Article
Engineering, Environmental
Xiaoli Wei, Yiwei Sun, Yifan Wei, Yu Wang, Jinchao Wang, Bing Liu, Shucheng Wang, Feixiang Zhou, Wucan Liu, Jianjun Zhang, Yongyong Cao, Wenfeng Han
Summary: CHF3, a super greenhouse gas, can be treated by F/Cl exchange reaction with CHCl3 to form CHCl2F and CHClF2 for resource utilization. The crystal structures of Al-based fluorides play a crucial role in catalytic activity, and AlClxFy species act as the active sites for CHF3 conversion.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2022)
Article
Engineering, Chemical
Hyunglok Chu, Kyuchul Shin
Summary: Xenon (Xe) and krypton (Kr) are used in various important industries, but their separation is energy-intensive. This study shows that clathrate hydrates can be used for cost-effective Xe-Kr separation. The hydrate-based approach captures Xe selectively and requires milder temperature conditions compared to cryogenic distillation. It suggests that this method is an excellent alternative to the energy-intensive cryogenic distillation.
SEPARATION AND PURIFICATION TECHNOLOGY
(2023)
Article
Energy & Fuels
Erfan Khanmohammadian, Mohsen Mohammadi, Rohallah Hashemi, Sina Eslami, Mohammad Reza Ehsani
Summary: In this study, the separation of CO2 gas from a CO2/CH4 mixture was investigated using the gas hydrate formation method. Silica and APTES surface-modified silica nanoparticles with potassium hydroxide were used as additives. The presence of silica improved gas consumption, separation factor, and recovery factor. The optimal nanofluids with silica and potassium hydroxide showed a significant increase in gas consumption, separation factor, and recovery factor compared to pure water. The gas-liquid ratio and initial pressure affected the gas consumption, separation, and recovery factors.
Article
Engineering, Environmental
Gyeol Ko, Joonseop Lee, Yongwon Seo
Summary: The feasibility of hydrate-based sulfur hexafluoride (SF6) separation was examined by measuring the three-phase equilibria of SF6 + N-2 hydrates, constructing a pressure-composition diagram, identifying the hydrate type using powder X-ray diffraction, and measuring the dissociation enthalpy with a high-pressure micro-differential scanning calorimeter. Experimental results demonstrated the selective capture of SF6 in the hydrate phase, with the hydrate-based method requiring lower initial concentration and pressure compared to the liquefaction method.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Engineering, Environmental
Jae Hak Jeong, Minjun Cha, Jiyeong Jang, Sol Geo Lim, Chang Yeop Oh, Jong-Won Lee, Jeasung Park, Ji-Ho Yoon
Summary: The thermodynamic stability and spectroscopic properties of CO-C3H8 mixed gas hydrates were investigated for potential applications in hydrate-based gas separation (HBGS). The preferential occupation behavior of CO and C3H8 molecules in the hydrate cages was demonstrated, and predictions using thermodynamic models were in excellent agreement with experimental results. The HBGS process was found to be effective for selectively separating CO and C3H8 from gas mixtures.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Thermodynamics
Xiaoya Zang, Jing Wang, Yong He, Xuebing Zhou, Deqing Liang
Summary: In this study, TBAB hydrates were synthesized and their carbon capture capacity from a ternary gas mixture of CH4/CO2/N-2 was investigated. The addition of TBAB increased the specific surface area of the hydrate crystals and transformed the hydrate structure. These findings are important for the development of hydrate gas separation technology.
Article
Energy & Fuels
Namrata Gaikwad, Jitendra Sangwai, Praveen Linga, Rajnish Kumar
Summary: In this study, methane separation from CMM gas mixture was achieved by forming sII and sH hydrates with the use of different thermodynamic promoters at moderate temperature and pressure conditions. The formation of sII hydrate showed better methane recovery, while the formation of sH hydrate demonstrated a better separation factor. The use of water-soluble hydrate promoter sodium dodecyl sulfate (SDS) enhanced the rate of hydrate formation for better separation efficiency.
Article
Chemistry, Physical
Jinxiang Liu, Huanhua Wu, Sikai Wang, Yalin Zhang, Shengli Liu
Summary: We conducted first-principles calculations to study four new structures of two-dimensional hydrates and their potential applications in gas separation. The results show that these hydrates can be used for gas separation, with their stability in a highly confined environment following the order of N-2 > CO2 > NH3 > CH4. The kinetic diameter of gas molecules plays a crucial role in stabilizing the hydrate structure. The dynamic stability of the hydrates decreases with temperature, but they can still remain stable at 270 K.
JOURNAL OF MOLECULAR LIQUIDS
(2023)
Article
Energy & Fuels
Yingmei Wang, Aili Niu, Wenze Jiao, Ji Chen, Peng Zhang, Jinping Li
Summary: Carbon dioxide hydrate formation rate is improved by using different accelerator systems. The combination of nanographite-TBAB and SDS-TBAB shows better performance in reducing the nucleation time. TBAB shows the best nucleation amount, formation rate, and conversion rate among the single acceleration systems.
Article
Engineering, Marine
Yan Xie, Jingchun Feng, Liwei Sun, Junwen Wang, Weiqiang Hu, Bo Peng, Yujun Wang, Yi Wang
Summary: Methane leakage is a significant challenge in the exploitation of natural gas hydrates, and the mechanism and controlling factors of methane leakage during the hydrate dissociation process are still unclear. This study developed a coupled simulator that can simulate the exploitation of methane hydrates and simulate methane leakage, providing assistance in developing safe exploitation strategies.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2022)
Article
Engineering, Chemical
Ryosuke Ezure, Yuma Arai, Daiki Nakano, Hiroyuki Komatsu, Hideo Tajima
Summary: Hydrate-based gas separation is a method of separating gas mixtures based on their thermodynamic properties. This study proposes a new process for gas absorption and desorption under constant pressure with rising temperature. Theoretical calculations and experimental verification showed that SF6 can be concentrated up to 90% using this process.
SEPARATION AND PURIFICATION TECHNOLOGY
(2023)
Article
Green & Sustainable Science & Technology
Hongsheng Dong, Jiaqi Wang, Zhuoxue Xie, Bin Wang, Lunxiang Zhang, Quan Shi
Summary: This review discusses the potential applications of gas hydrates in energy and environmental fields, highlighting their advantages in gas storage, gas separation, wastewater treatment, and other areas. Challenges, limitations, and future directions for each application are also explored in the paper.
RENEWABLE & SUSTAINABLE ENERGY REVIEWS
(2021)
Article
Engineering, Chemical
Zucheng Cheng, Weiguo Liu, Shaohua Li, Sijia Wang, Yingying Liu, Xiang Sun, Cong Chen, Lanlan Jiang, Yongchen Song
Summary: This study evaluated the performance of SDS in the separation efficiency of simulated biogas. The experimental results showed that higher driving forces led to a significant increase in gas capture, dominated by the CH4 component. Hydrate growth mainly occurred in the liquid phase, and the separation factor was positively correlated with the induction time. Gas capture per unit volume of solution could be improved at higher gas-liquid ratios, while high-pressure failure behavior was observed. The defoamer had no significant effect on hydrate generation kinetics and separation efficiency.
SEPARATION AND PURIFICATION TECHNOLOGY
(2022)
Article
Chemistry, Physical
Minsu Choi, Youngseok Lee, Yebin You, Chulhee Cho, Wonnyoung Jeong, Inho Seong, Byeongyeop Choi, Sijun Kim, Youbin Seol, Shinjae You, Geun Young Yeom
Summary: This paper proposes the use of environmentally friendly alternatives as perfluorocarbon (PFC) and hydrofluorocarbon (HFC) precursors for SiO2 plasma etching, instead of conventional precursors. The study compares the etch performance and evaluates greenhouse gas (GHG) emissions. The results indicate that significant emissions reduction can be achieved without a deterioration in etching characteristics.
Article
Chemistry, Multidisciplinary
Gyeol Ko, Eunae Kim, Dongyoung Lee, Yongwon Seo
Summary: This study experimentally investigated the guest distributions and dissociation enthalpy of F-gas (CHF3 or C2F6)+N-2 hydrates with different F-gas concentrations. The results showed that at high N-2 concentrations, the occupancy of N-2 in the hydrates increased significantly, resulting in reduced hydration numbers. The Delta H-d values of the F-gas+N-2 hydrates decreased with increased N-2 concentration. These results provide useful insights into the design and operation of gas hydrate-based F-gas separation processes.
KOREAN JOURNAL OF CHEMICAL ENGINEERING
(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
Multidisciplinary Sciences
Sung Eun Kim, Yongwon Seo, Junshik Hwang, Hongkyu Yoon, Jonghyun Lee
Summary: Stochastic network modeling is often limited by high computational costs, but this study shows that DCGANs can effectively reproduce drainage networks using a novel connectivity-informed method. By converting drainage network images to directional information and training the network with different samples, DCGANs outperformed traditional methods in generating accurate drainage networks. This highlights the potential of DCGANs in high contrast images common in earth and material sciences.
SCIENTIFIC REPORTS
(2021)
Article
Engineering, Environmental
Gyeol Ko, Joonseop Lee, Yongwon Seo
Summary: The feasibility of hydrate-based sulfur hexafluoride (SF6) separation was examined by measuring the three-phase equilibria of SF6 + N-2 hydrates, constructing a pressure-composition diagram, identifying the hydrate type using powder X-ray diffraction, and measuring the dissociation enthalpy with a high-pressure micro-differential scanning calorimeter. Experimental results demonstrated the selective capture of SF6 in the hydrate phase, with the hydrate-based method requiring lower initial concentration and pressure compared to the liquefaction method.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Energy & Fuels
Joonseop Lee, Gyeol Ko, Junghoon Mok, Yongwon Seo
Summary: The study investigated the complex phase behaviors and structural coexistence of NGHs containing LMGSs, revealing the coexistence of sII and sH hydrates in CH4 + C2H6 + LMGS + water mixtures through NMR and PXRD analysis. The findings provide insights into the formation and dissociation processes of these hydrates, with sII being the final structure at equilibrium dissociation points.
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
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
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)