Effect of EMIM-BF<sub>4</sub> Ionic Liquid on Dissociation Temperature of Methane Hydrate in the Presence of PVCap: Experimental and Modeling Studies

Mardani, Meysam; Azimi, Arezoo; Javanmardi, Jafar; Mohammadi, Amir H.

doi:10.1021/acs.energyfuels.8b02176

Cited by 20 publications

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“…Hong et al 32 indicated that PVCap has an impact on the LHV curve and shifts the curve to higher temperatures and lower pressures (acting as a thermodynamic hydrate promoter). Mardani et al 33 conducted experimental and theoretical studies to investigate the effect of PVCap on methane hydrate equilibrium conditions. Their theoretical study was based on the van der Waals−Platteeuw (vdW−P) solid solution theory.…”

Section: Resultsmentioning

confidence: 99%

Experimental Determinations of the Complete Inhibition, the Slow Growth, and the Rapid Failure Regions of Methane Hydrate Formation in the Presence of Polyvinylpyrrolidone and Polyvinylcaprolactam Aqueous Solutions

et al. 2021

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Gas hydrate formation in gas transmission pipelines is one of the most critical troubles in the petroleum industry. One of the most convenient techniques to intercept gas hydrate formation is using inhibitors: e.g., thermodynamic hydrate inhibitors and kinetic hydrate inhibitors (KHIs). KHIs postpone the hydrate nucleation and slow down the hydrate growth rates by increasing the induction time. Because hydrate nucleation is probabilistic, the measurement of the induction time is difficult, and the measured data are normally nonrepeatable. It was observed that KHIs have repeatable behaviors by evaluating the KHIs based on the crystal growth inhibition approach in which the regions of inhibited hydrate growth can be considered as a function of subcooling: by increasing the subcooling from the complete inhibition region (CIR), reaching the slow growth rate region (SGR), and finally reaching the rapid failure region (RFR). In this study, the CIR, the SGR, and the RFR of methane hydrate formation in the attendance of polyvinylpyrrolidone (PVP) and polyvinylcaprolactam (PVCap) aqueous solutions were experimentally measured. Also, in the pressure range of 35−80 bar, the effects of KHIs concentrations, i.e., 0.0025, 0.0050, and 0.0100 mass fractions for PVP and 0.0010 and 0.0025 mass fractions for PVCap, were investigated in these regions. It was concluded that the optimum concentration of PVP was 0.0050 for CIR and SGR. Also, by comparing the CIR, SGR, and RFR of PVP and PVCap aqueous solutions, it was observed that PVCap has a stronger inhibition impact with respect to PVP.

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Section: Resultsmentioning

confidence: 99%

Experimental Determinations of the Complete Inhibition, the Slow Growth, and the Rapid Failure Regions of Methane Hydrate Formation in the Presence of Polyvinylpyrrolidone and Polyvinylcaprolactam Aqueous Solutions

et al. 2021

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“…Investigation on disperse oceanic MH reservoirs with low hydrate saturation using TOUGH-Fx/HYDRATE simulator upon depressurization showed low gas production potential, which was not economically feasible, with high amount of water production (Moridis and Sloan, 2007). Nowadays, researchers are performing more mathematical investigations on this field accompanying with comparison with real field or experimental results or using parameters from real reservoirs (Chen and Hartman, 2018;Konno et al, 2017;Mardani et al, 2018;Wang et al, 2019;Wang et al, 2016a;Zhao et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Analytical modeling of methane hydrate dissociation under thermal stimulation

Roostaie

Leonenko

2020

Journal of Petroleum Science and Engineering

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In this study, a one-dimensional analytical model to describe heat and mass transfer during methane hydrate dissociation under thermal stimulation in porous media has been developed. The model is based on a similarity solution that considers a moving dissociation boundary which separates the dissociated zone containing produced gas and water from the un-dissociated zone containing only methane hydrate. The results of temperature distribution, pressure distribution, energy efficiency, and parametric study considering various initial and boundary conditions as well as various reservoir properties are presented and compared with previous studies. Sensitivity analysis of gas production on reservoir properties is also presented in this paper. The dissociation boundary moves faster by increasing the heat source temperature while decreasing the heat source pressure simultaneously, but the associated energy efficiency decreases. Increasing the well thickness has a negative effect on the energy efficiency of the process. Among the proposed thermal properties of the system, only the thermal diffusivities and conductivites of the reservoir as well as the porosity of the sediment affect the dissociation. The main contribution of this work is investigating analytically the hydrate dissociation using thermal stimulation by taking into account the effect of wellbore thickness and structure.

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“…Both the rate of hydrate formation and dissociation can be affected by many factors, including gas composition/cage occupancy, , mass transfer limits, presence of liquid hydrocarbons, , presence of surfactants, , and length scales (pore scale or large scale). − Metastable hydrate can also exist at some conditions, for example, supercooled water below the freezing point may retard and slow down the dissociation of methane hydrate, i.e., it can exist as a metastable phase . Some kinetic hydrate inhibitors, e.g., poly- n -vinylcaprolactam (PVCap), also affect gas hydrate dissociation kinetics and metastable thermodynamic stability. − Hence, significant literature experimental and numerical modeling work has been undertaken with respect to the accurate measurement of gas hydrate phase behavior for different systems/conditions. ,− …”

Section: Introductionmentioning

confidence: 99%

Experimental Measurement of Multiple Hydrate Structure Formation in Binary and Ternary Natural Gas Analogue Systems by Isochoric Equilibrium Methods

2021

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Traditionally, it is commonly assumed that a single gas hydrate (or clathrate hydrate) structure/phase is formed in natural gas systemse.g., "s-II natural gas (NG) hydrates" or "s-I methane hydrates"based on that which is understood to be the most thermodynamically stable at incipient phase boundary conditions. This applies with respect to both studies of hydrates in natural sediments, and in the case of hydrocarbon production operations, including the testing of low-dosage hydrate inhibitors (LDHIs). Here, we present the results of experimental studies of simple propane (C 3 ), binary methane−propane (C 1 −C 3 ), and ternary methane−ethane−propane (C 1 −C 2 −C 3 ) hydrate systems, aimed at investigating phase behavior at higher subcoolings where significant water conversions to clathratesand associated gas fractionationmight be expected to result in the formation of more than one hydrate structure. Measurements were made by means of established, reliable, isochoric equilibrium step-heating/cooling approaches. In the single guest propane system, pressure−temperature (PT) conditions follow the gas hydrate phase boundary, in agreement with the univariant hydrate + gas + water (H + G + W) equilibrium. By contrast, binary and ternary mixes clearly show PT behavior consistent with the growth of at least two and four hydrate phases, respectively, with these forming sequentially on cooling, and dissociating in the corresponding reverse order upon heating. In-house hydrate model (HydraFLASH) predictions support experimental observations, pointing to processes being gas fractionation driven; the mixed C 3 −C 1 or C 3 −C 2 −C 1 s-II type hydrates formed first close to the phase boundary preferentially incorporating the most strongly clathrate cage (5 12 6 4 ) stabilizing propane, making the remaining gas leaner. Once C 3 is largely consumed, trends agree with less stable C 2 −C 1 structures (s-II followed by s-I) then growing (where ethane is present), with this, like C 3 uptake, making remaining free gas increasingly of almost pure C 1 . This ultimately drives systems toward the final simple, single guest C 1 s-I clathrate formation as the well-established univariant phase boundary for this structure is reached. As observed phase behavior arises because of gas fractionation, it can be expected to occur during hydrate formation in all mixed gas systems of relatively fixed composition (at constant volume or pressure). The findings highlight that care should be taken in the application of isochoric methods to multicomponent gas systems, given the potential for numerous (rather than just one) clear changes in heating curve slopes as different hydrate structures form/dissociate. In addition, results show that extending equilibrium steps well into the hydrate region can reveal important information on clathrate phase behavior with potentially significant implications for issues such as gas production from hydrates in sediments, hydrate technologies for gas capture/separation/storage in the energy industry, and flow assuranc...

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Effect of EMIM-BF₄ Ionic Liquid on Dissociation Temperature of Methane Hydrate in the Presence of PVCap: Experimental and Modeling Studies

Cited by 20 publications

References 50 publications

Experimental Determinations of the Complete Inhibition, the Slow Growth, and the Rapid Failure Regions of Methane Hydrate Formation in the Presence of Polyvinylpyrrolidone and Polyvinylcaprolactam Aqueous Solutions

Experimental Determinations of the Complete Inhibition, the Slow Growth, and the Rapid Failure Regions of Methane Hydrate Formation in the Presence of Polyvinylpyrrolidone and Polyvinylcaprolactam Aqueous Solutions

Analytical modeling of methane hydrate dissociation under thermal stimulation

Experimental Measurement of Multiple Hydrate Structure Formation in Binary and Ternary Natural Gas Analogue Systems by Isochoric Equilibrium Methods

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Effect of EMIM-BF4 Ionic Liquid on Dissociation Temperature of Methane Hydrate in the Presence of PVCap: Experimental and Modeling Studies

Cited by 20 publications

References 50 publications

Experimental Determinations of the Complete Inhibition, the Slow Growth, and the Rapid Failure Regions of Methane Hydrate Formation in the Presence of Polyvinylpyrrolidone and Polyvinylcaprolactam Aqueous Solutions

Experimental Determinations of the Complete Inhibition, the Slow Growth, and the Rapid Failure Regions of Methane Hydrate Formation in the Presence of Polyvinylpyrrolidone and Polyvinylcaprolactam Aqueous Solutions

Analytical modeling of methane hydrate dissociation under thermal stimulation

Experimental Measurement of Multiple Hydrate Structure Formation in Binary and Ternary Natural Gas Analogue Systems by Isochoric Equilibrium Methods

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Product

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Effect of EMIM-BF₄ Ionic Liquid on Dissociation Temperature of Methane Hydrate in the Presence of PVCap: Experimental and Modeling Studies