Electrochemical Kinetic of a Low Carbon Steel in Seawater at Different Flow Speed
- PDF / 415,519 Bytes
- 8 Pages / 432 x 648 pts Page_size
- 49 Downloads / 187 Views
Electrochemical Kinetic of a Low Carbon Steel in Seawater at Different Flow Speed A. Carmona1, R. Orozco-Cruz1, E. Mejía-Sánchez1, A. Contreras2, R. Galván-Martínez1* 1
Unidad Anticorrosión, Instituto de Ingeniería, Universidad Veracruzana, Av. S.S. Juan Pablo II s/n, Fracc. Costa Verde, C.P. 94294, Veracruz, México. * E-mail: [email protected]
2
Instituto Mexicano del Petróleo, Eje Central Lázaro Cárdenas Norte No.152, Col. San Bartolo Atepehuacan, Del. Gustavo A. Madero, C.P. 07730, México.
ABSTRACT An electrochemical impedance spectroscopy (EIS) corrosion study of API X70 steel was carried out in synthetic seawater with different rotation speeds using a rotating cylinder electrode (RCE) to control the hydrodynamic conditions at room temperature, atmospheric pressure and 24 h of exposure time. A superficial analysis through a scanning electron microscope (SEM) was used to analyze the corrosion type. The rotation speed used was 0 rpm (static condition), 1000, 3000 and 5000 rpm (turbulent flow). The results show that the turbulent flow conditions affect directly the corrosion rate (CR) of the steel, because all values of the CR under turbulent flow conditions are higher than the CR values at static conditions. In addition, it is important to point out that at turbulent flow conditions, the CR increased as the rotation speed also increased. The morphology of the corrosion in all experiments was localized corrosion.
INTRODUCTION The majority of processes in the oil industry involve the hydrocarbons transport, where this hydrocarbon could be a mix of the liquid or gas with water or humidity and it is transported by steel pipeline [1]. The most common steels used in the hydrocarbons transport belong to the 5L specification of the American Petroleum Institute (API) specifically the steels X52, X60 and X70 [2]. All studies are focused mainly in the API steel corrosion under static conditions, but it is important to point out that the principal regimen in the industry and specifically in pipeline of hydrocarbons transport is the turbulent flow; however, few corrosion studies in controlled turbulent flow conditions are available. With the increasing necessity to describe the corrosion of metals in turbulent flow conditions, some laboratory hydrodynamic systems have been used with different degrees of success [3]. The rotating cylinder electrodes (RCEs), pipe segments, concentric pipe segments, submerged impinging jets and close-circuit loops have been used as hydrodynamic systems in order to study the corrosion phenomenon under turbulent flow conditions [3-6]. The use of RCE, as a laboratory hydrodynamic test system, has been gaining popularity in corrosion studies under turbulent flow conditions [6-8]. This popularity is due to its characteristics such as, its operation mainly in turbulent flow conditions, its well-defined hydrodynamics, ease assembly and disassembly and smaller volume of fluid used [9-11]. In
73
order to analysis the corrosion process of the steel sample, the electrochemical impedance spectroscopy (E
Data Loading...
