Optimization of Methanol Reformation Using Cu/ZnO/Al2O3/CeO2(Cr2O3) Catalyst

• Main Authors: I-TE Tsai, 蔡一德
• Other Authors: 吳和生
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/93317899623589598168

碩士 === 元智大學 === 化學工程與材料科學學系 === 98 === The purpose of this research is to investigate the effect of modified Cu/ZnO/Al2O3 catalyst by Ce and Cr. The catalysts were prepared by oxalic coprecipatation method. First, study the effect of different pH values of Cu/ZnO/Al2O3 catalyst, and find the best activity of the catalyst which was determined by H2 production rate. Then, add the fourth metal(Ce,Cr) to the Cu/ZnO/Al2O3 catalyst and find the best Cu/Zn/Al/Ce(Cr) catalyst and compare with Cu/ZnO/Al2O3 catalyst. The operating temperature is in the range of 200oC to 260oC, and feed composition of H2O/CH3OH is 1.2 (molar ratio), WHSV(weight hourly space velocity) is 6.19 h-1: the weight of catalyst is 0.2 g,the flow rate of carrier gas is 20 sccm, the carrier gas is air. Catalysts were characterized by ASAP (BET), XRD, and SEM. According to experimental result, pH 7 has the best one because this catalyst can get the maximum value of H2 concentration (61.4 vol%). Surface area of the catalyst is 52.0 m2/g , and the highest surface area of Cu is 10.7m2/g, particle size is 14.8 nm, Cu dispersion is 3.7%; activity(Acu) is 165mmole/hr and turnover frequency (TOF) is 0.185 s-1. Then inporite CeO2 or Cr2O3 to Cu/ZnO/Al2O3(CZA) catalyst at pH 7. The result showed CZACr1(15:15:5:1 wt%) catalyst for 200oC; WHSV 6.19 1/h; H2O/CH3OH molar ratio is 1.2, the weight of catalyst is 0.2 g; air flow rate is 20 sccm. The optimum methanol conversion is 91.5 %; H2 production rate and concentration are 0.44 mole/h×g and 63.0 vol%; CO production rate and concentration are 2.0 mmole/h×g and 0.56 vol%. Based on instrument all analysis, we obtain Cu/ZnO/Al2O3/Cr2O3=15:15:5:1 which has the highest surface area of Cu of 12.5 m2/g; the particle size 13.8 nm, the dispersion 6.13%, activity(Acu) 166mmole/hr ,and the turnover frequency (TOF) 0.32 s-1。