Statistical Optimization of Process Variables for Methane Conversion over Zn‐Mo/H‐ZSM‐5 Catalysts in the Presence of Methanol

The direct conversion of methane to higher hydrocarbons is considered as one of the most promising methods to produce liquid fuels. Different percentages of Zn loaded on zeolitic 5 % Mo/H‐ZSM‐5 catalysts were prepared by using a conventional impregnation method; these catalysts were used to convert methane into a range of liquid hydrocarbon fuels in the presence of methanol. The catalysts were characterized by using Brunauer–Emmett–Teller surface area, temperature‐programmed reduction, temperature‐programmed desorption, SEM‐energy dispersive X‐ray, and XRD analysis. Response surface methodology was used to optimize the process variables for the conversion of methane into liquid hydrocarbon fuels. The catalytic activity tests were carried out in a fixed‐bed microreactor and methanol was used as a co‐reactant to activate the methane molecules. Central composite experimental design was used to study the effects of each variable on methane conversion. Analysis of variance indicated a high coefficient of determination value (R2=0.96), and a satisfactory prediction for a second‐order regression model was developed. The optimum methane conversion (30.7 %) was obtained with flow rates of 1500 and 1.25 mL h−1 for methane and methanol, respectively, over a 3 % Zn‐Mo/H‐ZSM‐5 catalyst. The major reaction products were ethane, ethylene, C4+ aliphatic hydrocarbons, and aromatic hydrocarbons. Kinetic studies were also performed for methane conversion using a power law model; the activation energy for the reaction was 61.6 kJ mol−1. Perfecting processes! xZn‐5 % Mo/H‐ZSM‐5 catalysts are prepared by using a conventional impregnation method. Methane conversion is studied using methanol to activate methane for improved conversion. Central composite experimental design is used to study the effects that different parameters have on methane conversion. Active component compositions, textural properties, metal dispersions, and acidity of the catalysts were determined by using a variety of analytical methods.