Gas Hydrate Decomposition Rate in Flowing Water

2006 ◽  
Vol 129 (2) ◽  
pp. 102-106 ◽  
Author(s):  
Ryokichi Hamaguchi ◽  
Yuki Nishimura ◽  
Gen Inoue ◽  
Yosuke Matsukuma ◽  
Masaki Minemoto
Keyword(s):  
Heat Transfer ◽  
Gas Hydrate ◽  
Decomposition Rate ◽  
Methane Hydrate ◽  
Lattice Gas ◽  
Production Systems ◽  
Simulation Method ◽  
Flowing Water ◽  
Public Attention ◽  
Hydrate Decomposition

The development of methane hydrate (MH), which exists under the ocean floor, has recently been brought to public attention. However, the production technology has not yet been established. It is important to understand the decomposition phenomenon of MH for an investigation of the safety and the profitability of production systems. In this research, the gas hydrate decomposition rate in flowing water was measured using HCFC141b hydrate as a substitute for MH. When the water temperature was higher than the boiling point of the decomposition gas, it was observed that the decomposition gas increased the decomposition rate. Moreover, the decomposition phenomenon was simulated by the lattice gas automaton method in order to establish the technique which analytically estimates the decomposition rate. The validity of the simulation method was shown by comparing the experiments. Furthermore, the formula between Reynolds number and Nusselt number was obtained, which express the heat transfer around the gas hydrate lump.

scholarly journals Numerical Investigation into the Development Performance of Gas Hydrate by Depressurization Based on Heat Transfer and Entropy Generation Analyses

Entropy ◽  
2020 ◽  
Vol 22 (11) ◽  
pp. 1212 ◽  
Author(s):  
Bo Li ◽  
Wen-Na Wei ◽  
Qing-Cui Wan ◽  
Kang Peng ◽  
Ling-Ling Chen
Keyword(s):  
Heat Transfer ◽  
Energy Loss ◽  
Entropy Production ◽  
Entropy Generation ◽  
Gas Hydrate ◽  
Methane Hydrate ◽  
Dynamic Properties ◽  
Entropy Production Rate ◽  
Entropy Flow ◽  
Hydrate Reservoir

The purpose of this study is to analyze the dynamic properties of gas hydrate development from a large hydrate simulator through numerical simulation. A mathematical model of heat transfer and entropy production of methane hydrate dissociation by depressurization has been established, and the change behaviors of various heat flows and entropy generations have been evaluated. Simulation results show that most of the heat supplied from outside is assimilated by methane hydrate. The energy loss caused by the fluid production is insignificant in comparison to the heat assimilation of the hydrate reservoir. The entropy generation of gas hydrate can be considered as the entropy flow from the ambient environment to the hydrate particles, and it is favorable from the perspective of efficient hydrate exploitation. On the contrary, the undesirable entropy generations of water, gas and quartz sand are induced by the irreversible heat conduction and thermal convection under notable temperature gradient in the deposit. Although lower production pressure will lead to larger entropy production of the whole system, the irreversible energy loss is always extremely limited when compared with the amount of thermal energy utilized by methane hydrate. The production pressure should be set as low as possible for the purpose of enhancing exploitation efficiency, as the entropy production rate is not sensitive to the energy recovery rate under depressurization.

scholarly journals Optimization of Methane Hydrate Recovery System from Ocean Floor (Basic Study on Hydrate Decomposition Rate)

2006 ◽  
Vol 72 (716) ◽  
pp. 901-907
Author(s):  
Ryokichi HAMAGUCHI ◽  
Hiroki YAHASHI ◽  
Yosuke MATSUKUMA ◽  
Gen INOUE ◽  
Masaki MINEMOTO ◽  
...  
Keyword(s):  
Decomposition Rate ◽  
Methane Hydrate ◽  
Ocean Floor ◽  
Basic Study ◽  
Hydrate Decomposition ◽  
Recovery System

Experimental Study on the Effect of Gas Hydrate Content on Heat Transfer

2015 ◽  
Author(s):  
Remi-Erempagamo T. Meindinyo ◽  
Runar Bøe ◽  
Thor Martin Svartås ◽  
Silje Bru
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Ethylene Oxide ◽  
Deep Water ◽  
Gas Hydrate ◽  
Atmospheric Pressure ◽  
Methane Hydrate ◽  
Hydrate Formation ◽  
Equilibrium Temperature ◽  
Gas Hydrate Formation

Gas hydrates are the foremost flow assurance issue in deep water operations. Since heat transfer is a limiting factor in gas hydrate formation processes, a better understanding of its relation to hydrate formation is important. This work presents findings from experimental study of the effect of gas hydrate content on heat transfer through a cylindrical wall. The experiments were carried out at temperature conditions similar to those encountered in flowlines in deep water conditions. Experiments were conducted on methane hydrate, Tetrahydrofuran hydrate, and ethylene oxide hydrate respectively in stirred cylindrical high pressure autoclave cells. Methane hydrate was formed at 90 bars (pressure), and 8°C, followed by a cooling/heating cycle in the range of 8°C → 4°C → 8°C. Tetrahydrofuran (THF) and ethylene oxide (EO) hydrates were formed at atmospheric pressure and system temperature of 1°C in contact with atmospheric air. This was followed by a heating/cooling cycle within the range of 1°C → 4°C → 1°C, since the hydrate equilibrium temperature of THF hydrate is 4.98°C in contact with air at atmospheric pressure. The experimental conditions of the latter hydrate formers were more controlled, given that both THF and EO are miscible with water. We found in all cases a general trend of decreasing heat transfer coefficient of the cell content with increasing concentration of hydrate in the cell, indicating that hydrate formation creates a heat transfer barrier. The hydrate equilibrium temperature seemed to change with a change in the stoichiometric concentration of THF and EO. While the methane hydrate cooling/heating cycles were performed under quiescent conditions, the effect of stirring was investigated for the latter hydrate formers.

Visualization of methane hydrate decomposition interface and analyses of decomposition rate and interfacial configuration

2020 ◽  
Vol 32 (4) ◽  
pp. 047105
Author(s):  
Yuki Kanda ◽  
Junnosuke Okajima ◽  
Shigenao Maruyama ◽  
Atsuki Komiya
Keyword(s):  
Decomposition Rate ◽  
Methane Hydrate ◽  
Hydrate Decomposition

scholarly journals Axisymmetric hydrate monolith destruction problem

2021 ◽  
Vol 2094 (2) ◽  
pp. 022014
Author(s):  
M V Stolpovsky ◽  
A S Chiglintseva ◽  
M R Davletshina
Keyword(s):  
Mathematical Model ◽  
Gas Hydrate ◽  
Cylindrical Cavity ◽  
Methane Hydrate ◽  
Initial Temperature ◽  
Conservation Of Mass ◽  
Hydrate Decomposition ◽  
Temperature Distributions

Abstract A mathematical model is proposed for the destruction of a methane hydrate monolith containing gas inclusions. In this formulation of the problem, it is assumed that there is a cylindrical cavity inside the hydrate monolith, initially filled only with methane. Since the conditions on the surface of the particle correspond to the conditions for the free existence of gas and water, the gas hydrate begins to decompose. On the basis of the obtained system, consisting of the equations of conservation of mass and heat, the temperature distributions in the “cavity - gas hydrate” system were obtained, and the influence of the initial temperature of the system and the temperature in the cavity on the dynamics of hydrate decomposition was analyzed.

SS - Gas Hydrate: Gas production from methane hydrate sediment layer by thermal stimulation with hot water injection

2010 ◽  
Author(s):  
Kyuro Sasaki ◽  
Shinzi Ono ◽  
Yuichi Sugai ◽  
Norio Tenma ◽  
Takao Ebinuma ◽  
...  
Keyword(s):  
Gas Hydrate ◽  
Methane Hydrate ◽  
Water Injection ◽  
Gas Production ◽  
Hot Water ◽  
Thermal Stimulation ◽  
Sediment Layer
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