中高溫碳分離材料與固定技術開發研究

Abstract

近年來燃料電池逐漸地成為潔淨新能源的代名詞，而其中所使用的燃料為氫氣和氧氣，氧氣可取自於大氣，氫氣可由儲氫材料或重組製氫來供應。使用儲氫材料，其填充上不方便，而且儲氫的密度低。因此利用各種不同原料來進行重組反應來製氫，則顯得更重要。其中以甲醇的重組反應溫度為最重要，因其具有較低反應溫度(約250～350℃)、轉換效率達95%以上、易於貯存、運輸等優點，室溫為液體。因反應過程中產生CO對於電極將造成毒化作用，因此有必要添加金屬氧化物觸媒材以降低CO產出，同時在反應過程中常會添加部份氧氣使之完全反應成CO2，但CO2亦造成環境大氣污染，因此本研究將設計以NiO-CaO-based LDH (NCL)奈米多孔性複合材料為主，利用水熱均質析出製程來開發具有催化及吸附CO2之多功能粉體，並且進一步與傳統的共沉析出製程的粉體做比較，來進行甲醇催化及二氧化碳捕捉的研究。本研究利用XRD、TGA和BET量測探討合成的適當條件及中低溫下奈米孔洞複合材料分離氣體之熱力學/動力學及再生試驗，利用水對甲醇莫耳比(S/C)、氧氣對甲醇莫耳比(O/C)、反應溫度及進料率、酸鹼值的改變，來當實驗參數，觀察甲醇重組器的性能表現，如氫氣濃度、一氧化碳濃度、氫氣莫耳產生率及甲醇轉化率等。最後希望能透過NCL粉體對於CO2的補捉來強化甲醇重組反應製氫的功能，並搭配水合氣反應(WGS)，發展一個可在中低溫(250-450 °C)下催化/捕獲二氧化碳的新型複合材料。

Due to the ever increasing demand for energy, an effective alternative energy generation capability is essential to replace the dwindling supply of petroleum. In comparison to the several novel energy generation techniques, hydrogen is one of the most environmentally friendly sources. However, the challenges associated with supply and storage of hydrogen is enormous obstacles for its industrial scale application. In this regard, the reforming reaction of methanol is considered to be an attractive option for hydrogen generation, because of the ease of handling and possibility of hydrogen synthesis from various feedstocks1 by this method. Moreover, methanol also happens to be the best source for hydrogen generation. Here, we report the preparation of multi-composition NiO/CaO/LDH (NCL) catalyst by hydrothermal homogeneous precipitation (HP) method using urea treatment. Compared to the conventional co-precipitation (CP) method, the HP method used here improves the uniformity of metal mixing through homogeneous generation of hydroxide ions as a result of hydrolysis of urea in the solution. In this study, optimization of the conditions to prepare NCL catalyst was achieved by adjusting the urea concentration, amount of water, reaction temperature and reaction time; to control the pH value. An improved performance in methanol reforming reaction, in terms of methanol conversion, yield of hydrogen production, and higher carbon dioxide capture/selectivity, will be achieved. In future, Sorption enhanced steam reforming of ethanol (SESRE) along with a CO2-capture sorbent will be evaluated for realizing sustainable H2 production.