| The flue gas of coal-fired power plant after the wet desulfurization process will also have some fine dust emissions into the atmosphere,resulting in the concentration of haze.In order to reduce the discharge of fine dust and improve the performance of demister in desulfurization tower,the flow field in baffle demister was simulated,analyzed and optimized.The main contents and conclusions of this paper are as follows:Firstly,the splashing morphology change of single droplet in the demister under different impact Weber number and film thickness was studied by using volume of fluid(VOF)method,and the movement mechanism of single droplet in the demister was studied.Secondly,the defrost principle and the gas-liquid two-phase flow process in the demist were improved.The mathematical model of inertia separation,collision and convergence between liquid droplets,fragmentation and the interaction between liquid films were analyzed,which laid a foundation for the following numerical simulation calculation.Then,the Euler wall model(EWF)and Discrete phase model(DPM)were used to numerically simulate the effects of the secondary splash of droplets and the hook plate structure on the removal performance of the mist eliminator.The flow field,particle trajectory and liquid film distribution in the mist eliminator under different inlet velocity conditions were analyzed,and an experimental system was built to compare and verify the data..It is found that when the inlet air velocity exceeds the critical value of the secondary entrainment of droplets,the liquid film on the demister plate will be peeled off and separated,resulting in the secondary spatter of droplets,which leads to the degradation of the separation performance of the demister.The installation of hook plate reduces the shear force of airflow on the liquid film,making it difficult to peel and separate the liquid film,and the phenomenon of secondary entrainment of liquid droplets is well improved,so the defogging efficiency is greatly improved.Finally,the structural parameters of the hook plate of the mist eliminator are optimized by the response plane analysis method.The performance prediction model of hook-plate mist eliminator was obtained by second-order polynomial fitting,and the influence degree of key size parameters of hook-plate on mist eliminator performance was determined by variance analysis of regression model,the interaction of the quality factors of the demister is also analyzed,in which the length of the hook plate and the angle between the hook plate and the main plate have a greater influence on the demister performance,and the extension length of the hook plate and the angle between the hook plate have lesser influence.And Design-Expert12 is used to solve the fitting result,the best parameter combination of the hook-plate demister is obtained. |
