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국내 최대 정보 기계·건설 공학연구정보센터
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  • 학위논문초록

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    학위논문초록 제목 게시판 내용
    제목(국문)
    제목(영문) Clathrate hydrate-based CO2 separation from sour natural gas and inhibition effect of diamines on CH4 clathrate hydrate
    저자 Lim, Jiyeon
    초록

    abstract is not available for this article

    초록(영문) This study focused on two topics related to the natural gas production and transport; CO2 separation acidic natural gas using clathrate hydrate and flow assurance using diamine inhibitors. Hydrate-based CO2 separation was conducted with the synthetic CO2 (50%)/CH4 (50%) mixed gas representing CO2-rich natural as well as biogas. In order to identify the thermodynamic property of CO2/CH4 mixed gas hydrate, three-phase equilibrium (H-Lw-V) was measured. Thermodynamic promotors such as TBAC and THF were used to improve the equilibrium temperature. The promoters had an influence on the thermodynamic stability, gas uptake profile, and CO2 selectivity. CO2 composition in the hydrate phase increased to 77% in the TBAC semi-clathrate and decreased to 44% in THF hydrate from 50% of CO2 in the feed gas. TBAC showed the highest selectivity due to thermodynamic and structural effects despite lower gas capacity than pure water hydrate. Furthermore, kinetic characteristics during hydrate formation were observed by in-situ Raman spectroscopy. The faster growth of CO2 than CH4 in the pure water system was found and it implies the kinetic selectivity of CO2 in the early stage of hydrate formation. In order to investigate the kinetic and thermodynamic inhibition effects of piperazine (PZ) and hydrazine (HZ), thermodynamic, spectroscopic, and computational analyses were applied. The phase behavior demonstrated that the addition of PZ and HZ shifts the CH4 hydrate equilibrium condition to the higher pressure or lower temperature regions. Spectroscopic analysis implied that PZ and HZ are not enclathrated in the cages of CH4 hydrate and do not affect the structure transition of the hydrate. The time-dependent growth patterns and the induction time of CH4 hydrate in the presence of diamines were observed via in-situ Raman spectroscopy. HZ showed a more significant thermodynamic inhibition effect, slower hydrate growth, and longer induction time than PZ did. The calculated interaction energy between an inhibitor and hydrate cage indicated that diamine molecules could disrupt the hydrogen bonding networks of hydrate cages, leading to destabilization of gas hydrate and retardation of hydrate nucleation and growth. Experimental and computational results demonstrated that both PZ and HZ can function as both kinetic and thermodynamic hydrate inhibitors for CH4 hydrate.
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    학교 울산과학기술대학교
    지도교수 Seo, Yongwon
    학위구분 석사
    • 페이스북아이콘
    • 트위터 아이콘

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