Study On Dynamic Control Method Of Particle Distribution Uniformity In Rolling Circulating Fluidized Bed

Due to its high reaction efficiency and heat transfer characteristics,the circulating fluidized bed(CFB)combines with a marine engine to form a new type of marine engine exhaust gas treatment device.The new exhaust gas treatment device removes nitrogen and sulfur oxides from the exhaust gas through chemical reaction,and at the same time recovers a large amount of waste heat in the exhaust gas to achieve the effect of purifying the exhaust gas and saving energy and environmental protection.Since this system is installed on board,its performance is affected by the swinging or tilting motion of the ship,which makes the particles accumulate in the upstream bed,reduces the gas velocity,affects the overall fluidization rate,and reduces the desulfurization efficiency of the fluidized bed.In order to ensure the high desulfurization efficiency of the fluidized bed during the swinging process,this paper applies the numerical simulation method to study the distribution of the particle phase in the circulating fluidized bed during the swinging process,and proposes to adjust the inclination of the air distribution plate.The angle changes the inlet direction of the gas,thereby solving the phenomenon of uneven distribution of particles in the bed under the inclined state,and provides a reference for the influence of the swinging or tilting motion of the ship on the working performance of the fluidized bed.In this paper,the continuous swinging process of the circulating fluidized bed is firstly dispersed into a fixed tilting state with different tilting angles.The tilting angle of the air distribution plate is adjusted in each tilting state,so that the stacked particles can be evenly distributed,and the three-dimensional modeling software is applied.The fluidized bed under different tilting states is geometrically modeled,and the three-dimensional flow field calculation domain model of the fluidized bed is extracted.Then,the Gambit meshing software is used to mesh the three-dimensional flow field model of the fluidized bed and generate a mesh file.Finally,the grid file is imported into Fluent for numerical simulation of gas-solid two-phase flow.The Euler-Euler model was used to simulate the original size circulating fluidized bed.The simulation results were compared and analyzed.The influence of different inclined angles of the air distribution plate on the particle distribution in the fluidized bed in the fixed inclined state was analyzed.Further,the relationship between the inclination angle of the air distribution plate and the inclination angle of the fluidized bed is obtained,and the functional relationship between the two is fitted,which is used as the boundary condition of the wind plate movement,and the dynamic mesh in Fluent is applied.The model realizes the dynamic regulation process of the air distribution plate during the continuous swing of the fluidized bed,and further verifies the correctness of the scheme.