Studies On Technology Of Wet Dust Collection Under High Gravity

With the burning of fossil fuels and the emissions of industrial waste gas, the fine particlesin the dust increased dramatically. It has caused a heavy burden to the atmosphere which leadsto the “haze” phenomenon happens frequently in recent years. Therefore, it is necessary toexploit a new high-efficient dust remover. The technology of wet dust collection under highgravity receives much concern because of its high collection efficiency and low gas pressuredrop. The rotating packed bed (RPB) which be researched and used mostly is counter-currentflow, but it has the problem of limit of gas velocity and large air resistance. Based on this, thecollection efficiency and gas pressure drop of cross-current flow RPB were studied in thispaper, and contrasted with the counter-current flow RPB. Wetting agents and wet dustremoval under high gravity were coupled in this paper in order to improve the dust removalefficiency of RPB.The fly ash with average particle size of2.25μm was used as simulated dust, the collectionefficiency of these two RPB was investigated under different concentration of dust,high-gravity factor, liquid spraying density, gas velocity, and the optimum operatingconditions of cross-current flow RPB was obtained. The results show that, under therespective appropriate operating conditions, the total efficiency of cross-current flow andcounter-current flow RPB is99.6%and99.8%. The results of classification efficiency showthat the classification efficiency to PM2.5of cross-current flow and counter-current flow RPBis94.3%and96.1%, the classification efficiency to PM1.0is79.4%and85.3%. The results of gas pressure drop of the dust removal process of cross-current flow RPB andcounter-current flow RPB show that, the pressure drop of both RPB increases with increasingof high-gravity factor and gas velocity, and the counter-current flow RPB is more obvious,while the liquid spraying density has a negligible effect on it. Under the same operatingconditions, the efficiency of both cross-current flow and counter-current flow RPB are similar,the gas pressure drop is only51%of the letter,.and the resistance loss of transportation islittle.After the testing of the change of surface tension of the solutions and the wetting velocityto dust of the solutions, four kinds of wetting agents were screened out preliminary to couplewith the RPB. The results show that SDBS present the best performance under the conditionsthat the SDBS solutions with concentration of0.03%, the high-gravity factor, which from80to58.7, reduces by26.6%, the liquid spraying density is unchanged. At the same operatingconditions, the total efficiency increased by1%, and the classification efficiency of PM2.5andPM1.0increased by3.43%and by8.44%respectively.In conclusion, the cross-current flow RPB has high collection efficiency and low gaspressure drop, is well suited to applying to dust removal. Addition of wetting agent canimprove the removal efficiency to fine particles in RPB and reduce energy consumption. Itcould provide the theoretical basis and practical foundation for industrialization of removal offine particles by wet method under high gravity.