The Research Of P92 Steel Oxidation Kinetics Considering Of The Oxide Scale Voids In Supercritical Water

Thermal power is the main way of generating in China. In recent years, with the increasing attention to the environment and energy efficiency issues, developing the supercritical (ultra-supercritical) unit is the most promising direction of thermal power development. However, the requirement of the reheater material performance in supercritical (ultra-supercritical) unit pipeline is very strict, while the oxidation corrosion of materials under such condition jeopardizes the boiler safety as well as the efficiency of the entire plant. Therefore, it is particularly necessary to conduct the research of the oxidation resistance of these materials in power plant.The Thirteenth Five-year Plan instructs that coal will still be the main part of energy costing in recent years. As the environment getting worse and worse, researching more effective and cleaner method to use coal is more and more important to help release the pressure causing of pollution. So we have to pay enough attention to develop high-parameter, large-capacity thermal power units. At the same time, with the increase of both temperature and pressure, the metal material in thermal power units need to be researched and improved.Because the steam parameters are getting higher and higher, oxidation occurring on thermal power units metal materials becomes worse, more researchers focus on finding ways to solve this problem by studying units metal oxidation kinetics. The voids in scale are proved causing scale falling and the deviation of kinetics lines. Considering of the voids in scale, this article revises P92 steel oxidation kinetics in supercritical water.The supercritical water oxidation experiment is executed in different temperature 550℃ and 600℃, different oxygen content 0,100,300,2000 ppb, and different oxidation time 200,400,600,800 hours. Observe the voids morphology with Scanning Electron Microscopy after grounding samples in a small angle, count and analysis the porosity data. Study the influences of oxidation time, oxygen content and temperature to scale voids. Propose and explain voids self-healing mechanism.Fit proper oxidation kinetics formula, combined with porous medium theory, according to the oxide film porosity variation with time. Coupling the fitting formula and widely used Wagner classical oxidation kinetics to revise P92 oxidation kinetics in supercritical water.