Nitrogen Oxides Reduction by Using Cold Plasma Discharge (Réduction des Oxydes d'azote par Plasma Froid de Décharge)
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Date
2026
Authors
Journal Title
Journal ISSN
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Publisher
Djilali BENYOUCEF
Abstract
This thesis reports a detailed numerical investigation of nitrogen oxides (NOₓ) mitigation
using a dielectric barrier discharge (DBD) reactor operating at atmospheric pressure. The study
examines the electrical behavior of the discharge, including voltage–current characteristics,
discharge power, and specific energy density, and investigates their relationship with NOₓ
removal performance. Simulations were performed for various working gas compositions (69%
N₂, 20% O₂, and 1% Ar), and a simulated exhaust gas containing NO, under different operating
conditions such as applied voltage(10kV), excitation frequency(3kHz), and NO flow rate. The
numerical model was developed and implemented using COMSOL Multiphysics to analyze the
coupled plasma dynamics and chemical kinetics involved in the discharge process. Particular
attention is given to the temporal development of micro-discharges in order to elucidate the
plasma-chemical pathways responsible for the generation of reactive species, including atomic
oxygen, ozone, and electronically excited molecules of nitrogen and oxygen. These species are
shown to govern the oxidation of NO and its subsequent transformation into NO₂, N₂O₅, and
other less hazardous nitrogen compounds. The simulations were carried out for atmosphericpressure gas mixtures composed of N₂, O₂, Ar, and NO under optimized operating conditions.
The results indicate that higher applied voltages, combined with the presence of low oxygen
fractions, markedly increase the formation of oxidative radicals, thereby improving NO
conversion efficiency. In addition, the effect of argon admixture is analyzed, revealing its role in
enhancing electron-impact processes and discharge homogeneity, which in turn leads to
improved plasma reactivity. The obtained results demonstrate a NO reduction efficiency
reaching approximately 99% under optimal operating conditions, confirming the strong potential
of DBD plasma technology for air pollution control. The energetic performance of the process is
evaluated to assess its suitability for large-scale implementation. Overall, the outcomes confirm
that non-thermal plasma generated by DBD reactors constitutes an effective, energy-efficient,
and environmentally sustainable approach for NOₓ reduction. The reactor demonstrates
significant removal efficiencies, underscoring its potential for advanced air purification. Finally,
strategies for reactor optimization and prospects for coupling DBD technology with catalytic
systems are discussed.
Description
THESIS
Submitted in fulfillment of the requirements for the degree of
DOCTORATE (LMD)
Field: Electrotechnics
Specialty: Electrical Networks
Keywords
Cold plasma, Dielectric barrier discharge (DBD), Nitrogen oxides (NOₓ)