Hello everyone, I hope you all have a nıce day.
We had a problem in sulfuric acid %99 conct. drum nozzle.
After 2 years of operation, suddenly our nozzle has been failured.
We checked api 571.Concentration of acid is ok, it is %99.Speed of acid is lower than critical level.
But, when we examine flange and piping of nozzle. There is general corrosion and thickness of weld neck is thinned . Our material is carbon steel. But, in pipe thickness is not thinned.
Do you have suggestion for reason of this problem ? What could it be ?