Monitoring of the corrosion processes in the context of the decarbonisation idea and conversion of coal-fired power plant units to multi-fuel systems

The article presents the possibility of the corrosion process monitoring using a new type of diagnostic probe. The proposed solution consists of a probe composed of three pipes made of steel inserted into the combustion chamber, covered or not with protective coatings. Each probe tube is individually cooled with water at a temperature of 40°C. Each probe pipe is also measured with a thermocouple, which allows the actual temperature of the pipe wall to be determined. The probe is placed in the technological opening of the boiler in the area of most significant exposure to low-oxygen corrosion processes. The length of the probe ensures that the material is exposed to work in a wide range of temperatures and exhaust gas environments with different corrosive aggressiveness. The temperature of the pipe can also be controlled by the pressure of the process water used to cool the probe. This structure of the probe provides a significant extension of diagnostic possibilities in real-time mode, which may be particularly useful in the case of testing new materials and coatings dedicated to the evaporator tight walls, especially in the case of modification of combustion processes, e.g. by introducing biomass. The possibility of simple disassembly of the probe at any time during exposure also makes this solution very attractive from the point of view of monitoring the corrosivity of combustion processes in the context of converting conventional coal-fired power units into multi-fuel units.