Thermodynamic characterization and microscopic analysis of natural gas and mixed hydrates containing guest molecules of low molecular weight : applications to environmental and energy system

• Main Author: Uhm, Tae-Won(엄대원)
• Other Authors: Lee, Huen(이흔)
• Format: Other/Unknown Material
• Language: English
• Published: 한국과학기술원 2005
• Subjects: $N_2$; $CH_4$; environmental; energy; microscopic analysis; thermodynamic characterization; Gas hydrate; $CO_2$; 이산화탄소; 질소; 메탄; 환경; 에너지; 미세분석; 가스 하이드레이트; 열역학적 특성; Okhotsk; okhotsk sea
• Online Access: http://hdl.handle.net/10203/29861; http://library.kaist.ac.kr/index.php?TargetPageName=wSrchAllDetailView.php&bibctrlno=243733

학위논문(석사) - 한국과학기술원 : 생명화학공학과, 2005.2, [ ix, 79 p. ] Clathrate hydrates are crystalline compounds formed by the physically stable interaction between water and relatively small guest molecules. Under suitable conditions of pressure and temperature, water molecules, via hydrogen bonding, form into polyhedral cavities that stack to give space-filling frameworks. Because of partial cage filling, these crystalline compounds are non-stoichiometric. They can be divided into three distinct structural families I (sI), II (sII), and H (sH), which differ in the combination of cavities of different sizes and shapes. Since each volume of hydrate was known to contain as much as 184 volume of gas, it has been suggested the potential application of crystal hydrate nature to large-scale storage of greenhouse gases and removal of organic pollutants from aqueous solutions. The thermodynamic phase equilibria and structural characteristics of clathrate hydrate provide the fundamental variables contributed to develop the industrial processes. In this study, the phase equilibrium conditions of pure and mixed hydrates were determined to identify the thermodynamic stability region and the microscopic approaches draw the structural characteristics related to actual cage occupancy of guest molecules in hydrate structure In order to understand the characteristics of clathrate gas hydrate, natural gas hydrates from Oregon offshore and Okhotsk sea were investigated in macro and microscopic. In contrast to the researches of laboratory-made gas hydrate, this study has been performed on naturally grown clathrate hydrates from the sea floor. The X-ray diffraction pattern of natural gas hydrate showed that it is ordinary structure I hydrate. $^{13}C$ NMR spectrum was used for natural gas hydrate in order to identify the cage occupancy of guest molecules and determine the hydration number and ensure the hydrate structure. The NMR spectra revealed that natural gas hydrates used in this study contains only methane with no noticeable amount of other . 한국과학기술원 : 생명화학공학과