Experimental Study On Nitrogen Oxide Removal By High Voltage Pulse Dielectric Barrier Discharge Combined With MOF Catalyst

NOx emission from motor vehicles accounts for a large proportion of air pollution components,but also has a relatively bad impact on the environment and human health.The purification and treatment of NOx has gradually attracted more and more people's attention.At present,the low temperature plasma technology under study has a good prospect for denitration.The technology consumes less energy and has no redundant structure design,which is convenient for practical application.Catalyst denitration needs to be carried out at high temperature with high energy consumption,so the combination of the two technologies is one of the main prospects of denitration technology.In this paper,high voltage pulse dielectric barrier discharge combined with MOF catalyst was used to remove NOx under the condition of oxygen enrichment.Using quartz glass as the medium,a wire barrel discharge reactor was made to optimize the parameters of the reactor and determine the optimal material thickness and discharge gap.The effects of discharge voltage,discharge frequency,total gas flow,O₂ concentration,C₂H₂ return gas and heating temperature on denitrification were studied.A series of metal organic framework materials,i.e.composite MOF materials,were prepared by hydrothermal synthesis.The effect of high voltage dielectric barrier discharge and composite MOF materials on denitration was investigated.Finally,the composite MOF materials were characterized by XRD and SEM.The main achievements are as follows:?1?The smaller the thickness of quartz material,the higher the no conversion.The reactor with a dielectric thickness of 1 mm has better volt ampere characteristic curve and higher discharge energy,and the maximum current reaches 14.2%.When the voltage is fixed,the smaller the discharge gap is,the higher the discharge energy is and the larger the discharge current is.The discharge gap is 2 mm and the maximum effective current is 15.12%.?2?With the increase of pulse voltage,the conversion of no and the removal of NOx increase.With the increase of frequency,the purification effect of nitrogen oxides shows a trend of first increasing and then decreasing.When the applied voltage is±12 kV,the denitrification effect is the best when the pulse frequency is 55 Hz,the maximum no conversion rate is 43%,and the NOx removal rate is 23.7%.?3?It was found that the removal efficiency of NOx decreased with the increase of total gas flow.With the increase of the total flow rate,the no conversion rate decreased gently.When the gas flow rate was 0.8 L/min,the no conversion rate was 41.5%.It can be seen from the experiment that the removal rate of nitrogen oxides decreases with the increase of O₂concentration.When the concentration of O₂ is 2%and the initial concentration of NOx is 400ppm,no conversion rate and NOx removal rate are the highest,37.5%and 19.5%,respectively.?4?HC gas exists in the tail gas of locomotive.If HC is properly used as reducing gas,the removal effect of NOx can be effectively improved.In the experiment,C₂H₂ was added as reducing gas,the no conversion rate was obviously improved.When the concentration of C₂H₂ is600 ppm,the no conversion is 62.9%.?5?High voltage pulse discharge combined with mil-100?Fe?was used for denitrification experiment at different temperatures.The denitrification efficiency increased with the increase of temperature,and the no conversion rate and NOx removal rate increased greatly when the temperature was higher than 150?.When the reaction temperature is 250?,the denitrification efficiency is the best,the no conversion rate is 86.5%,and the NOx removal rate is 72.3%.?6?The denitration efficiency of mil-100?Fe?material loaded with CeO₂ increases first and then decreases with the increase of Ce doping amount,and the denitration effect is the best when the Ce doping amount is 0.08,the no conversion rate is 91.1%,and the NOx removal rate is 81.6%.