Gas Hydrate Storage Research Articles

Effect of Different Concentrations of NiMnGa Micro/Nanoparticles on the Kinetics of Natural Gas Hydration

To improve gas hydrate storage and transportation technology, ferromagnetic intermetallic compound NiMnGa particles with martensitic transformation endothermics were used to form micro/nanofluids with sodium dodecyl sulfate (SDS) to further strengthen the gas hydration process. In this work, the kinetic process of gas hydration in NiMnGa fluids with different concentrations (0, 0.1, 1, 2, and 3 wt.%) was investigated using a rotating magnetic field gas hydration separation experimental setup. The results show that the induction time of the 3 wt.% NiMnGa system was shortened by 98.3%, the gas consumption was increased by 50.5%, and the gas consumption rate was increased by 351.9% compared with the SDS system. Therefore, it is inferred from the mass transfer that NiMnGa micro/nanofluids can accelerate the formation of hydrates.

Tuning cyclopropanecarboxaldehyde clathrate hydrates for enhancement of methane storage

This study investigates the tuning behavior of guest molecules in gas hydrates to achieve an optimal balance between the storage capacity and moderate formation conditions for CH4 gas storage. A new structure II hydrate-forming agent, cyclopropanecarboxaldehyde (CPCAld), was examined, and the guest inclusion behavior, crystal structure, and tuning behavior of the binary (CPCAld + CH4) clathrate hydrate were analyzed using 13C solid-state nuclear magnetic resonance (NMR), Raman spectroscopy, and synchrotron powder X-ray diffraction (PXRD). The phase equilibria and CH4 storage capacity of the binary (CPCAld + CH4) clathrate hydrates were also investigated. The experimental results provide insights into the design and optimization of gas hydrate storage systems for CH4 gas and other applications. The study demonstrates the potential for tuning CH4 content in clathrate hydrates by adjusting the concentration of CPCAld from 0.5 mol% to 5.56 mol%, which enhanced the storage and transportation of CH4 gas. The CH4 storage capacity of the binary (CPCAld + CH4) clathrate hydrate at 3.0 mol% CPCAld concentration was approximately 25 % higher than that of (CPCAld + CH4) hydrate at 5.56 mol% of CPCAld concentration. Overall, the exploration of a new hydrate former, CPCAld, and the understanding of the tuning behaviors of the binary (CPCAld + CH4) hydrate provide important insights into enhancing the storage capacity and contribute to the development of efficient and safe CH4 gas storage technologies using gas hydrates.

A Review of Gas Capture and Liquid Separation Technologies by CO2 Gas Hydrate

Gas hydrates, being promising energy sources, also have good prospects for application in gas separation and capture technologies (e.g., CO2 sequestration), as well as for seawater desalination. However, the widespread use of these technologies is hindered due to their high cost associated with high power consumption and the low growth rates of gas hydrates. Previous studies do not comprehensively disclose the combined effect of several surfactants. In addition, issues related to the kinetics of CO2 hydrate dissociation in the annealing temperature range remain poorly investigated. The presented review suggests promising ways to improve efficiency of gas capture and liquid separation technologies. Various methods of heat and mass transfer enhancement and the use of surfactants allow the growth rate to be significantly increased and the degree of water transformation into gas hydrate, which gives impetus to further advancement of these technologies. Taking the kinetics of this into account is important for improving the efficiency of gas hydrate storage and transportation technologies, as well as for enhancing models of global climate warming considering the increase in temperatures in the permafrost region.

Increasing the thermal resistance of shell gas-support structures for use as gas hydrates storages

Currently, in the world and Ukraine there are difficulties with the provision of natural gas. However, one of the problems is its storage. So, the object of research is the process of storing natural gas in land storages in gas hydrate form. An alternative to traditional technologies can be the transportation and long-term storage of natural gas in the form of gas hydrates. However, the existing reinforced concrete and metal structures, in addition to a significant price, also cannot sufficiently provide effective thermal insulation of the gas hydrate and its tightness. The paper substantiates the possibility of using gas support structures and pneumatic building structures as gas hydrate storage facilities. The possibility of improving the proposed structures by using non-hardening foams as a thermal insulation material has been proposed and confirmed by calculations. The study was aimed at calculating and analyzing the effectiveness of such a method of thermal insulation of a ground gas storage facility for storing natural gas in gas hydrate form. A method acceptable for the current level of technology development is proposed for increasing the thermal resistance of gas support structures for their use as gas storages in the gas hydrate state. It consists in using stable liquid foams as an effective thermal insulation material to fill the space between the layers of a two-layer coating. In the course of the study, the high efficiency of the proposed method of thermal insulation of ground hydrate reservoirs with stable liquid foams was shown. Calculation of thermodynamic characteristics of gas support storages for gas hydrates at their thermal insulation by liquid foam is made. The efficiency of the technological process of storing gas hydrate in the form of blocks is analyzed depending on the time of year. The main parameters of operation of such facilities are substantiated. It has been established that storage of hydrate blocks in storage without their dissociation during insulation with a layer of foam requires short-term additional cooling during the summer period of storage. Thus, this technology has prospects for widespread adoption.

Dissociation of a powder layer of methane gas hydrate in a wide range of temperatures and heat fluxes

In spite of the widespread interest in gas hydrates, there are still many unsolved fundamental problems that hinder the development of these technologies. Key tasks are to reduce the cost of storage and transportation of gas hydrates in powder form or in the form of compressed tablets, to improve the energy conversion efficiency. Approximate models are obtained to describe the dissociation of methane gas hydrate in a wide range of negative temperatures for cases: diffusion, kinetic, and filtration models. The simulation takes into account the parameters: the powder layer thickness, the diameter of pores, the diameter of particles, the temperature, the pressure of the gas and the ambient medium, as well as the combined effect of the filtration resistance of the particle and the porous cylinder (a porous layer consisting of particles). The paper offers ways to reduce the rate of dissociation and increase the shelf life of gas hydrates. The results obtained can be applied to further improvement of the technology of storage and transportation of both artificial methane hydrate and natural gas hydrate.

Stability analysis of methane hydrates for gas storage application

Solidified Natural Gas (SNG) technology offers an attractive option for compact and safe, large-scale natural gas storage. Gas storage technologies are gaining traction due to the increasing demand for natural gas and the expected transition to hydrogen gas-based economies in the near future. Introduction of thermodynamic promoters like THF into the classical methane-water system enables rapid gas uptake at moderate pressure and temperature due to sII hydrate formation, with highly stable storage characteristics. Herein, we compare the stability of cylindrical mixed methane-THF (sII) and pure methane (sI) hydrate pellets, produced using freshwater. Storage pressure for both types of pellets was 1 atmosphere (atm) whereas the storage temperature was 268 K for sII hydrate and 268 K and 253 K for sI hydrate. While only 7.06% gas evolution occured from a methane-THF (sII) hydrate pellet stored at 1 atm and 268 K over a 10 day period, % gas evolution from two pure methane (sI) hydrate pellets stored at 268 K for similar duration was 41.45% and 37.05% individually. Correspondingly, % gas evolution from an sI pellet stored at 253 K was 51.09%. We also report 2 year uninterrupted stability testing of methane-THF (sII) hydrate pellets produced using both fresh and seawater, stored at atmospheric pressure and temperatures of 271 K and 268 K, respectively. To the best of our knowledge, this is the longest successful storage demonstration of any type of methane hydrates ever reported, showcasing the extraordinary stability of sII hydrates produced using both fresh and seawater. The results obtained in the present study resolve the challenge of hydrate stability in SNG technology and strengthen its commercial viability by reducing downstream complications related to gas hydrate storage.

High-efficiency natural-gas storage method involving formation of gas hydrate in water/oil-cyclopentane emulsion

This study proposes a high-efficiency natural gas hydrate (NGH) storage method involving the formation of NGH in a water/oil emulsion with the addition of suitable thermodynamic additives. First, the CH4 hydrate formation conditions in a water/diesel emulsion with the addition of hydrate thermodynamic additives, including tetrabutylammonium bromide (TBAB), tetrahydrofuran (THF), and cyclopentane (CP), were measured for the first time. Interestingly, in contrast to the case of the aqueous solution, both the TBAB and THF could not promote the formation of CH4 hydrate in the water/diesel emulsion, and they exhibited a hydration inhibition effect. The CP substantially reduced the CH4 hydrate formation pressure in the water/diesel emulsion, and the resulting hydrate/diesel slurry exhibited good fluidity. The CH4 storage characteristics of the water/diesel-CP emulsion under hydrate formation conditions were systematically studied. At 276.15 K and 6 MPa, for a water/diesel-CP emulsion containing 30 wt% water cut, the CH4 storage volume (S) per unit volume water in the emulsion reached 152.32 m3/m3, with the hydrartion reaction rate was 2.27 mmol/min, which was significantly higher than that for pure water, a water-CP solution, and a single water/diesel emulsion. S increased to 163.6 when the water cut decreased to 20 wt%; the entire experimental process lasted 90 min. An increase in the temperature from 274.15 to 282.15 K had a limited influence on S, indicating the wide range of application conditions of the water/diesel-CP emulsion for the production of NGH crystals. Furthermore, in situ particle video microscope observations and focused beam reflectance measurements confirmed the good flowability of the formed CH4 hydrate/diesel slurry. Continuous production of NGHs can theoretically be achieved using the water/diesel-CP emulsion.

Solution of the Problem of Natural Gas Storages Creating in Gas Hydrate State in Porous Reservoirs

Underground gas hydrate storage of natural gas is a rather promising way of creating underground storage facilities for hydrocarbon raw materials in porous reservoirs. This paper presents a solution to the problem of the formation of CH4 hydrate in a porous medium during the injection of methane into a reservoir at a temperature lower than the initial temperature of the reservoir. Self-similar solutions of the problem in axisymmetric approximation are given, describing the pressure and temperature distribution in separate reservoir regions at the formation of gas hydrate on the frontal surface. On the basis of the method of sequential change of stationary states, an analytical solution was obtained, which allowed us to determine the position of the methane hydrate formation boundary depending on different parameters for any moment of time. The limits of the applicability of the proposed model are also given. Thus, the analysis of the calculation results showed that the constructed solution allows one to sufficiently and accurately determine the values of parameters at the frontal surface for a highly permeable medium (k0 > 10−13 m2). It was proved that in the case of a highly permeable medium, the methane hydrate formation intensity will be limited by convective heat dissipation during hydrate formation.

Ways to improve the efficiency of carbon dioxide utilization and gas hydrate storage at low temperatures

The dissociation of gas hydrate in the form of pressed granules of different diameters has been investigated. Kinetic equations to describe dissociation of gas hydrates at negative temperatures have been obtained for the first time. The activation energy for CO2 hydrate is higher than for methane hydrate, and the intrinsic decomposition rate constant value, on the contrary, is almost 15 times lower for CO2 hydrate. The article proposes methods to improve the efficiency of gas hydrate storage and utilization of carbon dioxide. The pressed granules were obtained from gas hydrate particles of the same size (0.5 mm). The activation energy was found to be practically independent of the diameter of the pressed granules and the thickness of the powder layer, but to be determined by the minimum (“effective”) size of particles, forming the granules or a layer. The “effective” size refers to the diameter of uniform particles for which coalescence, pressing and any other packaging are excluded. It is shown for the first time that the value of the pre-exponential factor depends on the radius of the granule R (layer thickness h) if the radius (layer thickness h) exceeds the characteristic critical size Rcr (hcr). The Rcr value is determined by the thermal and diffusion resistance of the layer and is different for different gas hydrates.

Methane hydrate formation in the presence of ZnO nanoparticle and SDS: Application to transportation and storage

Due to natural gas benefits such as less carbon dioxide production compared to the other fossil fuels, its transmission technologies to the market are noticed these years and gas hydrate storage method could be considered as an option to storage and transportation. One way to overcome the low rate gas hydrate formation is using a mixture of surfactant and nanoparticles to enhance the hydrate formation rate. Hence, in this present contribution sodium dodecyl sulfate (SDS) (as a surfactant) and zinc oxide nanoparticles are used to promote hydrate formation process. The experiments were carried out at the temperature of 274.65 and 276.65 K, and the initial pressure of 50 and 60 bar in different additives concentrations. The results show that these additives can increase the amount of methane consumed, the rate of methane consumed and the mole number of water to hydrate conversion increases, however, these additives do not significantly affect the gas hydrate storage. Moreover, experimental results reveals that addition of SDS to the water not only improve the stabilization of zinc oxide nanoparticles in water but also increases the solubility of methane in water by lowering the surface tension. Also, as the novel outcome, these additives (SDS+ ZnO nanoparticles) decrease the induction time, however, the final storage capacity does not change significantly.

Aboveground storage of hydrocarbon gas hydrates

The work objective is to substantiate the technical bases for the production of gas hydrate blocks directly on-site for further transportation and storage in above ground storages, as an alternative to transporting and storing gas in underground gas storages. The theoretical bases have been considered and processes of gas hydrate blocks producing, physical-mechanical characteristics of artificial hydrates with the purpose of determining the conditions of their storage and prolonged storage were tested in laboratory conditions. The construction of above ground gas hydrate storage in the form of a building, partially deepened in a ground, which is separated from the environment by a wall of gravel cement elements made by the mixing method were substantiated. It is proved that such a constructive solution for a long-term storage of gas hydrate blocks is the most economical in terms of energy consumption to maintain internal negative temperature.

Experimental Study of Gas-Hydrate Dissociation Kinetics at Constant Temperatures Above 0°C

Recently, gas-hydrate storage technology has been drawing increasing attention as a new means of gas storage and transportation and may in the future become the optimal means of gas storage as compared with LNG technology because of its economic and safety advantages. The main purpose of the present work was to investigate experimentally the hydrate dissociation mechanism using a kinetic model at different temperatures and atmospheric pressure in the range 5-15°C. The obtained results have great significance for gas-hydrate storage technology and its application in industry.

天然气水合物技术的应用

本文论述了天然气水合物储运技术的概念和优缺点，水合物法淡化海水、开发湖盐、制冷、净化沼气的技术原理，从理论上证明了利用气体水合物法开发湖盐、净化沼气的实际可行性，并指出了水合物技术在制冷领域的价值和现状，最后预测了水合物技术在其他方面的应用。 This paper has discussed the concept of storage and transportation technology of natural gas hydrate and the technical principle of desalinizing seawater, developing lake salt, refrigerating and purifying biogas with natural gas hydrate method. Then, the practicability of developing lake salt and purifying biogas with natural gas hydrate method has been demonstrated theoretically. In the same time, the value and the present situation of hydrate technology have been indicated in refrigeration region. Ultimately, this paper has predicted possible applications that can be utilized in other regions.

Effects of Tetrahydrofuran and Cetyltrimethylammonium Bromide on Carbon Dioxide Hydrate Formation

The slow formation rate and low conversion of water to hydrates hinder the production of gas hydrate storage and transportation of gas in industry. The presence of Tetrahydrofuran (THF) in the gas hydrate system was discovered that it could reduce the energy required for pressurization or cooling of hydrate drastically. Not only reducing the energy required was very important, but also increasing the rate formation of hydrates. cetyltrimethyl ammonium bromide (CTAB) was reported to increase hydrate formation rate because of reducing the interfacial surface tension between gas and water. The carbon dioxide hydrate formation in the presence of different THF and CTAB concentrations were investigated in terms of kinetic and thermodynamic. The formation experiment was conducted in the quiescent condition and closed system at 3.5 MPa and 4 °C. The dissociation experiment was carried out after the formation was completed at 2.5 MPa with the driving force of 21 °C. The results showed that the carbon dioxide hydrates formed in the presence of 10 mol% THF, while carbon dioxide hydrates did not form in the presence of CTAB in the quiescent closed system.

Surfactant Effect of Promoting Research on Hydrate Formation

Gas hydrates are a major concern in oil and gas industry, Gas hydrates form in small amounts of water, gas, and the appropriate pressure and temperature conditions. Gas hydrate storage and transportation technology starts a new way for energy storage and transportation industry. The most critically technical problem is how to improve the hydrate formation rate, storage capacity and form continuously. The influences of surfactants on induction time in three types of solution with equal concentration were studied by means of visual hydrate experimental equipment, and generalized induction time was measured by direct observation method. Specific effects of different surfactants on hydrate formation were summarized, as well as the hydrate formation mechanism of surfactants . The lack of research and the research direction of the future were concluded . The further study of surfactant mechanism and build kinetics model containing surfactant have important theoretical value . The result shows that the gas molecules saturated due to the solubilization of surfactant, which promotes the progress of mass transfer in the hydrates. And driving force is provided for the complexation of host molecules and guest molecules during the formation progress of gas hydrates.

The Research about Storage and Transportation of Natural Gas Based on LNG Technology

Nowadays, we are in great lack of the technology theory for the storage and transportation of gas hydrate. Under this condition, after checking out related theory of these, we established the technology roadmap of the storage and transportation of gas hydrate by LNG technology. Study has shown that the technology of LNG is more saving than that of pipeline. Then we came out with the new idea of storage and transportation of hydrate by LNG technology.

Study on Enhanced Heat Transfer of the Gas Hydrate Storage Tank in the Cool Storage Process

The object of this study is an internal heat transfer/external promote crystal small coil gas hydrate cool storage device.HCFC-141b hydrate is the cool storage medium, and water is secondary refrigerant . This paper studies on the influence of different structural parameters on storage tank heat transfer characteristics, such as the coil arrangement and coil spacing. This paper builds nine tubes model. And it uses fluent to simulate the temperature field variation of the model. In order to make the research easier, this paper fixes other variables and studies for a variety in the course of studying. An analysis of the temperature variation of the four points was carried out. By comparing aligned arrangement and staggered arrangement, we can draw some conclusions.(1)Coil spacing has great influence on the heat transfer efficiency of cool storage tank.(2)The temperature variation of aligned arrangement is faster than staggered arrangement. And within a certain time, the final temperature of aligned arrangement is lower than staggered arrangement.

Formation and Economic Study on Hydrate Technology with NGH Pellets

This study presents economic and formation investigations on hydration effects by looking at natural gas hydrate (NGH) storage and transportation processes and formation conditions. The investigation includes experiments with methane. The obtained results show that the methane formation time increased linearly as the subcooling temperature decreased. Furthermore, the economic result indicates that the energy consumption parameter is appropriate for examining resource consumption for a system that, in turn, results in optimal capital investment through the storage and transportation process of NGH. The results also show that energy consumption increases logarithmically as the hydrate formation pressure increases. Finally, the study shows that the initial cost of the NGH transport chain is lower than the initial liquefied natural gas (LNG) transport cost.

Study on Promotion of Surfactant on Gas Hydrate Formation

Natural gas hydrate has huge gas storage capacity, natural gas hydrate storage and transportation technology opens up a new road for energy storage and transportation industry. The current biggest technical problem is how to improve the hydrate formation rate, to increase storage capacity and form continuously. This paper analyses existing research results, and find that SDS is researched the most widely currently, but there are many insufficient. Specific effects of different surfactants on hydrate formation were summarized, hydrate formation mechanism of surfactants were expounded. The lack of research and the research direction of the future were pointed out. It is thought that further study of surfactant mechanism and build kinetics model containing surfactant have important theory value.

Molecular dynamics simulations of the mechanisms of thermal conduction in methane hydrates

The thermal conductivity of methane hydrate is an important physical parameter affecting the processes of methane hydrate exploration, mining, gas hydrate storage and transportation as well as other applications. Equilibrium molecular dynamics simulations and the Green-Kubo method have been employed for systems from fully occupied to vacant occupied sI methane hydrate in order to estimate their thermal conductivity. The estimations were carried out at temperatures from 203.15 to 263.15 K and at pressures from 3 to 100 MPa. Potential models selected for water were TIP4P, TIP4P-Ew, TIP4P/2005, TIP4P-FQ and TIP4P/Ice. The effects of varying the ratio of the host and guest molecules and the external thermobaric conditions on the thermal conductivity of methane hydrate were studied. The results indicated that the thermal conductivity of methane hydrate is essentially determined by the cage framework which constitutes the hydrate lattice and the cage framework has only slightly higher thermal conductivity in the presence of the guest molecules. Inclusion of more guest molecules in the cage improves the thermal conductivity of methane hydrate. It is also revealed that the thermal conductivity of the sI hydrate shows a similar variation with temperature. Pressure also has an effect on the thermal conductivity, particularly at higher pressures. As the pressure increases, slightly higher thermal conductivities result. Changes in density have little impact on the thermal conductivity of methane hydrate.