Abstract

TORRES ISLAS, Álvaro  and  SERNA BARQUERA, Sergio. Electrochemical evaluation of a protective film by the carboxiamidoimidazoline inhibitor on a new microalloyed pipeline steel, under sour environment. Rev. Soc. Quím. Perú [online]. 2008, vol.74, n.2, pp.125-137. ISSN 1810-634X.

The results of the evaluation of a carboxiamidoimidazoline corrosion inhibitor by means of electrochemical impedance spectroscopy (EIS) and electrochemical noise analysis (ENA) are reported. A new microalloyed pipeline steel was used to perform the electrochemical tests under sour environment in the presence of the corrosion inhibitor. The sour environment in which steel coupons were immersed simulates the composition of an aqueous phase during the production and transportation of natural gas at 50 ºC with oxygen removal by means of high purity nitrogen gas flux. Carboxiamidoimidazoline inhibitor formulation was tested in five different concentrations in parts per million (ppm). EIS and ENA data were analyzed as indicators for monitoring the development of a protective film by the inhibitor. It was found that the maximum inhibiting efficiency, IE, was of approximately 80% having added only 5 and 10 ppm. Moreover, this compound have a good persistency in steel surface that follows and adsorption mechanism, which can be adequately described by the Temkin isotherm.

Keywords : Carboxi-amido-imidazoline; sour environmen; microalloyed steel; electrochemical test.

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