| Micron/submicron suspended fine particles（PM10,PM2.5,etc.）in industrial waste gas are one of the main factors of air pollution and harm to human health.Based on the characteristics of the primary flue gas of the converter,traditional dust removal technologies such as OG（oxygen converter gas recovery system）wet dust removal,LT（Lurgi and Thyssen）method+bag dust removal,converter dry primary dust removal,etc.These methods are not efficient in capturing fine particles（particle size<2μm）and are difficult to meet ultra-low emission standards.Therefore,it is necessary to develop efficient removal technologies for fine particles.In addition,the white plume produced by converter OG dust removal also causes visual pollution to the surrounding environment of the plant.Acoustic agglomeration coupling technology can be used as a dust removal pretreatment measure to make the fine particles of flue gas generate large particles that can be removed by subsequent conventional dust removal devices and reduce PM2.5 emissions.Acoustic coupling condensation phase change can effectively reduce the humidity of wet plume and eliminate visual pollution.In order to study the removal efficiency of fine particles,the acoustic wave combined multi-field coupling agglomeration experiment was first carried out.The particle size distribution and morphological characteristics of fine particles in flue gas were investigated.The effects of operating parameters such as sound pressure level,sound frequency,residence time and swirl atomization on acoustic coupling agglomeration were studied.The results show that the reduction rate of particle concentration in primary flue gas of converter increases with the increase of sound pressure level.There is an optimal frequency for acoustic agglomeration,and the optimal frequency is 1 400 Hz under the experimental conditions.The swirling flow enhances the turbulence of particles,promotes the collision of particles,and increases the probability of particle agglomeration.The optimal acoustic coupling swirling flow conditions are sound pressure level 140 d B,sound frequency 1 400 Hz,and residence time 8 s.Under these conditions,the particle concentration reduction rate is 33%.Secondly,the effect of acoustic coupling chemical agglomeration agent on the reduction rate of particle concentration was studied.The results showed that the zeta potential of potato starch increased with the increase of agglomeration agent concentration.When the solution concentration was 0.2g/L,the zeta potential of the solution could be increased from-22.6 m V to the maximum-10.3 m V,and the solution instability was enhanced,which was beneficial to the agglomeration of particles.The concentration reduction rate of sodium dodecyl sulfate particles by acoustic wave coupling chemical agglomeration was up to 93.6%.The highest concentrations of potato starch,sodium alginate and polyacrylamide were 93.4%,93.2%and91.2%,respectively.Compared with single atomization or single chemical agglomeration,the reduction rate of particle concentration increased by 10%～13.4%,and the lowest concentration of particle outlet could be 3.2 mg·m-3.Finally,the acoustic coupling condensation phase change whitening test was carried out.The test results showed that when potato starch was added as a chemical agglomerant,the white plume phenomenon of the primary flue gas of the converter could be significantly eliminated and the removal efficiency of particulate matter in the flue gas could be improved.When the acoustic frequency is 1 400 Hz,the sound pressure level（SPL）is 140 d B,the cooling water temperature is 0°C,and the cooling water flow rate is 20 L/min,the maximum particle removal efficiency can reach 96.8%,and the relative humidity of the flue gas is 3.276g·kg-1（dry air）,which can achieve ultra-low emissions and completely eliminate white plumes. |
PDF Full Text Request