RE: [MW:9960] Chemical cleaning of CS internal surfaces of vessels

HelloYes, you can use citric acid to clean and passivate carbon steel. After cleaning the surface with an alkaline cleaner, you can use citric acid to remove the iron oxides. There are pH adjustments required to perform these cleaning. After the citric cleaning phase, another pH adjustment is required prior to adding an oxidizer to form a protective magnetite film (passivation) on the surface.

After passivation, the system is dried under nitrogen purge. Passivation film is stable if moisture is kept out of the system. This process was designed by Pfizer many years ago and called Citrosolv process.

Daryl L. Roll Astro Pak Corporation Costa Mesa, California, USA

 Ali:
Please read the following statement:
 
 

---

Date: Sun, 20 Feb 2011 22:17:36 +0300
From: mhaskar.aly@gmail.com
To: materials-welding@googlegroups.com
Subject: [MW:9947] Chemical cleaning of CS internal surfaces of vessels

Dear All, Thank you for reading my question & answering the same.   We have one vessel having heavy rust on internal surfaces. The vessel is mounted on skid & Blast cleaning is not possible.   Can anybody suggest what chemical can be used for   Cleaning. Passivation after cleaning For inhibitor .   Thank you in advance   Aly Kuwait

--
To post to this group, send email to materials-welding@googlegroups.com
To unsubscribe from this group, send email to materials-welding+unsubscribe@googlegroups.com
For more options, visit this group's bolg at http://materials-welding.blogspot.com/
The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.