TY - JOUR A1 - Kranzmann, Axel A1 - Neddemeyer, Torsten A1 - Ruhl, Aki Sebastian A1 - Hünert, Daniela A1 - Bettge, Dirk A1 - Oder, Gabriele A1 - Saliwan Neumann, Romeo T1 - The challenge in understanding the corrosion mechanisms under oxyfuel combustion conditions N2 - Basic research on the corrosive effect of flue gases has been performed at the BAM Federal Institute for Materials Research and Testing (Germany). Conditions at both high and low temperatures were simulated in specially designed experiments. Carburization occured in flue gases with high CO2 content and temperatures higher than 500 °C. In SO2 containing flue gases sulphur was detected in the oxide scale. At lower temperatures no corrosion was observed when gases with low humidity were investigated. Humidity higher than 1500 ppm was corrosive and all steels with Cr contents lower than 12% revealed corroded surfaces. At low temperatures below 10 °C a mixture of sulphuric and nitric acid condensed on metal surfaces. Acid condensation caused severe corrosion. Humidity, CO2, O2, and SO2 contents are the important factors determining corrosion. Below 300 °C acid condensation is the primary reason for corrosion. Low humidity and low temperatures are conditions which can be expected in the CO2 separation and treatment process. This work includes major conditions of the flue gas and CO2 stream in CCS plants and CCS technology. KW - Coal KW - Oxyfuel power plant KW - Corrosion KW - Carburization KW - Sulphur KW - Sulphuric acid PY - 2011 U6 - https://doi.org/10.1016/j.ijggc.2011.05.029 SN - 1750-5836 VL - 5 IS - Supplement 1 SP - S168 EP - S178 PB - Elsevier CY - New York, NY [u.a.] AN - OPUS4-24705 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hünert, Daniela A1 - Kranzmann, Axel T1 - Impact of oxyfuel atmospheres H2O/CO2/O2 and H2O/CO2 on the oxidation of ferritic-martensitic and austenític steels N2 - In future power plant technologies, oxyfuel, steels are subjected to steam rich and carbon dioxide rich combustion gases. The effect of simulated combustion gases H2O/CO2/O2 (30/69/1 mol%) and H2O/CO2 (30/70 mol%) on the corrosion behavior of low alloyed steels, 9-12% chromium steels and an austenitic steel were studied. It was discovered that the formation of protective chromium rich oxides is hampered due to the carburization of the base material and the formation of chromium rich carbides. The kinetics of corrosion and carburization are quantified. The effect of temperature and the effect of gas pressure are analyzed statistically. KW - A. Steel KW - C. Oxidation KW - C. Carburization KW - C. High temperature corrosion PY - 2011 U6 - https://doi.org/10.1016/j.corsci.2011.03.015 SN - 0010-938X VL - 53 IS - 6 SP - 2306 EP - 2317 PB - Elsevier CY - Orlando, Fla. AN - OPUS4-23833 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 - Hünert, Daniela A1 - Schulz, Wencke A1 - Kranzmann, Axel 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 A1 - Schulz, Wencke A1 - Nitschke, Heike A1 - Saliwan Neumann, Romeo A1 - Oder, Gabriele A1 - Kranzmann, Axel T1 - Corrosion behaviour of ferritic and martensitic power plant steels under conditions of dual atmospheres T2 - NACE 2009 CY - Atlanta, GA, USA DA - 2009-03-22 PY - 2009 AN - OPUS4-22713 LA - deu 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 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 - CONF A1 - Hünert, Daniela A1 - Schulz, Wencke A1 - Kranzmann, Axel 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 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 A1 - Schulz, Wencke A1 - Nitschke, Heike A1 - Saliwan Neumann, Romeo A1 - Oder, Gabriele A1 - Kranzmann, Axel T1 - Corrosion behaviour 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 simultaneously exposed to combustion gas and air/steam on their opposite surfaces. The corrosion behaviour of ferritic-martensitic steels under such dual atmospheres is nondistinctive and has therefore been investigated in a special designed test equipment between 500 and 620°C. The power plant conditions were simulated wi th a flowing and pressurised (80 bar) combustion gas on the inner side of the tube which mainly consists of H2O and/or CO2. On the outer side, the tube material was exposed to air. It was discovered that under similar temperatures the oxides formed on the air side under dual atmosphere conditions were significantly different to the oxide scales formed when the alloy was exposed to air only. It is assumed that the anomalous corrosion behaviour during the dual atmosphere exposure is due to the hydrogen transport through the bulk alloy from the combustion gas side to the air side. T2 - NACE International corrosion conference 2009 CY - Atlanta, Georgia, USA DA - 2009-03-22 KW - High temperature corrosion KW - Dual atmosphere KW - Corrosive gases KW - Mild steels KW - 9-12% Cr-steels KW - Hydrogen transport PY - 2009 SP - 1 EP - 10 (Paper 09263) AN - OPUS4-22335 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 -