The removal of CO2 and N2 from natural gas: A review of conventional and emerging process technologies

Application of gas hydrate formation in separation processes: A review of experimental studies

Gas hydrates have received considerable attention due to their important role in flow assurance for the oil and gas industry, their extensive natural occurrence on Earth and extraterrestrial planets, and their significant applications in sustainable technologies including but not limited to gas and energy storage, gas separation, and water desalination Given not only their inherent structural flexibility depending on the type of guest gas molecules and formation conditions, but also the synthetic effects of a wide range of chemical additives on their properties, these variabilities could be exploited to optimise the role of gas hydrates This includes increasing their industrial applications, understanding and utilising their role in Nature, identifying potential methods for safely extracting natural gases stored in naturally occurring hydrates within the Earth, and for developing green technologies This review summarizes the different properties of gas hydrates as well as their formation and dissociation kinetics and then reviews the fast-growing literature reporting their role and applications in the aforementioned fields, mainly concentrating on advances during the last decade Challenges, limitations, and future perspectives of each field are briefly discussed The overall objective of this review is to provide readers with an extensive overview of gas hydrates that we hope will stimulate further work on this riveting field

Gas hydrates in sustainable chemistry

Coke formation during the thermolysis of petroleum residua is postulated to occur by a mechanism that involve the liquid-liquid phase separation of reacted asphaltene to form a phase that is been in abstractable hydrogen. This mechanism provide the basis of a model that quantitatively describe the kinetics for the thermolysis of ColD Lake vacuum residuum and its deasphalted oil in a open fuse reactor at 400°C. The previously unreacted asphaltene were found to be the fraction with the highest rate of thermal reaction but with the least extend of reaction. Further evidence of the liquid-liquid phase separation was the observation of spherical particle of liquid crystalline coke and the preferential conversion of the most associated asphatene to coke

A phase separation kinetic model for coke formation

Over the past century, fossil fuels have provided the majority of China's energy. However, their extensive utilization leads to a shortage and environmental pollution. Recently, submarine and permafrost gas hydrate deposits have been investigated as a possible clean and sustainable energy source by governmental institutions, research organizations, and energy industries in China. The primary objective of this paper is to review the potential studies pertaining to gas hydrate exploration and resource assessment, the safe and efficient exploitation of gas hydrates and the basic properties of gas hydrates. To date, there are over 20 institutions and organizations in China committed to gas hydrate investigation, among which the Guangzhou Marine Geological Survey (GMGS) and the Chinese Academy of Geological Sciences (CAGS) etc. primarily focus on gas hydrate exploration research, while the China National Offshore Oil Corporation (CNOOC) Research Center, Guangzhou Institute of Energy Conversion (GIEC) and China University of Petroleum-Beijing (CUPB) etc. concentrate on gas hydrate mining technologies. In this paper, the occurrence and exploration of gas hydrates in both permafrost regions and the continental slope of China have been determined from numerous research contributions and are presented. Moreover, the latest progress in gas hydrate fundamental studies, including hydrate phase equilibria, hydrate formation mechanisms, hydrate thermal physical properties and the acoustics and resistivity characteristics of gas hydrates are briefly reviewed, and relevant data are gathered and compared. Emphasis is also placed on gas hydrate mining technologies and gas production using depressurization methods, thermal stimulation methods or other methods. Furthermore, the security of natural gas hydrate-bearing sediments during gas production and the environmental impacts of gas hydrate are identified. With additional financial and political support and advanced research facilities, research on gas hydrates in China is progressing rapidly but is still in its early developing stage, thus, future work should be undertaken with greater diligence.

The status of natural gas hydrate research in China: A review

Mechanical properties of carbon steel by compound arc and vibration shock forging-rolling

The thermodynamic equilibrium conditions for binary gas mixtures of CH4 and H2 in the presence of TBAB were measured using the T-cycle method in this study. The experiments were conducted in the temperature range from (282.37 to 296.45) K and the pressure range from (0.46 to 15.47) MPa. The mole fraction of H2 in gas mixtures varied from 0.15 to 0.85. The mass fraction of TBAB solution ranged from 0.10 to 0.50. The experimental results showed that the addition of TBAB can dramatically reduce the pressure required for hydrate formation at a fixed temperature. The equilibrium pressure increased along with the increasing composition of H2 in the gas mixture. In order to gain a better understanding on the impact of TBAB on the thermodynamic equilibrium conditions for binary gas mixtures, a comparison was made between our data and phase equilibrium conditions for THF hydrates formed from the same gas mixture. The results showed that the thermodynamic promoting effect of TBAB was superior to that of THF when th...

Equilibrium Conditions of Binary Gas Mixture CH4 + H2 in Semiclathrate Hydrates of Tetra-n-butyl Ammonium Bromide

Formation conditions and thermodynamic model predictions of carbon monoxide hydrates

Experimental and modelling study on the effect of maltose as a green additive on methane hydrate

A continuous operation approach to separate gas mixture via hydrates formation was developed in this paper. We measured the formation condition of CH 4 /N 2 /TBAB hydrates, and investigated the continuous separation of CH 4 /N 2 via hydrates formation and subsequent dissociation in the presence of TBAB. As an effective hydrate thermodynamic promotor, TBAB significantly reduces the pressure formation of CH 4 /N 2 hydrates and enables the rapid hydration in the crystallizer at relatively low pressures. The separation effects of pressure, temperature, liquid flow, gas flow and TBAB concentration were examined. The concentration of CH 4 was shown to increase from 37.5 mol% to 52.4 mol% in the hydrate phase after continuous separation; the concentration of CH 4 in the unhydrated gas decreased to as low as 23.1 mol%. The novel and significant achievement of the continuous separation of gas mixtures via hydrates formation shown in this paper is extremely useful in the potential industrial application.

Qiang Sun

Papers

Mechanical properties of carbon steel by compound arc and vibration shock forging-rolling

Equilibrium Conditions of Binary Gas Mixture CH4 + H2 in Semiclathrate Hydrates of Tetra-n-butyl Ammonium Bromide

Formation conditions and thermodynamic model predictions of carbon monoxide hydrates

Experimental and modelling study on the effect of maltose as a green additive on methane hydrate

Continuous separation of CH4/N2 mixture via hydrates formation in the presence of TBAB