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PLASMA CONVERSION OF CO₂ FOR OXYGEN PRODUCTION ON MARS

V. Vasilev, N. Lazarov, S. Lazarova, Ts. Paunska, St. Kolev�Faculty of Physics, Sofia University, 5 James Bourchier Boulevard, �1164 Sofia, Bulgaria

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Oxygen extraction on Mars

Atmosphere ~ 96% CO₂, 2% Ar, 2% N₂
The need for oxygen

Conditions on Mars

Dissociation of CO₂

Using a solid oxide electrolysis cell (like MOXIE)

Oxygen extraction

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Oxygen extraction on Mars

1. Martian atmosphere: CO₂, N₂, Ar 0.007 bar

2. Compressor

0.2-1 bar

3. Plasma conversion of CO₂

4. O₂ extraction

CO₂, CO, N₂, Ar release

CO₂ O₂

CO N₂ Ar

5. Further purification of O₂ and storage

Study scope

O₂

98%

Conceptual diagram of a system, using plasma conversion of CO₂ to produce oxygen on Mars

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Quenching to reduce recombination

Recombination into CO₂

Rate coefficient

Lowering the gas temperature after it passes through the plasma increases performance

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Experimental setup

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Experimental setup

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Results – DC power supply

Quenching

Benchmark

Mass flow rates – 1, 3, 5 L/min. Current – 50, 100, 150 mA

Energy efficiency is lower at lower pressure (200 mbar)

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Results – DC power supply

More power consumption at the same conversion rate -> lower energy efficiency

Arc regime

Glow regime

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Solution – high current pulses

High current (~500 mA) ensures operation in arc regime

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Pulsed power supply – input parameters

200, 350, 612.5 mbar

Pressure

2, 4, 8 L/min

Mass flow rate

Frequency - 5000 Hz
Duty cycle – 10, 25, 50%

Power supply

Quenching alumina plate at a distance of 5 mm from the electrodes

Configuration

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Pulsed power supply – results

Higher mass flow rates lead to both higher oxygen production rate and lower energy cost

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Conclusion

A novel magnetically stabilized arc discharge for oxygen production on Mars was developed

At lower pressures and currents a less efficient glow discharge was observed, hence a high current power supply was developed

Operation at higher mass flow rates results in higher oxygen production rate at a lower energy cost

Integration with an oxygen separation unit is needed to assess final performance

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THANK YOU FOR YOUR ATTENTION!

This research was funded by the Bulgarian National Science Fund, Ministry of Education and Science, research grant KP-06-N78/1 from 05.12.2023 and partially by the European Space Agency grant number 4000146712/24/NL/MH/mp