2015-01-012024-05-15https://scholars.lib.ntu.edu.tw/handle/123456789/665154摘要：天然氣水合物是一項新型態的天然氣資源，台灣自民國93年開始，在經濟部中央地質調查所的推動下，目前已完成西南海域天然氣水合物的的賦存潛力與分布範圍調查，各種證據顯示該區域普遍有天然氣水合物的賦存徵兆。然而為進行天然氣水合物的開採以及後續儲存及運送，皆必須先得知天然氣水合物系統的熱力學與動力學性質。有鑑於此，本計畫之目的在於結合實驗、理論模型與熱分析實驗及分子模擬等方法，從不同層面研究天然氣水合物之動力學與熱力學性質。在前一期之四年期(97~100)計畫，我們已建立國內天然氣水合物熱力學研究的基礎，包括建構國內第一套可視性低溫高壓實驗設備、利用狀態方程式成功地描述氣體水合物三相平衡、以及建立完整且適合氣體水合物的分子模擬平台。在現有基礎上，我們將於天然氣水合物中加入添加劑(熱力學或動力學之抑制劑、促進劑)，以實驗方法了解不同添加劑對天然氣水合物形成的動力學與熱力學相平衡的影響。此外，我們也擬進行高壓掃描式熱卡計實驗，探討添加劑對天然氣水合物解離熱的影響。在分子模擬計算方面，我們將著重於天然氣水合物在有添加劑存在時之生成與融解等動力學機制的研究，藉此可以輔助解釋實驗結果並驗證理論模型。本年度的工作，在熱分析實驗部分:擬運用高壓掃描式熱卡計進行三成份系統水+甲烷+添加劑(環戊醇與1,3-二氧六環)的甲烷水合物系統的熱分析實驗共計20個數據點。在實驗量測部分:我們將持續進行添加劑（例如：醯胺類、環胺類物質）的篩選，期能找到具有熱力學與動力學效果的添加劑，並分別以等容溫度循環法及補充壓力法來研究此添加劑對天然氣水合物生成的熱力學相平衡，在動力學方面將測量添加四氫呋喃等物質對於甲烷水合物生成（融解）速率的影響。在分子模擬方面，我們將針對四氫呋喃-甲烷水合物進行熱力學與動力學分析。這些工作將可提供台灣西南海域天然氣水合物探採、開發與儲運等模擬分析或工程設計上的參考依據。<br> Abstract: Gas hydrate is a new resource for natural gas. Since year 2004 Taiwan started identifying and quantifying the occurrences of methane hydrate in the Southwestern sea of Taiwan. However, for methane hydrate recovery and the subsequent storage and transportation, it is necessary to have a good understanding of the thermodynamic and kinetic properties of gas hydrate. In this project, we propose to study these properties of gas hydrate via experiment, theoretical modeling and thermal analysis, and molecular simulations. In the last 4-year (2008~2011) project, we have established Taiwan's first visible cell for high-pressure and low temperature experiments of gas hydrate systems, an equation of state-based model suitable and successful for correlating experimental data, and a comprehensive platform for performing molecular dynamic simulations on gas hydrates. Based on this foundation, we propose to measure the change of phase behavior and kinetics in gas hydrate systems when different additives (thermodynamic and kinetic promoters and inhibitors) are added. In addition, we will use the differential scanning calorimetry to explore the effect of additives (promoter, inhibitor and kinetic promoter) on the dissociation enthalpy of gas hydrate systems. Experimental and theoretical work will benefit from a thorough understanding of gas hydrate formation and melting mechanism from molecular dynamic simulations. In this year, the high pressure differential scanning calorimetry is used to perform the thermogram of hydrate formation for ternary water + methane + additive (cyclopentanol and 1,3-dioxane) systems to obtain at least 20 data points. We will continue finding effective additives (e.g., amide and/or cyclic amine compounds) which have influence on thermodynamic phase equilibrium and kinetic formation/decomposition rate of methane hydrate. In order to study the effects of additives on the methane hydrates, we propose to measure the methane-hydrate-liquid water phase equilibrium boundary curve using the isochoric method. We will also measure the formation/dissociation rate of methane hydrates in the presence of additives such as tetrahydrofuran using the isochoric method. The thermodynamic and kinetic properties of tetrahydrofuran-methane hydrate will be analyzed via molecular dynamic simulations.These efforts serve as an important basis for the design and optimization of processes for the recovery, storage, and transportation of methane hydrate.天然氣水合物熱力學動力學分子模擬狀態方程式液固相平衡融解熱gas hydratethermodynamicskineticsmolecular simulationequation of statesolid-liquid equilibriadissociation enthalpy