| Summary: | 碩士 === 國立中興大學 === 化學工程學系所 === 95 === In the dissertation, the purpose of this study is to prepare nanocatalyst Cu/ZnO supported on Zirconia and to apply it on steam reforming of methanol. The operating parameters, including the choice of the solvent, the molar ratio of H2O to Zr(OC3H7)4, the difference between agitation and ultrasound, the concentration of Zr(OC3H7)4 dissolved in n-propanol and the temperature of calcination, were all performed to find the optimal preparation conditions. The operatiy parameters of methanol steam reforming were included the weight hourly space velocity, the H2O/CH3OH molar ratio, the amount of copper, the amount of ZnO and time-on-stream activity testing.
The results show that the particle size of ZrO2 is related to the of choice the solvent, the molar ratio of H2O to Zr(OC3H7)4, the concentration of Zr(OC3H7)4 dissolved in n-propanol, the stirring method, the temperature of calcinations and the addition of dispersant. And adding the dispersant influenced the pore size of catalyst. The optimum operating conditions were obtained, the n-propanol as solvent, the molar ratio of H2O to Zr(OC3H7)4 is 0.25M of the concentration of 4.5 Zr(OC3H7)4 dissolved in n-propanol with ultrasound agitation,400℃ of the calcinations temperature for 5 hours and the CTAB as the dispersant for the support.
When ZnO-promoter was added to Cu/ZrO2 catalyst ,the methanol conversion and H2 yield improved greatly by methanol steam reforming. The catalyst with active Cu metal shows higher activity for the reaction of methanol steam reforming and the best weight ratio of Cu/ZnO/ZrO2 was 14/5/81. Using Cu/ZnO/ZrO2 as the catalyst, we obtained the hydrogen yield to be 96.44% at 320℃ with 1.3 of molar ratio of water to methanol. The higher hydrogen production, higher selectivity of CO2 and lower CO concentration were also observed. 10-hour duration of test for Zr-1 catalyst showed that the catalyst had good stability with H2 yield kept at 82 % and CO2 selectivity > 99 % , and CO Vol % 0.06-0.22 %. But another method of simultaneous adding Cu and ZnO precursors for the preparation Cu/ZnO/ZrO2 (Zr-2) obtained the H2 yield much lower than with by which Zr-1. H2 yield was kept at 20 %, and CO2 selectivity >92%
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