MODELLING OF COAL SLAG FLOW AND LAYER THICKNESS IN A HIGH TEMPERATURE ENTRAINED FLOW GASIFIER

Abstract

A 2-D model for the slag flow simulation in an entrained flow gasifier has been developed. In addition to
mass, momentum and energy conservation equations, volume of fluid (VOF) equation was solved to track the
liquid-gas interface. Liquid phase consists of melted coal ash particles which deposits on the wall and move
downward. The gasification reaction is not considered here but it is postulated to have a mass flow through
the interface towards the mass of the liquid phase. The reactor walls are usually kept cold so a temperature
gradient and then a solid layer form within the slag layer. The solidification and its effect on the slag layer
thickness are also considered here. Results show that, depending on the ash composition which determines the
fluid’s rheological properties, the solid phase constitutes a large part of the slag layer.