Optimization Design Of Blade Type Mist Eliminator Based On CFD

Mist eliminator is a wilely used gas-liquid separation device in industrial production, the wire mesh mist eliminator,the leaf-type mist eliminator,the cyclone-type leaf-type mist eliminator and the electric vortex board type demister are commonly used. Due to the varied size and structure, and has the advantages of high efficiency, low pressure drop,allowing big gas velocity and no-blocking etc.,the leaf-type mist eliminator is widely used in chemical separation. At present, the research methods of mist eliminator are mainly including the experimental and numerical simulation. However,because of high investment,long cycle, complicated process of experimental, it gradually replaced by numerical simulation.This paper is based on the computational fluid dynamics (CFD) method,and the ANSYS Fluent software is used to simulate the defogging flow field of the leaf-type mist eliminator.The process parameter of the leaf-type mist eliminator have been optimized to improve the defogging efficiency and reduce pressure of leaf-type mist eliminator. The hole paper is mainly carried out the following aspects:(1) The principle and application of gas liquid separation technology were discussed in this paper, comparison and analysis of the application of all kinds of mist eliminator,and analysis of the structure of the leaf-type mist eliminator and defogging principle,clearing the main factors affecting the defogging efficiency and pressure drop;(2) Based on the separation principles of droplet particles in defogging flow field and gas liquid two-phase flow numerical simulation method,established the computational fluid dynamics model of the leaf-type mist eliminator;the defogging flow field was simulated by Fluent,when simulate it the simulation grid mainly used structured quadrilateral mesh, droplet particles was calculated using the DPM model, the continuous phase methane turbulence was desdribed by RNG k-? model,and dicsrete form were selected dicsrete second order upwind to complete the simulation calcutions;(3) The five types (streamlined, streamlined barbed, triangle bent, bent with single sump and bent with double sump) of leaf-type mist eliminator have been carried on the comparative analysis research, determined the preliminary design of leaf-type mist eliminator;(4) Simulated the defogging flow field of the leaf-type mist eliminator under the different conditions, focused on the analysis of the pitch blades, blade angle, blade height, set tank length, flow velocity and temperature effect on the defogging efficiency and pressure drop. The influences of various factors on the efficiency and pressure drop were drawn,and analysis of the processing capacity of the leaf-type mist eliminator for different diameter droplets, obtained the optimal parameter combination;(5) Using orthogonal experimental design methodcan clearly know the factors and levels of leaf-type mist eliminator, analyzed the test results by means of range analysis method,got the primary and secondary order of the effects of various parameters on the efficiency and pressure drop,and compared to determine the optimal values the parameters of leaf-type mist eliminator;(6) The optimal parameter combination of bent with single sump leaf-type mist eliminator within the scope of the study are:blade pitch 25mm, the blade angle of 90°, blade height 160mm, sump length 14mm, flow velocity 3m/s, temperature 100?The research result show that:The leaf-type mist eliminator has good processing capacity to the particles with a diameter greater than 15?m;the primary and secondary order of the effects of various parameters on the efficiency is:blade angle>blade pitch>flow velocity>blade height>sump length>temperature; the primary and secondary order of the effects of various parameters on the pressure drop is:flow velocity>blade angle>sump length>blade pitch>temperature>blade height; after parameter optimization of leaf-type mist eliminator, it can make the defogging efficiency reached 100%, compared with before the parameters optimization, the defogging efficiency increase 19.42%.