Modelling of solid particle flow in moving bed of COREX melter/gasifier based on discrete element method

Abstract

Solid particle flow patterns in the moving bed zone of a melter/gasifier were studied using discrete element method (DEM). Interparticle forces were calculated using the Hertz–Mindlin no slip contact model. The simulation results of the solid particle flow patterns agree well with the experimental results exhibited by tracer particles. The solid particle flow pattern and descending velocity were studied, as well as the effect of the discharge rate of solid particles in the raceway on solid particle flow pattern in the moving bed.

Results show that the moving bed could be divided into four subdomains based on the velocity of solid particles. A stagnation zone with semielliptic geometry is formed at the central bottom of the moving bed during drainage of solid particles. Furthermore, the simulated results of compressive force among solid particles in the moving bed zone indicate that the deadman zone undergoes a high degree of compressive force, especially at the centre of the gasifier. This finding implies that more compressive force resistant solid material should be placed at the centre zone by manipulating solid particles fed into the melter/gasifier.

Keywords:

• COREX
• Melter/gasifier
• Moving bed zone
• Solid particle flow
• Discrete element method