摘要
多段分级转化流化床煤气化反应器是由鼓泡射流流化床和快速流化床耦合而成的新型气化炉,采用欧拉双流体模型对其气固两相流动行为进行了数值模拟。模拟结果表明,两种流型的耦合,并非两种流态形式的简单叠加,回料口下段床内轴向浓度呈"C"型分布,上段轴向浓度呈指数分布,与实验结果较接近。同时考察了局部位置的颗粒浓度分布及其随操作条件的变化情况,表明快速床稀相段边壁区域颗粒浓度波动较中心强烈,且对操作条件的变化敏感,回料口附近的偏流现象以及过渡渐缩段的颗粒弹溅现象均与实验观察一致。研究得到的规律可指导多段分级转化流化床的设计和优化。
Flow behavior of a multi-stage fluidized bed （MFB） which couples a bubbling fluidized bed and a fast fluidized bed （FFB） was simulated using Eulerian two-fluid model. The simulations show that there are multiple flow regimes existing in the MFB, and the flow field is not the simple superposition of the two flow patterns. Solid concentration profile is a typical ＂C＂ shape below the entrance of circulation region, while it is an exponential shape along the upper FFB; that agrees with the cold-model experiments very well. Meanwhile the influence of gas velocity and solid circulation rate on the solid distribution was also studied. The results show that the solid concentration near the wall regions fluctuates more severely, and it is more sensitive to the change of operating condition in the upper FFB. A biased flow near the entrance of circulating solid region and a particle splash in the reduced pipe region were predicted; both phenomena were observed in the experiments. The simulation results can be used to guide the design and optimization of MFB.
出处
《化学反应工程与工艺》
CAS
CSCD
北大核心
2013年第1期42-50,共9页
Chemical Reaction Engineering and Technology
基金
中国科学院战略性先导科技专项(XDA07050100)
