Abstract
WtE (Waste to Energy) plants contribute to the realization of a low-carbon society. Therefore, promotion of high-efficiency WtE power generation plants is expected in Japan. However, WtE plants have severe problems with the corrosion of boiler tubes, especially super-heater tubes. For this reason, the steam conditions of WtE boiler plants have been limited to 4 MPa and 400 °C.
It is very important to understand the high-temperature corrosion characteristics of super-heater tubes in actual WtE plants in order to design boilers that can have higher temperature steam conditions compared to current plants.
We developed a new tool for measuring the corrosion rate in a short period of time compared to conventional methods. Using this tool, we have measured many corrosion rates of SUS310J1 stainless steel in WtE plants with stoker type waste incinerators. SUS310J1 has been widely used as a high-temperature corrosion-resistant material for super-heater tubes in Japan.
Through this research, we found that the corrosion rate of SUS310J1 at gas temperatures below 550 °C and metal temperatures from 350 °C to 450 °C reaches a maximum at a metal temperature of around 400 °C after which it stays nearly constant. At higher gas and metal temperatures, however, the corrosion rate increases rapidly.
