TY - GEN A1 - Pfennig, A. A1 - Linke, B. A1 - Kranzmann, Axel T1 - Predicting the long term corrosion behaviour of pipe steels used at the CCS-site Ketzing, Germany in laboratory CO2-saturated saline aquifer CCS-environment T2 - First international conference on materials for energy CY - Karlsruhe, Germany DA - 2010-07-04 KW - CCS KW - Corrosion KW - Steels KW - Injection pipe PY - 2010 SN - 978-3-89746-117-8 IS - Paper 1067 SP - 1005 EP - 1007 AN - OPUS4-21684 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pfennig, Anja A1 - Kranzmann, Axel T1 - Oxidation of a single crystal nickel-base superalloy at 950 °C - a kinetic and microstructure study N2 - The nickel-base single crystal alloy investigated is a widely used material for first and second row blades in stationary gas turbines. Nickel-base superalloys are especially designed to resist high temperature oxidation by process gases. To determine this high temperature behaviour oxidation testing was carried out using samples cut perpendicular to (001)-direction. Microstructures were characterized by X-ray diffraction XRD, Light Microscopy LM, Scanning Electron Microscopy SEM, and X-ray energy dispersive spectroscopy (EDS), after a series of heat treatments (950 °C, 0 h - 1000 h). Mass gain and the respective thicknesses of the different oxide layers were measured to determine oxidation kinetics. In general, the isothermal oxidation behaviour at 950 °C, as defined by weight gain, follows a parabolic law with a parabolic rate constant around 1.4 · 10-2 mg2/(cm4 · h). A short incubation time is followed by the constitution of a multi-layered oxide scale. The oxide scale consists of a three layer structure. An outer scale contains a Ti-bearing thin film associated as TiO2 and NiTiO3 but mostly Cr attributed to Cr2O3, (Ni/Co)Cr2O4 beside NiTaO4. This outer scale is connected to a discontinuous layer of inner oxidation consisting mainly of Al2O3, which is followed by an area of γ´-depletion within the base material. PY - 2008 SP - 1 EP - 9 AN - OPUS4-17263 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hünert, Daniela A1 - Schulz, Wencke A1 - Kranzmann, Axel ED - Roland Span, ED - Ingo Weber, T1 - Corrosion of steels in H2O-CO2 atmospheres at temperatures between 500°C and 700°C N2 - The introduction of carbon capture technology into thermal power plants benefits from combustion of fuel and pure oxygen due to high partial pressures of CO2 in the flue gas. The consumption of energy for carbon capture devices and oxygen production plants has to be compensated by higher efficiencies of the power plant. Consequently IGCC plants with 80 bar reactors and high temperature turbine equipment, boilers with 700 °C steam raising units will be the next generation power plants. All plants have in common locally in the process gas compositions with high CO2 partial pressure and steam. In our test we applied a gas composition with 30% H2O and 70% CO2 an composition in between the water content of coal burned in pure oxygen and Methane-oxygen combustion. Additional gas fractions such as SO2 will be added in coming experiments. In this paper we discuss the attack of our model gas composition on different typical power plant construction steels with chromium contents in the range of 1 to 24%. The test conditions were annealing time up to 1000 h, 80 bar pressure, fast flowing gas and temperatures between 500 and 700°C depending on the maximum working temperature of the individual steel. Dependent on the test parameters and in particular the chromium content the oxide scale growth mechanism, the scale thickness, the scale microstructure and phase sequences differed. In particular we observe the growth of FeO at temperatures lower than 570°C which is the eutectic decomposition temperature in the Oxygen-iron phase diagram. Iron carbides are primarily formed in low alloyed steels near the oxide steel interface. The steels studied containing more then 9% chromium the growth of Fe3O4 and Fe-Cr-Spinel was typical. Co and W influenced the reaction in 9 - 12% Cr-steel. The attrition of Mn and other alloying additions was monitored. In no case a dense and protective Cr2O3 or an other Metal-Cr-oxide layer was observed. The oxide scale thickness increases strongly with temperature and decrease with raising chromium content. Data of oxide scale thickness up to corrosion time of 1000 h will be presented. A model will be presented, which deals with possible reactions paths during the corrosion processes in flowing CO2 and water. The steels can be arranged according the reaction with gas and their alloying elements such as Mn, Co and W. In the test environment the maximum working temperature of the steels decreased 50K compared to working temperature in current power plant environment. T2 - 15th International Conference on the Properties of Water and Steam (ICPWS XV), "Water, Steam, and Aqueous Solutions - Advances in Science and Technology for Power Generation" CY - Berlin, Germany DA - 2008-09-07 KW - High temperature corrosion KW - 9-12% Cr-steels KW - H2O-CO2 PY - 2008 SN - 978-3-931384-64-7 IS - Session 06: Electro-12 SP - 1 EP - 7 AN - OPUS4-19061 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kranzmann, Axel A1 - Hünert, Daniela T1 - Technologien für den Klimaschutz und ihre Anforderungen an Werkstoffe N2 - Der Klimaschutz erfordert die Reduzierung des Ausstoßes von Kohlendioxid. Neue Kraftwerke mit Sauerstoffverbrennung und möglicherweise CO2-Abscheidung sollen eine Reduktion des CO2 im Bereich der Energietechnik ermöglichen. Die heute üblichen Hochtemperaturwerkstoffe werden anderen Umgebungsbedingungen ausgesetzt, und es sind andere Korrosionsraten und Korrosionsreaktionen zu erwarten. In diesem Beitrag werden die Kraftwerkstechnologien kurz vorgestellt und an einem Beispiel erläutert, dass die Oxidation an Luft mit der Oxidation in Wasser nicht direkt vergleichbar ist. KW - Klimaschutz KW - CO2-arme Kraftwerke KW - Werkstoffe PY - 2006 DO - https://doi.org/10.1002/cite.200600030 SN - 0009-286X SN - 1522-2640 VL - 78 IS - 12 SP - 1809 EP - 1817 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-19040 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hünert, Daniela A1 - Kranzmann, Axel T1 - Influence of pressure and chromium content on corrosion reactions at 600°C in a CO2-H2O atmosphere T2 - NACE - International Corrosion Conference CY - New Orleans, USA DA - 2008-03-16 KW - High temperature corrosion KW - Corrosive gases KW - Mild steels KW - 9-12% Cr-steels KW - Pressure effect PY - 2008 SN - 0010-9312 SN - 1938-159X IS - Paper No. 08447 SP - 1 EP - 19 PB - National Association of Corrosion Engineers CY - Houston, Tex. AN - OPUS4-19041 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Pfennig, Anja A1 - Linke, Barbara A1 - Kranzmann, Axel T1 - Carbon capture and storage technique (CCS): Reliability of pipe steels used in Ketzin, Germany verified in laboratory saline aquifer corrosion experiments N2 - During the compression emission gasses in deep geological layers (Carbon Capture and Storage, CCS) CO2-corrosion will become a relevant safety issue. The reliability of the steels used at the geological onshore CCS-site at Ketzin, Germany, (heat treated steel 42CrMo4 (1.7225, AISI 4140) used for casing, and the martensitic stainless injection pipe steels X46Cr13 (1.4034, AISI 420 C), X20Cr13 (1.4021, AISI 420 J), X35CrMo17 (1.4122)) is demonstrated in 1 and 2 years laboratory experiments. Samples were kept in a synthetic aquifer environment similar to the geological CCS-site at Ketzin, Germany at T=60 °C. This corrosive environment is then saturated with technical CO2 at a flow rate of 3 l/h. Microstructures were characterized by X-ray diffraction, light microscopy, scanning electron microscopy, and energy dispersive X-ray, after a series of heat treatments (700 h to 2 years). Due to very slow mass loss at extended exposure times to CCS-environment one year is sufficient to predict stable surface corrosion rates from laboratory experiments. The non-linear isothermal surface corrosion behaviour of the steels reveals surface corrosion rates around 0.1 to 0.8 mm/year, when obtained by mass gain. The loss of the base material is higher when calculated from the corrosion layer magnitude due to the unpredictable local corrosion attacks. Severe pit corrosion (pit heights ca. 4.5 mm) are only located on the high chromium steels. Main phases of the continuous scales are siderite FeCO3 and goethite α-FeOOH. The formation of the non-protective layer is likely to form via a transient Fe(OH)2-phase. T2 - MWWD & IEMES 2010 - 6th International conference on marine waste water discharges and coastal environment CY - Langkawi, Malaysia DA - 2010-10-25 KW - Saline aquiver KW - Environmental issues KW - CCS KW - CO2-injection KW - CO2-storage KW - Corrosion KW - Phase formation PY - 2010 SN - 978-9944-5566-4-4 IS - Paper 047_P SP - 1 EP - 17 AN - OPUS4-22333 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kranzmann, Axel A1 - Hünert, Daniela A1 - Rooch, Heidemarie A1 - Urban, Ingrid A1 - Schulz, Wencke A1 - Österle, Werner T1 - Reactions at the interface between steel and oxide scale in wet CO2 containing atmospheres N2 - The resistance of structural steels against corrosion in CO2-H2O and CO2-H2O-O2 atmospheres at temperatures above 550°C was observed with high magnification methods. The test atmosphere is the basic composition of an oxyfuel coal combustion atmosphere. The analytical information base was applied to develop reaction schemes for the oxidation of steels. It was demonstrated that the formation of phases and the kinetics of oxidation reactions in this atmospheres is affected by the formation of intermediate iron hydroxide and a high carbon activity. In the temperature regime above 550°C the thermal equilibrium between H2O, CO2 and Fe reacted and formed CO. CO triggers the formation of FeO and carbides and increases the reaction kinetics. Porosity at the interface is established by gaseous phases such as Fe(OH)2 or H2O. H2 formation is not limited to the steel - oxide interface but can occur in the whole oxide scale. Examples of the experimental results were compared with a thermodynamic approach. The objective of the work was to derive qualitative rules of the basic corrosion reactions. T2 - NACE International corrosion conference 2009 CY - Atlanta, Georgia, USA DA - 2009-03-22 KW - High temperature corrosion KW - Corrosion gases KW - Mild steels KW - 9-12% Cr-steels KW - Hydrogen transport KW - Oxyfuel combustion PY - 2009 SP - 1 EP - 10 (Paper 09265) AN - OPUS4-22334 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hünert, Daniela A1 - Schulz, Wencke A1 - Kranzmann, Axel T1 - Simultaneous oxidation and carburization under oxyfuel conditions N2 - The combustion of coal in CO2-reduced Oxyfuel power plants requires creep resistant and corrosion resistant materials, which can withstand high temperatures up to 600°C and CO2 rich atmospheres. Among the heat resistant materials, the 9-12% chromium steels are proven to resist high wall temperatures in conventional power plants and are suitable as membrane wall, superheaters and steam piping. During Oxyfuel combustion a flue gas is generated, which consists mainly of H2O (30 mol %) and CO2 (70 mol %). The present paper is focused on the corrosion of 9-12% chromium steels under oxyfuel conditions in a temperature range between 550 and 625°C. Depending on Chromium content of the 9-12%chromium steels, carburization of the base material, perlite formation and carbide formation were observed. Alloys with lower chromium content form a non protective oxide scale with perlite at the scale-alloy interface. Steels with 12% chromium have a small growing oxide scale with enlarged M23C6-particles at the scale-alloy interface. The carburization of the base material is found to be increased for the 9% Cr-steel. Higher pressure of the flue gas results in the formation of less resistant scales and cause accelerated carburization of the base materials. However, the carburization has an impact on the mechanical properties at the surface and leads to an embrittlement, which is deleterious during thermal cycling. Oxidation kinetics, phase analysis of the scale (transmission electron microscope) and carburization depths (microprobe) of the base materials are presented. T2 - EUROCORR 2009 CY - Nice, France DA - 2009-09-06 KW - High-temperature corrosion KW - Carburization KW - 9-12 % Cr-steel KW - M23C6-particles KW - Power plant steels PY - 2010 IS - Paper 7805 SP - 1 EP - 11 AN - OPUS4-22500 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hünert, Daniela A1 - Schulz, Wencke A1 - Kranzmann, Axel T1 - Corrosion behavior of ferritic and martensitic power plant steels under conditions of dual atmospheres N2 - The most efficient construction materials for boiler water walls and superheaters in steam power plants are ferritic and martensitic steels. In practical operation, tubes are exposed simultaneously to combustion gas and air/steam on their opposite surfaces. The corrosion behavior of ferritic-martensitic steels under such dual atmospheres is nondistinctive and has been investigated in a specially designed test equipment between 500°C and 620°C. The power plant conditions were simulated with a flowing and pressurized (80 bar) combustion gas on the inner side of the tube, which contains water (H2O) and carbon dioxide (CO2). On the outer side, tube material was exposed to air. Oxides that formed on the air side under dual atmosphere conditions were significantly different from the oxide scales formed when the alloy was exposed to air only. It is assumed that the anomalous corrosion behavior during the dual atmosphere exposure is due to hydrogen and carbon diffusion through the bulk alloy from the combustion gas side to the air side. Both species are produced when the material reacts with the gas phase. Because of its high diffusivity, hydrogen is thought to affect the corrosion process on the air side from the beginning of the corrosion exposure, whereas carbon reaches the opposite side after a considerably longer time period. KW - Chromium steels KW - Corrosive gases KW - Dual atmosphere KW - High-temperature corrosion KW - Hydrogen transport KW - Mild steel PY - 2010 SN - 0010-9312 SN - 1938-159X VL - 66 IS - 12 SP - 126001-1 - 126001-7 PB - National Association of Corrosion Engineers CY - Houston, Tex. AN - OPUS4-23217 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pfennig, A. A1 - Linke, B. A1 - Schulz, Sabrina A1 - Kranzmann, Axel T1 - CO2-corrosion of steels exposed to saline water environment N2 - With CO2 being one reason for climate change carbon capture and storage (CCS) is discussed to mitigate climate change. When emission gases are compressed into deep geological layers CO2-corrosion can easily cause failure of injection pipes. Different steels 42CrMo4, X46Cr13 and X20Cr13 were tested as well as X35CrMo17 and X5CrNiCuNb16-4 in a laboratory Environment similar to the conditions of the CCS engineering site at the Northern German Bassin. Samples were exposed to synthetic aquifer water saturated with technical CO2 at a flow rate of 3 NL/h. Corrosion rates obtained via mass loss vary in a wide range (0,005 to 2.5 mm/year). The precipitations within the corrosion scale revealed a complicated multiphase layer containing siderite FeCO3, goethite α-FeOOH, lepidocrocite γ-FeOOH, mackinawite FeS and akaganeite Fe8O8(OH)8Cl1,34 and spinelphases of various compositions. T2 - TMS 2011 - 140th Annual Meeting & Exhibition CY - San Diego, CA, USA DA - 27.02.2011 KW - CCS KW - Steel KW - Corrosion KW - Carbon Capture and Storage PY - 2011 DO - https://doi.org/10.1002/9781118062173.ch102 VL - 3 IS - 0807 SP - 807 EP - 814 AN - OPUS4-23472 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -