| Summary: | The direct conversion of natural gas, and in particular, the principal component, methane to useful products has been intensely studied over the past decades. ZSM-5 zeolite has been known to be a suitable catalyst for olefin oligomerization, but it is known to be a suitable catalyst for olefin oligomerization, but it is not resistant to high temperatures. In this work, HZSM-5 was modified with copper and tungsten to develop a highly active and heat resistant bifunctional oxidative-acid catalyst. The performances of Cu modified W/HZSM-5 were compared with HZSM-5 for the oxidation of methane to liquid hydrocarbons. The characterization results revealed that the addition of tungsten to HZSM-5 zeolite improved its thermal stability. Response Surface Methodology (RSM) was employed to determine the optimum methane conversion and C5+ selectivity. Numerical results indicated the optimum methane conversion of 29.54% with the corresponding C5+ selectivity of 57.2% were achieved at 12.3 vol % of O2, 203.9 ml/min of total feed flow rate, and % W doped of 3.2 wt%. The optimum C5+ selectivity of 70.2% was attained at 7.6 vol % of O2, 208.9 ml/min of total feed flow rate, and 3.2 wt% of W content with the corresponding methane conversion of 26.7%. By means of variance analysis and additional experiments, the adequacy of this model was confirmed.
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