Evaluation of Corrosion Inhibitor with High Speed Rotating Cage

摘要

In this study, the effect of turbulence on corrosion inhibitor performance was investigated with a rotating cage autoclave (RCA) in order to select a corrosion inhibitor for a Japanese field piping. The maximum rotating speed is 2,000 rpm, corresponding to 8 m/s in circumferential speed of 80 mm diameter of the cage. The capacity of the autoclave is 2.3 L The flow pattern was observed through a transparent acrylic resin container. As the rotating speed became higher, a vortex appeared clearly on the free surface of test solution. The bottom of vortex reached the top of the rotating cage at 1,000 rpm and air bubbles were dragged into the cage. Computational fluid dynamics (CFD) modeling revealed the same phenomena of vortex and bubbles. The maximum wall shear stress (WSS) was estimated at 180 Pa in CFD modeling at 2,000 rpm. The WSS range of this RCA covered the actual field piping. Three brands of oil-soluble water-dispersible inhibitors were evaluated with the RCA. Some inhibitors showed enough efficiency at high rotating speed but the others require more dosage to maintain the same result.