Upscaling Plasma-Based CO₂ Conversion: Case Study of a Multi-Reactor Gliding Arc Plasmatron

Area of Science:

• Plasma Science and Engineering
• Chemical Engineering
• Environmental Technology

Background:

• Atmospheric pressure plasmas are increasingly vital for chemical, oil, and environmental industries, driven by climate change mitigation and greenhouse gas conversion needs.
• Existing high technology readiness level (TRL) plasma systems rely on costly volumetric and power scaling of thermal plasmas.
• Scaling challenges limit the industrial adoption of plasma technologies for converting greenhouse gases like CO2 into valuable chemical feedstock.

Purpose of the Study:

• To scale a quasi-thermal (warm) plasma setup, a gliding arc plasmatron, from lab-scale to pilot-scale with a tenfold increase in throughput.
• To investigate the parallelization of multiple plasmatron reactors within a single housing to improve cost-efficiency and maintain a warm plasma regime.
• To evaluate the safety and control features necessary for industrial integration of the scaled-up plasma system.

Main Methods:

• Development and testing of a multi-reactor gliding arc plasmatron (MRGAP) by parallelizing gliding arc reactors within a single housing.
• Investigation of performance metrics including conversion, energy efficiency, and energy cost under varying flow rates and numbers of active reactors.
• Analysis of the impact of reactor placement on monitored performance metrics.

Main Results:

• The parallelization strategy successfully scaled the gliding arc plasmatron to pilot capacity with a 10x throughput increase.
• Optimal performance was achieved with five active reactors at a flow rate of 80 L/min, yielding 9% conversion and 19% energy efficiency.
• Reactor location had a negligible effect on conversion, energy efficiency, and energy cost.

Conclusions:

• Parallelization of plasmatron reactors in a single housing is a viable method for scaling up plasma systems for industrial applications.
• Increasing power (via more reactor channels) and flow rate while maintaining specific energy input (SEI) around 5.3 kJ/L (1 eV/molecule) enhances conversion rates.
• The MRGAP design offers a promising pathway for cost-effective and efficient greenhouse gas conversion using plasma technology.