Methane dry reforming using oil palm shell activated carbon supported cobalt catalyst: Multi-response optimization

Dry reforming of methane with carbon dioxide was investigated using oil palm shell activated carbon (OPS-AC) supported cobalt catalyst. The cobalt loaded OPS-AC catalysts were prepared by wet-impregnation method and characterized using SEM, FESEM, BET, TPR and TPD. Surface morphology of OPS-AC supported cobalt catalysts exhibited higher porosity, surface area and micropore volume with different densities of cobalt particles and support. Furthermore, greater amount of H₂ chemisorbed and acidity were observed with increasing cobalt contents. Response surface methodology (RSM) was employed to design the experiments based on factorial central composite design. Catalytic testing was performed using a micro reactor system by varying four variables: temperature, gauge pressure, CH₄/ CO₂ ratio and gas hourly specific velocity (GHSV). H₂ and CO yields were analyzed and quantified by gas chromatography with thermal conductivity detector (TCD). Both responses (H₂ and CO) yields were optimized simultaneously using desirability function analysis. Reaction temperature was the most influential variable with high desirability prevalent for both responses. The optimum response values of H₂ and CO yields corresponded to 903 °C, 0.88 bar(g), CH₄/ CO₂ = 1.31 and GHSV = 4,488 mL/h.g-catalyst.