Institute for Energy Technology

About: Institute for Energy Technology is a facility organization based out in Lillestrøm, Norway. It is known for research contribution in the topics: Computer science & Neutron scattering. The organization has 295 authors who have published 305 publications receiving 5271 citations. The organization is also known as: Institutt for Energiteknikk.

An Electrochemical Model for Prediction of Corrosion of Mild Steel in Aqueous Carbon Dioxide Solutions

Abstract: A predictive model was developed for uniform carbon dioxide (CO2) corrosion, based on modeling of individual electrochemical reactions in a water-CO2 system. The model takes into account the electrochemical reactions of hydrogen ion (H+) reduction, carbonic acid (H2CO3) reduction, direct water reduction, oxygen reduction, and anodic dissolution of iron. The required electrochemical parameters (e.g., exchange current densities and Tafel slopes) for different reactions were determined from experiments conducted in glass cells. The corrosion process was monitored using polarization resistance, potentiodynamic sweep, electrochemical impedance, and weight-loss measurements. The model was calibrated for two mild steels over a range of parameters: temperature (t) = 20°C to 80°C, pH = 3 to 6, partial pressure of CO2 (PCO2) = 0 bar to 1 bar (0 kPa to 100 kPa), and ω = 0 rpm to 5,000 rpm (vp = 0 m/s to 2.5 m/s). The model was applicable for uniform corrosion with no protective films present. Performance of...

Role of Conductive Corrosion Products in the Protectiveness of Corrosion Layers

Abstract: In carbon dioxide (CO2) corrosion of steels, the bicarbonate ion (HCO3−) is simultaneously the buffer for carbonic acid (H2CO3), the source of iron carbonate (FeCO3) precipitation, and the product of the cathodic reaction. In addition to spatial separation of the production of Fe2+ and HCO3−, galvanic coupling between the steel and cementite (Fe3C) layers is the principal cause of internal acidification in these layers, since the HCO3− ions are removed from the steel surface by electromigration. This can facilitate localized corrosion by lateral galvanic coupling. This mechanism explains the role of traces of free acetic acid (CH3COOH, or HAc) and the existence of multiple steady states. Transposition to corrosion of iron by hydrogen sulfide (H2S) or to corrosion of copper is discussed.

Neutron diffraction refinement of the structure of gypsum, CaSO4.2H2O

Abstract: The crystal structure of gypsum, CASO4.2H20, has been refined to R w -0.023 and R -0.036 for 610 neutron diffraction intensities collected at room temperature (294 K) for a unit cell with a = 5.679 (5), b = 15.202 (14), c 6.522 (6) A, fl 118.43 (4) °, and space group I2/a, Z = 4, V = 495.2 A a, d c = 2.3 g cm -3. The refinement was based on a model with anisotropic thermal motion for all atoms, and an isotropic secondary-extinction coefficient. The O H bonds of the water molecule are 0.942(3) and 0.959 (3)A and hence significantly different. The difference, 0.017 (4)A,, is in accordance with spectroscopic stretching-frequency differences for the two O H bonds. The water molecule donates two hydrogen bonds of 1.856 (2) and 1.941 (2) A to sulfate O atoms. The shortest hydrogen bond is not linear, the O H . . . O angle being 170.9 (2) °, whereas the other bond has an angle of 177.2 (2) °. H H is 1.533 (3) A and H O H 107.5 (2) °. The sulfate ion is definitely not a regular tetrahedron. The S O distances are equal [1.474 (1) and 1.471 (1)A], but the O S O angles are not [111.1(1), 111.0(1), 111.1(1) and 106.3 (1)°], leading to differences in the O O tetrahedral edges [2.429 (1), 2.432 (2), 2.426 (2) and 2.357 (1)A]. The shortest edge is shared between the sulfate tetrahedron and the square-bipyramidal CaO s group.