Preferential oxidation of CO in a double-stage packed-bed reactor

Abstract

Preferential oxidation (PROX) of CO is typically used to lower the CO concentration in the H₂-rich stream derived from hydrocarbon reforming. In this study, Au supported on a TiO₂ catalyst prepared by deposition-precipitation was tested for the PROX reaction in the temperature range of 30-120℃. The effects of calcination temperature, Au loading, and storage condition on the catalytic performance were studied. The prepared catalysts were characterized by X-ray Diffraction (XRD), UV-visible spectrophotometry and Atomic Absorption Spectrometry (AAS). The results indicated that the 1 wt% Au/TiO₂ calcined at 200℃ operated in a single-stage reactor exhibited 100% CO conversion with a maximum selectivity of approximately 54%. The effects of H₂O and CO₂ present in the stream for the PROX reaction were also investigated. Then, the catalyst was applied for the PROX in a double-stage reactor unit of the fuel processor, starting from methanol. In addition, the catalyst was tested in a double-stage reactor at the appropriate operating conditions by varying stage temperature, oxygen split ratio, and weight split ratio. In a double-stage reactor, the PROX selectivity at 30℃ was increased to 80%.