EFFECT OF ULTRASOUND ON CO_2 CORROSION AND THE DEVELOPMENT OF A SLUG FLOW SIMULATOR

摘要

This paper outlines the development of an ultrasound-based, bench-top test to measure the effectiveness of corrosion inhibitors when subjected to cavitating bubbles. It is proposed that the cavities produced by an ultrasonic probe are analogous to the collapsing bubbles that are found in the mixing region of slug flow; a type of flow that is common in multiphase pipelines. Therefore the test is a rapid and economical way of evaluating inhibitors under the regime of slug flow. Linear polarisation resistance measurements were made to determine the effect of ultrasound on the corrosion rate of carbon steel electrodes in a 1M sodium chloride (- 6 percent w.v.) solution saturated with CO_2. Inhibitors that perform well in the bubble test, including two commercial inhibitors that inhibit to virtually identical corrosion rates, making inhibitor selection difficult, have been subjected to the new test. In the ultrasound-based test the inhibitors are clearly distinguishable.