Prediction of slag occurrence in a Lignite-Fired utility boiler

Abstract

Lignite from Mae Moh mine is the largest source of solid fuel for electricity generation in Thailand. It is used in pulverized coal-fired boilers of a 2400 MW thermal power plant. Its high CaO content in ash is a major concern that can affect severe slagging. In this paper, potential of slag occurrence in the power plant was investigated by numerical simulation. The FactSage thermochemical package was used to predict ash and slag behaviour, as well as ash fusion temperature. A commercial CFD package was also employed to simulate gas velocity and temperature distribution, particle trajectory and temperature, and wall heat flux in a utility boiler of the power plant. The results were found to show good quantitatively and qualitatively prediction of slag formation. They can be applied to predict slag deposition inside the boiler effectively.