Plasma-assisted CO_2 conversion as alternative to conventional fuel processing

摘要

The (inorganic) conversion of CO_2 into hydrocarbons in a non-equilibrium plasma has been studied as an alternative conversion route in synthetic fuel processing. The focus was on the efficiency of CO_2 depletion and selectivity of CH_4 production in a low-temperature plasma expansion. The plasma is created from mixtures of argon and hydrogen while CO_2 is injected into the expansion part where the dissociation mechanism might be radical- and/or ion-driven. Complementary experiments were carried out for CO injection. The (steady-state) gas composition was studied by means of mid-infrared tuneable diode laser absorption spectroscopy and mass spectrometry. Two regimes of either high CO_x dissociation (up to 50 %) or efficient CH4 formation (～ 20 %) can be clearly identified. These results suggest the successive hydrogenation of CO as main reaction path. An efficient CO_2 → CO conversion is thus an essential criterion.