11085 A New Methodology for Monitoring Corrosion Under Sales Gas Conditions Using the Quartz Crystal Microbalance

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Product Number: 51300-11085-SG

ISBN: 11085 2011 CP

Author: Kyle Cattanach, Vladimir Jovancicevic, Sunder Ramachandran and Abdelmounam M. Sherik

Publication Date: 2011

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A new method for determining the mass change due to oxidation of iron and the associated corrosion rate under sales gas conditions using the quartz crystal microbalance (QCM) is presented. The method involves four steps: 1) determining the overall frequency change of QCM, 2) subtracting the frequency change due to water film formation from the total frequency change, 3) calculating the resulting mass change of the QCM, and 4) determining the corresponding corrosion rates. In this paper, QCM is used to determine the effects of critical system parameters such as ?T/relative humidity, oxygen partial pressure, and carbon dioxide partial pressure on the QCM weight gains and the corresponding corrosion rates. The relative humidity (RH) of the gas system and temperature difference (?T) between the gas and the metal surface play a critical role in determining the iron oxide formation and associated corrosion rates. The RH determines the thickness of the water condensation layer on the metal surface that in turn controls the corrosion rate. Some uncertainty with maintaining the water film thickness was observed. The results show that there is an increase in corrosion rate with increasing oxygen partial pressure. For a system with oxygen partial pressure of 0.2 psia, carbon dioxide was shown to have little effect on the oxide formation and corrosion rate.

Keywords: Black powder, corrosion testing, carbon dioxide corrosion, oxygen corrosion, quartz crystal microbalance