TY - CONF A1 - Hünert, Daniela T1 - Corrosion of steels in H2O-CO2 atmospheres between 500°C and 700°C T2 - 15th International Conference on the Properties of Water and Steam CY - Berlin, Germany DA - 2008-09-07 PY - 2008 AN - OPUS4-18051 LA - deu 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 - 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 - CONF A1 - Hünert, Daniela T1 - Carburization and Oxidation of Power Plant Steels under Oxyfuel-Conditions N2 - Modern CO2-reduced power plants with Oxyfuel-Combustion operate with gas compositions of high CO2 partial pressure and steam (Boiler, Recycling). The corrosion process occurring under such service conditions is different from that under current conditions with air combustion. The effect of temperature, pressure, chromium content on the corrosion reaction of typical power plant steels in CO2 -H2O and CO-H2O-O2 was investigated. T2 - 3rd World Materials Research Institute Forum & Energy Symposium (WMRIF) CY - Gaithersburg, MD, USA DA - 21.06.2009 PY - 2009 AN - OPUS4-22625 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hünert, Daniela T1 - Impact of hot CO2 rich gases on steels T2 - Clean Coal Conference (CCT) CY - Dresden, Germany DA - 2009-05-18 PY - 2009 AN - OPUS4-22714 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hünert, Daniela T1 - Simultaneous Oxidation and Carburization under Oxyfuel conditions T2 - Eurocorr 2009 CY - Nice, France DA - 2009-09-06 PY - 2009 AN - OPUS4-22676 LA - deu 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 -