Numerical Simulation Of Semi-dry Flue Gas Of Deacidification Process In A Deacidification Tower

The flue gas of municipal solid waste?MSW?contains many pollutions,this will lead serious by-pollution if they are not properly disposed without any decontamination.MSW was burned with coal for stable burning because it contains a lot of water.On the base of comparing drying,semi-drying and wetting,we selected Semi-drying to decontaminate smoke.It has the advantage of low investment low dissipation,better decontamination efficiency and dry production.This paper first a 3D deacidification tower in a waste incineration plant with steady and unsteady was carried out by using Fluent,and the influence of the internal flow characteristics and residence time distribution on the flow field and deacidification efficiency was discussed;The flow characteristics of different flue gas velocities in deacidification tower was compared;The local and overall flow field characteristics under different rotating speed of the atomizing disk and the influence of the factors such as the amount of spray on the flow field were studied.The deacidification tower as the simulation object of waste incineration plant,the mass transfer model and chemical model of gas-liquid-solid were established.the rotation of the spray is established to analyze the model of slurry droplet evaporation and mass transfer process.through the comparison of the calculation model and the experimental model,to verify the accuracy of the proposed chemical reaction model and slurry droplet model.Finally,Barracuda software is used to simulate the deacidification process of the deacidification tower,and the reliability of the mathematical model is further verified by comparing with the actual working conditions;By numerical simulation,the effects of inlet gas velocity,stoichiometric ratio,particle diameter,spray volume and initial concentration of acid gas on deacidification efficiency were calculated and analyzed.The research shows that changing the inlet velocity of the flue gas will change the liquid gas ratio,the velocity distribution in the tower and the mixing degree of gas and liquid,and form different flue gas recirculation zones;The gas flow rate is closely related to the residence time;Changing the speed of the atomizing disk will affect the droplet size,and then change the internal flow characteristics of the tower;The temperature gradient and the concentration gradient of acid gas in the upper part of the central axis of the acid tower are the main parts of the deacidification removal reaction;A small part of the drops without completely evaporating because of flue gas recirculation zone is blow to the tower wall,easily lead to slagging and corrosion of the tower wall;Deacidification of flue gas mainly occurred in the upper part of deacidification tower.The temperature near the central axis of the tower is higher,and the temperature gradient,concentration gradient of SO₂ and HCl are larger.When the slurry drops into the acid removal tower,it is evaporated in 5 seconds,that is,the reaction time of the acid drop is mainly within 5s.The excellent deacidfication performance of the deacidification tower is expected under following operating conditions:the flue gas inlet velocity of 7.1 m/s,drop size of50-70?m and water spray rate of 600L/h.