coating for caustic storage tanks/pipes
coating for caustic storage tanks/pipes
(OP)
Hello all,
Just a quick one I feel. I'm designing a caustic scrubber and I would some info on suitable coatings that's typically used to protect metals any other materials against caustic corrosion.
Thanking you in advance..





RE: coating for caustic storage tanks/pipes
I have seen caustic scrubbers with up to 60 HP fans and every one was PVC or FRP for body and tanks. PVC pumps, piping, valves and nozzles. Except, cast iron drive pumps for really large units.
In the metal finishing business, mild steel tanks are used for hot caustic solutions. I think the traditional reason for not using sheet steel for scrubbers was that the caustic would eat through the paint, and when cleaned, rust. Maybe a contributing factor is that commercial caustic soda contains pretty much (0.5% NaCl). However, with better paints nowadays, a good epoxy paint should work.
304 SS is usually used for fasteners. Expensive stuff like Ti works great, too.
Don't even think about using non-ferrous Al, Cu, Mg, Zn or alloys thereof (including galvanize) anywhere. Massive corrosion.
If you don't have a good corrosion book, all of the pump manufacturers have chemical compatability charts. There is a decent one in the back of the Grainger catalog, and Harrington Plastics has one on-line but with less data: http://www.harringtonplastics.com/
RE: coating for caustic storage tanks/pipes
There is information on material selection for caustic systems on the following:
www.hghouston.com/naoh_gph.html
www.hghouston.com/x/20.html
www.corrosionsource.com/technicallibrary/nidi/literature/literature9.htm
www.eng-tips.com/gviewthread.cfm/lev2/7/lev3/37/pid/135/qid/23683
Let us know how you make out......
Please post again with information of your final decision..
MJC
www.tipmaster.com/includes/refinfo.cfm?w=450&h=350')
RE: coating for caustic storage tanks/pipes
http://www.nidi.org/index.cfm/ci_id/6648/la_id/1.htm
RE: coating for caustic storage tanks/pipes
FRP is my prefered option for tankage and storage. PVC for pipes.
Thanks for all the really helpful links.
RE: coating for caustic storage tanks/pipes
What convinced you to use FRP/PVC? Any technical data from vendors/manufacturers to support your decision that is available for others to reference?
Thanks