Metal Dusting Failure in an Aniline Processing Plant

The paper summarizes the results of the analysis made on the ruptured tube of the reactor made of austenitic stainless steel in which the conversion of aniline to diphenylamine occurs at elevated temperature and pressure and in the presence of a catalyst. The tube wall perforation occurred in the piping used to measure the pressure in the reactor and a fire occurred after an aniline, ammonia and catalyst vapour leak. The material analyses carried out clearly showed that the thinning and subsequent perforation of the tube wall was due to a specific corrosion attack, so-called metal dusting, which occurs at elevated temperatures and in the presence of a carburizing atmosphere.