当前位置: X-MOL 学术Chem. Eng. Res. Des. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Study of wall-to-bed heat transfer in circulating fluidized bed riser based on CFD simulation
Chemical Engineering Research and Design ( IF 3.9 ) Pub Date : 2020-02-28 , DOI: 10.1016/j.cherd.2020.02.021
Waritnan Wanchan , Parinya Khongprom , Sunun Limtrakul

Circulating fluidized bed (CFB) riser reactors are widely used in several industrial gas–solid flow systems to achieve a high reaction rate and a high heat of reaction. Thus, understanding wall-to-bed heat transfer is essential for optimizing CFB operation and design. This study aims to analyze the wall-to-bed heat transfer in a CFB riser reactor. A two-fluid model with the kinetic theory of granular flow was used to solve the hydrodynamics and heat transfer behavior in the bed. The wall-to-bed heat transfer coefficient is strongly dependent on the CFB operating conditions, but correlations for the wall-to-bed heat transfer coefficient are often defined in terms the suspension density, which is not an operating parameter. This makes the correlations difficult to use because the solid fraction in the system must be known. Thus, in this study, a correlation was developed that defines the heat transfer coefficient in terms of two operating parameters: the solid circulation rate (Gs) and the superficial gas velocity (Ug). The developed correlation exhibited fairly accurate prediction for several particle sizes because this correlation is based on fluid catalytic cracking (FCC) particles having a specific diameter. To better address the effect of different particle sizes, the correlation was further modified to be a function of the particle diameter in addition to Ug and Gs. The modified correlation can predict the simulated and experimental data within a ±20% deviation and an averaged absolute relative error of 5.72%.



中文翻译:

基于CFD模拟的循环流化床立管壁间传热研究。

循环流化床(CFB)提升管反应器广泛用于几种工业气固流系统中,以实现高反应速率和高反应热。因此,了解壁到床的传热对于优化CFB的运行和设计至关重要。这项研究旨在分析CFB提升管反应器中的壁床热传递。使用具有颗粒流动动力学理论的双流体模型来求解床内的流体动力学和传热行为。壁对床传热系数在很大程度上取决于CFB的运行条件,但是壁对床传热系数的相关性通常是根据悬浮密度(不是运行参数)来定义的。由于必须知道系统中的固体成分,因此很难使用相关性。因此,在这项研究中s)和表观气体速度(U g)。所建立的相关性对几种粒径显示出相当准确的预测,因为该相关性是基于具有特定直径的流化催化裂化(FCC)颗粒。为了更好地解决不同粒径的影响,除U g和G s之外,还对相关性进行了进一步修改,使其成为粒径的函数。修改后的相关性可以在±20%的偏差和5.72%的平均绝对相对误差范围内预测模拟和实验数据。

更新日期:2020-02-28
down
wechat
bug