Article
Engineering, Environmental
Lingjie Sun, Tian Wang, Bo Dong, Man Li, Lei Yang, Hongsheng Dong, Lunxiang Zhang, Jiafei Zhao, Yongchen Song
Summary: A method utilizing pressure oscillation during CH4/CO2 replacement is proposed in this study, which effectively promotes the replacement process by breaking the balance of the hydrate layer and forming a CO2/CH4 mixed hydrate layer. This newly proposed method significantly enhances the recovery of CH4 and the efficiency of CO2 sequestration.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Engineering, Environmental
Yohan Lee, Woojin Go, Yunju Kim, Junkyu Lim, Wonjung Choi, Yongwon Seo
Summary: This study investigated the CH4-CO2 replacement in the sH CH4 + MCP hydrate using both experimental and computational approaches. The results showed that the sI hydrates were thermodynamically favored in CO2-rich gas mixtures, and a structural transformation from sH to sI occurred when the CO2 composition exceeded 20%. The 13C NMR spectra indicated that CO2 molecules preferred to occupy specific cages during replacement. The MD simulations further confirmed the structural transformation and lower CO2 concentration in the newly formed sI hydrate compared to the CH4 + NH - CO2 replacement system.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Energy & Fuels
Stian Almenningen, Arne Graue, Geir Ersland
Summary: This paper reviews experimental studies of CH4-CO2 exchange in CH4 hydrate-bearing sandstone core plugs, highlighting the critical role of water saturation in these processes. The results presented are important for assessing natural gas hydrate reservoirs as candidates for CO2 injection with concurrent CH4 gas production.
Article
Engineering, Environmental
Tian Wang, Lunxiang Zhang, Lingjie Sun, Ran Zhou, Bo Dong, Lei Yang, Yanghui Li, Jiafei Zhao, Yongchen Song
Summary: This study explored the characteristics of CH4/CO2 replacement in fine marine sediments, with pressure and temperature identified as the main controlling factors. The content of initial methane hydrate and water in reservoir was found to have a more significant effect on CO2 storage than CH4 recovery. The unique properties of fine marine sediments, including small grain size, clay swelling, and high proportion of bound water, inhibited gas exchange kinetics and CO2 diffusion in the replacement process.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Energy & Fuels
Jyoti Shanker Pandey, Charilaos Karantonidis, Qian Ouyang, Nicolas von Solms
Summary: CH4/CO2 mixed hydrates can be dissociated effectively using the multistep cyclic depressurization method, leading to improved CH4 recovery below the stability pressure of CH4 hydrate. The study also highlights the impact of chemicals in the aqueous phase and reservoir temperature on recovery and storage yield. Additionally, the morphology study demonstrates the expansion of hydrate volume during cyclic depressurization, confirming hydrate reformation from released water from dissociation.
Article
Engineering, Environmental
Mengya Niu, Guozhong Wu, Zhenyuan Yin, Yifei Sun, Kai Liu, Daoyi Chen
Summary: The study demonstrates that recovery of CH4 hydrate at marine conditions through CO2-N2 gas injection is technically feasible, but careful control of the composition of the mixed gas is required to ensure replacement efficiency.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Chemistry, Physical
Phakamile Ndlovu, Saeideh Babaee, Paramespri Naidoo
Summary: Vast methane hydrates found in seabeds and permafrost areas can be used as an energy source and provide a storage solution for greenhouse gases by encapsulating carbon dioxide. The article presents experimental results on the replacement process using a laboratory reactor and various additives to enhance the reaction.
JOURNAL OF MOLECULAR LIQUIDS
(2023)
Article
Engineering, Environmental
Jyoti Shanker Pandey, Qian Ouyang, Nicolas von Solms
Summary: Recent limited studies have shown that multistep slow depressurization of mixed CH4/CO2 hydrates can enhance CH4 recovery and increase CO2 storage after injection. The resistivity variation, gas recovery and storage were investigated to study hydrate saturation and production/storage yield changes. Results indicate the presence of two stability zones during mixed hydrate dissociation, providing opportunities for additional CH4 recovery and CO2 storage.
CHEMICAL ENGINEERING JOURNAL
(2022)
Review
Energy & Fuels
Salvatore F. Cannone, Andrea Lanzini, Massimo Santarelli
Summary: Natural gas is seen as a useful transition fuel to reduce emissions from conventional power plants, particularly when considering the removal of carbon dioxide from hydrates using membrane separation technology. The economic analysis and technical aspects of this process are explored in detail, alongside discussions of other carbon capture methods and long-distance CO2 transportation and storage.
Article
Chemistry, Multidisciplinary
Yinglong Zhang, Mao Cui, Dexiang Li, Gongming Xin
Summary: The use of the CO2 replacement method for exploiting natural gas hydrates and storing CO2 is significant for energy access and environmental protection. Molecular dynamic simulations were used to analyze the replacement of CH4 with CO2 under different temperature and pressure conditions. The results showed that temperature had a greater influence than pressure, and appropriate temperature oscillations could improve CO2 capture and hydrate stability.
Article
Thermodynamics
Wenfeng Guang, Zhenyu Zhang, Lei Zhang, P. G. Ranjith, Shengpeng Hao, Xiaoqian Liu
Summary: This study investigates the transport and diffusion behavior of CO2-CH4 mixture in coal nanopores using Monte Carlo and molecular dynamics simulation. A modified computational method for multi-component transport diffusivity is proposed. The results show that the confinement effect of nanopores significantly affects the diffusion behavior, and the pressure has different effects on the transport diffusivity. The CO2-CH4 mixture under greater confinement effect manifests higher diffusion selectivity, which benefits the separation and CH4 recovery.
Article
Energy & Fuels
Bernadette R. Cladek, A. J. Ramirez-Cuesta, S. Michelle Everett, Marshall T. McDonnell, Luke Daemen, Yongqiang Cheng, Paulo H. B. Brant Carvalho, Christopher Tulk, Matthew G. Tucker, David J. Keffer, Claudia J. Rawn
Summary: Natural hydrate deposits are a rich source of CH4. Recent studies have shown that CH4 can be extracted from hydrates by CO2 exchange, which also has the potential for carbon sequestration. Understanding the impact of guest variation in CH4, CO2, and mixed hydrates on their stability and the processes of methane extraction and CO2 sequestration is crucial. The use of inelastic neutron scattering has revealed the dynamic modes in hydrate structures and the behavior of CH4, providing valuable insights for further research.
Article
Engineering, Chemical
Min Gu, Shuo Duan, Qirong Wu
Summary: The adsorption characteristics of CO2 and CH4 are different, with CO2 injection leading to an increase in CH4 recovery over time, but a decrease in the mole fraction of CH4. Adsorbents with larger SCO2/CH4 can prolong the stage of CH4 recovery.
Article
Energy & Fuels
Qi Liao, Junping Zhou, Xuefu Xian, Kang Yang, Chengpeng Zhang, Zhiqiang Dong, Hong Yin
Summary: This study measured the adsorption of pure and binary CO2 and CH4 in shale using the volumetric method. The results showed that CO2 was preferentially adsorbed in shale, and the adsorption amount of binary CO2/CH4 increased with the increase of CO2 composition. The selectivity factor of CO2 over CH4 was closely related to pressure and CO2/CH4 concentration, and the injection strategy of CO2 can be optimized based on the results.
Article
Chemistry, Physical
Hideki Tanaka, Masakazu Matsumoto, Takuma Yagasaki
Summary: This study proposes substitution schemes for methane-carbon dioxide (CH4-CO2) hydrates and investigates the advantages and efficiencies of the substitution under three-phase and two-phase coexistence conditions. The study finds that although substitution is feasible in three-phase coexistence, its working window in temperature-pressure space is narrower compared to the two-phase coexistence condition. It also suggests a significant endothermic substitution in the medium pressure range.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Engineering, Environmental
Wonjung Choi, Woojin Go, Yohan Lee, Junghoon Mok, Yongwon Seo
Summary: This study investigated the kinetics of guest exchange in sII hydrate - flue gas replacement and elucidated the replacement mechanism and guest exchange characteristics. The results showed that at higher pressure during replacement, increased CO2 inclusion led to higher production of CH4 and C3H8 and a lower N-2/CO2 ratio in the hydrate phase. Additionally, molecular dynamics simulations demonstrated that the expansion or shrinkage of hydrate cages caused by guest exchange had a significant impact on the lattice parameter of the replaced hydrates.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Thermodynamics
Joonseop Lee, Dongyoung Lee, Yongwon Seo
Summary: This study investigated the complex phase behavior and structures of natural gas hydrates containing large molecule guest substances (LMGSs). Methylcyclopentane (MCP) and 2,2-dimethylbutane (neohexane, NH) were chosen as LMGSs for CH4 (90%) + C3H8 (10%) hydrates. The presence of LMGSs did not affect the equilibrium curves of the CH4 + C3H8 hydrates, with CH4 and LMGSs primarily in sH and CH4 and C3H8 encapsulated in sII. The experimental results provide insights into the role of LMGSs in natural gas hydrates.
Article
Thermodynamics
Wonjung Choi, Junghoon Mok, Yohan Lee, Jaehyoung Lee, Yongwon Seo
Summary: The study experimentally investigated three driving forces for the dissociation of CH4 hydrates and found that a constant modified chemical potential-based driving force (Δμ) can consistently control the depressurization process, demonstrating remarkable consistency across a wide temperature range.
Article
Engineering, Environmental
Junghoon Mok, Wonjung Choi, Yongwon Seo
Summary: This study investigated the thermodynamic stability and kinetic growth behavior of HFC-152a hydrate, finding that HFC-152a hydrate has a higher hydration capacity in the presence of NaCl. The results suggest that HFC-152a may be a superior candidate for the HBD process.
Article
Thermodynamics
Junghoon Mok, Wonjung Choi, Jonghyuk Lee, Yongwon Seo
Summary: The guest swapping process of CH4 - CO2 + N-2 replacement in NGH reservoirs can be influenced by pressure and temperature conditions, leading to accelerated CO2 and enhanced N-2 inclusion during the replacement process. This study provides valuable insights into the replacement mechanism occurring in NGH reservoirs with different conditions.
Article
Engineering, Environmental
Woojin Go, Dongyoung Lee, Yongwon Seo
Summary: The study suggests that glycine is the best kinetic hydrate inhibitor among urea, acetamide, and glycine, while combinations of urea and acetamide, urea and glycine, and acetamide and glycine, show synergistic inhibition effects on CH4 hydrate. Among these combinations, urea and acetamide exhibit the best synergism. The findings also highlight the potential of hydrophilic monomeric substances as effective KHIs and propose a new method to understand the mechanism of hydrate inhibition through experimental and computational analyses.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Engineering, Chemical
Junghoon Mok, Wonjung Choi, Yongwon Seo
Summary: This study examined the thermodynamic and kinetic features of different gas hydrate formers to determine the energy-efficient gaseous hydrate former for hydrate-based desalination (HBD). The results showed that the efficiency of HBD was affected by factors such as initial salinity, operating pressure, and initial subcooling temperature. The study also found that the thermodynamic stability and intrinsic formation kinetics of gas hydrates significantly impacted HBD efficiency.
Article
Thermodynamics
Junghoon Mok, Wonjung Choi, Yongwon Seo
Summary: This study closely investigated the dissociation behavior and time-dependent guest distributions of methane (CH4) hydrate after injecting gaseous N-2 at different temperatures and pressures. Results showed that higher temperature and lower N-2 injecting pressure accelerated the dissociation kinetics of CH4 hydrate. Raman and NMR spectra confirmed the immediate capture of N-2 molecules in hydrate cages at 268.8 K, with N-2 incorporation increasing at higher pressure. C-13 NMR spectra revealed N-2-induced structural transitions in hydrates and the preferential capture of N-2 in small cages. The findings provide insights into the roles of N-2 molecules in inhibitor injection and CH4 - CO2 + N-2 replacement methods for gas hydrate exploitation.
Article
Green & Sustainable Science & Technology
Jungjoon Park, Joon Ho Park, Dongyoung Lee, Yongwon Seo, Yong Tae Kang
Summary: Hydrate-based CO2 capture technology has vast potential and cost effectiveness. However, the direct capture and utilization of hydrate slurries are challenging. Thermodynamic promoters have been introduced to alleviate the formation conditions. By evaluating key parameters, optimal conditions for hydrate slurry-based cold thermal transportation are determined. It is proposed to replace conventional systems with a CO2 hydrate slurry cooling system, demonstrating a significant reduction in energy consumption.
JOURNAL OF CLEANER PRODUCTION
(2022)
Article
Environmental Sciences
Wonjung Choi, Joonseop Lee, Young-Gyun Kim, Hanwoong Kim, Tae Siek Rhee, Young Keun Jin, Ji-Hoon Kim, Yongwon Seo
Summary: This study investigated the thermodynamic and structural characteristics of NGHs retrieved from the Chukchi Sea, finding that NGHs from AM03 and AM06 were almost identical in composition, structure, and environment. An abnormal salinity enrichment in the sediment of AM06 was discovered, which may induce the dissociation of NGHs at a lower temperature.
SCIENCE OF THE TOTAL ENVIRONMENT
(2021)
Article
Chemistry, Multidisciplinary
Gyeol Ko, Woojin Go, Yongwon Seo
Summary: The time-dependent selectivity of SF6 in the hydrate-based gas separation process was investigated through experimental and computational approaches. The study found that there was no significant kinetic selectivity difference between SF6 and N2 during hydrate formation and dissociation, with the SF6/N2 ratio in the hydrate structure remaining constant over time. These findings contribute to the development of the hydrate-based SF6 separation process by providing insights into guest-filling and guest-liberating behaviors during formation and dissociation.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2021)
Article
Engineering, Environmental
Abdolreza Farhadian, Woojin Go, Soyeong Yun, Alireza Rahimi, Mohammad Reza Nabid, Danial Iravani, Yongwon Seo
Summary: In this study, the performance of newly synthesized waterborne polyurethanes (WPUs) as dual-function gas hydrate and corrosion inhibitors was evaluated through experimental and computational approaches. The results showed that WPUs effectively inhibited hydrate formation and protected against corrosive gases.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Engineering, Environmental
Hyuk-Jun Noh, Dongyoung Lee, Woojin Go, Gyucheol Choi, Yoon-Kwang Im, Javeed Mahmood, Yongwon Seo, Jong-Beom Baek
Summary: Fused aromatic networks (FANs) have attracted attention due to their electronic properties and stability. 3D organic networks and 2D layered structures were found to be effective gas hydrate inhibitors with outstanding stability under high-pressure/low-temperature conditions.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Thermodynamics
Woojin Go, Soyeong Yun, Dongyoung Lee, Yongwon Seo
Summary: This study evaluated easily decomposable monomeric substances as kinetic hydrate inhibitors for CO2 hydrate. Experimental and computational results showed that glycine exhibited the best inhibition effect among single inhibitors, and combinations of urea with acetamide and acetamide with glycine had synergistic inhibition effects on CO2 hydrate. Molecular dynamics simulations provided insights into the nucleation and formation behaviors of CO2 hydrate in the presence of inhibitors. The findings contribute to the development of new biodegradable CO2 hydrate inhibitors and enhance the safety of CO2 transportation and storage.
Article
Chemistry, Physical
Junghoon Mok, Junkyu Lim, Wonjung Choi, Soyeong Yun, Joonseop Lee, Gyeol Ko, Yongwon Seo
Summary: A new sI-sII dual hydrate former was investigated for its potential significance in gas separation, showing that external guests like CH4 and N-2 can promote the formation of sII hydrates with CHClF2. The study revealed the thermodynamic and structural features of CHClF2 hydrates, providing insights for understanding and designing the hydrate-based CHClF2 separation process.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
