Synergistic effect of Kinetic Hydrate Inhibitor (KHI) and Monoethylene Glycol (MEG) in gas hydrate management

Navaneetha Kannan, Seetharaman; Delgado-Linares, Jose G.; Makogon, Taras Y.; Koh, Carolyn A.

doi:10.1016/j.fuel.2024.131326

Cited by 7 publications

(3 citation statements)

References 47 publications

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“…The most common chemicals used as thermodynamic hydrate inhibitors (THIs) are methanol (MeOH) and monoethylene glycol (MEG), which function by altering the thermodynamic equilibrium conditions for hydrate formation by increasing the pressure and decreasing the temperature at which hydrates can form. ,,− This method shifts the conditions under which hydrates become stable. The choice of THI depends on project-specific requirements.…”

Section: Introductionmentioning

confidence: 99%

Influence of Varying Underinhibition on Methanol in Gas Hydrate Agglomeration

Navaneetha Kannan,

Delgado-Linares,

Sun

et al. 2024

Energy Fuels

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The influence of methanol (MeOH) on gas hydrate agglomeration is investigated. The study addresses the knowledge gap in understanding how underinhibition and varying subcooling conditions affect gas hydrate agglomeration tendencies under different concentrations of MeOH in gas condensate systems, which is critical for improving hydrate management in the oil and gas industry. In systems underinhibited with MeOH, the hydrate volume percent (HVP) was higher than that obtained in the base system (without MeOH), indicating a higher rate of hydrate formation. The addition of MeOH produced an emulsion with smaller droplets compared to the base system. The new findings confirm that these smaller water droplets within the oil phase significantly increase hydrate formation rates in MeOH systems. The impact of subcooling with various MeOH concentrations (0, 12.5, 20, 25, and 30 wt %) was analyzed and allowed the categorization of the gas hydrate transportability/occurrence into three transition zones based on HVP: nonflowable gas hydrates, flowable underinhibited hydrate slurries, and full inhibition. A flowable underinhibited hydrate slurry is defined by the concentration of THI and the degree of subcooling that effectively reduces the risk of hydrate blockage in underinhibition conditions. Visual observations indicated differences in hydrate plug morphology, with the base system displaying solid plugs (hard) and systems underinhibited with methanol exhibiting permeable plugs (porous). Our findings indicate that MeOH-based systems demonstrate a reduced tendency for hydrate plugging and delayed nucleation under conditions of lower subcooling temperatures, highlighting the importance of temperature control in hydrate management.

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Section: Introductionmentioning

confidence: 99%

Influence of Varying Underinhibition on Methanol in Gas Hydrate Agglomeration

Navaneetha Kannan,

Delgado-Linares,

Sun

et al. 2024

Energy Fuels

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“…The method, however, has the following drawbacks: it involves water-polluting surfactants, requires a long time for synthesis, and its output is relatively low. Navaneetha Kannan et al evaluated the efficiency of kinetic hydrate inhibitors using a rocking cell setup consisting of sapphire tubes in a stainless-steel body. The cells were immersed in a temperature-controlled water-filled container.…”

Section: Introductionmentioning

confidence: 99%

Production Phases of Methane and Carbon Dioxide Hydrates Intended for Energy Conversion

Vinogrodskiy,

Shlegel,

Strizhak

2024

Ind. Eng. Chem. Res.

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Today, natural gas is transported by pipelines or in a liquefied state, which is extremely cost-intensive. Using gas hydrates for gas transportation can substantially reduce these costs. However, far too little attention has been paid to developing fast and economical ways to synthesize gas hydrates. To address this research gap, we conducted several series of experiments on the synthesis of methane and carbon dioxide hydrates in a reactor with a magnetic stirrer and a working volume of 500 mL. The thermobaric conditions, stirring speed, and initial volume of water were varied to determine the optimal parameters for hydrate production. The experiments have shown that the effective hydrate production requires nonmonotonic mechanical agitation of liquid and crystals in the reactor. The stirring speed should be varied during the transitions between hydrate formation phases. As a result, the reactor input power can be reduced by 10−15%, while maintaining high production efficiency. The research findings served as a basis for a newly developed conceptual framework for the use of gas hydrates in the power industry.

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“…However, in most cases, only one end of the flowline is accessible for depressurization, leading to 1SD being used. THIs are chemical additives, such as monoethylene glycol (MEG) and methanol (MeOH), that alter the hydrate phase equilibrium curve by lowering its freezing point . When THI comes into contact with the hydrate plug, the freezing point of the hydrate is reduced, creating a thermal gradient between the pipe wall and the hydrate plug.…”

Section: Introductionmentioning

confidence: 99%

Modeling Two-Step Mechanism of Thermodynamic Hydrate Inhibitor Injection for Gas Hydrate Plug Dissociation

Kannan,

Ravichandran,

Estanga

et al. 2024

Energy Fuels

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Gas hydrate blockage in oil and gas flowlines is a major flow assurance issue that results in operational disruptions, safety hazards, and economic losses. Typically, one-sided depressurization (1SD) is deployed, followed by the injection of a thermodynamic hydrate inhibitor (THI) to accelerate the plug dissociation process. This study introduces a novel two-step mechanistic model for predicting gas hydrate plug dissociation time, addressing a critical challenge in deepwater production operations. The model uniquely integrates field 1SD and the subsequent injection of THI, incorporating simultaneous heat and mass transfer changes across the plug. The model highlights that in horizontal pipes, axial convection is the primary mechanism for THI-induced plug dissociation with rates influenced by plug characteristics (permeability, porosity, and plug length), fluid properties, and dilution due to water liberated from dissociating hydrates. The model considers the effect of the THI flow rate and THI dilution across the plug due to water liberation from dissociating hydrates. The model addresses the safe operating conditions for hydrate plug depressurization and the influence of major variables contributing to hydrate plug dissociation with THI. The advancement of this model lies in its ability to offer a realistic representation of field conditions that aids operational and design engineers in establishing safety protocols for hydrate plug remediation strategies.

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Synergistic effect of Kinetic Hydrate Inhibitor (KHI) and Monoethylene Glycol (MEG) in gas hydrate management

Cited by 7 publications

References 47 publications

Influence of Varying Underinhibition on Methanol in Gas Hydrate Agglomeration

Influence of Varying Underinhibition on Methanol in Gas Hydrate Agglomeration

Production Phases of Methane and Carbon Dioxide Hydrates Intended for Energy Conversion

Modeling Two-Step Mechanism of Thermodynamic Hydrate Inhibitor Injection for Gas Hydrate Plug Dissociation

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