Effective kinetic inhibitors for natural gas hydrates

Lederhos, J.P.; Long, Jinping; Sum, Amadeu K.; Christiansen, Richard L.; Sloan, E. Dendy

doi:10.1016/0009-2509(95)00370-3

Cited by 385 publications

(281 citation statements)

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“…It can therefore be perceived that this definition of the hydrate induction time involves both the process of hydrate nucleation and the growth stage of hydrate. All the influencing factors of both hydrate nucleation (Natarajan et al, 1994;Lederhos et al, 1996;Natarajan, 1993;Kashchiev and Firoozabadi, 2002a) and hydrate growth (Kashchiev et al, 1991) would thus affect this defined hydrate induction time. Hydrate formation curve of test natural gas.…”

Section: Resultsmentioning

confidence: 99%

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Experimental Study on Hydrate Induction Time of Gas-Saturated Water-in-Oil Emulsion using a High-Pressure Flow Loop

Shi

Wang

et al. 2014

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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and available online here Cet article fait partie du dossier thématique ci-dessous publié dans la revue OGST, Vol. 70, n°6, pp. 909-1132 et téléchargeable ici D o s s i e rOil & Gas Science and Technology -Rev. IFP Energies nouvelles, Vol. 70 (2015), No. 6, pp. 909-1132 Copyright © 2015, IFP Energies nouvelles > Editorial -Enhanced Oil Recovery (EOR), Asphaltenes and HydratesÉditorial -EOR «récupération assistée du pétrole», Asphaltènes et Hydrates D. Langevin and F. Baudin ENHANCED OIL RECOVERY (EOR) > HP-HT Drilling Mud Based on Environmently-Friendly Fluorinated ChemicalsBoues de forage HP/HT à base de composés fluorés respectueux de l'environnement Abstract -Hydrate is one of the critical precipitates which have to be controlled for subsea flow assurance. The induction time of hydrate is therefore a significant parameter. However, there have been few studies on the induction time of the natural gas hydrate formation in a flow loop system. Consequently, a series of experiments were firstly performed, including water, natural gas and Diesel oil, on the hydrate induction time under various conditions such as the supercooling and supersaturation degree, water cut, anti-agglomerant dosage, etc. The experiments were conducted in a high-pressure hydrate flow loop newly constructed in the China University of Petroleum (Beijing), and dedicated to flow assurance studies. Then, based on previous research, this study puts forward a method for induction time, which is characterized by clear definition, convenient measurement and good generality. Furthermore, we investigated the influences of the experimental parameters and analyzed the experimental phenomena for the hydrate induction time in a flowing system.

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Section: Resultsmentioning

confidence: 99%

“…Kashchiev et al (1991) combined the mononuclear and polynuclear theories to generate an integrated model to calculate the induction time for the single-component gas hydrate: Typical gas consumption plots (Lederhos et al, 1996). where G is the growth rate when the nuclei grow into visible crystals.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Hydrate Induction Time of Gas-Saturated Water-in-Oil Emulsion using a High-Pressure Flow Loop

Shi

Wang

et al. 2014

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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“…47 Compound 3 and PVCap were found to perform well at moderate pressures (6.89 MPa) whilst performance at higher pressures (10.3 MPa) was significantly reduced. 47 Copolymers of VP/VCap were also studied. The work showed that when the ratio of VP/VCap is equal to or less than 55 1:3, copolymer inhibitor performance is equal to that of PVCap or 3.…”

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confidence: 99%

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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“…They discovered that a principle mechanism of hydrate kinetic suppression involves surface adsorption onto the growing crystals accompanied by slowing of the growth. Another mechanism of inhibition involves an association between the hydrate-forming components and the polymer, which might act to alter the nucleation behavior, as suggested by Lederhos et al (1996).…”

Section: Prevention Of Clatrate Formationmentioning

confidence: 99%

“…Becke, Kessel and Rahimian (1994) determined that liquid hydrocarbons add to the effects of inhibitors in lowering the critical decomposition temperatures of gas hydrates. In addition to alcohols, glycols, and electrolytes, which are known as thermodynamic inhibitors, water-soluble polymers are found to have inhibiting potential (Englezos 1992;Lederhos et al 1996).…”

Section: Prevention Of Clatrate Formationmentioning

confidence: 99%

Effects of Water in Synthetic Lubricant Systems and Clathrate Formation: A Literature Search and Review

Rohatgi

2001

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EXECUTIVE SUMMARYMoisture is a universal contaminant of refrigeration systems, and a scientific understanding of the effects of water in these systems is needed for their proper design, efficient operation, and reliable service. The effects of water on chlorofluorocarbons and mineral oil have been extensively studied. In these non-polar systems with low solubility for water, moisture levels are usually controlled to twenty five parts per million or less to avoid free water and the associated corrosion of metals, compatibility problems with polymeric materials, and possible ice formation in expansion valves, capillary tubes, or evaporators. The phase-out of chlorofluorocarbon/mineral oil systems and the introduction of alternative hydrofluorocarbon (HFC) refrigerants and their compatible synthetic lubricants have once more raised concerns about the effects of water on the stability of refrigeration systems. The HFC/synthetic lubricant systems are polar and have good solubility for moisture, thus present reduced risk of free water with its associated problems. The current common practice of equipment manufacturers is to allow moisture levels of 50-100 parts per million (ppm) or less in new equipment with HFC and synthetic lubricants. However, service practices are not well controlled and may lead to high levels of water in the refrigeration system. Because of the different types of synthetic lubricants and system designs encountered in the refrigeration and airconditioning industry, initial investigations into the effects of excess water with the HFC/synthetic lubricant working fluids are limited, proprietary, or of a screening nature.There has not been a reported in-depth study of the effects of moisture on the long-term stability of the HFC/synthetic lubricant systems. Such a study would assist the equipment manufacturers in defining allowable maximum limits of water concentration for ii satisfactory long-term operation of the HFC/synthetic lubricant systems, and evaluating potential difficulties associated with the presence of excessive water.Under ARTI 21-CR Project 610-50035-01, Spauschus Associates, Inc. has compiled and critically evaluated the current state of knowledge of the effects of water on the stability of HFC/synthetic lubricant systems to identify key areas requiring further investigation. An extensive literature search was conducted and a confidential survey was prepared and sent to compressor, lubricant, desiccant and filter-drier manufacturers to determine the industry specifications on the amount of water allowable in the HFC/synthetic lubricant systems. Following are highlights from the extensive literature review and analysis of the survey:• Clathrate hydrates, first discovered in 1810, are solid solutions formed when water molecules are linked through hydrogen bonding creating cavities that can enclose various guest molecules also know as hydrate formers. The formation, nucleation, growth, decomposition, structures, properties, and thermodynamic phase equilibria have been reported for a num...

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Effective kinetic inhibitors for natural gas hydrates

Cited by 385 publications

References 6 publications

Experimental Study on Hydrate Induction Time of Gas-Saturated Water-in-Oil Emulsion using a High-Pressure Flow Loop

Experimental Study on Hydrate Induction Time of Gas-Saturated Water-in-Oil Emulsion using a High-Pressure Flow Loop

The chemistry of low dosage clathrate hydrate inhibitors

Effects of Water in Synthetic Lubricant Systems and Clathrate Formation: A Literature Search and Review

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