I am looking for the suitable MOC combination of stainless steel material for making the vessel for soda roasting of spent catalyst material. Kindly drop your suggestion, thank in advance.
Dr. K. Muthukumar
Austenitic stainless steel will perform well in basic mediun of soda water.
Thank you Mr Olayide, right now I am using SS-316 for our application, the problem is corrosion due to the high oxidative and corrosive nature of soda roasting.
Perhaps we first need to clarify the exact environment. Soda to me indicates sodium hydroxide. With that chemical, the max. temperature is very important. What is the highest temperature the metal will be exposed to?
The NACE Corrosion Data Survey, Metals Section (I have the 6th Edition on my shelf) has some tables at the back for much higher temperatures than the standard tables. For sodium carbonate (100%), it indicates high corrosion rates for 304 and 316/317 type materials from 400C to 900C, with a note that stress cracking is possible. There are only a limited number of materials in the listing, but it shows that NiCrFe, referring to Alloy 600 (N06600), is suitable up to around 700C, with no data above that temperature. While it is a fairly expensive material, my philosophy would be to use a thinner sheet to line the vessel in the areas where it will come in contact with sodium carbonate. Of course you have to be concerned about thermal expansion affect against the backing material.
I think that SS316 stainless steel will be most suitable for the material and process concerned.