CFD Simulation Of Hydrodynamics And Combustion On Internally Circulating Fluidized Bed

Internally Circulating Fluidized Bed has been widely used in energy andchemical industry because of several advantages over conventional CFBs, such aslong retention time of fule, small loss of fly ash and the discharge of pollutants.Therefore, it is important to obtain the gas-solid flow behavior and combustion for thedesign and large-scale of ICFB. The gas-solid flow and combustion characteristics ofthe35t/h oil shale-combustion Internally circulating fluidized bed boiler （Developedby Wangqing Longteng Energy Development Co., Ltd） is simulated by thecommercial CFD software package, Fluent.The gas-solid flow characteristics of the35t/h oil shale-combustion internallycirculating fluidized bed boiler is simulated using Eulerian-Eulerian model （EEM）,which is based on the kinetic theory of granular. Three-dimensional（3D） steady flowis simulated for the gas and solid phase. Firstly, the turbulence model is studied bycomparing a variety of turbulence models. The simulated results show that RNGk-ε-Per phase model could predict preferably the internal circulation process. ThenThe gas-solid flow is simulated by the closed model which has been established.Gas-solid flow profiles are obtained by3D steady simulation for pressure, solidvolume fraction, solid velocity and the internal circulation characteristics of the boilerwere further understood in detail.Three-dimensional （3D） steady simulation about the combustion characteristic inthe35t/h ICFB has been performed using the non-premixed combustion model.Combustion characteristic are obtained for the temperature, CO₂and O₂distribution.Adequate oxygen in the furnace dense phase region provides good fire conditions forthe fuel combustion. Owing to the mixing of air and fuel sufficient, the coal port andthe second outlet achieve the optimum combustion. The sharp decline in theconcentration of O₂, CO₂concentration increases to the maximum. Reflux hole is closer to the air distribution system, although the particle concentration is relativelylarge; in the role of a low flow of air temperature, the temperature will be relativelylow.