流化床内多组分颗粒传质过程模拟

Mass Transfer Simulation of Multi-component Particles in a Fluidized Bed

为了揭示活性颗粒的传质特性,采用Euler-Euler双流体模型,并结合气泡介尺度曳力模型和多组分传质模型,利用计算流体动力学(CFD)软件对存在惰性颗粒情况下多组分颗粒流化床内水蒸气吸附过程进行了数值模拟,得到流化床内固体颗粒体积分数和水蒸气质量分数分布,验证了气泡介尺度曳力模型的合理性,分析了入口表观气体速度、水蒸气质量分数和床层压强对水蒸气吸附过程的影响。结果表明:气泡介尺度曳力模型可以较好地再现水蒸气的吸附过程;减小入口表观气体速度及增大入口水蒸气质量分数有利于改善传质特性,有效增大了水蒸气吸附速率。

To reveal the mass transfer characteristics of active particles, the Euler-Euler multi-fluid model was used to simulate the adsorption process of steam in a multi-component fluidized bed with the presence of inert particles by means of CFD approaches, simultaneously using the bubble-based drag model and multi-component mass transfer model, so as to obtain the volumetric distribution of solid particles and mass concentration of steam in the fluidized bed, verify the rationality of the bubble-based drag model, and to analyze the effects of inlet gas velocity, steam mass concentration and bed pressure on the process of steam adsorption. Results show that the bubble-based drag model can reproduce the process of steam adsorption well;both the decrease of inlet gas velocity and the increase of inlet steam mass concentration are beneficial to the improvement of mass transfer characteristics and steam adsorption rate.