Development Of A High-Temperature Pulse DBD System And Its Discharge Characteristics

For industrial production processes which need to be developed under high temperatures,such as preparation of ceramic fiber,desulfurization of high temperature calcined petroleum coke,catalytic combustion of organic waste gas,etc.,using plasma in each conventional process to activate gas molecules and accelerate the reactions is a potential breakthrough.The question is dielectric barrier discharge(DBD)so far cannot run steadily at high temperature above 400?.In this paper,a system with coaxial tube type electrode structures was designed to be used stably under high temperature environment.The discharge characteristics of DBD were tested from room temperature to 800? in nitrogen,argon and helium atmospheres.The denitrification effect and the discharge characteristics of high-temperature DBD in ammonia gas were studied and the effect of increasing boron nitride fiber production efficiency was summarized.The main research contents and conclusions are as follows:(1)The high temperature dielectric barrier discharge system with pulse power supply was designed.Three design difficulties are introduced.The system test results show that the developed high voltage insulation structure can work stably for a long time at a temperature of up to 800?,the electrical parameters change little and the performance under high temperature is excellent.(2)The performance under different atmospheric conditions is slightly different.The nitrogenous environment exhibits obvious filamentous discharge.It is difficult to change the discharge form whatever the temperature or the voltage is raised.Argon discharge is filamentous,and gradually changes from filament to more uniform discharge with the temperature rising.The discharge in helium is not filamentous,a relatively uniform discharge can be achieved at low voltage.(3)The breakdown voltage and peak voltage under nitrogen atmosphere are significantly higher than that of argon and helium,and the temperature dependence is the strongest in nitrogen.Increasing the temperature,voltage,power frequency or gas flow rate can all increase the effective current and power.The energy provided by power supply is mainly consumed in the reactor.As the temperature increases,the energy consumed in the reactor increases and then stabilizes.(4)Using the high-temperature pulsed dielectric barrier discharge system to remove nitrogen oxides(NOx),the efects of temperature,voltage and frequency on the NOx removal were studied.The results shows that increasing the temperature,voltage or power frequency is all beneficial to improve the denitrification effect.(5)The high temperature DBD characteristics in ammonia were tested and the method of preparing boron nitride fibers by traditional technology with DBD was studied.The results show that the discharge power can reach up to 550 W at 800?.The preparation process of boron nitride fiber is improved because of combining DBD.The nitrogen content of the fiber can be increased by 13%after 90-minute DBD treatment.