Optimization of reaction parameters by response surface methodology for the tri-reforming process over a Ni-silica catalyst to produce synthesis gas

Abstract

CO₂ and CH₄ are the most anthropogenic gases, and their rising concentration in the atmosphere is a global challenge. Tri-reforming of methane (TRM) offers a sustainable approach to directly convert these greenhouse gases into synthesis gas. In this study, a Ni-silica catalyst is synthesized, characterized by various techniques, and tested for TRM. The influence of reaction parameters, including temperature (600–800°C), catalyst amount (0.3–1.0 g), and O₂/CH₄ feed ratio (0.1–0.3) over CO₂ conversion, H₂/CO molar ratio, and H₂ selectivity is systematically analyzed using Design of Experiments. The optimization of these variables is performed through response surface methodology (RSM) using a central-composite design. The analysis of variance exhibits the significant effect of each parameter on the corresponding response within the proposed model. At the optimized reaction conditions suggested by RSM, the synthesis gas with an H₂/CO ratio of 1.6 is produced which is an ideal feedstock for the Fischer-Tropsch process for the production of dimethyl ether, methanol, and other valuable chemicals. The observed H₂/CO ratio is in good agreement with the value predicted by the model, further confirming the accuracy and reliability of the model.