Several Failure Analysis Cases of Pressure Equipment Under the Conditions of Complex Medium Environment

There are several hundred of failure cases of pressure vessels and piping in China every year. The causes for part of accidents have been clearly analyzed, and preventive measures have been taken making the similar accidents substantially reduced, but the causes for quite a few failure accidents are still not found effectively, the similar accidents is still taking place. Through study, the authors find that the major reason for deviation of failure analysis lies in that equipments are mostly operating in complex medium environment, and mutual competition may exist among multiple failure mechanisms. Sometimes changes of some influential factors may cause the dominant failure mechanism change, even leads to totally different analysis conclusions. Combining with the analysis and verification of several failure cases of pressure vessels and piping in petrochemical enterprises, the judgment method for the dominant failure mechanism under multiple failure mechanisms is discussed in this paper, which may be helpful to provide some effective means for failure prevention of pressure equipment under complex environment.