Experimental study on the kinetic effect of N-butyl-N-methylpyrrolidinium tetrafluoroborate and poly(N-vinyl-caprolactam) on CH4 hydrate formation

Ren, Jian‐Fang; Lü, Zheng; Zhang, Long; Liang, Deqing

doi:10.1039/c9ra10998f

Cited by 4 publications

(3 citation statements)

References 50 publications

(55 reference statements)

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“…The performance of PVlactams is known to be enhanced by several classes of nonpolymeric molecules, including alcohols, glycol ethers, polyglycols, tetraalkylammonium salts, trialkylamine oxides, hexaalkylguanidinium halides, ionic liquids, and acetylenic diols. − Therefore, we were interested in comparing the use of some of these synergists with the oxyvinylenelactam copolymers. The results are summarized in Table .…”

Section: Resultsmentioning

confidence: 99%

Oxyvinylenelactam Polymers─A New Class of Lactam-Based Kinetic Hydrate Inhibitor Polymers

et al. 2022

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The deployment of kinetic hydrate inhibitors (KHIs) is a chemical method for the prevention of gas hydrate plugging in gas, condensate, and oil production flow lines. Polymers made using the monomer N-vinylcaprolactam (VCap) are one of the most common KHI classes. Alternative classes of polymers containing caprolactam groups are rare. Here, we present a study on oxyvinylenelactam polymers and copolymers with pendant piperidone or caprolactam groups. Low-molecular-weight homo- and copolymers were obtained. The nonrotating vinylene groups impart rigidity to the polymer backbone. Poly(oxyvinylenecaprolactam) (POVCap) was insoluble in water, but poly(oxyvinylenepiperidone) (POVPip) and OVPip:OVCap copolymers with 60+ mol % OVPip were soluble with low cloud points. KHI screening tests were carried out using the slow constant cooling method in steel rocking cells. POVPip was water soluble with no cloud point up to 95 °C but showed a poor KHI performance. In contrast, OVPip:OVCap copolymers with about 60–70 mol % OVPip were also water soluble and showed a reasonable KHI performance, better than that of poly(N-vinylpyrrolidone) but not as good as that of poly(N-vinylcaprolactam). Surprisingly, several additives known to be good synergists for VCap-based polymers showed negligible synergy or were antagonistic with the 62:38 OVPip:OVCap copolymer with regard to lowering the onset temperature of hydrate formation. However, a blend with hexabutylguanidinium chloride showed a strong effect to delay the onset of rapid hydrate formation.

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Section: Resultsmentioning

confidence: 99%

Oxyvinylenelactam Polymers─A New Class of Lactam-Based Kinetic Hydrate Inhibitor Polymers

et al. 2022

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“…The addition of a certain amount of kinetic inhibitor to the system cannot alter the thermodynamic conditions of hydrate formation; however, the growth of hydrates can be hindered, thereby prolonging the induction time. Common kinetic hydrate inhibitors include lactam-based polymers − and polymers that contain amide groups in the main chain or branch. − Methanol, ethanol, diethylene glycol, and other electrolytes are extensively used as thermodynamic hydrate inhibitors. , These inhibitors prevent hydrate formation by altering the thermodynamic equilibrium of water molecules and hydrocarbon molecules, moving the phase equilibrium curve to lower-pressure and higher-temperatures zones. Kim et al used ethylene glycol and PVP as hydrate inhibitors and found that a small amount of PVP mixed with ethylene glycol can prolong the induction time of hydrate formation.…”

Section: Resultsmentioning

confidence: 99%

“…The liquid loading is the total volume of liquid relative to the total volume of the loop. The experiments with three system pressures (5.0, 5.5, and 6.0 MPa), three liquid-holding capacities (28,32, and 36 L), three flow rates (180, 240, and 360 L/h), and different concentrations of PVP and NaCl were performed. The experimental protocol is shown in Table 1.…”

Section: Experimental Protocolmentioning

confidence: 99%

Formation and Flow Characteristics of Methane Hydrates in High-Pressure Pipelines

Huang

Zang

et al. 2022

Ind. Eng. Chem. Res.

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To ensure the safe flow of the hydrate slurry in the pipeline, a high-pressure flow loop with visual capability was designed, and flow characteristics and growth kinetics of methane (CH 4 ) hydrates from the pure water system were investigated. Experiment results showed that with an increase in the flow rate, the induction time first increased and subsequently decreased. When the flow rate was higher than 360 L/h, the loop was not blocked. The effect of NaCl on polyvinylpyrrolidone (PVP) as the kinetic inhibitor on the nucleation and growth of methane hydrates was studied by measuring the hydrate induction time and gas consumption. The results show that the addition of PVP was found to significantly prolong the hydrate induction time and decrease the amount of gas consumption; the presence of NaCl enhanced the inhibition strength of PVP. Through the focused beam reflectance measurement (FBRM), the results indicated that the hydrate particle size in the loop decreases with an increase of flow rate, and the added PVP to the system led to smaller average particle size. Based on the analysis of pressure difference and flow rate, the mechanism of pipe clogging in the pure water system was put forward. We believe that this research can provide theoretical support for the industrial application of CH 4 hydrate slurry flow to some extent.

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Test research progress on mechanical and physical properties of hydrate-bearing sediments

Liu,

Kong,

Zhao

et al. 2024

International Journal of Hydrogen Energy

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Experimental study on the kinetic effect of N-butyl-N-methylpyrrolidinium tetrafluoroborate and poly(N-vinyl-caprolactam) on CH₄ hydrate formation

Abstract: The kinetic inhibition performance of N-butyl-N-methylpyrrolidinium tetrafluoroborate ([BMP][BF4]), poly(N-vinylcaprolactam) (PVCap) and compound inhibitor systems on methane hydrate were studied from both macroscopic and microscopic perspectives.

Cited by 4 publications

References 50 publications

Oxyvinylenelactam Polymers─A New Class of Lactam-Based Kinetic Hydrate Inhibitor Polymers

Oxyvinylenelactam Polymers─A New Class of Lactam-Based Kinetic Hydrate Inhibitor Polymers

Formation and Flow Characteristics of Methane Hydrates in High-Pressure Pipelines

Test research progress on mechanical and physical properties of hydrate-bearing sediments

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