添加物對甲烷水合物相平衡影響之實驗量測

Experimental Measurements for the Phase Equilibrium of Methane Hydrate in the Presence of Additives

郭炳震(Ping-Chen Kuo)

指導教授 ： 陳延平

國立臺灣大學/工學院/化學工程學研究所/碩士(2009年)

https://doi.org/10.6342/NTU.2009.00402

摘要

本研究建立一套實驗設備以研究甲烷水合物之熱力學性質，主要研究內容為量測水相-水合物相-汽相三相平衡之平衡條件，在量測平衡條件方面使用等容溫度循環法來進行量測。在本研究中，主要研究甲烷+水+添加劑之水合物系統的相平衡條件，探討加入添加劑後對於甲烷水合物之相平衡條件所產生的效應。在加入添加劑前，本研究首先進行甲烷+純水系統之水合物平衡點量測，設定標準實驗流程，並與過去文獻結果比對以確定本實驗設備所量測結果之準確度。
在添加劑方面選用界面活性劑(SDS、CTAB)及第三丁醇(tert-butanol)進行實驗。實驗結果發現加入界面活性劑時，對於水合物系統熱力學上沒有顯著的影響，其平衡點量測結果與純水系統時相同。然而發現加入SDS時在動力學上有明顯的促進效應，但CTAB方面則僅有些微的影響。當加入第三丁醇時，實驗結果發現其對於水合物系統熱力學上有明顯的促進效應，且在加入濃度為20wt%時達到最佳的促進效果，在相同的平衡壓力下可增加平衡溫度值約6 K。本研究中也量測甲烷＋鹽水＋第三丁醇之水合物系統相平衡條件，探討在海水環境下加入第三丁醇對於水合物熱力學之效應。由實驗結果發現，在此系統中加入第三丁醇對於水合物系統熱力學上仍然具有促進的效應，但此時因受到鹽度之影響，其促進效應較純水系統低。

關鍵字

天然氣水合物 ； 相平衡 ； 添加劑 ； 等容溫度循環法 ； 界面活性劑 ； 第三丁醇 ； 鹽水

並列摘要

An experimental apparatus was established in this study to investigate the thermodynamic properties of gas hydrate. The Lw-H-V three-phase equilibrium conditions were measured using the isochoric method. The experimental systems consist of methane + water + additives where the effect of hydrate formation due to various amounts of additives was discussed. The thermodynamic phase equilibrium measurements for methane with pure water had been firstly conducted in this study. Satisfactory agreement with literature data confirmed the validity of our experimental equipments and procedures.

Two surfactants (SDS, CTAB) and tert-butanol were used as the additives in this study. It was observed that both surfactants had no significant influence on the thermodynamics of methane hydrate formation. Adding SDS showed a strong promotion on the kinetics of methane hydrate formation while CTAB had a relatively lower effect. It is demonstrated that the addition of tert-butanol had a significant promotion effect on the phase equilibrium of methane hydrate formation. The equilibrium temperature increased 6K at a given pressure with the concentration of 20wt% tert-butanol. Finally, the methane hydrate phase equilibrium data for brine system with the addition of tert-butanol were measured in this study. Tert-butanol again showed promotion effect on the thermodynamics of methane hydrate in seawater environments. The promotion effect in the presence of salt was, however, less than that in pure water.

並列關鍵字

Gas hydrate ； phase equilibrium ； additive ； isochoric method ； surfactants ； tert-butanol ； brine

參考文獻

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