Simulation And Optimization Of Smelting Flue Gas Scrubber

With the large amount of smelting flue gas emissions,the fine particles in the flue gas are more harmful to the social environment and human health.How to improve the fine particle trapping performance of the scrubber has become an urgent problem to be solved today.Among them,the reverse turbulent scrubber has the advantages of simple structure,low investment cost,small floor space and wide application range compared with other conventional scrubbers.The optimization study of the structure and process parameters of the scrubber has important guiding significance for the dust removal effect of the scrubber.The reverse turbulent scrubber is a high-speed collision by countercurrent contact of the washing liquid with the dust-containing gas stream.When the washing liquid and the gas reach momentum balance,a strongly turbulent foam zone is generated in the washing pipe.In this area,the gas-liquid surface renewal speed is fast and the contact area is large,and the energy of gas-liquid two-phase is fully utilized to achieve the effect of enhancing gas-liquid mass transfer and collision.So,the foam area is favorable for the removal of fine particles in the gas flow.According to the similarity theory,the physical model of the turbulent scrubber is set up.And in the water-air and oxygen-water-air experimental systems by using the method of high speed camera and measuring the pressure drop,the jet height and the dissolved oxygen resolution,this paper researches the effects of operating parameters and equipment parameters such as gas flow,liquid flow,liquid-gas ratio,nozzle type,and arrangement on the hydrodynamic and dissloved oxygen relationship of the gas-liquid two phases in the scrubber.Therefore,the scrubber is simulated and optimized,in order to enhance the effect of fine particle trapping in the scrubber.This paper has obtained the following conclusions through a large number of experiments:(1)By comparing the spiral nozzle and the three-injet nozzle,the hydrodynamic performances such as the pressure drop and jet jet height of the three-inlet nozzle with the axial shear ratio of 0.5 are better than those of the spiral nozzle arranged in an equilateral triangle.Moreover,the foam are of the three-inlet nozzle is larger than that of the spiral nozzle.The L/G range of the three-inlet nozzle foam zone is 0.00262?0.00605,the gas flow range is 180?350 m3/h.The L/G range of the spiral nozzle foam zone is 0.0047?0.0104,and the gas flow range is 150?330 m3/h.(2)Adjusting the axial shear ratio of the three-inlet nozzle and the liquid-gas ratio of the scrubber,the gas-liquid two-phase flow in the washing tube will appear in four types:hollow cone type,bubble type,annular type and liquid column type.Among them,the hollow cone type and the bubble type have a higher pressure drop than the annular type and the liquid column type.(3)Investigating the influence of the operating parameters of the three-inlet nozzle on the hydrodynamic characteristics,it can be found that the foam area of axial shear ratio of 0.5 is the largest and the collision between gas and liquid is the best by comparing the foam area of the axial shear ratio of 1.0 and 1.5.When liquid flow is constant,the pressure drop gradually increases with the increase of the gas volume,and the jet height decreases with the increase of the gas flow.When the gas flow is about 200?250 m3/h,the pressure drop curve is abrupt and begins to enter the foam zone.When the gas flow is constant,the pressure drop and the jet height gradually increase as liquid flow increasing.When the liquid flow is in the range of 0.75?0.95 m3/h,the pressure drop curve is abrupt and begins to enter the foam zone.(4)The research on the mass transfer characteristics of the scrubber shows that,from the perspective of structural parameters,the dissolved oxygen resolution of the three-inlet nozzle with the axial shear ratio of 0.5 is greater than that of the spiral nozzle under the same liquid-gas ratio and gas flow.Its gas-liquid mass transfer effect is better;From the perspective of operating parameters,for a three-inlet nozzle with an axial shear ratio of 0.5,when the gas flow is 250 m3/h,the resolution increases with the increase of the liquid-gas ratio.When the liquid-gas ratio is 0.004,the resolution reaches the maximum value.when the liquid flow is 0.9707 m3/h,the resolution increases first and then decreases with the increase of gas flow,and the resolution reaches the extreme value when the gas flow is about 250 m3/h;When the liquid-gas ratio is 0.0048,the resolution increases first and then gradually stabilizes as the gas flow increase.