Nanosecond high-voltage pulses for air purification (Vol. 49, No. 2)

NO removal (and by-product formation) with fast high voltage pulses

Transient plasmas generated by high-voltage pulses have been widely studied and used for industrial and environmental applications for more than 100 years. The highly reactive species that are generated in these plasmas can react with particles in polluted gas and water streams. We focus on plasma for environmental applications and developed a new, very fast high-voltage pulse source for this purpose (0.5-10 ns pulse duration, 200 ps rise time and 50 kV amplitude). We showed that with this pulse source, we can achieve extremely high energy yields in ozone generation (typically used for water decontamination) and nitrogen oxide (NO) removal (a typical exhaust gas for diesel engines). Interestingly, the pulse duration, a figure of merit that has long been claimed as the key success in high-yield plasma processing (the shorter the better), had no significant influence on our yields. It appears that the key to these high yields is the very fast rise time of our high-voltage pulses. They are so fast that the complete electric field is applied to the gas while the plasma is still developing, which results in higher electron densities and ultimately in more reactive species.

T. Huiskamp, W. F. L. M. Hoeben, F. J. C. M. Beckers, E. J. M. van Heesch and A. J. M. Pemen , (Sub)nanosecond transient plasma for atmospheric plasma processing experiments: application to ozone generation and NO removal, J. Phys. D: Appl. Phys. 50, 405201 (2017)