新型液固流化床粗煤泥分选与数值模拟

Coarse slime separation and numerical simulation of a new liquid-solid fluidized bed

试验研究了一种变径和内置倾斜板的新型液固流化床的粗煤泥分选特性.与传统液固流化床相比,新型液固流化床强化了颗粒按密度分离.当要求精煤灰分为8.00%时,精煤产率相比传统液固流化床超出4个百分点,可能偏差(Ep)值降低约80 mg/cm^3.对新型分选机内部流场和颗粒受力进行了数值模拟,分析了新型液固流化床的强化分选机制.分选机直筒段和变径段流态为紊流,倾斜板间流态呈层流;颗粒在倾斜板间受垂直板面方向的升力作用,越靠近板面升力越大;变径段和倾斜板共同强化了颗粒分层,是新型液固流化床分选效果提高的根本原因.

For a new liquid-solid fluidized bed with variable diameter and built-in inclined plates, the separating characteristics of the coarse slime were experimentally studied. Compared with the conventional liquid-solid fluidized bed, the new sorter enhanced separating effect of particles by density. When the clean coal ash was required to be 8.00%, the clean coal yield exceeded 4 percent, and the Ep value reduced by about 80 mg/cm^3. Moreover, the flow field and particle force in new sorter were simulated, and the mechanism of reinforcing density-dominant separation was analyzed. The results show that flow regime in straight and variable section is turbulent, while between two inclined plates is laminar. The particles are subjected to the lift force in a direction perpendicular to the inclined plates. The closer to the plate surface, the greater the lift force. The variable diameter section and inclined plates together strengthen the particle stratification, which is the fundamental reason for the improvement of the separating effect of the new liquid-solid fluidized bed.