On a Probable Catalytic Interaction between Magnetite (Fe3O4) and Petroleum

Magnetic and nonmagnetic iron compounds were detected as part of asphaltene deposits formed on tubing wall surface. To shed light on the probable role of the iron compounds in the formation of such deposits, magnetite (Fe3O4), one of the intrinsic components of the iron oxide multilayer scale of any carbon steel surface, was contacted with crude oil at 170 °C, a temperature similar to that of the bottom well, and subsequently aged at room temperature. Characterization of the samples was made by using XRD, Mo¨ssbauer, IR, TGA, EDS, and microscopic (SEM and TEM) techniques. Small amounts of new iron phases, magnetic (oxidized magnetite) and nonmagnetic (iron oxyhydroxides), an increase in the content of CdC and C-O bonds of the organic phase, and an increase of the thermal stability of the organic phase indicated the formation of iron complexes of Fe ions and FeOOH with the oxygen functionalities

Formation of petroleum organic deposits on steel surfaces

An adhered organic deposit, formed within the petroleum well on the steel surface of the tubing walls, was systematically characterized following a sequence of bulk and surface techniques. The results allowed the identification of the tubing wall and its internal surface structures. As a consequence of the contact with sulphur-bearing compounds such as H2S and brine from petroleum, the pre-oxidized steel surface was modified by non-stoichiometric iron compound formation. These new iron phases favour adsorption and chemisorption of the petroleum polar compounds on the steel surface. Copyright  2002 John Wiley & Sons, Ltd

Effect of temperature on the level of corrosion caused by heavy petroleum on AISI 304 and AISI 444 stainless steel

This work presents a study on the influence of national heavy petroleum in the corrosion of the AISI 444 and AISI 304 stainless steels in simulated refining operation conditions. The petroleum was first characterized through physicochemical analysis (density, fluidity point, viscosity, sulfur concentration). In an attempt to understand the corrosion effect of temperature and of the type of heating the referred types of steel thermal treatments were carried out at three levels of temperature (200, 300 and 400 °C). The procedure was done in conditions close to those in the distillation column. Heat was gradually increased from room temperature, and directly heated to working temperature. Each treatment took 4 hours to be completed. Scanning electronic microscopy (SEM) and the analysis of X rays dispersive energy (EDX) were used after the trials to characterize the samples. The results show that treatment temperature, as well as the type of heating, has distinct influences on each type of steel