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標題: | 固態電解質純水電解器產氫元件之設計與性能分析 Design and Performance Analysis of Solid Polymer Electrolyte (SPE-type) Water Electrolyzer |
作者: | Ying-Ying Hsu 許盈盈 |
指導教授: | 郭景宗(Jing-Tsung Kuo) |
關鍵字: | 水電解,固態電解質,氫氣生產, water electrolysis,solid polymer electrolyte,hydrogen generation, |
出版年 : | 2005 |
學位: | 碩士 |
摘要: | 因石油日漸枯竭與全球溫室氣體排放管制的關係,近年逐漸興起的”氫能經濟”成為了最有可能取代現今碳經濟體系的新寵兒。隨著再生能源設施與燃料電池等潔淨能源技術逐漸成熟,氫能市場看來已日趨成熟;如今最大的問題在於此一經濟體系是否有足夠的基礎設施來支撐,因此產氫技術成為氫能經濟體系中不可或缺的重要環節。
本實驗室所研發之固態電解質純水電解器,其主要用途為搭配各種電能來源(再生能源電力或市電網路)做為產氫之用途。其優點在於1.不含腐蝕性電解液,危險性低且易於維護 2.產氣純度高,不依賴後段氣體純化處理 3.能量轉換效率高,且可在大電流密度下操作。本實驗嘗試自行設計一固態電解質純水電解器,從基本的電解理論與電極材料選擇開始,並輔以計算流力軟體的幫助設計最佳的流道形式幫助產生的氣體移除,最終以自製的膜電極組與透明壓克力製的流道板加以組合操作,並改變操作參數測試其操作特性、轉換效率與觀測流道的排氣狀況。 實驗結果發現如理論的預測,加溫可相當有效的降低電解電壓提升效率,但是改變流道中的循環流量似乎影響不大;最有效的方法是提高陽極觸媒量,不但可提升轉換效率並且可將最大能量轉換效率區向大電流密度處移動,有利於高電流操作的情況。產氣量方面,因為僅和輸入的電子量有關,大致上電量-氣量的轉換效率都可達到90%左右。在氣密方面,氣體純度測試結果皆在97%以上,證明設計的氣密效果不錯。在流道觀測方面,並無氣體堆積情況,需要注意的是移除情況不因提高循環流量而改變,因此過高的循環流量僅會造成能量的浪費而已。 自行設計的電解器目前單電池電壓在陰極觸媒量0.4 mg/cm2、陽極觸媒量3.0mg/cm2、電流密度200mA/cm2的操作條件下已可達到2.8V,產氣量60mL/min,電壓效率53.8%,法拉第效率89.6%,能量轉換效率50.67%。 Due to the exhaust of petroleum and the global emission control of green-house gas, “Hydrogen economic” gradually becomes the most potential solution instead of recent carbon-based economic system. With the improvement of renewable energy and fuel cell techniques, the time is ripe for the new market of hydrogen energy. But the key point of this economic system is if the basic facilities for hydrogen evolution are ready or not to support the new market needs. This issue makes the hydrogen evolution technique plays an important role in the future hydrogen economic system. The main purpose of the SPE-type water electrolyzer is to operate with renewable energy power sources or grid power network, converts electric power into hydrogen gas by electrochemical reaction. The advantages are 1. No corrosive electrolyte is used. 2. Higher hydrogen gas purity without extra purification. 3. Higher energy conversion efficiency and easy to operate under high current density. The design process starts from basic water electrolysis theory and selection of electrode materials, assisted with computational fluid dynamic (CFD) software to find the optimum flow field geometry design. Finally we set up an experimental prototype with self-made MEA and transparent acrylic flow field plates. In order to verify the operating characteristic, conversion efficiency and how gas bubble removal from flow field, the prototype is operated under different operating parameters. The results reveal that the cell voltage could greatly low down by increasing operating temperature. However, the effect of different recirculation flow rate did not affected much. The most effective method was increasing the anode catalyst amount; this made the maximum energy conversion zone moved to higher current density and increased conversion efficiency. Gas generation rate only affected by input current; in our results, the conversion rate between electrons and hydrogen molecules could reached 90%. Gas purity test reported that the gas purity can up to 97%, which means the sealing is reliable. The flow field observation result revealed no gas was piled up inside flow field; the only thing needs to be noticed is the recirculation flow rate should be set in appropriate value to help removing gas and makes no waste in power required. Under the situation that cathode catalyst amount 0.4mg/cm2, anode catalyst amount 3.0mg/cm2, operating current density 200mA/cm2, the self-designed electrolyzer single cell can achieve cell voltage 2.8V, gas generation rate 60mL/min, voltage efficiency 53.8%, Faraday efficiency 89.6%, energy conversion efficiency 50.67%. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/36746 |
全文授權: | 有償授權 |
顯示於系所單位: | 機械工程學系 |
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