The study of scale up for the oxidative coupling of methane （OCM） has been carried out in a 200 ml stainless steel fixed-bed reactor over a 5wt% Na2WO4-1.9wt% Mn/SiO2 （W-Mn/SiO2） catalyst. The effects of reaction ...The study of scale up for the oxidative coupling of methane （OCM） has been carried out in a 200 ml stainless steel fixed-bed reactor over a 5wt% Na2WO4-1.9wt% Mn/SiO2 （W-Mn/SiO2） catalyst. The effects of reaction conditions were investigated in detail. The results showed that, with increasing reaction temperature, the gas-phase reaction was enhanced and a significant amount of methane was converted into COx; with the CH4/O2 molar ratio of 5, the highest C2 （ethylene and ethane） yield of 25% was achieved; the presence of steam （as diluent） had a positive effect on the C2 selectivity and yield. Under lower methane gaseous hourly space velocity （GHSV）, higher selectivity and yield of C2 were obtained as the result of the decrease of released heat energy. In 100 h reaction time, the C2 selectivity of 66%-61% and C2 yield of 24.2%-25.4% were achieved by a single pass without any significant loss in catalytic performance.展开更多
By calcinating commercial silica gel at 1500℃or adding Na2C2O4 and then calcinating at 850℃,α cristobalite was formed.On the basis of the vibration spectroscopy of silica support,Na W Mn/SiO2 catalyst was character...By calcinating commercial silica gel at 1500℃or adding Na2C2O4 and then calcinating at 850℃,α cristobalite was formed.On the basis of the vibration spectroscopy of silica support,Na W Mn/SiO2 catalyst was characterized by Raman spectroscopy.The results show that the structure of support and the interaction among metal components have significant effect on the dispersion and the structure of metal sites,and the tetrahedrally coordinated formed on α cristobalite surface is the most possible site of methane activation with high C2 selectivity.展开更多
文摘The study of scale up for the oxidative coupling of methane （OCM） has been carried out in a 200 ml stainless steel fixed-bed reactor over a 5wt% Na2WO4-1.9wt% Mn/SiO2 （W-Mn/SiO2） catalyst. The effects of reaction conditions were investigated in detail. The results showed that, with increasing reaction temperature, the gas-phase reaction was enhanced and a significant amount of methane was converted into COx; with the CH4/O2 molar ratio of 5, the highest C2 （ethylene and ethane） yield of 25% was achieved; the presence of steam （as diluent） had a positive effect on the C2 selectivity and yield. Under lower methane gaseous hourly space velocity （GHSV）, higher selectivity and yield of C2 were obtained as the result of the decrease of released heat energy. In 100 h reaction time, the C2 selectivity of 66%-61% and C2 yield of 24.2%-25.4% were achieved by a single pass without any significant loss in catalytic performance.
文摘By calcinating commercial silica gel at 1500℃or adding Na2C2O4 and then calcinating at 850℃,α cristobalite was formed.On the basis of the vibration spectroscopy of silica support,Na W Mn/SiO2 catalyst was characterized by Raman spectroscopy.The results show that the structure of support and the interaction among metal components have significant effect on the dispersion and the structure of metal sites,and the tetrahedrally coordinated formed on α cristobalite surface is the most possible site of methane activation with high C2 selectivity.
