An Experimental And Numerical Study Of The Flow Characteristics In Circulating Fluidized Bed Desulfurization Reactor

Flue gas desulfurization in a circulating fluidized bed is quite a novel techonolgyat home and abroad, and which promises to have benefits for the future. The subjectinvestigated in this paper was the circulating fluidized bed desulfurization reactor. Theexperimental facility was established along with the venturi distributor, which was thelatest technology utilized in the industry. By means of the experimental study andnumerical simulation on the flow fields of single phase and gas-solid two phases, theflow characteristics in circulating fluidized bed were described, and the methods ofevaluating the flow behavior were put forward. The results provide a good platformfor the further improvement of venturi inlet structure, and give a favorable referenceto the technological design of heat and mass transfer.The experimental study and simulation analysis of the flow of the single phasemodel showed that the flow profiles in the riser were badly affected by the side inletduck and the recirculated solid feed inlet pipe, which results in a vortex behind therecirculated solid inlet pipe. Based on the numerical simulation of two-equationk ?ε model, the concepts of nonuniformity of gas velocity and dead zone percentagewere used to quantitatively analyze the gas flow field in the riser.The experimental study on the radial profile of the local solid concentration inthe riser at different conditions was performed by using an optical fiber probe. Theresults showed that the flow field of gas-solid phases was seriously affected by theside inlet duck and recirculated solid feed inlet pipe. At the same time, the deflectedsolid flow appeared and the radial profile of the local solid concentration was veryuneven, which became better obviously after the gas inlet configuration wasimproved.The two-fluid model combined with the kinetic theory of the particulate phasewas built. In the model, the effect of particles on gas turbulence was taken intoaccount and the source term of the gas k ?ε model was modified. The numericalsimulation of gas-solid flow in the experimental facility was completed. The resultsshow that the revised model can better describe the gas-solid flow phenomenon in thereactor.The industrial unit was designed and the proposed gas-solid flow model wasapplied to predict the flow field. It provides a foundation for the design of anengineering unit.