Technological Solutions for the Realization of NGH-Technology for Gas Transportation and Storage in Gas Hydrate Form

2018 ◽  
Vol 277 ◽  
pp. 123-136 ◽  
Author(s):  
Mykhailo Pedchenko ◽  
Larysa Pedchenko ◽  
Tetiana Nesterenko ◽  
Artur Dyczko
Keyword(s):  
Gas Hydrates ◽  
Gas Hydrate ◽  
Atmospheric Pressure ◽  
High Stability ◽  
Hydrated Form ◽  
Hydrate Form ◽  
Capital Costs ◽  
Large Size ◽  
Long Time ◽  
And Storage

The technology of transportation and storage of gas in a gas-hydrated form under atmospheric pressure and slight cooling – the maximum cooled gas-hydrated blocks of a large size covered with a layer of ice are offered. Large blocks form from pre-cooled mixture of crushed and the granulated mass of gas hydrate. The technology of forced preservation gas hydrates with ice layer under atmospheric pressure has developed to increase it stability. The dependence in dimensionless magnitudes, which describes the correlation-regressive relationship between the temperature of the surface and the center gas hydrate block under its forced preservation, had proposed to facilitate the use of research results. Technology preservation of gas hydrate blocks with the ice layer under atmospheric pressure (at the expense of the gas hydrates energy) has designed to improve their stability. Gas hydrated blocks, thus formed, can are stored and transported during a long time in converted vehicles without further cooling. The high stability of gas hydrate blocks allows to distributed in time (and geographically) the most energy expenditure operations – production and dissociation of gas hydrate. The proposed technical and technological solutions significantly reduce the level of energy and capital costs and, as a result, increase the competitiveness of the stages NGH technology (production, transportation, storage, regasification).

scholarly journals Rapid Gas Hydrate Formation—Evaluation of Three Reactor Concepts and Feasibility Study

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3615
Author(s):  
Florian Filarsky ◽  
Julian Wieser ◽  
Heyko Juergen Schultz
Keyword(s):  
Gas Hydrates ◽  
Gas Hydrate ◽  
Hydrate Formation ◽  
Synthetic Natural Gas ◽  
Operation Conditions ◽  
Gas Hydrate Formation ◽  
Gas Conditioning ◽  
And Storage ◽  
Economic Considerations ◽  
High Storage

Gas hydrates show great potential with regard to various technical applications, such as gas conditioning, separation and storage. Hence, there has been an increased interest in applied gas hydrate research worldwide in recent years. This paper describes the development of an energetically promising, highly attractive rapid gas hydrate production process that enables the instantaneous conditioning and storage of gases in the form of solid hydrates, as an alternative to costly established processes, such as, for example, cryogenic demethanization. In the first step of the investigations, three different reactor concepts for rapid hydrate formation were evaluated. It could be shown that coupled spraying with stirring provided the fastest hydrate formation and highest gas uptakes in the hydrate phase. In the second step, extensive experimental series were executed, using various different gas compositions on the example of synthetic natural gas mixtures containing methane, ethane and propane. Methane is eliminated from the gas phase and stored in gas hydrates. The experiments were conducted under moderate conditions (8 bar(g), 9–14 °C), using tetrahydrofuran as a thermodynamic promoter in a stoichiometric concentration of 5.56 mole%. High storage capacities, formation rates and separation efficiencies were achieved at moderate operation conditions supported by rough economic considerations, successfully showing the feasibility of this innovative concept. An adapted McCabe-Thiele diagram was created to approximately determine the necessary theoretical separation stage numbers for high purity gas separation requirements.

Self-preservation Effect of Gas Hydrates

2021 ◽  
Vol 23 ◽  
pp. 346-355
Author(s):  
Anatoliy Pavlenko
Keyword(s):  
Gas Hydrates ◽  
Gas Hydrate ◽  
Experimental Studies ◽  
Interphase Surface ◽  
Quantitative Characteristics ◽  
Nonequilibrium Conditions ◽  
Water Simulation ◽  
Gas Loss ◽  
Physical And Mathematical Models ◽  
And Storage

This work was performed to improve the storage and transportation technology of gas hydrates in nonequilibrium conditions. At atmospheric pressure and positive ambient temperature, they gradually dissociate into gas and water. Simulation of the gas hydrate dissociation will determine optimal conditions for their transportation and storage, as well as minimize gas loss. Thermodynamic parameters of adiabatic processes of forced preservation of pre-cooled gas hydrate blocks with ice layer were determined theoretically and experimentally. Physical and mathematical models of these processes were proposed. The scientific novelty is in establishing quantitative characteristics that describe the gas hydrates thermophysical parameters thermophysical characteristics influence on the heat transfer processes intensity on the interphase surface under conditions of gas hydrates dissociation. Based on the results of experimental studies, approximation dependences for determining the temperature in the depths of a dissociating gas hydrate array have been obtained. Gas hydrates dissociation mathematical model is presented.

scholarly journals Promoting Effect of Ultra-Fine Bubbles on CO2 Hydrate Formation

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3386
Author(s):  
Tsutomu Uchida ◽  
Hiroshi Miyoshi ◽  
Kenji Yamazaki ◽  
Kazutoshi Gohara
Keyword(s):  
Gas Hydrates ◽  
Gas Hydrate ◽  
Hydrate Formation ◽  
Number Density ◽  
Promoting Effect ◽  
Gas Hydrate Formation ◽  
Long Time ◽  
Carbon Dioxide Co2 ◽  
Average Size ◽  
Small Bubbles

When gas hydrates dissociate into gas and liquid water, many gas bubbles form in the water. The large bubbles disappear after several minutes due to their buoyancy, while a large number of small bubbles (particularly sub-micron-order bubbles known as ultra-fine bubbles (UFBs)) remain in the water for a long time. In our previous studies, we demonstrated that the existence of UFBs is a major factor promoting gas hydrate formation. We then extended our research on this issue to carbon dioxide (CO2) as it forms structure-I hydrates, similar to methane and ethane hydrates explored in previous studies; however, CO2 saturated solutions present severe conditions for the survival of UFBs. The distribution measurements of CO2 UFBs revealed that their average size was larger and number density was smaller than those of other hydrocarbon UFBs. Despite these conditions, the CO2 hydrate formation tests confirmed that CO2 UFBs played important roles in the expression of the promoting effect. The analysis showed that different UFB preparation processes resulted in different promoting effects. These findings can aid in better understanding the mechanism of the promoting (or memory) effect of gas hydrate formation.

Thermodynamic Modelling of Gas Hydrate Formation in the Presence of Inhibitors and the Consideration of their Effect

2014 ◽  
Vol 14 (1) ◽  
pp. 45
Author(s):  
Peyman Sabzi ◽  
Saheb Noroozi
Keyword(s):  
Gas Hydrates ◽  
Gas Hydrate ◽  
Low Temperatures ◽  
Hydrate Formation ◽  
Transportation Systems ◽  
Flow Lines ◽  
Main Approach ◽  
Efficient Inhibitor ◽  
System A ◽  
Gas Hydrate Formation

Gas hydrates formation is considered as one the greatest obstacles in gas transportation systems. Problems related to gas hydrate formation is more severe when dealing with transportation at low temperatures of deep water. In order to avoid formation of Gas hydrates, different inhibitors are used. Methanol is one of the most common and economically efficient inhibitor. Adding methanol to the flow lines, changes the thermodynamic equilibrium situation of the system. In order to predict these changes in thermodynamic behavior of the system, a series of modelings are performed using Matlab software in this paper. The main approach in this modeling is on the basis of Van der Waals and Plateau's thermodynamic approach. The obtained results of a system containing water, Methane and Methanol showed that hydrate formation pressure increases due to the increase of inhibitor amount in constant temperature and this increase is more in higher temperatures. Furthermore, these results were in harmony with the available empirical data.Keywords: Gas hydrates, thermodynamic inhibitor, modelling, pipeline blockage

Mathematical Model of Energy Storage in Gas Hydrate and its Flow in Pipeline Systems

2016 ◽  
Author(s):  
Oluwatoyin Akinsete ◽  
Sunday Isehunwa
Keyword(s):  
Mathematical Model ◽  
Natural Gas ◽  
Gas Hydrate ◽  
Storage Capacity ◽  
Hydrate Formation ◽  
Momentum Conservation ◽  
Gas Pipeline ◽  
Energy Needs ◽  
Pipeline Systems ◽  
And Storage

ABSTRACT Natural gas, one of the major sources of energy for the 21st century, provides more than one-fifth of the worldwide energy needs. Storing this energy in gas hydrate form presents an alternative to its storage and smart solution to its flow with the rest of the fluid without creating a difficulty in gas pipeline systems due to pressure build-up. This study was design to achieve this situation in a controlled manner using a simple mathematical model, by applying mass and momentum conservation principles in canonical form to non-isothermal multiphase flow, for predicting the onset conditions of hydrate formation and storage capacity growth of the gas hydrate in pipeline systems. Results from this developed model shows that the increase in hydrate growth, the more the hydrate storage capacity of gas within and along the gas pipeline. The developed model is therefore recommended for management of hydrate formation for natural gas storage and transportation in gas pipeline systems.

and stored, such that they can be defrosted and grown on again later. This is cloning and storage of human cells in exactly the same way that cloning and storage of human embryos is. In many ways they are separated by a distinction without a difference and I would not like to be the person that had to tell a seriously, or even terminally, ill individual that it is not possible to treat them because the only way is to produce immunologically sound material which they will not reject by cloning – and that this is not allowed. It was decided on 15 November 2001 that cloning of embryos for therapeutic research should no longer be licensed, but cloning one for birth apparently is and there are medical practitioners who seem to think that this is a good and practical idea. It is suspected that the incredibly high failure rate of cloned foetuses will mitigate against pursuing human clones. To put numbers on this, of 277 attempts only one sheep, Dolly, was born and further successful examples of animal cloning have been just as hard won. However, failure in this context is not a simple, clear, non-viable embryo; it includes gross malformations and developmental problems. These would not be an acceptable outcome in human cloning. This problem of not thinking about questions on a ‘what if?’ basis before the practical necessity arises is exactly the same situation that seems to have occurred with DNA profiling and genetic testing for disease genes. We have simply not been ready as a society to address questions that are going to have profound effects for future generations. This, sadly, is a general failing. Statements such as ‘think of the children’, have very little power to motivate; what does motivate seems to be political will and commerce. It is true, as discussed earlier, that large numbers are not easily conceived of. What is also true is that long periods of time are not easily comprehended either. So, to take an example from a different science, but one which is very real now and can therefore give us pointers to the future of our ethical problems in genetics, let us consider the question of nuclear waste. We can visualise this not just as a physical problem but an ethical one which is dependent upon society and the good will of society as well. The long term control of nuclear waste is a problem. No matter how it is stored or dealt with it needs to be looked after for a very long time. Given the half-life of some of this material – that is the length of time it takes to reduce its radioactivity by half – the storage times are prodigiously long. It is not unrealistic to say that storage should be in excess of 10,000 years, but no civilisation has been around that long and it would require a great leap of faith to suggest that the current nuclear powers would remain intact, politically stable and financially able to look after such a potential problem for so long. It is to be hoped that humanity is going to out-last nuclear waste, but the questions regarding political stability remain. We simply do not know what sort of a government we will have 1,000 years hence; we do not know what sort of data they will hold about our genes, so now is the time to question their perceived right to hold such information. Now is the time to challenge the perceived right of testers to take samples to find out whatever they like about an individual and possibly pass it on.

2013 ◽  
pp. 112-112
Keyword(s):  
Nuclear Waste ◽  
Political Stability ◽  
Human Embryos ◽  
Disease Genes ◽  
Medical Practitioners ◽  
Animal Cloning ◽  
Large Numbers ◽  
Long Time ◽  
Therapeutic Research ◽  
And Storage

scholarly journals Role of Salt Migration in Destabilization of Intra Permafrost Hydrates in the Arctic Shelf: Experimental Modeling

Geosciences ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 188 ◽  
Author(s):  
Evgeny Chuvilin ◽  
Valentina Ekimova ◽  
Boris Bukhanov ◽  
Sergey Grebenkin ◽  
Natalia Shakhova ◽  
...  
Keyword(s):  
Gas Hydrates ◽  
Methane Emission ◽  
Gas Hydrate ◽  
Negative Temperature ◽  
Arctic Shelf ◽  
The Arctic ◽  
Permafrost Degradation ◽  
Stability Zone ◽  
Local Pressure ◽  
Hydrate Stability

Destabilization of intrapermafrost gas hydrate is one possible reason for methane emission on the Arctic shelf. The formation of these intrapermafrost gas hydrates could occur almost simultaneously with the permafrost sediments due to the occurrence of a hydrate stability zone after sea regression and the subsequent deep cooling and freezing of sediments. The top of the gas hydrate stability zone could exist not only at depths of 200–250 m, but also higher due to local pressure increase in gas-saturated horizons during freezing. Formed at a shallow depth, intrapermafrost gas hydrates could later be preserved and transform into a metastable (relict) state. Under the conditions of submarine permafrost degradation, exactly relict hydrates located above the modern gas hydrate stability zone will, first of all, be involved in the decomposition process caused by negative temperature rising, permafrost thawing, and sediment salinity increasing. That’s why special experiments were conducted on the interaction of frozen sandy sediments containing relict methane hydrates with salt solutions of different concentrations at negative temperatures to assess the conditions of intrapermafrost gas hydrates dissociation. Experiments showed that the migration of salts into frozen hydrate-containing sediments activates the decomposition of pore gas hydrates and increase the methane emission. These results allowed for an understanding of the mechanism of massive methane release from bottom sediments of the East Siberian Arctic shelf.

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