The Progress of the Pulsing Airflow Fluidized Bed for Separating the Fine Coal

Because of the bubbles and intense backmixing of the medium in the conventional air dense medium fluidized bed (ADMFB), the alternative size range of the feeding is +6mm. The innovation of employing the pulsing airflow to the fluidized bed (PFB) can significantly strengthen the gas-solid contact and reduce the formation of the bubbles. To study the bubble behavior and energy transfer in the fluidized bed, the simulation of the Eulerian- Eulerian (EE) model was conducted on the gas-solid system. The results show that the lower bed height can decrease the energy collision and mergers. The comparison between ADMFB and PFB indicates that pulsing energy flow can effectively decrease the vortexes and make the energy flow transfer along with the vertical direction of the bed. The software of “Design Expert” was adopted to conduct an orthogonal test with the factors of gas velocity and pulsing frequency. As for the best separation results, the E value of 0.093g/cm3 and the clean coal ash content of 33.69% were achieved with the yield 52.04% and maximum ash content drop 22.46%.