CO₂ mitigation by carbon nanotube formation during dry reforming of methane analyzed by factorial design combined with response surface methodology

Abstract: A factorial experimental design was combined with response surface methodology (RSM) to optimize the catalyzed CO₂ consumption by coke deposition and syngas production during the dry reforming of CH₄. The CH₄/CO₂ feed ratio and the reaction temperature were chosen as the variables, and the selected responses were CH₄ and CO₂ conversion, the H₂/CO ratio, and coke deposition. The optimal reaction conditions were found to be a CH₄/CO₂ feed ratio of approximately 3 at 700 °C, producing a large quantity of coke and realizing high CO₂ conversion. Furthermore, Raman results showed that the CH₄/CO₂ ratio and reaction temperature affect the system’s response, particularly the characteristics of the coke produced, which indicates the formation of carbon nanotubes and amorphous carbon.