Filtration of fly ash using fluidized bed at 300–500 °C

The filtration of the coal-burning fly ash using fluidized beds with silica sand of 770 μm under temperatures of 36, 300, 400, and 500 °C was studied. The variations of the outlet concentration and particle size distribution (PSD) with time were measured to evaluate the dynamic characteristics of the process. Experimental results showed that the overall collection efficiency decayed with the operation time, revealed the effect of the elutriation of fly ash on particle filtration. The collection efficiency rose when the temperature increased from 36 °C to 500 °C. The strong attrition at high temperature released more small particles than that at room temperature, increased the concentration of the particles less than 10 μm (PM10) at high temperature. The removal efficiency of the particles in a size of 4–7 μm, not the submicron particles, is the lowest because they are most easily elutriated from fluidized beds.