Development of a Swirl‐Induced Rotating Glow Discharge Reactor for CO₂ Conversion: Fluid Dynamics and Discharge Dynamics Studies

Abstract

Herein, CO2 conversion is conducted in a newly developed swirl flow–induced rotating glow discharge reactor. The swirl injector is designed to produce forward vortex by eight inclined guided vanes. A glow‐type rotating discharge is formed between two electrodes of constant height. The discharge and fluid dynamics studies reveal that the magnitude of tangential velocity and secondary vortex formation affects the rotational frequency of the discharge. It is also found that the anchoring point of the plasma column root is greatly influenced by the increased pressure gradient, especially in the turbulent regime. The conversion of CO2 as a function of flow rate is found to increase in the laminar regime and decrease in the turbulent regime. With increasing specific energy input from 0.25 to 3.4 kJ L−1, there is a rise in conversion from 1.2% to 4.6%, which indicates the high residence time and high energy deposition to lesser number of CO2 molecules. Higher energy efficiencies (54.9–63.7%) at turbulent flow rates show that this swirl design enhances the distribution of electron energy to incoming fresh molecules by formation of circulation zones and turbulence.

Selective Production of Hydrogen and Solid Carbon via Methane Pyrolysis Using a Swirl-Induced Point–Plane Non-thermal Plasma Reactor

“…These vanes were mounted on a central hub of 20 mm diameter. Our previous work on CO 2 dissociation to CO and O 2 employed a similar swirl injector, but a ring electrode was employed instead of a point electrode used in this study . Initial experiments using the ring electrode suggested that carbon channelling occurred in between the ring electrode and swirl electrode as a result of the cracking of methane gas.…”

“…The present swirl injector has S = 0.9, which ensures the formation of the CRZ. On the basis of the limitation of machinability, swirl number requirement, and central recirculation zone size, the vane angle and number of slots were designed, which are detailed elsewhere . Carbon channelling hinders the rotation of the arc and leads to short circuiting of the electrode gap without any plasma.…”

“…On the basis of the limitation of machinability, swirl number requirement, and central recirculation zone size, the vane angle and number of slots were designed, which are detailed elsewhere. 25 Carbon channelling hinders the rotation of the arc and leads to short circuiting of the electrode gap without any plasma. Therefore, this study is performed by placing a point electrode in the central hub region of swirl flow.…”

CHEMampere: Technologies for sustainable chemical production with renewable electricity and CO2, N2, O2, and H2O

“…In terms of reactor designs already in use for CO 2 splitting (the most popular application), a tubular design using vortex flow was presented in 2019 by Trenchev et al [75] Just recently, Raja et al used a vortex gas flow and ring electrodes to prevent arc formation. [76] In a design, which will be further pursued for CHEMampere, collaborators of the initiative have presented a reactor using pin-discharge and an axial magnetic field, [77] which does not utilize a vortex flow and can thus be operated at arbitrary gas flow rates.…”

“…[75] Raja et al also used a vortex gas flow, but ring electrodes to prevent arc formation, being rewarded with a high energy efficiency of 60% at conversions ranging from 2% to 3%. [76] In a design that will be further pursued for CHEMampere, a reactor using pin-discharge and an axial magnetic field was presented, which achieved 27% energy efficiency at 17% conversion. [77] It does not utilize a vortex flow and can thus be operated at arbitrary gas flow rates.…”