Objectives

• To supply industry with a predictive tool to determine the oxidation limit of materials in steam environments
• To further increase the knowledge and understanding of steam oxidation in steam environments
• To increase understanding of the influence of key experimental parameters on oxide scale formation

Introduction

Steam oxidation is a major concern for the UK power generation industry. Components in high temperature plant, such as steam pipework, are exposed to steam atmospheres over a range of temperatures and pressures. The upper limits of temperature and pressure are being increased to improve efficiency of the thermal plant. This increase in plant efficiency is of great importance and impacts on key political and quality of life concerns such as fuel reserves, legislative concerns (e.g Kyoto agreement) and helping to supply low cost electricity, which would benefit consumer industry, employment and exports. It has been estimated that a 20 °C increase in operating temperature could save the UK £ 0.5 billion per annum in power generation costs.

Within a previous UK government funded programme a range of the most commonly used laboratory based steam exposure techniques were investigated to establish whether different oxidation kinetics and scale morphologies resulted from the different procedures. This work demonstrated that although the oxidation kinetics are relatively unaffected by the different techniques, scale morphology differed depending on which technique was used. Further work is required before a standard for steam oxidation testing can be produced and the laboratory techniques developed to better reproduce the oxide scales formed in service.