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Superheaters (SH) and reheaters (RH) in modern supercritical (SC) and ultra supercritical (USC) coal-fired steam power plants operate with maximum steam temperatures between 580 and 620°C and pressures up to [...]

Alumina scales that do not satisfy the conditions necessary to apply the Wagner oxidation theory is identified claimed by authors. It is revealed that the growth of alumina scales is by charged species and that the alumina growth rate could be altered by an applied current.

Several power generation technologies have interest in employing a supercritical CO2 (sCO2) cycle but relatively little compatibility work has been conducted at the target pressure range of 200-300 bar, particularly at ≥700 °C. With the goal of utilizing lower pressure data sets (especially with controlled O2 and H2O contents), this initial assessment compared the effect of CO2 pressure at 1-300 bar on the compatibility of potential Fe- and Ni-base structural alloys after 500 h exposures at 750 °C. For highly-alloyed alumina- and chromia-forming alloys, a minimal effect of pressure was observed on the mass change and reaction products, which were similar to those observed in 1 bar dry air, CO2, CO2-0.15%O2 and CO2-10%H2O. After these relatively short exposures, there was no obvious indication of internal carburization and the Cr depletion in the precipitation strengthened Ni-base alloys (740 and 282) was minimal. In addition to coupons, 25 mm long tensile specimens of alloy 740, 247, 310HCbN, and E-Brite (Fe-Cr) were exposed in each condition but did not show any detrimental effect of the high-purity CO2 environments on room temperature tensile properties. [ABSTRACT FROM AUTHOR]