Caustic soda storage tank corrosion allowances 1

[Tj01]

Mates,

I am designing Caustic soda storage tanks to API 650. The concentration for caustic soda is going to be as high as 50%. Initially for corrosion allowances, I have kept corrosion allowance 2mm. As this are caustic soda tanks and concentration of fluid can go up to 50%, I am bit worried about the corrosion allowances and other factors to be considered.

Can any one please help me out to advise on corrosion allowances and other important factors to be considered?..

Thank you in advance..

 

[MJCronin]

Captain,

I would consider 1/8 inch as a good starting point for caustic tanks at 50%. Carbon steel can be used if the temperature is <120F

But caustic storage at 50% may require internal heating to maintain fluid properties....

PPG (and others) have published some great guidelines about caustic storage and transfer systems.

http://www.dow.com/causticsoda/safety/design.htm

http://www.solvaycausticsoda.com/docroot/caustic/static_files/attachments/doc_1110_0005_w_en_ww.pdf

http://www.eng-tips.com/faqs.cfm?fid=1096

 

[chicopee]

I agree with the first article from MJC about tank lining. I have a customer who maintains a vertical open top sodium hydroxide steel tank of over 10,000 gallon capacity and this tank has a liner which is replaced I believe once every 10 years or so.