Numerical Simulation of Furnace Slag Waste Heat Recovery in Fluidized Bed

Furnace slag is discharged at the temperature of about 1500 K, it is obviously significative to recover the waste heat for energy saving. In this paper, a new-style fluidized bed is adopted to recover the waste heat after the liquid furnace slag has been granulated into particles for power generation. Considering the complexity of the flow field and the temperature field at so high temperature, the Computational Fluid Dynamics study (CFD) was carried out to simulate the flow field and the temperature field in the fluidized bed, which guides us to improve the structure of the fluidized bed to get a stable processing capacity and high efficiency of heat transfer. Based on the Eulerian-Eulerian molde, kinetic theory was adopted in the model. The impact of particle collision and friction upon the flow field was considered comprehensively in the model. The simulation was carried out with three different slag particles in size to analyse the impact of particle size on the flow. Comparison of the result shows that the fluidized bed with smaller particles tends to fluidization state earlier and gains higher height under the same air velocity and has better heat transfer coefficient to gain more high-grade energy. The result also indicates the size of particle hardly affects the heat transfer speed, but affects the heat transfer efficiency distinctly.