Physical-chemical transformations of iron corrosion products in oil facilities

Abstract

The main construction material of oil facilities is carbon steel. The exposition in some media such as atmosphere, waters or others, cause notable affectations due to the corrosion phenomenon. In the investigation, a study of corrosion products that were generated during the atmospheric corrosion process, were carried out in an oil treatment battery. The time interval selected for the study was one year, making evaluations since the first month of exposition. The objectives of this study are to determine physic-chemical properties of phases, by means of solid product characterization techniques, using FTIR (infrared spectroscopy) and XRD (X-ray diffraction) of the corrosion products to obtain the sortometric and porosimetric properties of the solid phases. The lepidocrocite (γ-FeOOH) claim to the orthorhombic crystallographic system, of punctual groups: 2 / m 2 / m 2 / m and magnetite (Fe3O4) was identified with the isometric system. The crystallines sizes were obtained by the area .of the high intensity DRX peak: 10 Å, 9 Å and 8 Å (γ-FeOOH, α-FeOOH and Fe3O4 respectively). The phase of smaller particle size belonged to the Fe3O4, which showed greater physical-chemical reactivity because it presented the upper surface area (39 m2 / g). The iron transformation effects in the three varieties presented positive enthalpies. The disorder component generated changes in the nature phases. The transformation mechanisms responded to: