UREX+ 304L Stainless Steel Centrifugal Contactor Corrosion due to Hydrodynamic Effects

During the centrifugal contactor operation in the UREX+ process there are two fluid phases, aqueous and organic, that flow continuously. These phases, which can be separate or mixed, they flow through two different regions called mixing and separation zones. In each zone there exist different hydrodynamic conditions as the rotor in the contactor spins at 2000 rpm. The geometry in the centrifugal contactor is quite complex because of the sharp section changes in relative short distances coupled with specific hydrodynamic conditions in each zone. It is expected that flow enhanced corrosion would occur in UREX+ centrifugal contactors specific to their geometry and turbulences created by the spinning rotor. The rotating cage (RC) technique was selected for this study to simulate the turbulent flow and multiphase conditions present in the two different zones of the centrifugal contactor. After the determination of the optimum solution volume, the 304L stainless steel corrosion coupons in the rotated cage were subject to the effect of different wall shear stresses and turbulences at the rotational speeds of 1,000, 1,500, and 2,000 rpm and at room temperature, 40, and 80oC. Corrosion data of rotated samples are based on mass loss and analysis of surface appearance, and composition via light microscopy and scanning electron microscopy.