| Fine particles emitted from industrial production is one of the important air pollutants,and its harm to human health and ecological environment should not be ignored.With the development of ultra-low emission of industrial flue gas,how to achieve efficient removal of fine particle in industrial flue gas is the key problem to be solved urgently in the current air pollution control.Cyclone dust collector is one of the most widely used industrial flue gas dust removal systems because of its simple structure and low cost.However,due to the limitation of dust removal mechanism,the removal efficiency of fine particles is low.Therefore,the coupling of atomization agglomeration and heterogeneous condensation technology is proposed in this paper to enhance the removal of fine particles by cyclone dust collector.In this paper,the influence of flue gas condition and operating parameters on the formation of water vapor supersaturation environment in the process of spray was systematically studied by using computational fluid dynamics(CFD)method.Subsequently,a simulation test platform was built to explore the enhanced characteristics and mechanism of atomization agglomeration and atomization-heterogeneous agglomeration on the removal of fine particles by cyclone dust collector.This study is expected to provide theoretical support and methodological guidance for further optimization of the technology and practical application in complex industrial flue gas.The main conclusions are as follows:(1)As the flow distance of flue gas in the spray chamber increases,the temperature of the flue gas first gradually decreases,then slowly rises,and finally stabilizes.The water vapor mass fraction shows a trend of first slowly increasing,then rapidly increasing,and finally stabilizing.The relative humidity shows a trend of first increasing,then decreasing,and finally stabilizing.The temperature drop and water vapor supersaturation of flue gas reach their maximum values near the atomization nozzle.The water vapor supersaturation region is mainly distributed around and above the nozzle where droplets are densely distributed.At the same time,when the original flue gas has a lower temperature or a higher moisture content,a supersaturated water vapor environment can be established in the spray tower.As the original flue gas temperature further decreases or the moisture content increases,the water vapor supersaturation increases,and the supersaturation region expands.In addition,the heat and mass transfer coefficient of micron droplets is mainly affected by the size of droplets.Therefore,larger spray flow rate and smaller droplet size are conducive to the establishment of supersaturated water vapor environment.(2)The experimental results show that compared with a single cyclone separator,the particle removal efficiency of atomization agglomeration condition is improved.The particle removal efficiency of the atomization agglomeration condition is increased by 11.6 % than the condition of a single cyclone separator,while the "2～4" μm zone particle removal efficiency has increased by 21.6 %.This is because the droplets will capture nearby particles and provide capillary force,leading to the aggregation and growth of particle,which can be effectively removed.Based on the atomization agglomeration condition,the occurrence of heterogeneous condensation further improves the particle removal efficiency,especially for fine particles.Compared with atomization agglomeration condition,the removal efficiency of particles in atomization-heterogeneous condensation condition is increased by 9 %,the removal efficiency of particle in "2～4" μm is increased by 21.1 %,and the removal efficiency of sub-micron particles is more than 99 %.In addition,the particle removal efficiency gradually increases and eventually stabilizes with the increase of atomization amount,and increases with the increase of inlet flue gas moisture content and the decrease of inlet flue gas temperature. |
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