Experimental investigation of CO₂ conversion in Boudouard reaction driven by an atmospheric-pressure microwave plasma torch

Abstract An atmospheric-pressure microwave plasma torch (APMPT) is employed to drive Boudouard reaction [C(s) + CO 2 (g) → 2CO(g)] to convert CO 2 into CO with storable chemical energy. In this experiment, the solid carbon is placed in the downstream of the afterglow of carbon dioxide APMPT, which is enclosed in reaction chamber, thereby the reaction occurs in the environment with a plenty of the active species and the large enthalpy. The conversion and energy efficiency are experimentally determined by measuring the change of the gas composition, which is analyzed with a Fourier transformation infrared spectrometer and gas chromatograph. The variations of conversion and energy efficiency are investigated with respect to the plasma state, which is tuned by changing microwave power, gas flow rate, and Ar-CO 2 mixture ratio, and the different forms of carbon material. And the high conversion efficiency is obtained with use of the herbaceous type of biomass as carbon material and by increasing microwave power, however, the large percentage of CO 2 in carrier gas and increasing gas flow rate impose a negative influence on CO 2 conversion.