| The development of society depend largely on the use of energy,energy is a source of fuel and power that human beings depend on for their survival and development,it is an important material basis for human developing production and improveing the standard of living.Coal is primary energy consumption in China,a large number of coal consumption and utilization has caused serious pollution to the living environment of human beings,the coal combustion process can produce large amounts of sulfur oxides,nitrogen oxides(NOx)and other atmospheric pollutants,which lead to acid rain and serious environmental pollution,a large number of NOx emissions are a serious threat to the ecological environment and human health.In order to achieve more efficient and environmental friendly NOx removal,many new technologies have been applied to the field of NOx removal.As a plasma technology,the dielectric barrier discharge(DBD)method has attracted more and more attention in the field of denitrification.This paper mainly deals with the experimental research and energy consumption analysis of dielectric barrier discharge(DBD)removal.of NOx.The main contents are as follows:In the process of separate denitrification,it is found that the denitration efficiency is linearly proportional to the input power of the plasma generator.The addition of NH3 has a positive effect on the removal of NO efficiency,compared with the flue gas without NH3,the removal efficiency of NO is obviously improved.With the increase of water vapor content,the removal efficiency of NOx increased obviously,and steam could promote the removal of nitrogen oxides.The change of temperature has a great influence on the removal of NO,under higher temperature,the DBD electric field intensity is stronger,the decomposition rate of O2 and NH3 is very fast,the reaction rate between NH and O radicals increases with NO,so the removal rate of NO and NOx increases.No matter the direct desulfurization and denitrification or the indirect desulfurization and denitrification,the removal efficiency is linearly proportional to the input power of the plasma generator too,and the denitration efficiency is better than the desulfurization efficiency.The efficiency of denitrification is very efficient.Direct desulfurization and denitrification,with the increase of power consumption of the plasma generator,the removal NO rate can reach 80%,the efficiency of desulfurization is not ideal,and the removal rate is maintained at 20%.Indirect desulphurization and denitrification,desulfurization and denitrification efficiency are very high,especially the denitration efficiency can reach more than 95%,desulfurization efficiency can also be up to 60%.It is indicated that the plasma produced by dielectric barrier discharge(DBD)non-thermal plasma(NTP)is stronger than the oxidation of SO2 to NO,and the decomposition and ionization of DBD-NTP to NO are also stronger than the decomposition and ionization to SO2.The quantity of DBD-NTP depends on the input power of the DBD-NTP generator.The number of plasma determines the degree of decomposition and oxidation of NO and SO2,reflecting the removal rate.direct simultaneous desulfurization and denitrification,compared to Direct separate denitrification and Direct separate desulfurization,the removal efficiency of SO2 is much lower,and the performance impact on the removal of NO is huge,the denitration efficiency is very low.In the process of indirect simultaneous desulfurization and denitrification,the denitration efficiency will be very high,and the desulfurization efficiency is also very good.This is because O3 plays a major role in addition to the reaction of free radicals with NO and SO2.In addition,the indirect case of reactor only ionize O2 or H2O,in the case of very small trigger voltage can produce plasma,low power consumption,energy saving effect is very obvious.For the need for simultaneous desulfurization and denitrification occasions,indirect method is worthy of popularization and application,the performance of the economy is high.In the case of low input power,good desulfurization and denitration efficiency are obtained.Indirect simultaneous desulfurization and denitrification,no matter the denitration efficiency or desulfurization efficiency,is more efficient than direct oxidation.CuO/?-Al2O3 as the catalyst,the denitrification efficiency was more than 90%at 300-400?,and the maximum denitrification activity reached 96%at 400 ?,and the desulfurization efficiency always was more than 95%from 150? to 500?.DBD cooperated with selective catalytic reduction(SCR)for NO and SO2 removal,some performances of various catalysts were compared,the experimental results show that DBD filled CuO/?-A12O3 catalyst promoted the formation of NO2,is favorable to NO removal,filling CuO/y-Al2O3 catalyst denitration efficiency than ?-Al2O3 catalyst was obviously improved.We made an attempt to reduce NO from exhaust gas using dielectric barrier discharge(DBD)plasma.According to the second law of thermodynamics which gives an objective description on thermal process directivity,exergy quality degradation and depreciation,the measures to increase denitration efficiency of dielectric barrier discharge plasma(DBDP)was analyzed.Based on denitration mechanism of DBD low temperature plasma,the exergy equation of low temperature plasma reactor system was established using exergy analysis method.Based on the principle of exergy loss and through analysis of irreversible factors,we investigated the effects of factors(reactor medium thickness,discharge spacing,discharge voltage,discharge space distance)on denitration efficiency.Results showed that a relatively denitration efficiency can be realized when the distance between high and low voltage electrode was 2mm and dielectric-barrier thickness was Zero point five millimeter.In the perspective of exergy analysis,the measure of reducing distance between highland low voltage electrode and decreasing dielectric-barrier thickness can both realize the purpose of reducing exergy loss and consumption.In addition,the measure of reducing the electrode length along airflow direction,distance between electrodes,and dielectric-barrier thickness can always decrease the trigger voltage for low temperature plasma reactor,so as to increase the sensitivity of plasma reactor.Following the approach of increasing exergy efficiency,it can successfully seek a measure to increase denitration efficiency and reduce reactor energy consumption,so as to realize the purpose of saving energy and actual value of DBDP-based denitration. |
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