研究生: |
賴醇純 Chun-chun Lai |
---|---|
論文名稱: |
製備中之溶劑對Cu/ZnO/Al2O3觸媒甲醇蒸氣重組活性的影響 Effects of solvent in preparation on the activity of Cu/ZnO/Al2O3 catalyst in methanol steam-reforming |
指導教授: |
劉端祺
Tuan-Chi Liu |
口試委員: |
萬本儒
Ben-Zu Wan 蕭敬業 Ching-Yeh Shiau |
學位類別: |
碩士 Master |
系所名稱: |
工程學院 - 化學工程系 Department of Chemical Engineering |
論文出版年: | 2007 |
畢業學年度: | 95 |
語文別: | 中文 |
論文頁數: | 86 |
中文關鍵詞: | 燃料電池 、Cu/ZnO/Al2O3 、氫氣 |
外文關鍵詞: | fuel cell, Cu/ZnO/Al2O3, hydrogen |
相關次數: | 點閱:442 下載:3 |
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燃料電池(fuel cell)為未來最具潛力的潔淨能源裝置,燃料電池以氫氣當燃料,所需之氫氣一般皆是以甲醇水蒸氣重組產生。本研究以共沉澱法製備甲醇水蒸氣重組之Cu/ZnO/Al2O3觸媒,使用四種不同溶劑(水、乙醇、丙醇、乙二醇)來製備所需的觸媒並探討溶劑對Cu/ZnO/Al2O3性質及重組活性的影響。
本研究利用熱重/熱示差分析儀(TG/DTA)決定製備時煅燒所需溫度,由氫氣程式升溫還原(H2-TPR)決定製備時還原所需溫度。所合成的Cu/ZnO/Al2O3觸媒以N2O的氧化測其銅分散度;以X光繞射分析(XRD)判定觸媒之晶相及銅的粒徑;以場發射掃瞄式電子顯微鏡(FESEM)取得觸媒之形狀;以感應耦合電漿原子發射光譜(ICP)測定觸媒組成;並以BET測定觸媒表面積。
觸媒的活性於常壓下進行測試;反應溫度介於180~280℃之間,其它實驗變數包括進料之H2O/CH3OH比(0.8~1.4),結果顯示,反應溫度以240℃最為適當,因此時CO選擇率僅為5%,為最低,提升進料之H2O/CH3OH比,不影響選擇率,但可提升甲醇之轉化率。由四種不同溶劑所製備的Cu/ZnO/Al2O3觸媒,依活性大小的順序並以溶劑表示為乙二醇>乙醇>丙醇>水。以乙二醇所製備的Cu/ZnO/Al2O3活性較高是因觸媒中的銅含量高達90%以上,以乙醇及丙醇所製備的Cu/ZnO/Al2O3則以銅的分散度高見長。
Fuel cell is a device of great potential in providing clean energy in the future. Fuel cell uses hydrogen as its fuel. The hydrogen is often produced from methanol steam reforming. In this study, coprecipitation was used to prepare the Cu/ZnO/Al2O3 catalyst for the steam reforming of methanol. Four different solvents, including water, ethanol, 1-propanol, and ethylene glycol were employed in preparing the catalysts. The effects of the solvent in the properties of the Cu/ZnO/Al2O3 catalyst were examined.
The calcination temperature in preparing the catalyst was determined by TG/DTA, the reduction temperature was determined by H2-TPR. The synthesized Cu/ZnO/Al2O3 catalysts were characterized by XRD for their crystalline phases, by FESEM for their morphologies, by ICP for their composition, and by nitrogen adsorption for their BET surface areas.
The activity of the Cu/ZnO/Al2O3 catalysts was examined under atmospheric pressure at a reaction temperature ranged between 180 and 280oC. The effect of the H2O/CH3OH ratio in the feed was also examined. The results showed that the optimum reaction temperature was 240oC at which the selectivity of CO was 5% , the lowest of among the temperatures studied. Varying the H2O/CH3OH ratio in the range of 0.8-1.4 would not affect CO selectivity. However, the conversion of methanol would increase with an increase in the ratio. The order of the activity of the Cu/ZnO/Al2O3 catalysts prepared by varied solvents, in terms of the solvent names, was ethylene glycol > ethyl alcohol > 1-propanol > water. The reason for the ethylene glycol catalyst exhibiting the highest activity was high content of copper in the catalyst. The catalyst contained more than 90% copper. The Cu/ZnO/Al2O3 catalysts prepared by ethyl alcohol and 1-propanol were characterized by their high dispersion of the components in the catalysts.
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