A Novel Multi-Needle-to-Cylinder Dielectric Barrier Discharge Reactor with Deflector Rings for Energy-Efficient Removal of Sulfides and Ammonia from Odor Gases

Non-thermal plasma is a promising technology for odor abatement from agricultural and domestic waste. However, its widespread application is often limited by the inherent trade-off between energy efficiency and processing capacity in conventional reactors. To address this challenge, we propose a novel multi-needle-to-cylinder dielectric barrier discharge reactor integrated with a deflector ring. By synergistically optimizing the electrode topology and modulating the flow field, this reactor achieves enhanced removal of complex ammonia–sulfur odor mixtures. The underlying mechanisms were elucidated through computational fluid dynamics (CFD) simulations coupled with systematic performance evaluation. Experimental results demonstrate that an 8-needle electrode configuration provides the optimal balance between discharge density and energy efficiency. CFD simulations further reveal that the deflector ring effectively suppresses gas bypass and promotes recirculation vortices downstream, thereby extending the residence time significantly. Mechanistic studies indicate that the removal of recalcitrant inorganic sulfides (e.g., CS2 and H2S) follows a synergistic mass-transfer–reaction controlled process, which is markedly improved by flow field optimization. In contrast, organic sulfides are governed primarily by chemical kinetics and show little dependence on flow variations. Under an extremely short residence time of 0.57 s (corresponding to a flow rate of 2.0 m3/h) and an ultra-low specific energy input of 6.26 J/L, the system achieved nearly complete removal of organic sulfides. Even for challenging inorganic sulfides, removal efficiencies reached 80.9% for H2S and 45.3% for CS2, while O3/NOx/SO2 byproducts were quantified. For industrial deployment, these byproducts can be managed by standard downstream polishing. By effectively coordinating discharge characteristics with flow dynamics, this study provides both theoretical insight and technical support for the development of next-generation, energy-efficient, high-throughput industrial odor control systems.