Numerical Simulation On Two New Circulating Fluidized Bed Reactor Of Flue Gas Desulfurization

The technology of circulating fluidized beds(CFB)for Semi-dry flue gas desulfurization(FGD)include low water consumption,low investment,high removal efficiency and many other advantages,although it is not used as widely as the wet desulfurization,its application prospect is considerable.In Pursuit of uniform velocity field,temperature field and reaction,the traditional CFB-FGD always use the air distribution plate or venturi as the intake,but the plug-flow fluidized turbulent flow field is not strong and does not contribute to strengthening reaction.In this thesis,the flow field in the CFB-FGD reactor which used the tangential inlet and different export structure was calculated based on the numerical simulation approach,then compare the impact of the composite flow in different straight-flow velocity and area ratio on flow field,and contrast the different of solid concentration distribution in pure stream of swirl and composite flow;moreover,a new type of integrated Semi-dry swirl desulfurization tower was proposed,and its internal solid flow field has been calculated and analyzed.This thesis use Fluent 14.0 software for numerical simulation,first,study the internal flow field distribution,symmetry and vortex core swing in the CFB-FGD reactor which used the tangential inlet and different export structure;second,after research and analysis of the impact of the composite flow in different straight-flow velocity and area ratio on flow field,and the different of solid concentration distribution in pure stream of swirl and composite flow could found that under the tower of the composite flow,velocity unevenness is relatively better than pure swirl fluidized and at the same straight-flow velocity,the smaller area ratio of swirl and straight-flow,the greater the pressure drop;increases the straight-flow velocity or decreases area ratio of swirl and straight-flow,the axial velocity in the central region increase more significantly,the peak of the tangential velocity become smaller and the junction of internal and outer vortex move outward;but decreases the area ratio,the flow inside the vortex core swing more violently.The desulfurization tower with Tangential inlet can effectively weaken paticle adhere to the tower wall,and contrast the concentrations distribution of particlesc could found that the composite fluidization could extending the particle’s arrival time from the bottom center of the particle ejection pipe to the wall.Based on the above,a new type of integrated Semi-dry swirl desulfurization tower has been proposed,the gas-solid simulation results show that the equipment subdivision is clear and cross-functional,not only can effectively achieve desulfurization reaction,separation and recycling desulfurizer,but also increases the path of flue gas in the reactor.It could effectively extending the residence time of the flue gas and contribute to the depth of the desulfurization reaction occurs.