Electrochemical Noise (ECN) and Electrochemical Impedance Spectroscope (EIS) measurements were made simultaneously in a 75 mm I.D., 10 m long acrylic pipeline using salt-water/carbon dioxide mixtures. Full pipe flow was studied for liquid velocities of 0.5, 0.75, 1.1, 1.5 m/s and slug flow for Froude numbers 4, 6 and 9. Experiments were carried out at a constant pressure of 136 kPa and temperature of 40 C. ECN data were measured with a fast auto zero resistance ammeter. The ECN technique is able to detect changes in flow regime, showing distinct differences between full pipe flow and slug flow. The choice of sampling rate when using ECN is very important. For slug flows, sampling rates as high as 100 Hz are necessary to include most of the transients in the flow. Distinct differences can be seen in the Fast Fourier Transforms where dominant frequencies exist which correspond to possible bubble action in the slug body. EIS can be used to measure corrosion rate in multiphase flows. It does show an increase in the corrosion rate with liquid flow rates for full pipe flow and Froude numbers for stationary slug flow. A simple statistical analysis of ECN response gives a correlation withmore » corrosion rate. These show ECN could be a very powerful tool for determining corrosion rate and corrosion mechanism in multiphase flow.« less

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Comparison Of Ecn And Eis Measurement For Corrosion Monitoring Under Multiphase Flow Conditions

Corrosion behavior of oil tube steels under conditions of multiphase flow saturated with super-critical carbon dioxide

Predictive Model for Sweet Corrosion in Horizontal Multiphase Slug Flow

The ability to analyze different electrochemical corrosion phenomena, in–situ, without requiring any form of electrode perturbation has strongly attracted the attention of corrosion researchers tow...

Electrochemical noise (EN) technique: review of recent practical applications to corrosion electrochemistry research

Corrosion inhibitor studies in large flow loop at high temperature and high pressure

Sweet corrosion in carbon steel pipelines carrying oil-water mixtures has long been a problem in the oil industry. A study to determine the corrosion rates and the type of deposits formed on the pipe surface under such multiphase flow conditions is described. Full pipe flow and slug flow conditions and the effect of a few inhibitors is studied. Temperatures up to 60C and several pressures, flow rates, oil-water fractions are also studied.

W.P. Jepsom

Papers

Study Of Sweet Corrosion In Horizontal Multiphase, Carbon Steel Pipelines