Abstract
A computational particle fluid dynamics simulation model for entrained-flow gasification was established in this study. The simulation results agree with the experimental data. The detailed particle information and residence-time distribution were obtained by injecting particle tracers in the simulation. The results show that the particles in the gasifier can be classified into three flowing zones, i.e. a fast-flowing zone, a recirculation zone and a spreading zone. The criterion for this classification was also provided. The rapid gas expansion caused by the fast reactions plays a significant role in forming the particle stream into these three zones. It accelerates the particles in the centre of the gasifier while pushing the particles near the expansion edge into the gas recirculation. Also, the concentrated oxygen distribution in the gasifier results in the formation of high- and low-temperature regions. The particles in the fast-flowing zone flow directly through the high-temperature region and most of these particles in this zone were fully reacted with a short residence time. Since particles in the recirculation zone are in a relatively low-temperature region, most of these particles are not fully gasified, although with a long residence time. The rest of particles in the spreading zone show moderate properties between the above two zones.
CPFD simulation on particle behaviour in an entrained-flow gasifier
