PVC类废塑料在冷态流化床中流化行为的研究

在Φ50 mm×800 mm圆柱体的冷态流化床反应器中,对PVC类废塑料、石英砂及其混合物的流化特性进行了研究。研究了PVC颗粒粒径与混合物料中PVC质量分数对混合物料的流化特性的影响规律,得到指导热态实验的关键参数。实验结果表明,PVC颗粒粒径与混合物料中PVC质量分数会影响混合物料的最小流化速度,也影响PVC颗粒与石英砂混合的均匀度。混合物料中PVC的质量分数越小,其最小流化速度就越小,混合物料也越容易实现充分混合;PVC颗粒为Geldart B类颗粒,但由于形状不规则,黏性力大,塌落特性明显,流化性能较差,显示出C类颗粒的流化特性,同时实际的最小流化速度要大于理论最小流化速度。PVC与石英砂混合物料冷态流化行为的研究结果为热态流化床降解PVC颗粒提供了基础数据和实践依据。

Study on fluidization characteristics of PVC wastes in cold fluidized bed

The fluidization characteristics of PVC wastes and quartz sand as well as their binary mixture are studied in the Φ50 mm×800 mm cold fluidized bed of cylinder.The effects of the size of PVC particles and the content of PVC in the mixture on the fluidization characteristics are investigated.Some important parameters are obtained.The results show that the minimum fluidization velocities and mixing extent are affected by the size of PVC particles and the mass fraction of PVC in the mixture.The less the mass fraction of PVC in the bed,the lower the minimum fluidization velocities and the better mixing is easily achieved.Due to strong viscous force and difficult to fluidize,the fluidization characteristics of PVC particles is similar to that of Geldart C,though it belongs to Geldart B group.The experimental minimum fluidization velocity is higher than the theoretical value.The results of fluidization characteristics in cold fluidized bed can be the reference for degradation of PVC in hot fluidized bed.