Thanks to rustbuster. I expect this is the main mechanism, but I do not yet understand the source of the oxide in the scale, when there should not be any water present. Any insights would be of interest.
A Fired Heater with a hydrocarbon process gas containing 1 mol% H2S and tubes of ASTM 106 Gr B suffered rapid internal corrosion at the tube outlets ie 4mm in 1.5 years. Process gas outlet conditions are 295 degC at 65 barg and the gas is dry. The scale is a mixture of iron oxides and sulfides...
A Fired Heater with a hydrocarbon process gas containing 1 mol% H2S and tubes of ASTM 106 Gr B suffered rapid internal corrosion at the tube outlets ie 4mm in 1.5 years. Process gas outlet conditions are 295 degC at 65 barg and the gas is dry. The scale is a mixture of iron oxides and sulfides...
