A study on the hydrodynamics of a circulating fluidized bed boiler:improved prediction of axial solid volume fraction in 1D simulation
In a fluidized bed combustion system, solid particles behave like fluid, which improves heat and mass transfers between particles and gas, leading to a stable combustion phenomenon through active mixing of fuel and oxidizer and a uniform distribution of heat generated by combustion.For design and operation of CFB boilers, it is very important to understand the hydrodynamics of the CFB system because axial solid volume fraction governs most physicochemical phenomena in a boiler such as combustion, heat transfer,desulfurization and denitrification.In this study, the hydrodynamics of a CFB combustor were investigated with two different numerical simulation approaches.IEA-CFBC model and Computational Particle Fluid Dynamics (CPFD) software BARRACUDA(R) were used for 1D and 3D simulation respectively.As a simple 1D model, IEA-CFBC model is useful to understand the basic performance of a CFB combustor.The model is able to predict the flow patterns of core and annulus region, particle size changes, homogeneous and heterogeneous reactions, and heat transfer on reactor wall and external heat exchanger.On the other hand, for 3D calculation with BARRACUDA, fluidizing agents act as a continuum by the Eulerian approach and simulation of the particles follows Lagrangian model in the governing equations.The CPFD couples particles and the fluid phase through particle momentum and energy equation.In order to evaluate the accuracy of numerical analysis according to different models, 1D and 3D numerical simulation were performed on 100kWth CFB combustor (inner diameter: 0.15m, riser height: 10m) and compared with experimental results.For 1D simulation, different approaches were investigated for the decay of axial solid volume fraction in the riser.Overall, 1D and 3D numerical results agree well with experimental results.From the viewpoint of accuracy, 1D simulation using two exponential functions for predicting the decay of axial solid volume fraction are closer to the experimental and 3D simulation result than 1D simulation using one exponential function.
Hydrodynamic characteristics numerical simulation circulating fluidized bed solid hold-up model
C.W.Yang Y.D.Kim B.R.Bang S.D.Park U.D.Lee
University of Science and Technology, Daejeon 34129, Korea;Korea Institute of Industrial Technology, Korea Institute of Industrial Technology, Cheonan 31056, Korea;Future Energy Plant Convergence Resea Korea Institute of Industrial Technology, Cheonan 31056, Korea;Future Energy Plant Convergence Resea
国际会议
Proceeding of 2nd Conference of Circulating Fluidized Bed Boiler ( 第二届国际循环流化床锅炉会议)
青岛
英文
15-18
2019-07-19（万方平台首次上网日期，不代表论文的发表时间）