Propane dry reforming in atmospheric-pressure microwave plasma with detailed kinetic mechanism generation using Reaction Mechanism Generator (RMG)

Dry reforming of C 2+ hydrocarbons remains relatively less explored than methane dry reforming, despite the need to understand how hydrocarbon chain length affects reaction pathways and product compositions. In this study, propane (C 3 H 8 ) and carbon dioxide (CO 2 ) reforming was performed using atmospheric-pressure microwave plasma, with propane selected as the main component of LPG. The plasma and product gas composition were characterized using optical emission spectroscopy (OES) and gas chromatography (GC), respectively. OES results showed that the rotational and vibrational temperatures of the plasma were approximately 5700 K, regardless of the total flow rate. For a fixed microwave power of 2 kW, the C 3 H 8 and CO 2 conversions were 99% and 67%, respectively, at 10 slpm, with H 2 and CO selectivities of 67% and 83%. Without heat recovery, the maximum energy efficiency was approximately 45% at 25 slpm. To further investigate the reaction process, a reduced-dimensional reactor network model was developed. A detailed kinetic mechanism was generated using Reaction Mechanism Generator (RMG) to include hydrocarbon pathways up to C 4 species. The simulated product concentrations agreed well with the GC measurements. Reaction pathway analysis showed that CO was mainly produced through H + CO 2 → OH + CO, while H 2 was primarily formed through hydrogen abstraction from hydrocarbons. Although C 4 pathways were included, CH 4 , C 2 H 2 , and C 2 H 4 were the major hydrocarbon byproducts, indicating that the temperatures in both the plasma and surrounding streams remained too high for C 3 and larger hydrocarbons to accumulate.