The Effect of Hydrate Formation on Heat Transfer

1994 ◽  
Author(s):  
F. Dorstewitz ◽  
Dieter Mewes
Keyword(s):  
Heat Transfer ◽  
Hydrate Formation

A Model of Multiphase Flow Dynamics Considering the Hydrated Bubble Behaviors and Its Application to Deepwater Kick Simulation

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Xiaohui Sun ◽  
Baojiang Sun ◽  
Yonghai Gao ◽  
Zhiyuan Wang
Keyword(s):  
Heat Transfer ◽  
Multiphase Flow ◽  
Void Fraction ◽  
Mass Transfer Rate ◽  
Hydrate Formation ◽  
Flow Dynamics ◽  
Fluid Temperature ◽  
Hydrate Shell ◽  
Free Gas ◽  
Mass And Heat Transfer

The interaction between hydrated bubble growth and multiphase flow dynamics is important in deepwater wellbore/pipeline flow. In this study, we derived a hydrate shell growth model considering the intrinsic kinetics, mass and heat transfer, and hydrodynamics mechanisms in which a partly coverage assumption is introduced for elucidating the synergy of bubble hydrodynamics and hydrate morphology. Moreover, a hydro-thermo-hydrate model is developed considering the intercoupling effects including interphase mass and heat transfer, and the slippage of hydrate-coated bubble. Through comparison with experimental data, the performance of proposed model is validated and evaluated. The model is applied to analyze the wellbore dynamics process of kick evolution during deepwater drilling. The simulation results show that the hydrate formation region is mainly near the seafloor affected by the fluid temperature and pressure distributions along the wellbore. The volume change and the mass transfer rate of a hydrated bubble vary complicatedly, because of hydrate formation, hydrate decomposition, and bubble dissolution (both gas and hydrate). Moreover, hydrate phase transition can significantly alter the void fraction and migration velocity of free gas in two aspects: (1) when gas enters the hydrate stability field (HSF), a solid hydrate shell will form on the gas bubble surface, and thereby, the velocity and void fraction of free gas can be considerably decreased; (2) the free gas will separate from solid hydrate and expand rapidly near the sea surface (outside the HSF), which can lead to an abrupt hydrostatic pressure loss and explosive development of the gas kick.

Simulation of Gas-Hydrate Slurry Stratified Flow With Inward and Outward Hydrate Growth Model

2016 ◽  
Author(s):  
Bohui Shi ◽  
Yang Liu ◽  
Lin Ding ◽  
Xiaofang Lv ◽  
Jing Gong
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Liquid Phase ◽  
Shell Model ◽  
Gas Hydrate ◽  
Hydrodynamic Model ◽  
Formation Rate ◽  
Hydrate Formation ◽  
Phase Flow ◽  
Two Phase

The topic of hydrate formation and blocking in offshore petroleum industry has attracted more and more attentions, which is known as one of the flow assurance issues. A new technology has been proposed to avoid the occurrence of hydrate blockage in multiphase transportation system, which is hydrate slurry flow technology, also named as cold flow technology. The low dosage hydrate inhibitor of anti-agglomerate was added into the flow systems to allow hydrate formation in the liquid phase while it prevented the aggregation of hydrate particles. Thus these particles were evacuated with the liquid phase as pseudo-fluid like slurry. In this work, an inward and outward hydrate growth shell model coupled with two phase flow hydrodynamic model was applied to investigate the characteristics of gas-hydrate slurry stratified flow. The inward and outward hydrate growth shell model considered the kinetics, mass transfer and heat transfer process of hydrate formation, which could predict the hydrate formation rate and the released heat. The two phase flow hydrodynamic model included mass, momentum and energy equations. A case for an inclined pipeline was simulated using the combined models. The results showed that once the kinetic requirements for hydrate crystallization was satisfied, hydrates would form quickly at the initial stage and then hydrate formation rate would decrease obviously due to the limitation of mass transfer and heat transfer. Meanwhile, the flow characteristics, such as the liquid holdup and pressure drop, were predicted by the model, which also provided an acceptable results about the state of hydrates (onset time of formation, formation rate, volume fraction, etc.) in multiphase system for the operation engineers in the field. The key parameters of the inward and outward hydrate growth shell model were determined by referring to the literatures. To investigate the reliability and influence of these set values on the results, a sensitivity analysis of the key parameters of the shell model was implemented. Further works should be done, such as the flow mechanism in other flow regimes as well as the influence of particle aggregation.

Mathematical model of natural gas flow in pipelines in the presence of hydrate formation

2008 ◽  
Vol 6 ◽  
pp. 205-209
Author(s):  
V.Sh. Shagapov ◽  
R.R. Urazov
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Mass Transfer ◽  
Natural Gas ◽  
Phase Transformations ◽  
Gas Hydrates ◽  
Heat Conductivity ◽  
Gas Flow ◽  
Hydrate Formation ◽  
Natural Gas Flow

The flow of wet natural gas in the pipeline is considered in the presence of the formation of gas hydrates on the internal walls of the channel. In the description of the phenomenon, such interrelated processes as phase transformations and mass transfer of water into the composition of gas hydrates, heat transfer between the gas stream and the environment, heat conductivity in the ground are taken into account.

Influence of Gas Supply Mode on CO2 Hydrate Formation in Water Spraying Reactor

2011 ◽  
Vol 236-238 ◽  
pp. 556-561 ◽  
Author(s):  
Ying Ming Xie ◽  
Dao Ping Liu ◽  
Ni Liu ◽  
Ying Xia Qi
Keyword(s):  
Heat Transfer ◽  
Driving Force ◽  
Initial Temperature ◽  
Formation Rate ◽  
Hydrate Formation ◽  
Water Spray ◽  
Gas Hydrate Formation ◽  
Gas Consumption ◽  
Supply Mode ◽  
Gas Supply

In order to study the influence of gas supply modes on CO2 hydrate formation characteristics, a specific water spray gas hydrate formation apparatus was designed. The gas consumption and temperature variation in the process of CO2 hydrate formation under continuous and oscillating gas supply modes were researched. The experimental results showed that hydrate formation rate in the oscillating gas supply mode was greater than in the continuous gas supply mode, which indicates mass transfer driving force caused by disturbance in oscillating gas supply mode is larger than that of continuous gas supply mode. Additionally, under the same initial pressures and the same gas supplying mode, the lower the initial temperature, the larger the heat transfer drive force, and the faster the hydrate formation rate.

scholarly journals Problem of conjugate heat transfer between main gas pipeline and frozen ground

2019 ◽  
Vol 102 ◽  
pp. 01001
Author(s):  
Edward Bondarev ◽  
Igor Rozhin ◽  
Kira Argunova
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Gas Flow ◽  
Hydrate Formation ◽  
Conjugate Problem ◽  
Gas Pipeline ◽  
Frozen Ground ◽  
Flow Area ◽  
Tube Cross Section ◽  
Main Gas Pipeline

Mathematical model of non-isothermal gas flow within the framework of tube hydraulics including change of tube cross-section due to hydrate formation and the dependence of coefficient of heat transfer between gas and hydrate layer on varying flow area is proposed. The corresponding conjugate problem of heat exchange between imperfect gas in the pipeline and the environment is reduced to the solution of differential equations describing non-isothermal flow of gas in pipes and heat transfer equations in ground with the corresponding conjugation conditions. In the quasi-stationary mathematical model of hydrate formation (dissociation), the dependence of gas-hydrate transition temperature on gas pressure is taken into account. Some decisions taken in the design of the first section of the main gas pipeline «Power of Siberia» have been analyzed. It has been shown that if gas is not sufficiently dried, outlet pressure may drop below the technological limit in about 6-7 hours. At the same time, for completely dry gas ,it is possible to reduce the cost of thermal insulation of the pipeline at least two fold.

Entropy Production of Hydrate Transport in Subsea Multiphase Pipeline Flows

2015 ◽  
Author(s):  
Adedoyin Odukoya ◽  
Greg F. Naterer
Keyword(s):  
Heat Transfer ◽  
Numerical Model ◽  
Entropy Production ◽  
Gas Flow ◽  
Oil And Gas ◽  
Fluid Layer ◽  
Hydrate Formation ◽  
Internal Diameter ◽  
Environment Temperature ◽  
Subsea Pipelines

A numerical model is developed to examine the flow conditions of multiphase heat transfer and entropy production during hydrate formation in subsea pipelines. The temperature and pressure gradients of the oil and gas flow in subsea pipelines lead to entropy generation. This paper examines the impacts and effects of thermodynamic irreversibilities on the nucleation and growth processes of hydrate crystals in the pipeline flows. The effects of heat transfer ratio, internal diameter of the pipe, molar gas density, and environment temperature on entropy production in subsea pipelines are predicted and discussed in this paper. The numerical model accounts for the temperature distribution along the axial length of the pipe, reaction kinetics, and mass transfer between the solid and fluid layer. The kinetic energy of the hydrate particles during the coagulation process is analyzed in the numerical model. The results indicate that entropy production is highest at the beginning of the nucleation process. Pipelines with smaller internal radii have a lower rate of hydrate formation in subsea pipelines. The results from the numerical model are verified by comparison with experimental results for structure type II natural gas hydrates.

scholarly journals Heat Transfer Related to Gas Hydrate Formation/Dissociation

10.5772/19711 ◽  
2011 ◽  
Author(s):  
Bei Liu ◽  
Weixin Pang ◽  
Baozi Peng ◽  
Changyu Sun ◽  
Guangjin Che
Keyword(s):  
Heat Transfer ◽  
Gas Hydrate ◽  
Hydrate Formation ◽  
Gas Hydrate Formation

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.

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