acid value is high, stainless steel or acid-resistant steel containing 2-3% Mo needs to be used to resist high-temperature naphthenic acid corrosion.
First, if the design temperature is 360°C and the design pressure is 2.54MPa, steel pipes of grade 4.0A1 or above should be selected.； Secondly, it contains sulfur and acid, so if you exclude seamless steel pipes, you must choose stainless steel. ； If the sulfur content is 1.5%, 1Cr5Mo will definitely not work, so you can choose 0Cr18Ni9 or 0Cr18Ni10Ti, the latter is more commonly used as pipe material.
You can check the piping manual. There are instructions in this book. Most design institutes have it.
If price factors are excluded, 316L is the first choice, as it has better corrosion resistance and welding construction.