CO₂ conversion by thermal plasma with carbon as reducing agent: high CO yield and energy efficiency

A key problem in CO₂ conversion by thermal plasma is suppressing the inverse reactions, CO+O→CO₂ and CO+0.5O₂ →CO₂, to simultaneously obtain high CO yield and energy efficiency. This can be done by quickly quenching the decomposed gas or rapidly taking away free oxygen from decomposed gas. In this paper, experiments of CO₂ conversion by thermal plasma with carbon as a reducing agent are presented. Carbon quickly devoured free oxygen in thermal plasma decomposed gas, and not only is the inverse reaction completely suppressed, but the discharge energy to form oxygen atoms, oxygen molecular, and thermal energy is also reused. A CO₂ conversion rate of 67%–94% and the corresponding electric energy efficiency of about 70% are achieved, both are much higher than that seen so far by other plasma implementations.