Study On Particle Motion Characteristics In Circulating Fluidized Bed Desulfurization Tower

The current environmental protection issue is a focal point worldwide,and China’s emphasis on environmental protection is also increasing year by year.Therefore,there is still extensive research value for the treatment of pollutant SO2.Due to the economic advantages of simple structure,small footprint,and low investment cost,semi dry desulfurization has gained widespread attention while maintaining high desulfurization efficiency and ensuring no sewage discharge.Among them,the circulating fluidized bed desulfurization tower serves as the main generator of the reaction,and analyzing its internal gas-solid flow field and studying the movement of solid particles is conducive to a deeper understanding of its motion law and further optimization and improvement of the desulfurization tower structure in the future.The movement speed of particles and their concentration distribution in the tower are two important indicators for exploring their movement characteristics.Therefore,this article adopts a combination of experimental measurement and numerical simulation to explore and consider these two physical quantities.Three important operating parameters,namely,apparent wind speed,solid mass flow rate and particle size,are mainly considered.In terms of experiments,a laser particle velocimeter(PIV)was used to achieve non-interference measurement of the flow field.The axial velocity distribution shows that the particle velocity distribution in the dense phase region is irregular in both radial and axial directions.The axial velocity distribution is high in the upper and low in the lower,and the overall flow is annular core flow.Specifically,as the apparent gas velocity increases,the axial velocity of particles also increases,showing a positive correlation with the apparent gas velocity.Ensure that the apparent gas velocity and particle size remain unchanged,and the mass flow rate increases,resulting in a decrease in particle velocity.And the increase in mass flow rate will make it difficult for particles to fluidize under low wind speeds.The larger the particle size of the same type,the more stable the movement trend of the particles.The smaller the particle size,the closer the distribution of particles in the flow field is to the flue gas in the watershed.The velocity distribution of small particles in the watershed is more vulnerable to the influence of smoke.Through numerical simulation,the axial and radial distribution function distribution laws of particle concentration in the whole watershed were explored.The numerical simulation calculation was carried out using the Euler dual fluid model.On the whole,the concentration distribution is thin at the top and thick at the bottom in the axial direction,and there is edge wall effect in the radial direction.An increase in apparent gas velocity is beneficial for reducing the non-uniformity of axial concentration distribution.An increase in solid-phase mass flow rate will increase the concentration of particles in the tower.The larger the particle size,the more uniform the radial concentration distribution of particles in the riser.