material for caustic brine tank

[diabeticoholic]

Good day!

What is the best material for a cylindrical tank storing caustic brine solution (Recycled solution coming from Ion Exchange regeneration)?

Currently, the tank in our plant is mild steel with rubber lining. We are planning on replacing it since corrosion is already evident on the mild steel shell. Is it practical to replace the tank with the same material? Or it would be better to use different material. If yes, what material is best suited for this application?

Thank you in advance!

 

[moltenmetal]

Rubber lining should work and should give you the best economy relative to alternatives. But it needs to be done right- a vessel needs to be designed for lining and the fabrication processes and inspections need to be done right or else no lining will last.

 

[moltenmetal]

Another option would be FRP with a synthetic (non-glass) corrosion veil. If it's a nonpressurized storage tank it will cost less that way than rubber lined steel construction. If it's a pressure vessel, the rubber lined steel will very likely be cheaper.

 

[LittleInch]

The only things I've seen work with warm aerated seawater, which is close to your application, is GRP vessels / pipes or Aluminium bronze as single base materials. There may be different internal linings such as glass flake epoxies, but they will all have the issue that a single defect will eat a hole though your base carbon steel in days / weeks.

Temperature, pressure and size all have a bearing on what options are available but not detailed so difficult to say much more.

Seawater is OK for carbon steel when you take the oxygen content down to < 50ppm (I think). Not sure about caustic brine, but it might also be an alternative if your oxygen levels are or can be made to be very low.

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