| 摘要 |
A process and apparatus for oxidizing methanol in a gas stream formaldehyde in a fixed bed reactor. The process first introduces a gas stream into a fixed bed reactor. The fixed bed reactor contains a catalyst bed having a depth, a width, a length, an inlet, an upstream region, a downstream region and an outlet. Preferably, the inlet, the upstream region, the downstream region and the outlet are provided in the order stated. A vanadia-titania catalyst is provided in the upstream region and a molybdena-titania catalyst is provided in the downstream region.The vanadia-titania catalyst in the upstream region is substantially free of MoO3 and initially (i.e., during oxidation some V2O5 may sublime and migrate to the downstream region) the molybdenatitania catalyst in the downstream region is substantially free V2O5. Next, the gas stream is contacted with a vanadia-titania catalyst under oxidizing conditions. Then, the gas stream is contacted with a molybdnea-titania catalyst under oxidizing conditions which provides a product stream containing formaldehyde at the desired conversion and formaldehyde selectivity. |
