A study of erosion phenomena in coal fired furnace using CFD modelling

Abstract

In pulverised coal fired boilers, entrained fly ash particles in the flue gas often leads to erosive wear on metal surfaces along the flow field. This can have a significant effect on the operational life of various sections of boiler (in particular regenerative heat exchanger tubes). In this work, CFD based code FLUENT is used in conjunction with erosion model developed by other researchers for a large-scale furnace to identify the areas likely to be subjected to erosion under various operating conditions.Eulerian- Lagrangian approach is considered to analyse continuum phase and particle tracking for the coal particle. Flow field has been thoroughly examined in terms of velocity, particle and temperature profiles along the gas flow path. The data obtained on particle velocities and trajectories have been utilised to predict the extent of erosion in selected areas of boiler components. Predictions have been found to be in good agreement with the published data as well as plant observations for velocities ranging from 15 to 32 m/s showing a deviation of approximately 4.9 % with 20° impact angle.The results obtained from the present work for understanding erosion pattern in boilers are not only of practical significance but also provides platform for the development of an erosion tool which could assist power utilities in avoiding unnecessary shutdowns and penalties associated with the replacement of boiler components.