Experimental Study On Removal Of Fine Particles And VOCs By Electrostatic Precipitator And Catalysis

People spend most of their time staying indoors.PM2.5 in the atmosphere enters the room through air conditioning and ventilation system,resulting in excessive concentration of PM2.5 indoors,which will seriously affect the human health.At the same time,indoor decoration materials will produce volatile organic compounds(VOCs)and other pollutants.Long-term exposure to formaldehyde containing air,even at a very low level of concentration,may cause serious health problems.The study researched the indoor air purification,including the design of dual-zone electrostatic dust removal system,discharge characteristics of electrostatic precipitator and the double-effect catalyst for decomposition of ozone and VOCs.Study the structure and performance optimization of electrostatic precipitator and the optimum parameters of discharge parameters.Study the influences of particle concentration,wind speed,voltage and relative humidity conditions on fine particles removal efficiency.Study how the catalyst formulation,load,velocity,relative humidity and other conditions affect the activity of catalyst,combing with the actual working conditions.Study the comprehensive effect for the dust,formaldehyde and ozone removal.Study the influences of operating parameters on the wire-plate corona discharge reactor,and use the finite element software for simulation.The study found that the electrostatic field of corona voltage is related to the pole diameter.The larger polar diameter,the steeper ?-? characteristic curve.Corona voltage and line spacing is very negative correlation,phase voltage at the same time,dust collecting device of polar wide spacing produced by corona current;line spacing is small,the volt ampere characteristic curve more steep;reducing the electrode spacing,discharge voltage and breakdown voltage decreased at the same time,and get more than corona current required to reduce the voltage is the same,the plate spacing small,the volt ampere curve more steep.The smaller the distance between the pre charged electrode and the plate,the lower the corona voltage,the lower the breakdown voltage,the higher the volt ampere curve.Meanwhile,under the same voltage,the smaller the distance between the pre charged electrode line and the polar plate,the greater the power that the reactor can input than the corona current.With the increase of the wind speed,the breakdown voltage gradually decreases,and the corona current decreases at the same voltage.With the increase of relative humidity,the corona onset voltage and breakdown voltage decrease at the same time,and the corona current increases at the same voltage.Study on the influence of electric parameters on the efficiency of electrostatic precipitator for two kinds of single and double power supply.In the single power supply condition,the dust removal efficiency is increased with the increase of the supply voltage.The dust removal efficiency decreases with increasing wind speed.When the wind speed reached 0.5m/s,the removal efficiency of PM0.3 and PM0.5 can be more than 99%.While reduce the wind speed,the removal efficiency can achieve in the low voltage.The higher relative humidity in a certain range can improve the removal efficiency of fine particles,but when the relative humidity is higher than the critical value,the removal efficiency of the particles decreased.The larger particles particle size,the higher the efficiency of electrostatic precipitator.In the double power supply conditions,when the pre-charge voltage is lower,purifier to low concentrations of fine particulate matter removal efficiency is higher when the pre-charge voltage gradually increased,the removal efficiency of fine particles with high concentration will be higher than the removal efficiency of low concentration.With the increase of pre-charge voltage,the removal efficiency of fine particles increased obviously.When the pre-charge voltage is lower,with the increase of collecting voltage,fine particles removal efficiency increased obviously.When the pre-charge voltage is higher,with the increase of collecting voltage,removal efficiency changed little.When the front polar to the pre-charged anode plate distance get smaller,the dust removal efficiency was higher under the same voltage.With the increase of voltage,the influence of different distance on the removal efficiency gradually decreased.Study the indoor air purification catalytic module,and the effects of catalysts for ozone and formaldehyde decomposition.The effects of different conditions on catalytic activity were investigated.Design the catalyst for formaldehyde decomposition with ozone.Study the ozone concentration of different concentrations under different discharge conditions,and the effect of ozone concentration on formaldehyde degradation efficiency.It was found that Mn-Cu/Al2O3 catalyst has the highest efficiency of ozone decomposition.With the increase of ozone concentration,the decomposition efficiency of ozone decreased significantly.The catalytic performance of Mn-Cu/Al2O3 for formaldehyde decomposition was related to the initial concentration of formaldehyde,capacity of Mn-Cu,space velocity and relative humidity of air.With the increase of initial concentration of formaldehyde,the decomposition efficiency reduced.With the increase of Mn-Cu loading,the catalyst efficiency increased.With the increase of space velocity,the catalytic efficiency decreased.The relative humidity increase is conducive to improving the catalytic oxidation of Mn-Cu/Al2O3 catalyst activity in a certain range.In the experimental study of the co-catalytic degradation of formaldehyde with ozone,it was found that the addition of ozone in the reaction system can improve the decomposition efficiency of formaldehyde.With the increase of the power supply voltage,the ozone concentration increased gradually in the outlet of the reactor,and the decomposition efficiency of formaldehyde increased.In the indoor air purification efficiency test,experiment velocity is 1.0m/s in reactor,and the formaldehyde concentration before the catalytic module was about l.Oppm,and the power supply voltage is 8kV.The results showed that removal efficiency of PM0.3 and PM0.5 reached above 90%,and the decomposition efficiency of formaldehyde is about 67%,and the ozone concentration was about 66ppb,which was lower than the national standard limit.