7th Asia-Pacific Conference on Plasma Physics, 12-17 Nov, 2023 at Port Messe Nagoya

High efficiency NOx synthesis and regulation using dielectric barrier discharge
in the needle array packed bed reactor
Yao Li1, De-Zheng Yang1
1
Key Lab of Materials Modification by Laser, Ion, and Electron Beams, Dalian University ofTechnology
e-mail (speaker): liyaoYTHY@mail.dlut.edu.cnNitrogen, existing in amino acids, chlorophyll, andnucleic acid, is the necessary component of livingorganisms. Above 99% of the nitrogen is present in theatmosphere as N2 which has the stable N≡N structure andelectron configuration. As a result, the nitrogen fixation
process is essential to use N2 reasonably. The HaberBosch (H-B) process, which takes primary responsibility
to global population survival and crop growth is an energy
intensive chemical process. In detail, accounts for 1%-2%of the world’s energy consumption and release 300
million tons of CO2 per year. Considering the grimsituation of world growing population and greenhouse gas
emission, the new nitrogen fixation technology which canreduce the environmental pressure and energy crisis isnecessary to be developed.
The plasma has been considered as a promisingtechnology to develop nitrogen fixation effectively.
Among different discharge types, the DBD, especially inthe packed bed reactor (PBR) which can generate nonthermal plasma and play good synergy effect with catalyst,
is widely used in NOx synthesis process. However,comparing with other plasma types, achieving thereduction of the energy cost or the increase of the NOx
production in PBRs is always a challenge and a lot ofresearch works has been carried out.
As can be concluded from previous works, most PBRs
used for gas-phase NOx synthesis are driven by alternating
current (AC) power supply, and the PBRs driving bynanosecond power supply is rarely applicated in gasphase NOx synthesis.

To further improve the energy efficiency of gas-phase
NOx synthesis in PBRs, the optimization of plasma
sources is an important path. In addition, much attention
should also be paid to the innovations of electrodestructure which can directly influence the utilization rateof raw material gases.
In this paper, a needle array packed bed reactor excited bynanosecond pulse voltage is employed to synthesize NOx
efficiently with α-Al2O3 and γ-Al2O3 packed materials.
The pulse width, pulse rising time, pulse repetition rate,
and oxygen content are adjusted to regulate the NOx
synthesis results, such as NOx concentration, productselectivity, and energy cost. The discharge power, key
reactive species, and the rate coefficient are calculated toprovide clear insight into the NOx synthesis pathways. It
is found that the NOx can be synthesized efficiently in thisneedle-tubes array packed bed reactor, the highest NOx
concentration of 1.12% and 0.97% are obtained in unfilled
reactor and γ-Al2O3 packed bed reactor, respectively,
which are nearly two times higher than the results reported
in previous works under the same energy cost and thesame type of discharge. In addition, increasing pulse
width and pulse repetition rate can significantly enhance
the NOx concentrations because of the increased energy
input and rate coefficient.
References[1] Y. Li et al, Chem. Eng. J. 461, 141922 (2023)[2] Y. Li et al, Appl. Sci. 12, 2215 (2022)Figure 1. experiment setup and magnified view of the PBR (left) and the NOx synthesis results under different pulse
width in PBR (right)