Standard Practice for Evaluating and Qualifying Oil Field and Refinery Corrosion Inhibitors Using the Rotating Cylinder Electrode

Abstract

5.1 Selection of corrosion inhibitor for oil field and refinery applications involves qualification of corrosion inhibitors in the laboratory (see Guide G170). Field conditions should be simulated in the laboratory in a fast and cost-effective manner (1).3 5.2 Oil field corrosion inhibitors should provide protection over a range of flow conditions from stagnant to that found during typical production conditions. Not all inhibitors are equally effective over this range of conditions so that is important for a proper evaluation of inhibitors to test the inhibitors using a range of flow conditions. 5.3 The RCE is a compact and relatively inexpensive approach to obtaining varying hydrodynamic conditions in a laboratory apparatus. It allows electrochemical methods of estimating corrosion rates on the specimen and produces a uniform hydrodynamic state across the metal test surface. (2-21) 5.4 In this practice, a general procedure is presented to obtain reproducible results using RCE to simulate the effects of different types of coupon materials, inhibitor concentrations, oil, gas and brine compositions, temperature, pressure, and flow. Oil field fluids may often contain sand. This practice does not cover erosive effects that occur when sand is present.