FAILURE ANALYSIS OF THE SEALING HEAD AT THE BOTTOM OF AMMONIA REFINING TOWER IN A HEAVY OIL CATALYSIS UNIT
重油催化氨精制塔塔底封头失效分析

A failure analysis of the sealing head at the bottom of the ammonia refining tower in a heavy oil catalysis unit has been made. It was found that martensite phase transformation occurred in the matrix of 304 stainless steel due to cold working (spinning). The 304 stainless steel containing deformation martensite was subjected to hydrogen sulphide stress corrosion cracking in the environment of wet hydrogen sulphide. Some protective measurements are proposed.