Simulation and Experimental studies of Oxidative Coupling of Methane in a Bench Scale Fixed Bed Reactor using Mn-Na2WO4/SiO2 catalyst

Oxidative coupling of methane (OCM) has been modeled in a fixed bed tubular reactor using one dimensional pseudohomogeneous model over Mn-Na2WO4/SiO2 catalyst. A nine step OCM reaction model has been considered for reaction kinetic study. A reactor tube with 20 mm in diameter and 400 mm length surrounded by molten salt for removing released heat from reactions was used for experimental study. Based on an objective function and using experimental data, kinetic parameters of OCM reactions are obtained. Good agreement has been observed betweensimulation and experimental data over operating conditions of experiments. Maximum calculated errors for methane conversion and C2+ selectivity are 12.4% and 4.8%, respectively. The effects of different factors such as CH4/O2 ratio and feed temperature were investigated for three different cases namely isothermal, adiabatic and constant wall temperature through simulation studies. Also the effects of CH4/O2 ratio, nitrogen content as a dilution material and contact time were studied experimentally. Experimental results indicate that C2 + selectivity has an optimum value for CH4/O2 ratio of 6 and 23% N2 content. Based on results obtained for above operating conditions, the isothermal operation has optimal performance.

Keywords:

Oxidative coupling of methane , OCM , Fixed bed tubular reactor , Pseudo-homogeneous model , Optimization