Mechanisms and Kinetics of Hydrate Formation

Christiansen, Richard L.; Sloan, E. Dendy

doi:10.1111/j.1749-6632.1994.tb38841.x

Cited by 174 publications

(138 citation statements)

References 35 publications

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“…9), identifying the clustering of water molecules when the appropriate temperature and pressure conditions occur. 86 Once gas molecules (guests) are dissolved within the water, labile clusters form, which are metastable species of below critical size which can either dissipate or 75 agglomerate. Upon agglomeration, and the attainment of a critical size, growth of the hydrate may then begin.…”

Section: Gas Hydrate Nucleation and Growthmentioning

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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Section: Gas Hydrate Nucleation and Growthmentioning

confidence: 99%

The chemistry of low dosage clathrate hydrate inhibitors

2013

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“…In this section, the driving force for these systems is discussed. Christiansen and Sloan [30] derived the driving force for hydrate formation on the basis of molar changes of the total Gibbs free energy of the system when a hydrate crystal forms from water and gas. With the application of the isothermal path, for calculating the DG of hydrate formation, they obtained the following equation for a multi-component system:…”

Section: Driving Force For Double Gas Hydrate Formationmentioning

confidence: 99%

Experimental and Theoretical Investigation of Double Gas Hydrate Formation in the Presence or Absence of Kinetic Inhibitors in a Flow Mini‐Loop Apparatus

2009

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Double gas hydrate formation in the presence or absence of kinetic inhibitors in a flow mini-loop apparatus was investigated. For the prediction of the gas consumption rate during hydrate formation in this system, the rate equation based on the Kashchiev and Firoozabadi model for simple gas hydrate formation in a batch system was developed for double gas hydrate formation in a flow mini-loop apparatus. To complete the theoretical evaluation of gas hydrate formation through the mini-loop apparatus in the presence or absence of kinetic hydrate inhibitors (KHI), a laboratory flow mini-loop apparatus was set up to measure the induction time for hydrate formation and the uptake rate when a gaseous mixture (such as 75 % C1/25 % C3, 25 % C1/75 % C3, 75 % C1/25 % i-C4, and 25 % C1/75 % i-C4) is contacted with water containing or not containing dissolved inhibitor under suitable temperature and pressure conditions. In each experiment, a water blend saturated with gas mixture was circulated up to the required pressure. The pressure was maintained at a constant value during the experimental runs by means of a required gas mixture make-up. The effect of pressure on gas consumption during hydrate formation was investigated in the presence or absence of polyvinylpyrrolidone (PVP) and L-tyrosine as kinetic inhibitors at various concentrations. A good agreement was found between the predicted and experimental data in the presence or absence of KHI. The total average absolute deviation percents between the experimental and predicted values of gas consumption were found to be 16.4 and 17.5 % for the double gas hydrate formation in the presence or absence of the kinetic inhibitors, respectively.

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“…Fundamental research in the field of gas hydrates includes, e.g., structural properties [3,4], phase equilibria [5 -7], nucleation and formation kinetics [8,9], and decomposition kinetics [10,11]. In the past several groups have contributed towards understanding the processes taking place during the two and three phase decomposition of gas hydrates.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of Methane Hydrate Decomposition Kinetics

Windmeier

Oellrich

2015

Chemie Ingenieur Technik

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Experimental investigations of methane hydrate dissociation kinetics were performed. The test rig consists of a stirred reactor equipped with particle size analysis. The observed dissociation rates were found to be about one order of magnitude faster than previously reported by others. A mass transfer control of the dissociation process is proposed to dominate in the proximity of a dispersed hydrate-liquid interface. The results are relevant for the design of processes employing dispersed gas hydrates in chemical engineering and the production of natural gas from dispersed deposits.

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Mechanisms and Kinetics of Hydrate Formation

Abstract: FIGURE 1. Size of molecules and hydrate structures.

Cited by 174 publications

References 35 publications

The chemistry of low dosage clathrate hydrate inhibitors

The chemistry of low dosage clathrate hydrate inhibitors

Experimental and Theoretical Investigation of Double Gas Hydrate Formation in the Presence or Absence of Kinetic Inhibitors in a Flow Mini‐Loop Apparatus

Experimental Study of Methane Hydrate Decomposition Kinetics

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