| The pollution caused by cooking fume as an urgent problem has attracted people's concern for a long term.Catering lampblack contains various toxic and harmful components,which will cause great harm to the quality of the atmospheric environment and the health of the human body if it cannot be effectively removed.Thus,in order to remove these pollutions effectively and improve urban air quality,the existing lampblack purification technology and equipment should be further optimized.In this paper,a college canteen in Lanzhou was selected as the design object.In order to solve the problem of excessive discharged catering lampblack,the newly design and reform of the canteen lampblack purification system were conducted.During the research,concentration of lampblack,concentration of lampblack particles and concentration of total volatile organic compounds(TVOC)were selected as the detection indicators to analyze the purification effect of the composite process on catering lampblack.The main works of this paper are as follows:(1)The fume emission and purification measures in canteens were surveyed to analyze the problem of lampblack existed in the canteen.Based on the existing fume purification system,a new technology of liquid spray + electrostatic deposition + ultraviolet light decomposition was selected.Besides,the operation principle of fume purification equipment was investigated,which provided the foundation of the design and transform of canteen lampblack purification system.(2)The main parameters of electrostatic fume purifier and ultraviolet photolysis device were designed and calculated.Moreover,the dispersant was added to the vent wash exhaust hood,and then the processed electrostatic fume purifier and ultraviolet photolysis device were installed in the fume purifying system.(3)The removal efficiencies of the new lampblack purification system were monitored.Results showed that the combined purification process of liquid spraying,electrostatic deposition and ultraviolet light decomposition exhibited the removal efficiency of 87.3% on lampblack concentration,67.9% on particle concentration and 61.5% on TVOC concentration.The emission concentrations of the three pollution indicators were all lower than the latest Beijing local standard(DB11/1488-2018),which proved the high feasibility and efficiency of the process.(4)The optimization experiments were carried out in each stage of the reformed lampblack purification system.The experimental results showed that the removal efficiency of soot increased to 39.62%,the removal rate of particulate matter was 50.10%,and the removal rate of TVOC was 30.03%.After 42 days of operation,the purifying efficiency of electrostatic lampblack purifier was reduced and lampblack emission could not reach the standard.Therefore,it is necessary to clean the electrode plate regularly to ensure high purification efficiency.In addition,the relationship between the number of ultraviolet lamps and the change of TVOC concentration was studied.It was found that large mounts of lamps could enhance the irradiated time of ultraviolet light,which therefore improved the purification efficiency of TVOC in lampblack by the ultraviolet light pyrolysis device.The total efficiency monitoring and optimization experiments proved that the composite process could not only make up for the shortage of the single process between each other,but also effectively control the particulate matter and volatile organic compounds in the soot.Therefore,the soot concentration and soot particles concentration and TVOC concentration could meet the latest soot emission standards.Furthermore,the process can solve the problem of the canteen lampblack pollution and possess a good application prospect. |
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