Study Of Membrane Catalyst For Direct Oxidation Of Methane To Methanol And Formaidehyde

A new catalyst—ZrO₂-CaO membrane catalyst for direct oxidation of methane to methanol and formaldehyde have been investigated.The ZrO₂-CaO membrane reactor is prepared by SOL-GEL, it can control the diffusion velocity of oxygen,oxygen diffusing through the membrane is activated and form active oxygen species which easily react with methane, so showing high selectivity to methanol and formaldehyde. By means of SEM and AES, many factors which influence the preparation of ZrO₂-CaO membrane and selectivity and conversion of raection have been studied. The experiment result shows that The optimum preparation condition is:calcination temperature T=700℃-800℃, film thickness b=45mg/cm²Zr-60mg/cm²Zr, CaO additive amount x=0.08 -0.15, 0.6μm pore supporter Al₂O₃ ceramics is better than 2 μm's.The reaction condition have also been investigated. At atmopheric pressure, the proper range of temperature is 350 ℃ or so, GHSV=8000h^-1 -10000h^-1, O₂ flow 50ml/min. Under optimum reaction condition we have got 96% selectivity of methnaol and formaldehyde , about 1% conversion of methane.