We have A516 Gr70 column. Iron Pyrite film formation was done on the wall of the column. the gas in the column has around 98% H2S, 2% CO2. When the column was opened after In-Service-Inspection group found out thinning of column wall. We have observed severe pitting on the inner wall. I would like to have know the mechanism of corrosion of Carbon steel with pyrite film on, by CO2. Can any body throw the light?
Thanks
sskumar