What material is used for the pipelines in the MTO alkali washing system?
Thread Content
Is carbon steel or stainless steel used for the pipelines in the MTO alkali washing system? If carbon steel is used, is there a risk of alkali embrittlement, and are there any other risks of corrosion?
For carbon steel pipelines, no case of alkali embrittlement has been observed so far; however, 32% alkali corrosion is relatively severe.
Do those 32% alkaline liquid pipelines need anti-corrosion treatment?
So do you think improvements are needed here during the piping design process?
It appears that ordinary pipelines are sufficient for normal use, and no corrosion-resistant lining is required.
Looking at the temperature, both CS and special materials have been used. It cannot be used for steam reheat with wall contact, otherwise the CS tubes will corrode rapidly. . . Had a hard time. @jiaguoyun
There should be an insulating layer between the main pipe and the steam tracing pipes; otherwise, due to direct contact, the surface temperature of the main pipe becomes very high, leading to rapid corrosion. . . It rotted in just a week. It has an insulation layer, which is commonly referred to as “light heat tracing”. @jiaguoyun
What material is used for the insulation layer?
We have direct contact with it; once the alkali pipeline is taken out of use, the alkali remaining in the pipeline is heated by the heat tracing, resulting in high temperatures that indeed accelerate corrosion. If the alkali in the alkali pipeline keeps flowing, there should be no major problems. But in the long run, it’s probably more appropriate to use the light heat tracing you mentioned.