以冰晶法製備甲烷水合物及其基本燃燒觀察

• Main Authors: 蔡明璁, Tsai, Ming-Tsung
• Other Authors: 航空太空工程學系, 趙怡欽, Chao, Yei-Chin
• Format: Thesis
• Language: Chinese; English
• Published: 2014
• Subjects: 甲烷水合物; 冰晶法; 孔隙度; 拉曼光譜; 燃燒; methane hydrate; ice seed method; porosity; Raman spectrum; combustion; Methane hydrate
• Online Access: http://ir.lib.ncku.edu.tw/handle/987654321/150357; http://ir.lib.ncku.edu.tw/bitstream/987654321/150357/-1/index.html

本研究成功架設以冰晶法為主的水合物製作設備，可調整合成壓力，升降溫度曲線，以自行生產適合後續研究所需的水合物，並可同步紀錄製程中的壓力與溫度。添加乙醇做催化劑，縮短製程時間，加速實驗的進行。 嘗試裝填不同孔隙度的冰晶，合成出的水合物樣本也會有不同的孔隙度。實驗發現裝填的孔隙度越大，合成出的水合物孔隙度就越大，以顆粒大小180~250μm的冰晶來說，最大裝填孔隙度約為63.3~66.4%，合成出的水合物孔隙度約為46.62~51.1%；最小孔隙度約為51.8~55.8%，合成出得水合物孔隙度約為40.7~44.9%。 此外對合成出的水合物做一系列的檢測，如水合指數與甲烷釋放率測定等，結果顯示不同孔隙度的水合物在不同部位其水合指數基本一致，介於6.28~6.6之間(轉化率約為87~91%)，樣本整體有均勻之轉化率(轉化率相差在4%以內)。而單位面積與單位體積的甲烷釋放率與面體比有較大的關係，面體比越大，則單位面積與單位體積的甲烷釋放率越快 最後進行水合物的燃燒觀測，發現相同半徑的水合物，孔隙度越大者可以較快點燃，火焰也較快熄滅。而孔隙度接近的水合物，半徑越小者可以越早點燃，燃燒時間也較短。 The purpose of this study is to develop a standard procedure for artificially synthesize the methane hydrate with consistent and uniform properties for further observation and experiments of the combustion phenomena of methane hydrate The synthesis procedure is based on ice-seed method and adding the ethanol as the catalyst to shorten the processing time if necessary By packing the ice-seed into different porosity the synthesized hydrates will also have different porosity With the larger porosity of the ice-seed the porosity of the synthesized hydrates will also be greater In this study the grain size of the ice-seed is between 180~250μm The largest packing porosity of ice-seed is between 63 3~66 4% and the resultant porosity of synthesized hydrate is between 46 62~51 1% The smallest packing porosity of ice-seed is between 51 8~55 8% and the porosity of synthesized hydrate is between 40 7~44 9% Experimental results show that the hydration number of methane hydrate samples that synthesized by ice-seed method is between 6 28~6 6 the hydrate samples have a uniform conversion rate between 87~91% In addition the mass release rate of methane hydrate sample per unit area or unit volume can be related to the surface/volume ratio of the sample the larger surface/volume ratio the faster release rate of methane per unit area or unit volume Finally the combustion phenomena of methane hydrate samples show that both the larger porosity of the methane hydrate sample with the same radius and the smaller radius of the methane hydrate sample with the same porosity can be ignited earlier with shorter ignition delay time and the flame extinguishes earlier with shorter flame lifespan