Conversion Of Carbon Dioxide By Dielectric Barrier Discharge At Atmospheric Pressure

From the industrial revolution on,energy needs increase greatly due to the aggravation of human activities.The utilization of fossil fuels has increased significantly.As a result,the rate of CO₂ emissions is growing faster in the atmosphere,resulting in a significant increase in the CO₂ level and the greenhouse effect.DBD plasma technology can overcome the thermodynamic barrier to decompose CO₂with low energy cost.In addition,DBD plasma technology has the advantages of simple device and low cost,so it has been concerned widely.In this paper,atmospheric pressure nanosecond pulse discharge and AC discharge are used to convert CO₂.The reactor is filled with glass or zirconia pellets with different sizes.The effects of pulse peak voltage,AC voltage,frequency and CO₂ flow rate on CO₂ conversion rate,energy efficiency,discharge power and emission spectrum intensity of active species are investigated.The main contents are as follows:1.The image of nanosecond pulse DBD at atmospheric pressure,the variation of CO₂conversion rate,energy efficiency and discharge power with voltage and the diameter of glass pellets are studied.When the diameter of glass pellets increases from 3 mm to 4 mm,the CO₂conversion rate,energy efficiency and discharge power increase.When the reactor is only filled with quartz wool,the discharge power is less than that of the filled glass pellets under the same voltage.The highest carbon dioxide conversion rate is 3.8%;When the pulse peak voltage is 26 kV,the pulse repetition frequency is 160 Hz,and the flow rate of CO₂ is 50ml/min,the energy efficiency of the reactor filled with 4 mm glass pellets is the highest,which is 0.79 mmol/kJ.When the diameter of the filling dielectric beads is larger,the carbon dioxide conversion rate is higher.2.The image of AC DBD at atmospheric pressure,the variation of CO₂conversion rate,energy efficiency and discharge power with discharge voltage,frequency and CO₂ gas flow rate are studied.CO₂ conversion rate increases with the increase of AC voltage and frequency,and decreases with the increase of CO₂ gas flow rate.The energy efficiency increases with the increase of AC voltage and is less affected by frequency;The discharge power increases with the enhancement of AC voltage and frequency,and is not affected by CO₂ gas flow rate.The emission spectra intensities of CO(B-A)and CO(b-a)increase with the increase of AC voltage and frequency.When the AC voltage is 22 kV,the frequency is 10 kHz,and the flow rate of CO₂ is 40 ml/min,the maximum CO₂ conversion rate is 20.9%in the reactor filled with 4 mm zirconia pellets.When the reactor is filled with dielectric beads with a higher dielectric constant,the carbon dioxide conversion rate is higher.