Corrosion of Pipe Steel in CO2 Containing Impurities and Possible Solutions

Abstract

CO2 flue gases acquired from different sources contain a significant amount of impurities and water, which are corrosive to the pipeline steel. To design the pipelines for large scale of CO2 flue gas transport, the corrosion of pipeline steels has to be investigated in the realistic conditions. In this paper, corrosion behaviour of steel S355 and stainless steel 316L in CO2 flue gas solutions has been investigated using electrochemical techniques in an autoclave. The corrosion rates of the steels in different environments were measured by polarization and mass loss measurements. The corrosion morphology and products on the steel surface were analyzed by photo- And electron microscope and x-ray diffraction, respectively. Three types of polymer coatings on the steel S355 have been studied in 3.5% NaCl solution plus CO2 in the autoclave at 100 bar and 60°C. The corrosion resistance of the coatings has been measured by electrochemical impedance measurements. The structures and the adhesion of the coatings before and after the autoclave tests have been investigated using microscope and pull-off test. The results show that the Coating B has better corrosion resistance than the other two types of coatings, which is a good candidate for internal coatings of a pipeline. © 2013 The Author.