Study On Dust-removal Performance Of 3D Mass Transfer Scrubbing Tray

Industrial dust is a type of particulate matter produced in industrial production.The environmental,economic,and health problems caused by industrial dust are current social hot spots,and efficient dust removal technology is also an important research direction in industry and academia.This study combines experiments and CFD simulations with 3D(three-dimensional)mass transfer trays and coal-fired fly ash in power plants as the research objects,exploring the influence of operating parameters on dust removal performance,analyzing the movement distribution of dust particles in the scrubber,and studying the influence of device structure parameters such as the height of the overflow weir,the aperture ratio of the cap and the height of the bottom gap of the cap on the dust removal performance.Firstly,the hydrodynamic performance and dust removal performance of the 3D mass transfer tray were studied by the method of experimental determination.Using air-water-dust as the experimental medium,a cold mold experiment was carried out in a square plexiglass scrubber with a side length of 600 mm × 600 mm,and the total dust removal efficiency and grade dust removal efficiency under different operating conditions was determined by filter weighing and particle size analysis.The research shows that the increase of gas-liquid-phase load will increase the pressure drop of the tray and increase the energy consumption of the scrubber.The dust removal efficiency using the single-layer tray can be up to 92%,and the dust removal efficiency using the three-layer tray can be more than 99%;the increase in air flow mainly helps the collection of particles above 8 μm,and the capture efficiency of particles below 8 μm decreases with the increase of the air flow rate;the increase of the liquid flow rate promotes the collection of all the particles;when the dust concentration increases,there is a little obvious increase in the dust removal efficiency only with the particles in the range of 2.5-8μm.Then,through the gas-liquid-solid three-phase unsteady CFD simulation on a single cap tray,the movement distribution of particles on the tray was mainly investigated.The results show that during the stable operation of the scrubber,the number of particles on the cross-section of the tray decreases rapidly as the height increases,and a small amount of particles accumulate at the top of the cap.The larger the particle size,the smaller the particle number in areas above the cap.Finally,the effect of equipment structural parameters on the dust removal performance of the 3D mass transfer tray was studied using the CFD steady simulation method.The results show that:the increase in the height of the overflow weir can increase the height of the clear liquid layer on the plate,which increases the amount of liquid lifting and the gas-liquid contacting area,therefore improving the dust removal efficiency;the backmixing phenomenon in the cap decreases after the aperture ratio is increased,and the dust removal efficiency decreases accordingly;the liquid lifting amount increases after the bottom gap of the cap expands therefore increasing the gas-liquid contacting area and resulting in an increase in the dust removal efficiency.This study provides basic data for the application of 3D mass transfer trays in gas scrubbing processes and for the design of scrubbers,showing certain practical value.