添加 2,5-二氫?喃、3,4-二氫-2H-?喃與異丙胺對於甲烷水合物分解狀態之實驗量測

• Main Authors: 鄭智恬, Cheng, Chih-Tien
• Other Authors: 臺灣大學: 化學工程學研究所, 陳延平
• Format: Thesis
• Language: Chinese; English
• Published: 2011
• Subjects: 甲烷水合物;等容溫度搜尋法;2,5-二氫?喃;3,4-二氫-2H-?喃;異丙胺;2,5-二甲氧基四氫?喃; methane hydrate;isochoric method;2,5-dihydrofuran;3,4-dihydro-2H-pyran;isopropylamine;2,5-dimethoxytetrahydrofuran;N,N-diethylhydroxylamine; Methane hydrate
• Online Access: http://ntur.lib.ntu.edu.tw/handle/246246/252234; http://ntur.lib.ntu.edu.tw/bitstream/246246/252234/1/ntu-100-R98524030-1.pdf

本研究主要目的是建立一套高壓設備利用等容溫度搜尋法，量測甲烷水合物在各種添加劑存在時的分解狀態，也就是量測甲烷水合物相、水相、氣相三相共存的相平衡數據。本實驗以添加環醚類中的2,5-二氫呋喃與3,4-二氫-2H-吡喃、2,5-二甲氧基四氫呋喃，以及添加胺類中的異丙胺與N,N''-二乙羥基胺在甲烷水合物中，並探討在不同添加劑存在時，相平衡邊界移動的方向，了解這些化合物對甲烷水合物生成的抑制或促進效果。本研究發現添加環醚類2,5-二氫呋喃與3,4-二氫-2H-吡喃、以及胺類中的異丙胺，都可以擴大水合物生成的區域，使相平衡邊界往低壓高溫的方向移動。此三種化學添加劑皆可促進水合物生成，因此被認為是促進劑。促進水合物在2,5-二氫呋喃+甲烷+水之三成分水合物系統中，促進溫度隨2,5-二氫呋喃濃度增加而上升。當2,5-二氫呋喃濃度為10 wt%時，系統有最佳促進水合物生成效果可達13 K。此外，另一系統則添加不溶水化合物3,4-二氫-2H-吡喃在甲烷水合物中，平衡溫度最高增加13 K。而另一種添加劑異丙胺，在15 wt%異丙胺+甲烷+水之三成分水合物系統的相平衡數據中，在一給定壓力下，可增加平衡溫度約5 K。另外，為了模擬海水的環境，本實驗以3.5 wt%氯化鈉溶液做為鹽水系統的濃度，觀察到甲烷水合物在添加添加劑存在時受到鹽分的影響，促進溫度降低了1~2 K。 2,5-二甲氧基四氫呋喃與N,N''-二乙羥基胺此兩種添加劑對甲烷水合物的生成具有抑制的作用。當添加10 wt% 2,5-二甲氧基四氫呋喃，在一給定壓力下降低的平衡溫度約1 K，抑制水合物生成作用不明顯；然而當添加20 wt% N,N''-二乙羥基胺則有較佳的抑制效果，可降低平衡溫度約5 K。 This study demonstrated the equilibrium conditions for the formation of methane hydrates in the presence of cyclic ethers and alkyl amine, i.e. 2,5-dihydrofuran, 3,4-dihydro-2H-pyran and isopropylamine. The three-phase (H-Lw-V) and the four-phase (H-Lw-La-V) equilibrium data in methane + water + additives systems were measured by using isochoric method in the range of pressures from 6 to 12 MPa and temperature up to 301 K. When 2,5-dihydrofuran, 3,4-dihydro-2H-pyran and isopropylamine were added into methane hydrates systems respectively, the hydrate equilibrium temperatures showed a large increase approximately 13 K for 2,5-dihydrofuran, or 3,4-dihydro-2H-pyran and 5 K for isopropylamine at a specific pressure. The experimental results presented that 2,5-dihydrofuran, 3,4-dihydro-2H-pyran and isopropylamine had great promotion effects on the formation of methane hydrates.Moreover, in order to stimulate the sea-water environment, the methane + 3.5 wt% NaCl+ additive systems, for example, 2,5-dihydrofuran or 3,4-dihydro-2H-pyran, were measured to acquire the equilibrium data of methane hydrate dissociation. With the existence of 3.5 wt% NaCl, the equilibrium temperature of the brine system reduced 1 to 2 K compared to the original system.On the other hand, we also showed the phase equilibrium data of the methane +water+ 2,5-dimethoxytetrahydrofuran system and the methane +water+ N,N-diethylhydroxylamine. At a given pressure, the equilibrium temperature of two ternary systems both shifted the H-Lw-V phase boundary to the lower temperature region than the methane +water binary system. The measured pressure range is 8 to 14 MPa. Finally, the experimental results revealed that 2,5-dimethoxytetrahydrofuran and N,N-diethylhydroxylamine are both inhibitors for methane hydrates. The greatest reduction of the equilibrium temperature when 20 wt% N,N-diethylhydroxylamine was added into methane hydrates is approximately 5 K at a specific pressure.