Crystal Growth of Clathrate Hydrates Formed at the Interface of Liquid Water and Gaseous Methane, Ethane, or Propane: Variations in Crystal Morphology

Tanaka, Ryo; Sakemoto, Riki; Ohmura, Ryo

doi:10.1021/cg9001048

Cited by 110 publications

(174 citation statements)

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“…47 Inhibition performance can be monitored and compared through use of high pressure apparatus in which gas consumption indicates hydrate formation (an increased gas consumption is indicative of hydrate formation and therefore an ineffective inhibitor). 47 Inhibitors 2 85 and 3 are found to have significantly reduced gas consumption relative to 1 (when analysed at 277.2 K). 47 As a continuation of their work in this field, CSM investigated the inhibition properties of 3 which at the time was being 90 synthesised for alternative application within the hair-care industry.…”

Section: Development Of Khismentioning

confidence: 95%

“…28 The synthesis of glycoproteins has been undertaken and proven to be successful at interfering with hydrate crystal growth, however it did not prove to be an economically viable inhibition methodology. 34 Several studies 85 have been reported which compare the efficacy of AFPs with synthetic KHIs such as poly(N-vinyl pyrrolidone) (PVP, 1), indicating that AFPs may hold advantages in prolonging induction periods by having a more pronounced effect upon nucleation. 35 There has been considerable work probing the mechanism of action of AFPs at inhibiting ice growth, reporting a surface adsorption mechanism and the resulting Kelvin effect.…”

Section: Development Of Khismentioning

confidence: 99%

“…84 Recently, Ohmura and coworkers used videographs to study the 45 growth of crystals at the liquid-gas interfaces for systems containing gaseous methane, ethane or propane. 85 A water droplet was held on a Teflon stage placed within a test cell, wherein the temperature and pressure could be monitored and maintained. 85 The air environment within the test cell was replaced with 50 hydrocarbon gas (e.g.…”

Section: Gas Hydrate Nucleation and Growthmentioning

confidence: 99%

“…85 A water droplet was held on a Teflon stage placed within a test cell, wherein the temperature and pressure could be monitored and maintained. 85 The air environment within the test cell was replaced with 50 hydrocarbon gas (e.g. methane) and the temperature reduced to promote hydrate formation.…”

Section: Gas Hydrate Nucleation and Growthmentioning

confidence: 99%

“…57,58 Inhibition enhancement results from the differing geometries of PVCap and TPAB (or TBAB) enabling attachment at different hydrate crystal sites. 57,58 It has 85 been postulated that a pentyl group present on the TPAB will embed within a cavity on the hydrate surface and hence hinder hydrate growth, with this embedding mode of action explaining the reduced synergistic performance for analogues containing n-hexyl or n-propyl pendant arms. 57,58 In addition to acting as 90 KHI synergists, quaternary salts can also function as antiagglomerants upon transformation into surfactants, vide infra.…”

mentioning

confidence: 99%

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The chemistry of low dosage clathrate hydrate inhibitors

2013

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The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. This review aims to introduce the chemistry of low dosage inhibitors of clathrate hydrate formation 5 within the context of their role in the oil and gas industry. The review covers both kinetic hydrate inhibitors and anti-agglomerants from the point of view of structure-function relationships, focussing on recent refinements in mechanistic understanding and chemical design, and the consequently evolving and increasingly fine-tuned properties of these fascinating compounds. Clathrate hydrates 10Clathrate hydrates are crystalline, non-stoichiometric host-guest compounds comprising a hydrogen bonded water framework, into which small molecular guest species such as methane are included within cavities formed by the water cages. Because there are no strong directional interactions between guest and host the 15 guests are free to vibrate and rotate but possess limited translational motion. 1 Typically common clathrate hydrates comprise 85 mol% water and 15 mol% guest(s) when all of the cavities are occupied.2 These materials form when the components are subjected to ambient temperatures (generally less 20 than 300 K) and moderate pressures (>0.6 MPa); conditions frequently found in oil and gas pipelines. 3 The initial reporting of gas hydrates is accredited to Sir Humphrey Davy in 1811, who focussed upon the crystallisation 25 of a cold aqueous solution of chlorine (known as oxymuriatic gas at the time). 4 In 1934 a pivotal report by Hammerschmidt acted as a catalyst for stimulating research in this area, by confirming that clathrate hydrates are responsible for the plugging of gas and oil pipelines and thereby dramatically increasing industrial 30 investment and research on the topic. 5 Today clathrate hydrates pose a major problem to the oil and gas industry with pipeline blockage causing many safety concerns in addition to requiring the shutdown of the pipeline for a time 35 whilst the plug is removed. This shutdown period results in reduced field site performance and may cause significant financial loss. Avoidance of pipeline shutdown is a priority to many oil and gas companies, and as such considerable investment is being made into research into clathrate hydrate inhibition to 40 circumvent such potentially catastrophic effects. Problems associated with gas hydrate formation reached the headlines in 2010 due to their destructive effects during BP's efforts to contain the oil spillage after the Deepwater Horizon blowout, thereby illustrating the importance of research in this area. While...

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Section: Development Of Khismentioning

confidence: 95%

Section: Development Of Khismentioning

confidence: 99%

Section: Gas Hydrate Nucleation and Growthmentioning

confidence: 99%

Section: Gas Hydrate Nucleation and Growthmentioning

confidence: 99%

mentioning

confidence: 99%

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The chemistry of low dosage clathrate hydrate inhibitors

2013

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Initial thickness measurements and insights into crystal growth of methane hydrate film

Sun

Liu

et al. 2013

AIChE Journal

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The initial thickness of methane hydrate film was directly measured by suspending a single methane bubble in water at 274.0, 276.0, and 278.0 K. The results show that the initial hydrate film thickness decreases from tens of micrometers to about 10 mm with the subcooling increased from 0.5 K to about 3 K. When subcooling is higher than 1.0 K, all initial film thickness data measured under different temperatures vary inversely with the subcooling. Notable three-dimensional growths of hydrate crystals of different sizes and shapes at film front and emergence of new crystal were clearly observed at lower subcooling that resulting in the rougher surface of hydrate film and uncertainty of initial thickness measurement under lower subcooling. The hydrate film growth was dominated by film growth in thickness, not by lateral growth at low subcooling. The growth in thickness of hydrate shell covering one whole bubble surface was also investigated.

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Crystal Growth of Clathrate Hydrate in Gas/Liquid/Liquid System: Variations in Crystal‐Growth Behavior

Ishida¹,

Sakemoto²,

Ohmura³

2011

Chemistry A European J

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This paper reports the visual observations of the formation and growth of structure-II hydrate crystals on a water droplet partially immersed in liquid cyclopentane and exposed to difluoromethane gas. Each of the experiments was performed under prescribed temperature and pressure conditions in the range from 281.7 to 297.0 K and from 0.12 to 1.10 MPa in order to investigate the effect of the driving force for the hydrate crystal growth. The experiments were conducted at 25 different temperature-pressure conditions. It was found that the behavior of the hydrate crystal growth in this three-component system can be classified into three modes, which we called "cover", "expansion" and "line", depending on the temperature and pressure. The descriptions of the three types are summarized as follows. "COVER": Hydrate crystals first formed on the water-droplet surface and then grew to form a polycrystalline layer covering the surface. After complete surface coverage, no more hydrate growth and little change in the shape of the hydrate-covered water droplet were observed. "EXPANSION": Like "cover", the first crystals were observed on the water-droplet surface. They grew not only along the surface, but also toward the gas phase, and then continued to grow for more than several tens of minutes after complete coverage. "LINE": Unlike the other two modes, hydrate crystals first formed at the three-phase interfacial line and grew along this line. The shape of the hydrate crystals eventually became like a doughnut, since the center of the water droplet collapsed when they grew.

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Crystal Growth of Clathrate Hydrates Formed at the Interface of Liquid Water and Gaseous Methane, Ethane, or Propane: Variations in Crystal Morphology

Cited by 110 publications

References 11 publications

The chemistry of low dosage clathrate hydrate inhibitors

The chemistry of low dosage clathrate hydrate inhibitors

Initial thickness measurements and insights into crystal growth of methane hydrate film

Crystal Growth of Clathrate Hydrate in Gas/Liquid/Liquid System: Variations in Crystal‐Growth Behavior

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