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1
Li, Bo, You-Yun Lu, and Yuan-Le Li. "A Review of Natural Gas Hydrate Formation with Amino Acids." Journal of Marine Science and Engineering 10, no. 8 (August 17, 2022): 1134. http://dx.doi.org/10.3390/jmse10081134.
Анотація:
Natural gas is a kind of low-carbon energy source with abundant reserves globally and high calorific value. It is cleaner and more efficient than oil and coal. Enlarging the utilization of natural gas is also one of the important ways to reduce carbon emissions in the world. Solidified natural gas technology (SNG) stores natural gas in solid hydrates, which is a prospective, efficient, safe and environmental-friendly strategy of natural gas storage and transport. However, the slow growth rate and randomness of nucleation during natural gas hydrate formation in pure water hinder the industrial application of this technology. As a kind of new and potential additives, biodegradable amino acids can be adopted as favorable kinetic promoters for natural gas hydrate synthesis. Compared with other frequently used chemical additives, amino acids are usually more friendly to the environment, and are capable of avoiding foam formation during complete decomposition of gas hydrates. In this paper, we have reviewed the research progress of gas hydrate generation under the promotion of amino acids. The formation systems in which amino acids can enhance the growth speed of gas hydrates are summarized, and the impact of the concentration in different systems and the side chains of amino acids on hydrate growth have been illustrated. The thermodynamic and kinetic behaviors as well as the morphology properties of hydrate formation with amino acids are summarized, and the promotion mechanism is also analyzed for better selection of this kind of potential additives in the future.
2
Liu, Huaxin, Meijun Li, Hongfei Lai, Ying Fu, Zenggui Kuang, and Yunxin Fang. "Controlling Factors of Vertical Geochemical Variations in Hydrate-Rich Sediments at the Site GMGS5-W08 in the Qiongdongnan Basin, Northern South China Sea." Energies 17, no. 2 (January 14, 2024): 412. http://dx.doi.org/10.3390/en17020412.
Анотація:
Large amounts of natural gas hydrates have been discovered in the Qiongdongnan Basin (QDNB), South China Sea. The chemical and stable carbon isotopic composition shows that the hydrate-bound gas was a mixture of thermogenic and microbial gases. It is estimated that microbial gas accounts for 40.96% to 60.58%, showing a trend of decrease with the increase in burial depth. A significant amount of gas hydrates is thought to be stored in the mass transport deposits (MTDs), exhibiting vertical superposition characteristics. The stable carbon isotopic values of methane (δ13C1) in the MTD1, located near the seabed, are less than −55‰, while those of the methane below the bottom boundary of MTD3 are all higher than −55‰. The pure structure I (sI) and structure II (sII) gas hydrates were discovered at the depths of 8 mbsf and 145.65 mbsf, respectively, with mixed sI and sII gas hydrates occurring in the depth range 58–144 mbsf. In addition, a series of indigenous organic matters and allochthonous hydrocarbons were extracted from the hydrate-bearing sediments, which were characterized by the origin of immature terrigenous organic matter and low-moderate mature marine algal/bacterial materials, respectively. More allochthonous (migrated) hydrocarbons were also discovered in the sediments below the bottom boundary of MTD3. The gas hydrated is “wet gas” characterized by a low C1/(C2 + C3) ratio, from 2.55 to 43.33, which was mainly derived from a deeply buried source kitchen at a mature stage. There is change in the heterogeneity between the compositions of gas and biomarkers at the site GMGS5-W08 along the depth and there is generally a higher proportion of thermogenic hydrocarbons at the bottom boundary of each MTDs, which indicates a varying contribution of deeply buried thermogenic hydrocarbons. Our results indicate that the MTDs played a blocking role in regulating the vertical transportation of hydrate-related gases and affect the distribution of gas hydrate accumulation in the QDNB.
3
Graue, Arne, B. Kvamme, Bernie Baldwin, Jim Stevens, James J. Howard, Eirik Aspenes, Geir Ersland, Jarle Husebo, and D. Zornes. "MRI Visualization of Spontaneous Methane Production From Hydrates in Sandstone Core Plugs When Exposed to CO2." SPE Journal 13, no. 02 (June 1, 2008): 146–52. http://dx.doi.org/10.2118/118851-pa.
Анотація:
Summary Magnetic resonance imaging (MRI) of core samples in laboratory experiments showed that CO2 storage in gas hydrates formed in porous rock resulted in the spontaneous production of methane with no associated water production. The exposure of methane hydrate in the pores to liquid CO2 resulted in methane production from the hydrate that suggested the exchange of methane molecules with CO2 molecules within the hydrate without the addition or subtraction of significant amounts of heat. Thermodynamic simulations based on Phase Field Theory were in agreement with these results and predicted similar methane production rates that were observed in several experiments. MRI-based 3D visualizations of the formation of hydrates in the porous rock and the methane production improved the interpretation of the experiments. The sequestration of an important greenhouse gas while simultaneously producing the freed natural gas offers access to the significant amounts of energy bound in natural gas hydrates and also offers an attractive potential for CO2 storage. The potential danger associated with catastrophic dissociation of hydrate structures in nature and the corresponding collapse of geological formations is reduced because of the increased thermodynamic stability of the CO2 hydrate relative to the natural gas hydrate. Introduction The replacement of methane in natural gas hydrates with CO2 presents an attractive scenario of providing a source of abundant natural gas while establishing a thermodynamically more stable hydrate accumulation. Natural gas hydrates represent an enormous potential energy source as the total energy corresponding to natural gas entrapped in hydrate reservoirs is estimated to be more than twice the energy of all known energy sources of coal, oil, and gas (Sloan 2003). Thermodynamic stability of the hydrate is sensitive to local temperature and pressure, but all components in the hydrate have to be in equilibrium with the surroundings if the hydrate is to be thermodynamically stable. Natural gas hydrate accumulations are therefore rarely in a state of complete stability in a strict thermodynamic sense. Typically, the hydrate associated with fine-grain sediments is trapped between low-permeability layers that keep the system in a state of very slow dynamics. One concern of hydrate dissociation, especially near the surface of either submarine or permafrost-associated deposits, is the potential for the release of methane to the water column or atmosphere. Methane represents an environmental concern because it is a more aggressive (~25 times) greenhouse gas than CO2. A more serious concern is related to the stability of these hydrate formations and its impact on the surrounding sediments. Changes in local conditions of temperature, pressure, or surrounding fluids can change the dynamics of the system and lead to catastrophic dissociation of the hydrates and consequent sediment instability. The Storegga mudslide in offshore Norway was created by several catastrophic hydrate dissociations. The largest of these was estimated to have occurred 7,000 years ago and was believed to have created a massive tsunami (Dawson et al. 1988). The replacement of natural gas hydrate with CO2 hydrate has the potential to increase the stability of hydrate-saturated sediments under near-surface conditions. Hydrocarbon exploitation in hydrate-bearing regions has the additional challenge to drilling operations of controlling heat production from drilling and its potential risk of local hydrate dissociation (Yakushev and Collett 1992). The molar volume of hydrate is 25-30% greater than the volume of liquid water under the same temperature-pressure conditions. Any production scenario for natural gas hydrate that involves significant dissociation of the hydrate (e.g., pressure depletion) has to account for the release of significant amounts of water that in turn affects the local mechanical stress on the reservoir formation. In the worst case, this would lead to local collapse of the surrounding formation. Natural gas production by CO2 exchange and sequestration benefits from the observation that there is little or no associated liquid water production during this process. Production of gas by hydrate dissociation can produce large volumes of associated water, and can create a significant environmental problem that would severely limit the economic potential. The conversion from methane hydrate to a CO2 hydrate is thermodynamically favorable in terms of free energy differences, and the phase transition is coupled to corresponding processes of mass and heat transport. The essential question is then if it is possible to actually convert methane hydrate as found in sediments to CO2 hydrate. Experiments that formed natural gas hydrates in porous sandstone core plugs used MRI to monitor the dynamics of hydrate formation and reformation. The paper emphasizes the experimental procedures developed to form the initial natural gas hydrates in sandstone pores and the subsequent exchange with CO2 while monitoring the dynamic process with 3D imaging on a sub millimetre scale. The in-situ imaging illustrates the production of methane from methane hydrate when exposed to liquid CO2 without any external heating.
4
Khan, Muhammad Saad, Bhajan Lal, Hani Abulkhair, Iqbal Ahmed, Azmi Mohd Shariff, Eydhah Almatrafi, Abdulmohsen Alsaiari, and Omar Bamaga. "Formation Kinetics Evaluation for Designing Sustainable Carbon Dioxide-Based Hydrate Desalination via Tryptophan as a Biodegradable Hydrate Promotor." Sustainability 15, no. 1 (January 1, 2023): 788. http://dx.doi.org/10.3390/su15010788.
Анотація:
Desalination using hydrates is a developing field, and initial research promises a commercially feasible approach. The current study proposes the natural amino acid, namely tryptophan, as a biodegradable gas hydrate promotor for desalination applications to speed up the hydrate formation process. Its kinetic behavior and separation capabilities with CO2 hydrates were investigated. The studies were carried out with varying concentrations (0.5, 1, and 2 wt.%) of tryptophan at different experimental temperatures (274.15, 275.15, 276.15, and 277.15 K) at 3.5 and 4.0 MPa pressure and 1 wt.% brine concentration. The induction time, initial formation rates, gas uptake, and water recovery are characterized and reported in this work. Overall finding demonstrated that tryptophan efficiently acted as a kinetic hydrate promotor (KHP), and increased tryptophan quantities further supported the hydrate formation for almost all the studied conditions. The formation kinetics also demonstrated that it shortens the hydrate induction time by 50.61% and increases the 144.5% initial formation rate of CO2 hydrates for 1 wt.% addition of tryptophan at 274 K temperature and 4.0 MPa pressure condition. The study also discovered that at similar experimental conditions, 1 wt.% tryptophan addition improved gas uptake by 124% and water recovery moles by 121%. Furthermore, the increased concentrations of tryptophan (0.5–2 wt.%) further enhance the formation kinetics of CO2 hydrates due to the hydrophobic nature of tryptophan. Findings also revealed a meaningful link between hydrate formation and operating pressure observed for the exact temperature settings. High pressures facilitate the hydrate formation by reduced induction times with relatively higher formation rates, highlighting the subcooling effect on hydrate formation conditions. Overall, it can be concluded that using tryptophan as a biodegradable kinetic promotor considerably enhances the hydrate-based desalination process, making it more sustainable and cost-effective.
5
Jarrahian, Azad, and Ehsan Heidaryan. "Natural gas hydrate promotion capabilities of toluene sulfonic acid isomers." Polish Journal of Chemical Technology 16, no. 1 (March 1, 2014): 97–102. http://dx.doi.org/10.2478/pjct-2014-0017.
Анотація:
Abstract The purpose of this study was to investigate the natural gas hydrate promotion capabilities of the hydrotrope Toluene Sulfonic Acid (TSA) isomers as an additive. The capabilities of TSA isomers were measured with different concentrations. The optimum additive concentration for hydrate formation was determined for the given pressure, temperature, mixing condition, and cooling time. The natural gas hydrate promotability of para-TSA was found to be 20% and 35% more than meta-TSA and ortho-TSA respectively at the optimum concentration. Beyond the optimum TSA concentration, the hydrate formation declined as the ice formation reduced the overall gas-to-water volume ratio in the hydrates
6
Chuvilin, Evgeny, and Dinara Davletshina. "Formation and Accumulation of Pore Methane Hydrates in Permafrost: Experimental Modeling." Geosciences 8, no. 12 (December 10, 2018): 467. http://dx.doi.org/10.3390/geosciences8120467.
Анотація:
Favorable thermobaric conditions of hydrate formation and the significant accumulation of methane, ice, and actual data on the presence of gas hydrates in permafrost suggest the possibility of their formation in the pore space of frozen soils at negative temperatures. In addition, today there are several geological models that involve the formation of gas hydrate accumulations in permafrost. To confirm the literature data, the formation of gas hydrates in permafrost saturated with methane has been studied experimentally using natural artificially frozen in the laboratory sand and silt samples, on a specially designed system at temperatures from 0 to −8 °C. The experimental results confirm that pore methane hydrates can form in gas-bearing frozen soils. The kinetics of gas hydrate accumulation in frozen soils was investigated in terms of dependence on the temperature, excess pressure, initial ice content, salinity, and type of soil. The process of hydrate formation in soil samples in time with falling temperature from +2 °C to −8 °C slows down. The fraction of pore ice converted to hydrate increased as the gas pressure exceeded the equilibrium. The optimal ice saturation values (45−65%) at which hydrate accumulation in the porous media is highest were found. The hydrate accumulation is slower in finer-grained sediments and saline soils. The several geological models are presented to substantiate the processes of natural hydrate formation in permafrost at negative temperatures.
7
Luan, Hengjie, Mingkang Liu, Qinglin Shan, Yujing Jiang, Peng Yan, and Xiaoyu Du. "Experimental Study on the Effect of Mixed Thermodynamic Inhibitors with Different Concentrations on Natural Gas Hydrate Synthesis." Energies 17, no. 9 (April 26, 2024): 2078. http://dx.doi.org/10.3390/en17092078.
Анотація:
Natural gas hydrate (NGH) is a potential future energy resource. More than 90% of NGH resources exist in the pore medium of seafloor sediments. During the development of deep-sea oil and gas fields, wellbore pipelines are often clogged due to the synthesis of gas hydrates, and the addition of thermodynamic inhibitors is a common solution to prevent hydrate synthesis. In this paper, the effects of two single inhibitors, sodium chloride and ethylene glycol, as well as hybrid inhibitors combining these two inhibitors on the synthesis of methane hydrates were investigated using the self-developed one-dimensional gas hydrate exploitation simulation test apparatus. The effects of single and hybrid inhibitors were investigated in terms of the hydrate synthesis volume and gas–water two-phase conversion rate. The results show that the hybrid inhibitor has a better inhibitory effect on hydrate synthesis with the same initial synthesis driving force. When the concentration of inhibitors is low, salt inhibitors can have a better inhibitory effect than alcohol inhibitors. However, in the mixed inhibitor experiment, increasing the proportion of ethylene glycol in the mixed inhibitor can more effectively inhibit the synthesis of hydrates than increasing the proportion of sodium chloride in the mixed inhibitor.
8
Dmytrenko, Victoriia, Oleksandr Lukin, and Vasyl Savyk. "The influence of the gas hydrates morphology on the rate of dissociation and the manifestation of self-preservation in non-equilibrium conditions." Technology audit and production reserves 3, no. 1(65) (June 30, 2022): 39–43. http://dx.doi.org/10.15587/2706-5448.2022.261716.
Анотація:
The object for the research was samples of artificially formed gas hydrate of different morphology. Gas hydrates are clathrate compounds of water molecules and hydrate-forming gases. They create significant problems for the oil and gas industry. At the same time, they contain enormous natural gas resources. The study of gas hydrates requires the production of quality samples in laboratory conditions and the availability of appropriate laboratory equipment. However, it is customary to use averaged physical indicators when performing calculations and in works on modeling gas-hydrate processes. At the same time, their morphological differences are not taken into account. Therefore, there is a risk of obtaining distorted research results. Based on this, the paper presents an analysis of the morphological differences of artificially formed gas-hydrate structures depending on the method of their formation. An assessment of the influence of the method of gas hydrate formation and the morphology of artificially formed gas hydrate samples on its stability is also given. In addition, recommendations are provided for choosing a method of forming samples of gas-hydrate structures that simulate natural samples. Gas hydrate samples for research were obtained at a laboratory facility by changing the method of mixing the contents of the reactor. The basis of the research methodology was the analysis of enlarged images of gas hydrate samples. The morphology of the gas hydrate samples was studied through the transparent viewing windows of the reactor. For obtain high-quality images, an optical system with a light source inside the reactor was used. The stability of the gas hydrate samples was investigated with gradual pressure release in the reactor. The difficulty of obtaining adequate samples of artificial gas hydrates for modeling the properties of natural analogues is shown. It is shown that morphological differences in the macro- or microstructure of artificially formed gas hydrate samples can affect the results of research. It was concluded that the results of experimental studies with samples of artificially obtained gas hydrate cannot be considered adequate for real conditions without appropriate corrections.
9
Portnyagin, A. S., I. K. Ivanova, L. P. Kalacheva, and V. V. Portnyagina. "Studying the Formation of Natural Gas Hydrates in a Porous Medium from a Polymer – Solution – Oil Mixture." Chemistry and Technology of Fuels and Oils 638, no. 4 (2023): 24–28. http://dx.doi.org/10.32935/0023-1169-2023-638-4-24-28.
Анотація:
The article presents the results of studies of equilibrium conditions and kinetic characteristics of the processes of formation of natural gas hydrate in systems of porous medium - water - polymer - calcium chloride - oil under static conditions. It has been established that, formation of methane and natural gas hydrates mixture occurs in the systems under study. The presence of oil in the reaction system does not affect the equilibrium conditions of the gas hydrates formation within the error but reduces the hydrate formation rateand water-to hydrate convertion. The presence of the CaCl2 salt in the system shifts the equilibrium conditions of hydrate formationto the region of low temperatures. The effect of calcium chloride on the kinetics in a system without polymers has an extreme dependenceand makes it possible to double the gas uptake rate at 50 g/L. The addition of polymers (polyacrylamide, sodium carboxymethyl cellulose, or polyethylene glycol) to the system suppresses the salt effect. The data obtained can be useful in the developmentof reagents for polymer flooding of an oil reservoir during oil production under conditions of gas hydrate stability.
10
Goshovskyi, S. V., and Oleksii Zurian. "METHODS AND TECHNOLOGIES OF METHANE GAS EXTRACTION FROM AQUA GAS HYDRATE FORMATIONS." Мінеральні ресурси України, no. 4 (December 28, 2018): 26–31. http://dx.doi.org/10.31996/mru.2018.4.26-31.
Анотація:
In the bowels of the Earth and in the oceans of the World Ocean, there are practically unlimited resources of natural gas in the solid hydrate state, available to most countries of the world community. The development of gas hydrate deposits is based on the process of dissociation (separation), in which the gas hydrates break down into gas and water. In these technologies, three methods for the development of gas hydrate deposits are proposed: pressure reduction, heating and inhibitor input. Based on the systematized data, the above methods are suggested to be attributed to traditional methods, as the most studied and classical ones. It is proposed to identify a number of methods that imply the same results, but use other physical approaches and designate them as unconventional. 1. Decomposition of methane hydrates by nanoparticles. In this method, the use of nanoparticles commensurate with the gas hydrate cell (supplied as part of a hydrodynamic jet) is proposed for efficient and safe destruction of the gas hydrate. The application of nanotechnology provides effective and consistent study of the entire surface of the aquatic deposit of gas hydrates, with the necessary rate of their destruction and the production of planned volumes of methane. 2. Decomposition of methane hydrates by microorganisms (bacteria). In this process, in the process of the life of the bacteria, a gas must be released, replacing in the clathrate structure a molecule of methane per molecule of the given gas. In addition, the process must be controlled by the use of external factors that provide nutrition to the bacteria and at the same time, light, chemicals, electromagnetic radiation, etc. can be stopped at any time, which is absent in the natural conditions of formation of the gas hydrate.
11
Kvamme, Bjørn. "Environmentally Friendly Production of Methane from Natural Gas Hydrate Using Carbon Dioxide." Sustainability 11, no. 7 (April 2, 2019): 1964. http://dx.doi.org/10.3390/su11071964.
Анотація:
Huge amounts of natural gas hydrate are trapped in an ice-like structure (hydrate). Most of these hydrates have been formed from biogenic degradation of organic waste in the upper crust and are almost pure methane hydrates. With up to 14 mol% methane, concentrated inside a water phase, this is an attractive energy source. Unlike conventional hydrocarbons, these hydrates are widely distributed around the world, and might in total amount to more than twice the energy in all known sources of conventional fossil fuels. A variety of methods for producing methane from hydrate-filled sediments have been proposed and developed through laboratory scale experiments, pilot scale experiments, and theoretical considerations. Thermal stimulation (steam, hot water) and pressure reduction has by far been the dominating technology platforms during the latest three decades. Thermal stimulation as the primary method is too expensive. There are many challenges related to pressure reduction as a method. Conditions of pressure can be changed to outside the hydrate stability zone, but dissociation energy still needs to be supplied. Pressure release will set up a temperature gradient and heat can be transferred from the surrounding formation, but it has never been proven that the capacity and transport ability will ever be enough to sustain a commercial production rate. On the contrary, some recent pilot tests have been terminated due to freezing down. Other problems include sand production and water production. A more novel approach of injecting CO2 into natural gas hydrate-filled sediments have also been investigated in various laboratories around the world with varying success. In this work, we focus on some frequent misunderstandings related to this concept. The only feasible mechanism for the use of CO2 goes though the formation of a new CO2 hydrate from free water in the pores and the incoming CO2. As demonstrated in this work, the nucleation of a CO2 hydrate film rapidly forms a mass transport barrier that slows down any further growth of the CO2 hydrate. Addition of small amounts of surfactants can break these hydrate films. We also demonstrate that the free energy of the CO2 hydrate is roughly 2 kJ/mol lower than the free energy of the CH4 hydrate. In addition to heat release from the formation of the new CO2 hydrate, the increase in ion content of the remaining water will dissociate CH4 hydrate before the CO2 hydrate due to the difference in free energy.
12
Borodin, Stanislav L., Nail G. Musakaev, and Denis S. Belskikh. "Mathematical Modeling of a Non-Isothermal Flow in a Porous Medium Considering Gas Hydrate Decomposition: A Review." Mathematics 10, no. 24 (December 9, 2022): 4674. http://dx.doi.org/10.3390/math10244674.
Анотація:
Deposits of natural gas hydrates are some of the most promising sources of hydrocarbons. According to studies, at the current level of natural gas consumption, the traditional reserves will last for about 50 years, and the gas hydrate deposits will last for at least 250 years. Therefore, interest in the study of gas hydrates is associated first of all with gas production from gas hydrate deposits. Additionally, gas hydrates are widely studied for solving practical problems, such as transportation and storage of natural gas, utilization of industrial gases and environmental and technological disasters associated with gas hydrates. When solving practical problems related to gas hydrates, in addition to laboratory and field studies, mathematical modeling is also widely used. This article presents the mathematical models of non-isothermal flow in a porous medium considering the decomposition of gas hydrate. The general forms of the mass conservation equations, Darcy’s law and the energy conservation equation are given. The article also presents derivations of the equations for taking into account the latent heat of phase transitions and non-isothermal filtration parameters for the energy conservation equation. This may be useful for researchers to better understand the construction of the model. For the parameters included in the basic equations, various dependencies are used in different works. In all the articles found, most often there was an emphasis on one or two of the parameters. The main feature of this article is summarizing various dependencies for a large number of parameters. Additionally, graphs of these dependencies are presented so that the reader can independently evaluate the differences between them. The most preferred dependencies for calculations are noted and explained.
13
Zaporozhets, E. P., and N. A. Shostak. "Mathematical modeling of some features of gas hydrates dissociation." Proceedings of the Voronezh State University of Engineering Technologies 80, no. 2 (October 2, 2018): 313–22. http://dx.doi.org/10.20914/2310-1202-2018-2-313-322.
Анотація:
In the modern oil and gas industry, specialists often have to solve multifaceted problems associated with processes of dissociation of technogenic and natural gas hydrates. Known methods of calculation and dissociation studies mainly describe this process with the supply to heat hydrate. However, when using the method of pressure reduction for dissociation, hydrate metastability states are manifested - self-preservation and conservation effects, discovered by Russian and foreign researchers. Available in the literature descriptions of the effects of metastability were obtained as a result of experiments with hydrates from one-component gases and for specific thermobaric conditions. The existing dependencies for some hydrate systems do not apply to others, so that their direct application in solving practical problems, for example, with the extraction of natural gas or the elimination of man-made hydrates in a wide range of thermobaric conditions, is difficult. Therefore, the creation of a method for calculating the main parameters of the dissociation of hydrates from multicomponent gases is relevant. The article presents the developed physico-mathematical model of the features of hydrate dissociation process under isothermal pressure decrease of its environment. With the help of these models, the parameters of the hydrate dissociation process, including manifestations of their metastability states, are calculated. The mathematical dependencies connecting the parameters of the hydration dissociation process with the current parameters of the medium, as well as with the thermobaric conditions of the process of their formation (i.e. with their "history") can be used to solve practical problems of ensuring reliability and continuity of functioning systems of oil and gas industry. In addition, the obtained dependences can be used to develop promising reserves of hydrocarbons that are in the hydrate state in the depths and bottom sediments of the continental shelves, as well as to intensify oil and gas production using hydrate technologies.
14
Di Profio, Pietro, Simone Arca, Raimondo Germani, and Gianfranco Savelli. "Novel Nanostructured Media for Gas Storage and Transport: Clathrate Hydrates of Methane and Hydrogen." Journal of Fuel Cell Science and Technology 4, no. 1 (April 6, 2006): 49–55. http://dx.doi.org/10.1115/1.2393304.
Анотація:
In the last years the development of fuel cell (FC) technology has highlighted the correlated problem of storage and transportation of gaseous fuels, particularly hydrogen and methane. In fact, forecasting a large scale application of the FC technology in the near future, the conventional technologies of storage and transportation of gaseous fuels will be inadequate to support an expectedly large request. Therefore, many studies are being devoted to the development of novel efficient technologies for gas storage and transport; one of those is methane and hydrogen storage in solid, water-based clathrate hydrates. Clathrate hydrates (CH) are nonstoichiometric, nanostructured complexes of small “guest” molecules enclosed into water cages, which typically form at relatively low temperature-high pressure. In nature, CH of natural gas represent an unconventional and unexploited energy source and methane hydrate technology is already applied industrially. More recently, striking literature reports showed a rapid approach to the possibility of obtaining hydrogen hydrates at room temperature/mild pressures. Methane hydrate formation has been shown to be heavily promoted by some chemicals, notably amphiphiles. Our research is aimed at understanding the basic phenomena underlying CH formation, with a goal to render hydrate formation conditions milder, and increase the concentration of gas within the CH. In the present paper, we show the results of a preliminary attempt to relate the structural features of several amphiphilic additives to the kinetic and thermodynamic parameters of methane hydrate formation—e.g., induction times, rate of formation, occupancy, etc. According to the present study, it is found that a reduction of induction time does not necessarily correlate to an increase of the formation rate and occupancy, and so on. This may be related to the nature of chemical moieties forming a particular amphiphile (e.g., the hydrophobic tail, head group, counterion, etc.). Moreover, a chemometric approach is presented which is aimed at obtaining information on the choice of coformers for H2 storage in hydrates at mild pressures and temperatures.
15
Shahnazar, Sheida, Samira Bagheri, Amin TermehYousefi, Javad Mehrmashhadi, Mohd Sayuti Abd Karim, and Nahrizul Adib Kadri. "Structure, mechanism, and performance evaluation of natural gas hydrate kinetic inhibitors." Reviews in Inorganic Chemistry 38, no. 1 (June 27, 2018): 1–19. http://dx.doi.org/10.1515/revic-2017-0013.
Анотація:
AbstractIce-like crystal compounds, which are formed in low-temperature and high-pressure thermodynamic conditions and composed of a combination of water molecules and guest gas molecules, are called gas hydrates. Since its discovery and recognition as the responsible component for blockage of oil and gas transformation line, hydrate has been under extensive review by scientists. In particular, the inhibition techniques of hydrate crystals have been updated in order to reach the more economically and practically feasible methods. So far, kinetic hydrate inhibition has been considered as one of the most effective techniques over the past decade. This review is intended to classify the recent studies regarding kinetic hydrate inhibitors, their structure, mechanism, and techniques for their performance evaluation. In addition, this communication further analyzes the areas that are more in demand to be considered in future research.
16
Dou, Bin, Bin Bin Fan, and Lei Ren. "Research on Methane Hydrate Meta-Stable Property of Gas Hydrates for Application to Natural Gas Storage and Transportation." Advanced Materials Research 676 (March 2013): 97–102. http://dx.doi.org/10.4028/www.scientific.net/amr.676.97.
Анотація:
Gas hydrates are group ice-like crystalline compounds, which form through a combination of water and suitably sized guest molecules under low temperature and high pressure conditions. The important properties of hydrate are very high gas to solid ratio, 1m3 of hydrate may contain up to 175m3 of gas (at standard condition). When the conditions change, the methane hydrate can dissociate to methane and water. Hydrate meta-stable (self-preservation) property has been reported by some researchers in recent years. If we can utilize the property economically in addition to its high-density gas containing property, it is possible to store and transport stranded natural gas at higher temperature and lower pressure compared to the conventional liquid natural gas method. The authors conducted laboratory experiments of methane hydrate dissociation in order to examine its potential for application to natural gas storage and transportation. As the result, relatively extremely slow dissociation was confirmed within temperature range between -7.5°C and -3°C. These results seem to be very promising for practical application of self preservation property to natural gas storage and transportation.
17
Pedchenko, Larysa, and Mykhailo Pedchenko. "Increasing the thermal resistance of shell gas-support structures for use as gas hydrates storages." Technology audit and production reserves 3, no. 1(65) (June 30, 2022): 27–33. http://dx.doi.org/10.15587/2706-5448.2022.259738.
Анотація:
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.
18
Tharimela, Raghava, Adolpho Augustin, Marcelo Ketzer, Jose Cupertino, Dennis Miller, Adriano Viana, and Kim Senger. "3D controlled-source electromagnetic imaging of gas hydrates: Insights from the Pelotas Basin offshore Brazil." Interpretation 7, no. 4 (November 1, 2019): SH111—SH131. http://dx.doi.org/10.1190/int-2018-0212.1.
Анотація:
Mapping of natural gas hydrate systems has been performed successfully in the past using the controlled-source electromagnetic (CSEM) method. This method relies on differentiating resistive highly saturated free gas or hydrate-bearing host sediment from a less resistive low-saturated gas or brine-bearing host sediments. Knowledge of the lateral extent and resistivity variations (and hence the saturation variations) within sediments that host hydrates is crucial to be able to accurately quantify the presence of saturated gas hydrates. A 3D CSEM survey (PUCRS14) was acquired in 2014 in the Pelotas Basin offshore Brazil, with hydrate resistivity mapping as the main objective. The survey was acquired within the context of the CONEGAS research project, which investigated the origin and distribution of gas hydrate deposits in the Pelotas Basin. We have inverted the acquired data using a proprietary 3D CSEM anisotropic inversion algorithm. Inversion was purely CSEM data driven, and we did not include any a priori information in the process. Prior to CSEM, interpretation of near-surface geophysical data including 2D seismic, sub-bottom profiler, and multibeam bathymetry data indicated possible presence of gas hydrates within features identified such as faults, chimneys, and seeps leading to pockmarks, along the bottom simulating reflector and within the gas hydrate stability zone. Upon integration of the same with CSEM-derived resistivity volume, the interpretation revealed excellent spatial correlation with many of these features. The interpretation further revealed new features with possible hydrate presence, which were previously overlooked due to a lack of a clear seismic and/or multibeam backscatter signature. In addition, features that were previously mapped as gas hydrate bearing had to be reinterpreted as residual or low-saturated gas/hydrate features, due to the lack of significant resistivity response associated with them. Furthermore, we used the inverted resistivity volume to derive the saturation volume of the subsurface using Archie’s equation.
19
Liu, Li, Guo Sheng Jiang, Fu Long Ning, Yi Bing Yu, Ling Zhang, and Yun Zhong Tu. "Well Logging in Gas Hydrate-Bearing Sediment: A Review." Advanced Materials Research 524-527 (May 2012): 1660–70. http://dx.doi.org/10.4028/www.scientific.net/amr.524-527.1660.
Анотація:
In exploration for natural gas hydrates, drilling, coring and well logging are the most important access to make deep understanding of the nature of hydrate reservoirs, besides the seismic prospecting methods. Because of the harsh conditions for hydrate stability and the complex of occurrence formations, the drilling and coring generally have a great difficulty and high cost. Therefore, the well logging becomes the priority method. The resistivity and sonic logging method, which were applied as the earliest logging method in the evaluation of hydrate reserviors, have been continuously applied ever since and the evaluation results derived from them have a relative accuracy and reliability. Other logging tools, such as borehole imaging, density, electromagnetic, nuclear magnetic resonance, etc. are also used to make integrated interpretation and evaluation for the hydrate reservoirs. Until now the applied porosity and hydrate saturation evaluation models are better suitable to the homogeneous reservoirs. However, they still need to be amended or improved for the anisotropism (e.g., fracture sediment) and shale-rich reservoirs. In addition, the external factors such as drilling fluid washout and invasion will also affect the well logging results. The combination of various well logging methods is an effective way to improve the accuracy of identification and quantification of hydrate reservoirs.
20
Wang, Xiao-Hui, Qiang Xu, Ya-Nan He, Yun-Fei Wang, Yi-Fei Sun, Chang-Yu Sun, and Guang-Jin Chen. "The Acoustic Properties of Sandy and Clayey Hydrate-Bearing Sediments." Energies 12, no. 10 (May 14, 2019): 1825. http://dx.doi.org/10.3390/en12101825.
Анотація:
Natural gas hydrates samples are rare and difficult to store and transport at in situ pressure and temperature conditions, resulting in difficulty to characterize natural hydrate-bearing sediments and to identify hydrate accumulation position and saturation at the field scale. A new apparatus was designed to study the acoustic properties of seafloor recovered cores with and without hydrate. To protect the natural frames of recovered cores and control hydrate distribution, the addition of water into cores was performed by injecting water vapor. The results show that hydrate saturation and types of host sediments are the two most important factors that govern the elastic properties of hydrate-bearing sediments. When gas hydrate saturation adds approximately to 5–25%, the corresponding P-wave velocity (Vp) increases from 1.94 to 3.93 km/s and S-wave velocity (Vs) increases from 1.14 to 2.23 km/s for sandy specimens; Vp and Vs for clayey samples are 1.72–2.13 km/s and 1.10–1.32 km/s, respectively. The acoustic properties of sandy sediments can be significantly changed by the formation/dissociation of gas hydrate, while these only minorly change for clayey specimens.
21
Shi, Bohui, Jiaqi Wang, Yifan Yu, Lin Ding, Yang Liu, and Haihao Wu. "Investigation on the Transition Criterion of Smooth Stratified Flow to Other Flow Patterns for Gas-Hydrate Slurry Flow." International Journal of Chemical Engineering 2017 (2017): 1–13. http://dx.doi.org/10.1155/2017/9846507.
Анотація:
A stability criterion for gas-hydrate slurry stratified flow was developed. The model was based on one-dimensional gas-liquid two-fluid model and perturbation method, considering unstable factors including shear stress, gravity, and surface tension. In addition, mass transfer between gas and liquid phase caused by hydrate formation was taken into account by implementing an inward and outward natural gas hydrates growth shell model for water-in-oil emulsion. A series of gas-hydrate slurry flow experiments were carried out in a high-pressure (>10 MPa) horizontal flow loop. The transition criterion of smooth stratified flow to other flow patterns for gas-hydrate slurry flow was established and validated and combined with experimental data at different water cuts. Meanwhile, parameters of this stability criterion were defined. This stability criterion was proved to be efficient for predicting the transition from smooth to nonsmooth stratified flow for gas-hydrate slurry.
22
Huang, Ruifang, Yusheng Zhao, and Yiming Ma. "The Interaction of Talc, Montmorillonite, and Silica Sand with H2O Influences Methane Hydrate Formation." Energies 16, no. 17 (August 25, 2023): 6174. http://dx.doi.org/10.3390/en16176174.
Анотація:
Methane hydrates in natural geological settings are commonly distributed within sediments, with a variety of minerals (such as silica sand, talc, and montmorillonite). The mechanisms that control the influence of sediments on methane hydrate formation remain poorly understood. In this study, we performed experiments on methane hydrate formation in pure H2O with the addition of 3% sediments (montmorillonite, talc, and silica sand). A large-volume stirred reactor (80 mL) and a small-volume unstirred reactor (20 mL) were used. The results show that montmorillonite and talc severely inhibit methane hydrate formation. For experiments in the stirred reactor with pure H2O, normalized gas consumption is 30 (mmol/mol) after 1000 min. In contrast, normalized gas consumption in experiments with the addition of 3% montmorillonite and talc decreases greatly to <5 (mmol/mol) over the same period. The inhibiting effect of montmorillonite and talc is closely associated with the release of cations (Mg2+, Ca2+, K+, and Na+) into fluids, with higher concentrations of cations for slower rates of methane hydrate formation. The interaction of montmorillonite and talc with H2O consumes hydrogen ions (H+), resulting in alkaline solutions. It was found that alkaline solutions may not be favorable for methane hydrate formation. In contrast, silica sand slightly promotes methane hydrate formation in the unstirred reactor, which may be related to acidic solutions formed during the interaction of silica sand with H2O. The phase equilibrium temperatures and pressures of methane hydrate in the presence of 3% montmorillonite, talc, and silica sand are essentially the same as those in pure H2O, excluding the thermodynamic effect of minerals. The experiments of this study are important for understanding the formation of massive methane hydrates with low amounts of sediment (e.g., ≤3%). They suggest that methane hydrates may not be highly concentrated in sediments with abundant talc and montmorillonite. The experiments of this study may explain the close association of methane hydrates with silica sand.
23
Chirkova, Yulia F., Ulukbek Zh Mirzakimov, Matvei E. Semenov, Roman S. Pavelyev, and Mikhail A. Varfolomeev. "Promising Hydrate Formation Promoters Based on Sodium Sulfosuccinates of Polyols." Energies 16, no. 1 (December 28, 2022): 359. http://dx.doi.org/10.3390/en16010359.
Анотація:
The use of natural gas as an energy source is increasing significantly due to its low greenhouse gas emissions. However, the common methods of natural gas storage and transportation, such as liquefied or compressed natural gas, are limited in their applications because they require extreme conditions. Gas hydrate technology can be a promising alternative to conventional approaches, as artificially synthesized hydrates provide an economical, environmentally friendly, and safe medium to store energy. Nevertheless, the low rate of hydrate formation is a critical problem that hinders the industrial application of this technology. Therefore, chemical promoters are being developed to accelerate the kinetics of gas hydrate formation. In this paper, the effect of new sodium sulfosuccinate compounds, synthesized based on glycerol and pentaerythritol, on methane hydrate formation was studied. Experiments under dynamic conditions using high-pressure autoclaves demonstrated that the conversion of water-to-hydrate forms increased from 62 ± 5% in pure water to 86 ± 4% for the best promoter at concentration 500 ppm. In addition, the rate of hydrate formation increases 2-4 times for different concentrations. Moreover, none of the synthesized reagents formed foam, compared to sodium dodecyl sulfate, in which the foam rate was 3.7 ± 0.2. The obtained reagents showed good promotional properties and did not form foam, which makes them promising promoters for gas hydrate technology.
24
Ganteda, Rama Rao, Sai Kiran Burla, Jagan Mohan Reddy Boggu, and Pinnelli S. R. Prasad. "Efficient Storage of Methane in Hydrate Form Using Soybean Powder." Methane 1, no. 3 (August 18, 2022): 201–9. http://dx.doi.org/10.3390/methane1030016.
Анотація:
Natural gas is a promising future source for the increasing energy demand. It is partially clean energy with fewer environmental impacts, and it is necessary to develop technologies to cater to the supply chain. Due to their inherent structural properties, gas hydrates or clathrate hydrates are promising materials for capturing and storing methane gas. In the present study, the experimental investigations were performed to assess the utilization of soybean powder (SBP) as a promoting additive compared to sodium dodecyl sulfate (SDS) for methane hydrate formation. The methane hydrate formation temperature and pressure with SBP are 277.8 ± 3.2 K, 7050.9 ± 76.2 kPa, similar to SDS 277.2 ± 0.3 K, 7446.3 ± 5.7 kPa in the non-stirred system. The gas uptake capacity is about 94.2 ± 4.5 v/v and 92.4 ± 4.6 v/v with SBP and SDS, which is ~60% of the practical, achievable limit. The time for the 90% of hydrate conversion is ~4.6 times higher for SBP than SDS. The more prolonged kinetics is ascribed to the complex constituents in the SBP. In contrast to the SDS solution, no foam was produced in the sample of the SBP solution. The current studies demonstrate that SBP can be utilized to develop cleaner and more effective promoters for methane hydrate formation without foam creation.
25
Ni, Weijun, Guohao Yang, Jie Dong, Yansong Pan, Gang Chen, and Xuefan Gu. "Research and Evaluation of Foam-Drainage Corrosion-Inhibition Hydrate Anti-Aggregation Integrated Agent." Processes 11, no. 9 (September 14, 2023): 2745. http://dx.doi.org/10.3390/pr11092745.
Анотація:
In natural gas exploitation, foam drainage, corrosion inhibition and hydrate inhibition of wellbore fluid are conventional operations. However, there is often a problem where multiple chemical agents cannot be effectively used together and can only be used separately, resulting in complex production processes. In this study, the final integrated formulation was determined: 0.1% sodium alpha-olefin sulfonate (AOST) + 0.3% dodecyl dimethyl betaine (BS-12) + 0.3% sodium lignosulfonate + 0.5% hydrazine hydrate. The minimum tension of the integrated agent could be reduced to 23.5 mN/m. The initial foaming height of the integrated agent was 21.5 cm at 65 °C, the liquid-carrying capacity was 143 mL, and the liquid-carrying rate reached 71.5%. The maximum corrosion depth also decreased from 11.52 µm without the addition of hydrazine hydrate, gradually decreasing to 5.24 µm as the concentration of hydrazine hydrate increased. After adding an integrated agent, the growth rate of hydrates was slow and aggregation did not easily occur, and the formation temperature was also more demanding. Therefore, the integrated agent has a inhibitory effect on the formation of hydrates and has a good anti-aggregation effect. From the observation of the microstructure, the emulsion is an oil-in-water type, and the integrated agent adsorbs at the oil–water interface, preventing the dispersed water droplets in the oil phase from coalescing in one place. The oil-in-water type emulsion is more likely to improve the performance of the natural gas hydrate anti-aggregation agent.
26
Zhang, Yue, Zhi Li, Xiaodeng Yang, and Tianduo Li. "Synthesis of Chitosan Derivatives and Their Inhibition Effects on Methane Hydrates." Energies 15, no. 7 (April 6, 2022): 2675. http://dx.doi.org/10.3390/en15072675.
Анотація:
In recent years, the study of natural polymer products such as methane hydrate inhibitors has attracted more and more attention in the scientific research field. In order to achieve environmentally friendly and economical methane hydrate inhibitors with high activity, four chitosan derivatives were successfully synthesized and their methane hydrate inhibition effects were compared with chitosan (CS) and carboxymethyl chitosan (CMCS). Under the conditions of 6 MPa, 1 °C and 400 rpm, the induction time of methane hydrate was prolonged by 7.3 times with the addition of 0.1 wt% CS. It was found that chitosan with high hydrophobicity could effectively prevent methane gas from entering the water solution and reduce the driving force of methane hydrates, resulting in the extension of hydrate induction time. The hydrate inhibition effect of CMCS could be improved by the introduction of hydroxypropyl-3-trimethylamine and N-2-hydroxypropyl-3-isooctyl ether groups based on the enhancement of the molecular hydrophobicity. At the same time, the introduction of the trimethyl quaternary ammonium group increased the ion content in the aqueous solution, which further inhibited the nucleation and growth of methane hydrates. This work is supposed to serve as an inspiration for the further research and development of green kinetic hydrate inhibitors with high-efficiency.
27
Mel’nikov, V. P., N. S. Molokitina, A. O. Drachuk, K. A. Pletneva, A. A. Kibkalo, B. V. Grigor’ev, and G. Pandey. "A NEW BIODEGRADABLE PROMOTER OF METHANE HYDRATE FORMATION." Доклады Российской академии наук. Химия, науки о материалах 512, no. 1 (September 1, 2023): 107–13. http://dx.doi.org/10.31857/s2686953522600908.
Анотація:
The course of active development of the Arctic zone of the Russian Federation by companies of the fuel and energy complex implies the development of new methods and approaches to storage and transportation of natural gas in order to reduce the negative impact on the ecosystems of cold regions while maintaining the economic feasibility of its use. This paper proposes a method for optimising the technology of transporting and storing natural gas in the form of gas hydrates using soya lecithin as a promoting additive. Experimental methods show that soya lecithin additive at a concentration of 0.5 wt. % is not inferior to the most effective hydrate formation promoter – sodium dodecyl sulphate at a concentration of 0.1 wt. %. However, a comparison of the environmental characteristics shows a clear advantage for soya lecithin. It is also shown that the synthesis of methane hydrate from ground frozen solutions of soya lecithin is at least three times faster than from liquid solutions.
28
Kowalsky, Michael B., Seiji Nakagawa, and George J. Moridis. "Feasibility of Monitoring Gas-Hydrate Production With Time-Lapse Vertical Seismic Profiling." SPE Journal 15, no. 03 (March 22, 2010): 634–45. http://dx.doi.org/10.2118/132508-pa.
Анотація:
Summary Many studies involving the application of geophysical methods in the field of gas hydrates have focused on determining rock-physics relationships for hydrate-bearing sediments, with the goal being to delineate the boundaries of gas-hydrate accumulations and to estimate the quantities of gas hydrate that such accumulations contain using remote-sensing techniques. However, the potential for using time-lapse geophysical methods to monitor the evolution of hydrate accumulations during production and, thus, to manage production has not been investigated. In this work, we begin to examine the feasibility of using time-lapse seismic methods—specifically, the vertical-seismic-profiling (VSP) method—for monitoring changes in hydrate accumulations that are predicted to occur during production of natural gas. A feasibility study of this nature is made possible through the coupled simulation of large-scale production in hydrate accumulations and time-lapse geophysical (seismic) surveys. We consider a hydrate accumulation in the Gulf of Mexico that may represent a promising target for production. Although the current study focuses on one seismic method (VSP), this approach can be extended easily to other geophysical methods, including other seismic methods (e.g., surface seismic or crosshole measurements) and electromagnetic surveys. In addition to examining the sensitivity of seismic attributes and parameters to the changing conditions in hydrate accumulations, our long-term goals in this work are to determine optimal sampling strategies (e.g., source frequency, time interval for data acquisition) and measurement configurations (e.g., source and receiver spacing for VSP), while taking into account uncertainties in rock-physics relationships. The numerical-modeling strategy demonstrated in this study may be used in the future to help design cost-effective geophysical surveys to track the evolution of hydrate properties. Here, we describe the modeling procedure and present some preliminary results.
29
Wang, Zifei, Kangji Shi, Peng Gao, Lei Yang, and Yongchen Song. "Analysis of the Production Characteristics of Heterogeneous Reservoirs Assisted by Shallow Gas by Depressurization Path." Science Discovery 12, no. 1 (April 12, 2024): 14–19. http://dx.doi.org/10.11648/j.sd.20241201.13.
Анотація:
The problems of low gas production rate and low gas production restrict the commercial production of natural gas hydrate. The combined production of hydrate reservoirs and underlying shallow gas reservoirs is expected to make up for this shortcoming. Most natural gas hydrates in the formation exhibit vertical heterogeneous distribution characteristics; There is still little research on the mechanism of its impact on the characteristics of co harvesting. This work focuses on the interaction between vertical heterogeneous hydrate reservoirs and shallow gas layers, and analyzes the mechanism of the impact of depressurization pathway on the characteristics of combined production. The results indicate that before the pressure in the shallow gas layer is equal to the pressure in the hydrate layer, the change in pressure reduction method cannot significantly affect the characteristics of pressure changes in the shallow gas layer; In addition, there is a significant hysteresis effect in the pressure evolution of shallow gas layers compared to hydrate layers. Not limited to this, the presence of shallow gas layers will also weaken the impact of pressure reduction paths on the gas production characteristics of combined production, which makes the gas production characteristics at this time more inclined towards the gas production characteristics under direct pressure reduction. In summary, in order to effectively increase the temperature of shallow gas and enhance hydrate decomposition, it is necessary to flexibly adjust the pressure reduction indicators of the pressure reduction path in different mining stages. The results can lay the foundation for clarifying the mechanism of interlayer interference in multiple gas source reservoirs.
30
Li, Yanghui, Tingting Luo, Xiang Sun, Weiguo Liu, Qingping Li, Yuanping Li, and Yongchen Song. "Strength Behaviors of Remolded Hydrate-Bearing Marine Sediments in Different Drilling Depths of the South China Sea." Energies 12, no. 2 (January 15, 2019): 253. http://dx.doi.org/10.3390/en12020253.
Анотація:
The mechanical behaviors of hydrate-bearing marine sediments (HBMS) drilled from the seafloor need to be understood in order to safely exploit natural gas from marine hydrate reservoirs. In this study, hydrates were prepared using ice powder and CH4 gas, and HBMS from the Shenhu area in the South China Sea were remolded using a mixed sample preparation method. A series of triaxial tests were conducted on the remolded HBMS to investigate the effects of soil particle gradation and the existence of hydrate on the mechanical properties of hydrate reservoirs. The results show that the stiffness and failure strength of HBMS decrease along with the decrease of mean particle size and soil aggregate morphology change at different drilling depths, and the reduction of failure strength is more than 20% when the drilling depth drops by 30 m. A better particle gradation of marine sediments may boost the stiffness and failure strength of HBMS. In addition, the existence of hydrate plays an important role in the strength behaviors of HBMS. The reduction of failure strength of HBMS with 30% initial hydrate saturation is more than 35% after complete hydrate dissociation.
31
Shen, Shi, Lei Wang, Yang Ge, Xingyu Lu, Jiawei Chu, and Huiyong Liang. "Effect of Hydrate Saturation and Pore Pressure on the Safe Exploitation of Natural Gas Hydrate Resources." E3S Web of Conferences 520 (2024): 01027. http://dx.doi.org/10.1051/e3sconf/202452001027.
Анотація:
A comprehensive study of the mechanical behaviors of hydrate-bearing sediments (HBSs) is the key to safely exploiting hydrate resources. The mechanical behaviors of HBSs are related to many variables, among which hydrate saturation (Sh) and pore pressure (PP) are vital factors. In addition, Sh and PP are related to the location of hydrates in the subsea layer, so it is of positive significance to investigate their comprehensive influence on the mechanical behavior of HBSs. In this work, a series of triaxial tests were conducted on the HBSs synthesized in the laboratory to explore the influence of Sh and PP on the mechanical properties of the HBSs. The results show that the strength of HBSs increases with increasing PP and Sh. With increased PP and Sh, the stress-strain behaviors will shift from strain-hardening to strain-softening. Moreover, under different Sh conditions, a critical PP point of strain-hardening and softening transition exists in numerical perspective. The critical PP point will develop towards low pressure with increased Sh.
32
Wu, Peng, Shenghua Yang, Le Wang, Xiangge Song, and Yanghui Li. "Influence of Particle Size Distribution on the Physical Characteristics of Pore-Filling Hydrate-Bearing Sediment." Geofluids 2021 (June 19, 2021): 1–13. http://dx.doi.org/10.1155/2021/9967951.
Анотація:
Nature gas hydrates (NGHs) are regarded as a potential alternative energy source due to their huge reserves and wide distribution. According to the geophysical surveys, the pore-filling hydrates occupy a large proportion of the global hydrate reserves, especially for the marine regions. Therefore, with a novel pore-scale 3D morphological modeling algorithm, this study systematically studied the effect of the particle size on the physical characteristics of the pore-filling hydrate-bearing sediment (HBS). The pore system evaluations and permeability simulations were performed by utilizing pore network modeling (PNM), and the thermal and electrical simulations were conducted by utilizing a finite volume method (FVM). The results show that for the HBS with smaller particle size, the average radius of the pores and throats would also be reduced, and the fractal dimension of the pore system would be increased. In addition, with the increasing hydrate saturation, the fractal dimension of the pore system will increase firstly and then decrease. And these parameter evolutions could impact the physical properties correspondingly; specifically, the decreasing particle size in the HBS would reduce the permeability and electrical conductivity of HBS and enhance the apparent thermal conductivity of HBS.
33
Li, Qingchao, Lingling Liu, Baohai Yu, Linian Guo, Sheng Shi, and Linchun Miao. "Borehole enlargement rate as a measure of borehole instability in hydrate reservoir and its relationship with drilling mud density." Journal of Petroleum Exploration and Production Technology 11, no. 3 (February 18, 2021): 1185–98. http://dx.doi.org/10.1007/s13202-021-01097-2.
Анотація:
AbstractBorehole collapse will pose a threat to the safety of equipment and personnel during drilling operation. In this paper, a finite element multi-field coupling model for investigating borehole collapse in hydrate reservoir was developed. In this model, fluid seepage, heat transfer, hydrate dissociation and borehole deformation are all considered. Based on which, effects of drilling fluid density on both of hydrate dissociation and borehole collapse are investigated. The investigation results show that disturbance of drilling fluid invasion to hydrate reservoir will lead to hydrate dissociation around wellbore, and dissociation range narrows obviously with the increase in drilling fluid density. When the relative fluid density is 0.98, natural gas hydrates in reservoir with a width of about 16.65 cm around wellbore dissociate completely. However, dissociation range of natural gas hydrate has decreased to 12.08 cm when the relative fluid density is 1.10. Moreover, hydrate dissociation around wellbore caused by drilling fluid invasion may lead to borehole collapse, and borehole collapse can be significantly restrained with the increase in relative fluid density. Borehole enlargement rate is 33.67% when the relative fluid density is 0.98, but nearly no collapse area displays around wellbore when the relative fluid density increases to 1.12. In addition, investigation herein can provide an idea for designing drilling fluid density in hydrate reservoir when different allowable borehole enlargement rate is considered. The minimum fluid density designed for avoiding disastrous borehole collapse increases nonlinearly when higher requirements for borehole stability are proposed.
34
Yarakhmedov1, M. B., A. P. Semenov, and A. S. Stoporev. "Effect of Lower Alcohols on the Formation of Methane Hydrate at Temperatures below the Melting Point of Ice." Chemistry and Technology of Fuels and Oils 634, no. 6 (2022): 44–48. http://dx.doi.org/10.32935/0023-1169-2022-634-6-44-48.
Анотація:
This work revealed that most water-soluble compounds have a dual nature (thermodynamic promotion or hydrate inhibition) depending on thermobaric conditions. Indeed, by lowering the melting point of ice, water-soluble organic compounds expandthe region of water-containing liquid phase existence below 0°C. This work considered typical thermodynamic hydrate inhibitors as alcohols (methanol, ethanol, and isopropanol). It turned out that even methanol does not exhibit inhibitory properties below the ice crystallization line, and it does not affect the equilibrium conditions of methane hydrate formation. In this case, the observed four-phase hydrate-ice-solution-gas equilibrium either corresponds to the hydrate-ice-gas line for the water-methane system (in the case of methanol) or lies at higher temperatures (in the case of ethanol and isopropanol). This allowed us to assume that practicallyany water-soluble organic compounds will either exhibit the properties of thermodynamic hydrate promoters in a specific temperature range below 0°C or will not affect the hydrate-ice-gas equilibrium. In addition, the presence of the ice and an aqueous liquid mixture in the system accelerates the hydrate growth (compared to the hydrate growth from the bulk phase of ice). It should alsobe noted that, unlike conventional thermodynamic promoters, methanol does not alter the methane hydrate's structure and gas capacity, which is more favorable. The data obtained can contribute to developing hydrate-based technologies for gas storage and separation of gas mixtures.
35
Xu, Jianchun, Ziwei Bu, Hangyu Li, Xiaopu Wang, and Shuyang Liu. "Permeability Models of Hydrate-Bearing Sediments: A Comprehensive Review with Focus on Normalized Permeability." Energies 15, no. 13 (June 21, 2022): 4524. http://dx.doi.org/10.3390/en15134524.
Анотація:
Natural gas hydrates (NGHs) are regarded as a new energy resource with great potential and wide application prospects due to their tremendous reserves and low CO2 emission. Permeability, which governs the fluid flow and transport through hydrate-bearing sediments (HBSs), directly affects the fluid production from hydrate deposits. Therefore, permeability models play a significant role in the prediction and optimization of gas production from NGH reservoirs via numerical simulators. To quantitatively analyze and predict the long-term gas production performance of hydrate deposits under distinct hydrate phase behavior and saturation, it is essential to well-establish the permeability model, which can accurately capture the characteristics of permeability change during production. Recently, a wide variety of permeability models for single-phase fluid flowing sediment have been established. They typically consider the influences of hydrate saturation, hydrate pore habits, sediment pore structure, and other related factors on the hydraulic properties of hydrate sediments. However, the choice of permeability prediction models leads to substantially different predictions of gas production in numerical modeling. In this work, the most available and widely used permeability models proposed by researchers worldwide were firstly reviewed in detail. We divide them into four categories, namely the classical permeability models, reservoir simulator used models, modified permeability models, and novel permeability models, based on their theoretical basis and derivation method. In addition, the advantages and limitations of each model were discussed with suggestions provided. Finally, the challenges existing in the current research were discussed and the potential future investigation directions were proposed. This review can provide insightful guidance for understanding the modeling of fluid flow in HBSs and can be useful for developing more advanced models for accurately predicting the permeability change during hydrate resources exploitation.
36
ШАКИРОВА, М. В., Н. Л. СОКОЛОВА, Е. В. МАЛЬЦЕВА, Ю. А. ТЕЛЕГИН, and А. О. ХОЛМОГОРОВ. "The features of methane genesis of the gas hydrates in the Far Eastern Seas." Tihookeanskaia geografiia, no. 4(4) (December 25, 2020): 54–64. http://dx.doi.org/10.35735/tig.2020.4.4.006.
Анотація:
Метан является одним из важных представителей органических веществ в воздушной оболочке Земли. Помимо усиления парникового эффекта увеличение содержания метана в атмосфере может влиять на сокращение концентрации озона в ней, а роль озонового слоя в жизни планеты важна. Одним из важнейших звеньев цикла метана и сопутствующих его потокам других газов являются газовые гидраты. Отношения стабильных изотопов углерода (δ13C) метана и его гомологов – объективные характеристики гидратообразующих газов и связанных с ними газогеохимических полей. Важнейшее значение в оценке изотопных эффектов природных соединений имеет масс-балансное соотношение генетически разнородных соединений. Вопрос масс-балансного эффекта в формировании газогеохимических полей и газогидратов рассмотрен в рамках данной работы. В статье показано, что газогидратоносность Охотского и Японского морей следует рассматривать как проявление газогеохимического зонирования миграции углеводородных газов от их термогенных источников, предопределенных наличием нефтегазоматеринского вещества, тектоническим фактором и сейсмической активностью в регионе. В отдельных случаях вулканическая активность также способна влиять на газовый состав газогидратоносных осадков и газогидратов. Газогидратоносность окраинных морей в целом обусловлена потоками миграционных и микробных газов, которые концентрируются в зонах пересечений разломов на бортах тектонических прогибов. Признаки термогенных флюидов и многоярусное залегание газогидратов указывают на их возобновляемость и возможность использования как важных индикаторов цикла метана и углерода. Основными источниками миграционных углеводородных газов являются нефтегазоносные и угленосные толщи, в зонах проницаемости существует вклад глубинных компонентов. Methane is one of the important representatives of the organic substances in the atmosphere. In addition to enhancing the greenhouse effect, an increase in methane content in the atmosphere can affect the decrease in the ozone concentration in it, and the role of the ozone layer in the life of the planet is important. Gas hydrates are among the most important links in the methane cycle and the accompanying flows of other gases. The ratios of stable carbon isotopes (δ13C) of methane and its homologues are the objective characteristics of hydrate-forming gases and associated gasgeochemical fields. The mass balance ratio of genetically dissimilar compounds is an importance in assessing the isotope effects of natural compounds. The issue of the mass balance effect in the formation of gasgeochemical fields and gas hydrates is considered within the framework of this paper. It is shown that gas hydrate content in the Seas of Okhotsk and Japan should be considered as a manifestation of gas-geochemical zoning of hydrocarbon gases migration from their thermogenic sources based on a source substance, the tectonic factor and seismic activity in the region. In some cases, volcanic activity can also affect the gas composition of gas-hydrate-bearing sediments and gas hydrates. The gas-hydrate content of marginal seas is generally determined by the flows of migration and microbial gases, which are concentrated in the zones of intersections of faults on the sides of tectonic deflections. Signs of thermogenic fluids and multi-level occurrence of gas hydrates indicate that they are renewable and can be used as important indicators of the methane and carbon cycle. The main sources of migration of hydrocarbon gases are oil and gas-bearing and coal-bearing strata, and in the zones of permeability there is a contribution of deep components.
37
ШАКИРОВА, М. В., Н. Л. СОКОЛОВА, Е. В. МАЛЬЦЕВА, Ю. А. ТЕЛЕГИН, and А. О. ХОЛМОГОРОВ. "The features of methane genesis of the gas hydrates in the Far Eastern Seas." Tihookeanskaia geografiia, no. 4(4) (December 25, 2020): 54–64. http://dx.doi.org/10.35735/tig.2020.4.4.006.
Анотація:
Метан является одним из важных представителей органических веществ в воздушной оболочке Земли. Помимо усиления парникового эффекта увеличение содержания метана в атмосфере может влиять на сокращение концентрации озона в ней, а роль озонового слоя в жизни планеты важна. Одним из важнейших звеньев цикла метана и сопутствующих его потокам других газов являются газовые гидраты. Отношения стабильных изотопов углерода (δ13C) метана и его гомологов – объективные характеристики гидратообразующих газов и связанных с ними газогеохимических полей. Важнейшее значение в оценке изотопных эффектов природных соединений имеет масс-балансное соотношение генетически разнородных соединений. Вопрос масс-балансного эффекта в формировании газогеохимических полей и газогидратов рассмотрен в рамках данной работы. В статье показано, что газогидратоносность Охотского и Японского морей следует рассматривать как проявление газогеохимического зонирования миграции углеводородных газов от их термогенных источников, предопределенных наличием нефтегазоматеринского вещества, тектоническим фактором и сейсмической активностью в регионе. В отдельных случаях вулканическая активность также способна влиять на газовый состав газогидратоносных осадков и газогидратов. Газогидратоносность окраинных морей в целом обусловлена потоками миграционных и микробных газов, которые концентрируются в зонах пересечений разломов на бортах тектонических прогибов. Признаки термогенных флюидов и многоярусное залегание газогидратов указывают на их возобновляемость и возможность использования как важных индикаторов цикла метана и углерода. Основными источниками миграционных углеводородных газов являются нефтегазоносные и угленосные толщи, в зонах проницаемости существует вклад глубинных компонентов. Methane is one of the important representatives of the organic substances in the atmosphere. In addition to enhancing the greenhouse effect, an increase in methane content in the atmosphere can affect the decrease in the ozone concentration in it, and the role of the ozone layer in the life of the planet is important. Gas hydrates are among the most important links in the methane cycle and the accompanying flows of other gases. The ratios of stable carbon isotopes (δ13C) of methane and its homologues are the objective characteristics of hydrate-forming gases and associated gasgeochemical fields. The mass balance ratio of genetically dissimilar compounds is an importance in assessing the isotope effects of natural compounds. The issue of the mass balance effect in the formation of gasgeochemical fields and gas hydrates is considered within the framework of this paper. It is shown that gas hydrate content in the Seas of Okhotsk and Japan should be considered as a manifestation of gas-geochemical zoning of hydrocarbon gases migration from their thermogenic sources based on a source substance, the tectonic factor and seismic activity in the region. In some cases, volcanic activity can also affect the gas composition of gas-hydrate-bearing sediments and gas hydrates. The gas-hydrate content of marginal seas is generally determined by the flows of migration and microbial gases, which are concentrated in the zones of intersections of faults on the sides of tectonic deflections. Signs of thermogenic fluids and multi-level occurrence of gas hydrates indicate that they are renewable and can be used as important indicators of the methane and carbon cycle. The main sources of migration of hydrocarbon gases are oil and gas-bearing and coal-bearing strata, and in the zones of permeability there is a contribution of deep components.
38
Liu, Tao, and Xuewei Liu. "Identification of morphologies of gas hydrate distribution based on amplitude variation with angle analysis." GEOPHYSICS 83, no. 3 (May 1, 2018): B143—B154. http://dx.doi.org/10.1190/geo2017-0072.1.
Анотація:
There are two basic distribution morphologies of gas hydrates in nature: pore filling and fracture filling. Identification of gas hydrate morphologies is essential for improved resource evaluation and exploitation. Improper exploitation may cause seafloor instability, lead to atmospheric venting, and exacerbate the greenhouse effect. To identify gas hydrate morphologies, we combine rock-physics modeling and amplitude variation with angle (AVA) analysis to study the theoretical AVA patterns of the bottom simulating reflector (BSR) beneath the pore-filling and fracture-filling gas hydrate bearing sediments (GHBS), respectively. The theoretical results indicate completely different AVA patterns between these two morphologies. The AVA of the BSR beneath the pore-filling GHBS shows a class III anomaly with negative intercept and gradient. However, the AVA of the BSR beneath the fracture-filling GHBS exhibits a class IV anomaly with a negative intercept and positive gradient. In addition, the theoretical AVA intercept and gradient are affected by the fracture orientation, manifesting an anisotropic signature varying with the fracture dip and azimuth. The processed prestack data at well sites 08 and 16 in the northern South China Sea are selected for testing our method. The AVA analysis of the actual BSRs beneath the pore-filling and fracture-filling GHBS at these sites shows class III and IV responses, respectively, in agreement with our theoretical results. The gas hydrate saturations are also estimated by comparing the theoretical AVA with the actual AVA patterns. The estimations at site 08 are close to those estimated from the pore-water freshening.
39
Wang, Shu Li, Wei Jun Ma, Lin Zhang, and Shi Dong Zhou. "A New Additive Kinetics Model of Natural Gas Hydrate." Advanced Materials Research 512-515 (May 2012): 2103–9. http://dx.doi.org/10.4028/www.scientific.net/amr.512-515.2103.
Анотація:
The paper developed the new compound accelerator contains liquid hydrocarbons and surfactants, using the hydrate generator to experiment. On the basis of the researches on the generating conditions, mechanism of gas hydrate and experimental phenomena, the new kinetics model considering the compound accelerator affecting is built. A program which can compute the model is designed by Visual B compiler language. The induction time in the conditions of different pressures, different solutions and different gases is respectively calculated. The calculation is good agreement with the experimental data and the theory, we obtained that the calculated data are validated. The results show that the model can express completely the process of NGH formation, and provide the theory and model for its industry application.
40
Lv, X. F. F., J. Gong, W. Q. Q. Li, B. H. H. Shi, D. Yu, and H. H. H. Wu. "Experimental Study on Natural-Gas-Hydrate-Slurry Flow." SPE Journal 19, no. 02 (June 27, 2013): 206–14. http://dx.doi.org/10.2118/158597-pa.
Анотація:
Summary To better understand hydrate-slurry flow, a series of experiments was performed, including water, natural gas, and diesel oil, under 4-MPa system pressure and 1.25-m/s initial linear velocity. The experiments have been conducted in a high-pressure hydrate-flow loop newly constructed at China University of Petroleum (Beijing), and dedicated to flow-assurance studies. A focused-beam reflectance measurement (FBRM) probe is installed in this flow loop, which provides a qualitative chord length distribution (CLD) of the particles/droplets in the system. First, the influence of flow rate on the hydrate-slurry flow was discussed. Then, we studied other influencing factors—such as water cut and additive dosage—on the hydrate induction period and the CLD before/after hydrate formation. Third, a new correlation was fitted between the dimensionless rheological index n′ and water cut as well as additive dosage, according to these experimental data. Finally, a laminar-flow model for the prediction of the pressure drop for the quasisingle-phase hydrate slurry was established, and tested by comparison with the experimental results in this paper.
41
Miroshnichenko, Daria, Vladimir Teplyakov, and Maxim Shalygin. "Recovery of Methanol during Natural Gas Dehydration Using Polymeric Membranes: Modeling of the Process." Membranes 12, no. 12 (November 22, 2022): 1176. http://dx.doi.org/10.3390/membranes12121176.
Анотація:
A significant proportion of natural gas (NG) is produced in cold climates, where conditions are relevant to the formation of gas hydrates in raw gas stream. Methanol is often used as an effective inhibitor of hydrate formation. Further conditioning of NG includes dehydration, and the most common process of water vapor removal from NG is absorption. Absorption also provides removal of methanol vapors, which allows it reuse. The membrane method of natural gas dehydration is considered as a promising alternative; however, the study of methanol recovery by the membrane method, simultaneously to the dehydration of NG, has not been carried out previously. In addition, data on methanol vapor transfer in gas separation polymer membranes are almost absent in the literature. This paper evaluates the permeability coefficients of methanol vapors for several polymer materials, which are applied to the production of industrial membranes (PPO, PSf, CA). Mathematical modeling of the membrane process of NG dehydration with simultaneous recovery of methanol was performed. The dependencies of membrane area, methanol recovery and energy consumption for methane recycling and recompression on the process parameters are calculated. Obtained data show that the recovery of methanol during membrane dehydration of NG varies in the range 57–95%. The lowest values of membrane area and specific energy consumption were found for PPO based membrane.
42
Zhang, C. S., S. S. Fan, D. Q. Liang, and K. H. Guo. "Effect of additives on formation of natural gas hydrate." Fuel 83, no. 16 (November 2004): 2115–21. http://dx.doi.org/10.1016/j.fuel.2004.06.002.
43
Lv, Xiaofang, Bohui Shi, Shidong Zhou, Shuli Wang, Weiqiu Huang, and Xianhang Sun. "Study on the Decomposition Mechanism of Natural Gas Hydrate Particles and Its Microscopic Agglomeration Characteristics." Applied Sciences 8, no. 12 (December 3, 2018): 2464. http://dx.doi.org/10.3390/app8122464.
Анотація:
Research on hydrate dissociation mechanisms is critical to solving the issue of hydrate blockage and developing hydrate slurry transportation technology. Thus, in this paper, natural gas hydrate slurry decomposition experiments were investigated on a high-pressure hydrate experimental loop, which was equipped with two on-line particle analyzers: focused beam reflectance measurement (FBRM) and particle video microscope (PVM). First, it was observed from the PVM that different hydrate particles did not dissociate at the same time in the system, which indicated that the probability of hydrate particle dissociation depended on the particle’s shape and size. Meanwhile, data from FBRM presented a periodic oscillating trend of the particle/droplet numbers and chord length during the hydrate slurry dissociation, which further demonstrated these micro hydrate particles/droplets were in a dynamic coupling process of breakage and agglomeration under the action of flow shear during the hydrate slurry dissociation. Then, the influences of flow rate, pressure, water-cut, and additive dosage on the particles chord length distribution during the hydrate decomposition were summarized. Moreover, two kinds of particle chord length treatment methods (the average un-weighted and squared-weighted) were utilized to analyze these data onto hydrate particles’ chord length distribution. Finally, based on the above experimental data analysis, some important conclusions were obtained. The agglomeration of particles/droplets was easier under low flow rate during hydrate slurry dissociation, while high flow rate could restrain agglomeration effectively. The particle/droplet agglomerating trend and plug probability went up with the water-cut in the process of hydrate slurry decomposition. In addition, anti-agglomerates (AA) greatly prohibited those micro-particles/droplets from agglomeration during decomposition, resulting in relatively stable mean and square weighting chord length curves.
44
Wei, Minghui, Chenghuai Wu, and Yanxi Zhou. "Study on Wellbore Temperature and Pressure Distribution in Process of Gas Hydrate Mined by Polymer Additive CO2 Jet." Advances in Polymer Technology 2020 (January 10, 2020): 1–7. http://dx.doi.org/10.1155/2020/2914375.
Анотація:
In order to solve the problem of hydrate reservoir collapse and hydrate regenerated in the process of solid fluidization of natural gas hydrate, a new method of natural gas hydrate exploit by high‐polymer additive (low viscosity carboxymethyl cellulose LV‐CMC) carbon dioxide jet was proposed. The wellbore temperature and pressure changes during this process are analyzed, and the wellbore temperature and pressure model are established and solved by the state space method. This paper also analyzed the effects of relevant parameters on hydrate decomposition, such as injection flow, temperature, and pressure. The results show that increasing the injection pressure allows the hydrate decomposition site to be closer to the annulus outlet. Compared with water, with polymer additive CO2 fluid as the drilling fluid, the intersection point of phase equilibrium curve and annular pressure curve is closer to annular outlet, which is obviously more conducive to well control. In order to avoid phase changes, the injection pressure of the carbon dioxide fluid of the high‐polymer additive should not be lower than 10 MPa, and the injection temperature should not be higher than 285 K.
45
Mesbah, Mohammad, Ebrahim Soroush, and Mashallah Rezakazemi. "Modeling Dissociation Pressure of Semi-Clathrate Hydrate Systems Containing CO2, CH4, N2, and H2S in the Presence of Tetra-n-butyl Ammonium Bromide." Journal of Non-Equilibrium Thermodynamics 44, no. 1 (January 28, 2019): 15–28. http://dx.doi.org/10.1515/jnet-2018-0015.
Анотація:
Abstract In this study, the phase equilibria of semi-clathrate hydrates of methane (CH4), carbon dioxide (CO2), nitrogen (N2), and hydrogen sulfide (H2S) in an aqueous solution of tetra-n-butyl ammonium bromide (TBAB) were modeled using a correlation based on a two-stage formation mechanism: a quasi-chemical reaction that forms basic semi-clathrate hydrates and adsorption of guest molecules in the linked cavities of the basic semi-clathrate hydrate. The adsorption of guest molecules was described by the Langmuir adsorption theory and the fugacity of the gas phase was calculated by Peng–Robinson (PR) equation of state (EOS). The water activity in the presence of TBAB was calculated using a correlation, dependent on temperature, the TBAB mass fraction, and the nature of the guest molecule. These equations were coupled together and form a correlation which was linked to a genetic algorithm for optimization of tuning parameters. The results showed an excellent agreement between model results and experimental data. In addition, an outlier diagnostic was performed for finding any possible doubtful data and assessing the applicability of the model. The results showed that more than 97 % of the data were reliable and they were in the applicability domain of the model.
46
Kvamme, Bjørn. "Enthalpies of Hydrate Formation from Hydrate Formers Dissolved in Water." Energies 12, no. 6 (March 18, 2019): 1039. http://dx.doi.org/10.3390/en12061039.
Анотація:
The international interest in the energy potential related to the huge amounts of methane trapped in the form of hydrates is rapidly increasing. Unlike conventional hydrocarbon sources these natural gas hydrate deposits are widely spread around the world. This includes countries which have limited or no conventional hydrocarbon sources, like for instance Japan. A variety of possible production methods have been proposed during the latest four decades. The pressure reduction method has been dominant in terms of research efforts and associated investments in large scale pilot test studies. Common to any feasible method for producing methane from hydrates is the need for transfer of heat. In the pressure reduction method necessary heat is normally expected to be supplied from the surrounding formation. It still remain, however, unverified whether the capacity, and heat transport capabilities of surrounding formation, will be sufficient to supply enough heat for a commercial production based on reduction in pressure. Adding heat is very costly. Addition of limited heat in critical areas (regions of potential freezing down) might be economically feasible. This requires knowledge about enthalpies of hydrate dissociation under various conditions of temperature and pressure. When hydrate is present in the pores then it is the most stable phase for water. Hydrate can then grow in the concentration range in between liquid controlled solubility concentrations, and the minimum concentration of hydrate in water needed to keep the hydrate stable. Every concentration in that range off concentrations results unique free energy and enthalpy of the formed hydrate. Similarly for hydrate dissociation towards water containing less hydrate former than the stability limit. Every outside liquid water concentration results in unique enthalpy changes for hydrate dissociation. There are presently no other available calculation approaches for enthalpy changes related to these hydrate phase transitions. The interest of using CO2 for safe storage in the form of hydrate, and associated CH4 release, is also increasing. The only feasible mechanism in this method involves the formation of new CO2 hydrate, and associated release of heat which assist in dissociating the in situ CH4 hydrate. Very limited experimental data is available for heats of formation (and dissociation), even for CH4. And most experimental data are incomplete in the sense that associated water/hydrate former rate are often missing or guessed. Thermodynamic conditions are frequently not precisely defined. Although measured hydrate equilibrium pressure versus temperature curves can be used there is still a need for additional models for volume changes, and ways to find other information needed. In this work we propose a simple and fairly direct scheme of calculating enthalpies of formation and dissociation using residual thermodynamics. This is feasible since also hydrate can be described by residual thermodynamics though molecular dynamics simulations. The concept is derived and explained in detail and also compared to experimental data. For enthalpy changes related to hydrate formation from water and dissolved hydrate formers we have not found experimental data to compare with. To our knowledge there are no other alternative methods available for calculating enthalpy changes for these types of hydrate phase transitions. And there are no limits in the theory for which hydrate phase transitions that can be described as long as chemical potentials for water and hydrate formers in the relevant phases are available from theoretical modeling and/or experimental information.
47
Kang, Seong-Pil, Dongwon Lee, and Jong-Won Lee. "Anti-Agglomeration Effects of Biodegradable Surfactants from Natural Sources on Natural Gas Hydrate Formation." Energies 13, no. 5 (March 2, 2020): 1107. http://dx.doi.org/10.3390/en13051107.
Анотація:
Kinetic hydrate inhibitors (KHI) and anti-agglomerants (AA) rather than thermodynamic hydrate inhibitors (THI) are often used for flow assurance in pipelines. This is because they require much lower dosages than thermodynamic inhibitors. Although the hydrate-phase equilibria are not affected, KHI and AA prevent the formed hydrate crystals from growing to a bulky state causing pipeline blockage. However, these KHIs might have huge environmental impact due to leakages from the pipelines. In this study, two biodegradable AA candidates from natural sources (that is, lecithin and lanolin) are proposed and their performances are evaluated by comparing them with and without a conventional AA (Span 80, sorbitan monooleate). At 30% and 50% water cut, the addition of AA materials was found to enhance the flow characteristics substantially in pipelines and hardly affected the maximum value of the rotational torque, respectively. Considering the cost-effective and environmental advantages of the suggested AA candidates over a conventional AA such as Span 80, the materials are thought to have potential viability for practical operation of oil and gas pipelines. However, additional investigations will be done to clarify the optimum amounts and the action mechanisms of the suggested AAs.
48
Iskenderov, Elman Kh, Alovsat N. Baghirov, and Lala M. Shikhiyeva. "Method for assessing the hydrate formation from a mixture of natural gas flows of varying degrees of moisture content." Nafta-Gaz 80, no. 1 (January 2024): 39–44. http://dx.doi.org/10.18668/ng.2024.01.05.
Анотація:
The article deals with the issues of assessing the conditions of hydrate formation when mixing natural gas flows of various standards. An urgent problem of operation, especially of offshore subsea gas pipelines, is the prediction of the time, place and expected intensity of hydrate formation. Depending on the changing operating mode of the gas pipeline, dispatch service specialists must be able to adjust the process control tactics on their own, as quickly as possible. The predisposition of a particular gas pipeline to hydrate is also important for the dispatching service. Changes in the volumes of gas entering the region under consideration from different sources, due to the constant change in gas production, create the need to mix gases of different standards and pump them into subsea gas pipeline. To avoid hydrate formation, it is important to predict the thermobaric conditions that will be formed in the gas pipeline by considering the characteristics such as a volume in the mixture and the moisture content of the gas. The processes of hydrate formation proceed quickly and if the beginning of the process is overlooked, the problem of significant or complete blockage of the gas pipeline might appear. The paper gives a systematization of the risk of hydrate formation depending on several infrastructural factors – the presence of a preliminary gas drying system and a system for starting and receiving cleaning pistons. A method is proposed for estimating the moisture content and dew point temperature of a natural gas mixture by the condition and the proportion of primary flows. It has been shown that the addition of a small volume of undried gas to the main dried gas significantly increases the risk of hydrate formation. A formula is given for calculations for a mixture of multiple natural gas flows. The advantage of this method is the quick calculations, and the absence of the need for huge mathematical calculations and laboratory studies. This is an important element in the activities of the dispatch service, limited by a lack of time in the process of preventing hydrate formation.
49
Menia, Sabah, Ilyés Nouicer, Yasmina Bakouri, Abdelhamid M’raoui, Hammou Tebibel, and Abdallah Khellaf. "Production d’hydrogène par procédés biologiques." Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles 74 (2019): 34. http://dx.doi.org/10.2516/ogst/2018099.
Анотація:
L’hydrogène, s’il est produit à partir de matières premières renouvelables, est une source alternative viable pour remplacer les combustibles fossiles conventionnels en raison de son potentiel énergétique élevé (122 kJ/g). Quand l’hydrogène est utilisé comme carburant, son principal produit de combustion est l’eau, qui peut être recyclée pour produire plus d’hydrogène, mais contrairement aux combustibles fossiles, l’hydrogène n’est pas facilement disponible dans la nature et les méthodes de production couramment utilisées sont assez coûteuses. Actuellement, environ 98 % de l’hydrogène provient des combustibles fossiles. Globalement, 40 % de l’hydrogène est produit à partir de gaz naturel ou de reformage à la vapeur d’hydrocarbures, 30 % à partir de pétrole, 18 % à partir de charbon et 4 % partir d’électrolyse de l’eau. Cependant, ces processus sont coûteux et pas toujours respectueux de l’environnement. Les procédés biologiques pour la production d’hydrogène peuvent fonctionner dans des conditions opératoires moins énergivores et plus respectueuses de l’environnement par rapport aux méthodes chimiques conventionnelles. Cette approche est non seulement écologique, mais ouvre aussi de nouvelles voies pour l’exploitation de ressources énergétiques renouvelables illimitées. En outre, ils peuvent également utiliser différents déchets, ce qui facilite le recyclage des déchets. La production d’hydrogène biologique utilisant la biomasse riche en hydrates de carbone comme ressource renouvelable est l’une des différentes méthodes dans lesquelles les processus peuvent se produire via un processus anaérobie et un processus de photosynthèse. Dans cet article, les différents procédés biologiques de production de l’hydrogène sont décrits et comparés.
50
Shi, Bo-Hui, Shuai Chai, Lin-Yan Wang, Xiaofang Lv, Hui-Shu Liu, Hai-Hao Wu, Wei Wang, Da Yu, and Jing Gong. "Viscosity investigation of natural gas hydrate slurries with anti-agglomerants additives." Fuel 185 (December 2016): 323–38. http://dx.doi.org/10.1016/j.fuel.2016.07.113.