提升管进料段油剂间传质传热及混合特性研究

摘要

基于催化剂颗粒完全流态化理论,建立了提升管反应器进料段气液两相流数值模型,探究了射流油雾与连续气相间传质传热特性及油剂接触分布状况.实验结果表明,进料喷嘴所在轴向位置处油雾粒径、混合流体温度、油相组分含量沿提升管径向“环-核”不均匀分布程度最大;随轴向位置的增加,油雾气化程度增大,最终实现完全气化,管内温度和油剂间混合分布趋于均匀;适当增大喷雾锥角有助于促进油雾气化和改善“环-核”不均匀分布状况,提高催化裂化反应效率.%Based on the solid catalyst fluidization theory,a computational fluid dynamics(CFD) model for two phase flow in the feeding section of a FCC riser reactor was established,and the heat transfer and mass transfer between the feed injection and the continuous gas phase,and mixing characteristics of the feed and catalyst were investigated.It was showed that,the extents of the uneven "wall-core" distributions of the feed volume fraction,droplet diameter and temperature along the riser radius were the maximum.With the increase of axial position,the evaporation of the feed droplets was enhanced and finally the entire evaporation was achieved,so the heat transfer and mass transfer in the riser were improved.The increase of nozzle spray angle could promote the droplet evaporation rate,weaken the extents of the uneven "wall-core" distributions,and thus improve the FCC reaction efficiency.