Agitator Design And Flow Field Simulation Analysis Of Regenerating Pool

The traditional dual-alkali FGD has the serious problem of sodium loss.As the main component of the dual-alkali FGD system,the regeneration pool is the place where the regenerative reaction occurs.During the regeneration reaction,sodium ions are substituted and recycled.If the chemical reaction of the regeneration reaction is slow,it will result in incomplete substitution of sodium ions and finally loss of sodium.Improving the chemical reaction rate of regenerative reaction is the fundamental way to solve the loss of sodium ion.In this paper,a dual-alkali FGD system of a 2×40t/h hot-water boiler in China is taken as the research object,and the appropriate agitator is designed for regeneration tank,so as to improve the chemical reaction rate of regeneration reaction in the regeneration tank.The main function of the agitator is to provide the energy required for the mixing process and the appropriate flow state,so that the material is mixed evenly or strengthens the heat transfer and mass transfer.In recent years,the method of computational fluid dynamics(CFD)has been used to study the flow and mixing characteristics of the mixing equipment.With its excellent advantages,CFD technology has an immeasurable impact on the research,development and design of the future agitator.Based on the selection and initial design of the agitator,CFD method was used to explore the effect of the spacing and speed of the two agitators on the mixing effect.As there is a certain disturbance between the two agitators in the regeneration tank,how to determine the appropriate speed and spacing of the two agitators to achieve a good mixing effect is the focus of this article.In this paper,we first use a combination of theory and experience,based on the national standard,based on the raw data provided by the factory to carry out regeneration tank agitator selection and preliminary design.Then the three-dimensional physical model of regeneration tank and agitator was established by using Solidworks software.The structural grid was partitioned by ANSYS Icem,and the velocity distribution and turbulent intensity distribution of slurry in the regeneration tank were obtained by CFD software ANSYS Fluent.The purpose is to clarify the slurry flow within the regeneration tank,and to lay the foundation for the next simulation and optimization.Secondly,the simulation results under different operating conditions were analyzed,and the effect of spacing and speed of the two stirrers on the mixing effect was clarified.Then the reasonable spacing and speed of the two agitators were obtained.The main research purpose of this paper is to use CFD method to explore the effect of spacing and speed of two agitators on the velocity distribution,turbulence intensity distribution,mixing power and non-uniform coefficient in the regeneration tank.The agitator designed in this paper can effectively improve the chemical reaction rate of regeneration reaction in the regeneration tank.The design and optimization of the agitator in this paper have some guiding significance for the type selection and design of the agitator in the same situation.