Microstructural characterisation if high temperature oxidation of boiler materials for coal fuelled power plants

Due to the projected increase in global electricity demand, it is estimated that nearly 1400GW of new coal fired power plants will be built providing about 38% of global electricity demand in 2030. This growth will have a negative impact on the environment through the emission of CO2, a greenhouse gas detrimental to the climate, unless stringent emission targets for the coal fired power plants are put in place. This has resulted in placing more emphasis on the need for adopting the best available technologies for ‘new built’ plants or through retrofit of existing plants or the construction of high efficiency power plants with CO2 capture and storage technologies. The high efficiency power plants are mainly achieved by operating the boilers at higher temperatures of up to 700°C compared to the conventional power plants operating at ~ 565°C. This expected temperature increase will have an effect on the material degradation mechanisms of both the existing and proposed new alloy materials for the critical components of the boilers, that is, headers, superheaters, reheaters and wall membranes. This thesis explores the material degradation mechanisms associated with the high temperature oxidation and/or corrosion of the alloy materials found in these components. [Continues.