A Multiscale Approach for Gas Hydrates Considering Structure, Agglomeration, and Transportability under Multiphase Flow Conditions: II. Growth Kinetic Model

Bassani, Carlos L.; Sum, Amadeu K.; Herri, Jean‐Michel; Morales, Rigoberto E. M.; Cameirão, Ana

doi:10.1021/acs.iecr.9b04245

Cited by 20 publications

(59 citation statements)

References 68 publications

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“…Natural gas hydrates (NGHs) are crystalline compounds composed of water and hydrocarbon gas molecules . NGHs are readily formed under the low-temperature and high-pressure conditions in oil and gas industry and could therefore pose a great threat to subsea flow assurance by agglomerating, jamming, bedding, and depositing in the transmission pipelines. − So far, NGHs in subsea flow assurance have been extensively investigated, and several hydrate prevention/management strategies have been proposed. − Except for NGHs, another big concern in subsea flow assurance is about wax. When the pipeline operating temperature falls below the wax appearance temperature (WAT), wax molecules dissolved in the crude oil will gradually precipitate and may deposit on the pipe wall, which may further lead to pipeline plugging.…”

Section: Introductionmentioning

confidence: 99%

Investigation on Hydrate Growth at the Oil–Water Interface: In the Presence of Wax and Kinetic Hydrate Inhibitor

Song

Ning

et al. 2020

Langmuir

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In oil industry, the coexistence of hydrate and wax can result in a severe challenge to subsea flow assurance. In order to study the effects of wax on hydrate growth at the oil–water interface, a series of microexperiments were conducted in a self-made reactor, where hydrates gradually nucleated and grew on the surface of a water droplet immersed in wax-containing oil. According to the micro-observations, hydrate shells formed at the oil–water interface in the absence of kinetic hydrate inhibitor (KHI). The roughness and growth rate of hydrate shells were analyzed, and the effects of wax were investigated. In addition, vertical growth of the hydrate shell was observed in the presence of wax, and a mechanism was proposed for illustration. In the presence of KHI, small hydrate crystals formed separately at the oil–water interface instead of hydrate shells. The presence of KHI reduced the growth rate of hydrates and changed the wettability of hydrates. Moreover, the presence of wax showed no obvious effect on the effectiveness of KHI under experimental conditions.

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Section: Introductionmentioning

confidence: 99%

Investigation on Hydrate Growth at the Oil–Water Interface: In the Presence of Wax and Kinetic Hydrate Inhibitor

Song

Ning

et al. 2020

Langmuir

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“…physics associated to these equations were already presented in part II2 . determination of the shear rate in the rock-flow cell, and determination of Kolm k…”

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confidence: 99%

A Multiscale Approach for Gas Hydrates Considering Structure, Agglomeration, and Transportability under Multiphase Flow Conditions: III. Agglomeration Model

Bassani

Kakitani

Herri

et al. 2020

Ind. Eng. Chem. Res.

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In the third part of this series, we introduce the mathematical model for the agglomeration of gas hydrate in oil continuous flow. The aim is to develop an expression for the agglomeration efficiency that considers the existence of a wet or a dry particle. If the particle is wet, then water is available at its outer surface, thus allowing the formation of a liquid bridge that holds the aggregate together.The criterion for a wet or dry particle was developed in part II of this series and comes from the competitions between water permeation through the porous hydrate particle, and water consumption caused by crystallization in the particle's outer surface. The new expression for the agglomeration efficiency is coupled with a population balance solved through the Method of Moments and considering simple expressions for the collision rate and the shear rate induced by the flow coming from Smoluchowski's and Kolmogorov's theory, respectively. When compared to experimental data, the model stays within the ±40% deviation range and shows capable of predicting smaller agglomerate size for higher subcooling and lower interfacial properties (use of surfactant additives).The influence of subcooling into changing the porous medium parameters (especially the porous medium interconnectivity) shows to be important into the determination of the time taken for the particle to dry out. The model is simplified for engineering purposes considering gases much more soluble in oil than in water (hydrocarbon gases) in oil-continuous flow, and a simple criterion is proposed to predict if the system behaves as dispersed (slurry) or if it agglomerates after the onset of hydrate formation.

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“…Natural gas hydrates (NGHs) are solid compounds formed by water and natural gas molecules . In subsea oil and gas transportation processes, NGHs can form easily considering the high pipeline pressure and the low environmental temperature. − To date, NGHs have been widely studied for the prevention of pipeline plugging, and many different hydrate inhibition methods have been put forward. − In addition to NGHs, the precipitation and deposition of wax can also result in pipeline plugging . Due to the nature that both hydrate issues and wax issues normally appear under low-temperature conditions, hydrate and wax could exist simultaneously during subsea pipeline transportation processes and pose an even more serious threat to the oil industry. − Thus, investigations on hydrate issues under wax-containing conditions are badly needed.…”

Section: Introductionmentioning

confidence: 99%

Investigation on Hydrate Growth at the Oil–Water Interface: In the Presence of Wax and Surfactant

et al. 2021

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Natural gas hydrates can readily form in deep-water–oil production processes and pose a great threat to subsea pipeline flow assurance. The usage of surfactants and hydrate antiagglomerants is a common strategy to prevent hydrate hazards. In water/wax-containing oil systems, hydrate coexisting with wax could lead to more complex and risky transportation conditions. Moreover, the effectiveness of surfactants and hydrate antiagglomerants in the presence of wax should be further evaluated. In this work, for the purpose of investigating how wax and surfactants could affect hydrate growth at the oil–water interface, a series of microexperiments was conducted in an atmospheric visual cell where the nucleation and growth of hydrates took place on a water droplet surrounded by wax-containing oils. On the basis of the experimental phenomena observed using a microscope, the formation of a hydrate shell by lateral growth, the collapse of a water droplet after hydrate initial formation, and the formation of hollow–conical hydrate crystals were identified. These experimental phenomena were closely related to the concentration of wax and surfactant used in each case. In addition, it was shown that the effectiveness of the surfactant could be weakened by wax molecules. Moreover, there existed a critical wax content above which the effectiveness of the surfactant was greatly reduced and the critical wax content gradually increased with increasing surfactant concentration. This work could provide guidance for hydrate management in wax-containing systems.

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A Multiscale Approach for Gas Hydrates Considering Structure, Agglomeration, and Transportability under Multiphase Flow Conditions: II. Growth Kinetic Model

Cited by 20 publications

References 68 publications

Investigation on Hydrate Growth at the Oil–Water Interface: In the Presence of Wax and Kinetic Hydrate Inhibitor

Investigation on Hydrate Growth at the Oil–Water Interface: In the Presence of Wax and Kinetic Hydrate Inhibitor

A Multiscale Approach for Gas Hydrates Considering Structure, Agglomeration, and Transportability under Multiphase Flow Conditions: III. Agglomeration Model

Investigation on Hydrate Growth at the Oil–Water Interface: In the Presence of Wax and Surfactant

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