Failure analysis of steam jet pump at top of crude oil vacuum distillation tower

The steam jet pump made by SAF 2205 duplex stainless steel (DSS) provides vacuum for vacuum distillation tower to improve the distillation efficiency of crude oil. The pump suffers from severe local wall thinning during service, especially at diffuser section. Failure analysis of the pump is carried out using traditional characterization techniques and computational fluid dynamics (CFD) simulation. The results show that the pump suffer from not only the electrochemical corrosion of acidic droplets forming in HCl-H2S-H2O environment, but also the mechanical erosion by high speed flow with a large value of wall shear stress. A vicious erosion-corrosion circle built by electrochemical corrosion together with mechanical erosion leads to severe damage at the diffuser section of steam jet pump.