| Summary: | 碩士 === 長庚大學 === 化工與材料工程研究所 === 93 === Traditionally, steam reforming reaction of methanol is carried out under 300℃ with copper-zinc catalyst to avoid rapid decay of copper catalyst because of its low Tammann temperature. With progress in the palladium membrane assisted reactor, a higher reaction temperature would bring about a higher hydrogen permeance and result in higher efficient separation of hydrogen. Consequently it is highly desirable to have a stable high temperature steam reforming catalyst for hydrogen production with a catalytic membrane reactor. As a high temperature catalyst for this reaction; it is to be stable with long duration and it should maintain low percentage of carbon monoxide which is formed from reverse water gas shift reaction by consuming valuable hydrogen product.
In this report, we have utilized zirconia as a supplemental support to modify a series of copper-zinc catalysts with silica and γ-Al2O3 as the main support and tested these catalysts at 420℃. The compositions of catalysts studied are described below: [ⅠA] Cu/Fe/Zn/SiO2, [ⅠB] Cu/Cr/Zn/ SiO2, [ⅡA] Cu/Fe/Zn/ZrO2/SiO2, [ⅡB] Cu/Cr/Zn/ZrO2/SiO2, [ⅢC] Cu/Fe/Ni/Zn/ZrO2/Al2O3, [ⅢAC] Cu/Ni/Zn/ZrO2/Al2O3, [ⅣA] Cu/Fe/Zn/ZrO2. These catalysts were made either by impregnating the corresponding salts on SiO2 or ZrO2 support (for [ⅠA], [ⅠB] and [ⅣA]) or by prior coating of ZrO2 paste on the SiO2 or Al2O3 support followed by impregnation of the corresponding salts([ⅡA], [ⅡB], [ⅢC] and [ⅢAC] ).
The best catalyst [ⅢAC] shows a conversion decaying to 80% with a methanol-steam mixture of H2O/CH3OH = 1.2 mol forming H2 (70-73 %), CO2 (19-25 %) and CO (1.0-9.0 %) in a 600hr test.
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