Kinetics of Methane Hydrate Formation in the Presence of 1-Dodecyl-2-pyrrolidinone and Tetrahydrofuran in Pure Water

Abstract

The quest for novel kinetic promoters for efficient storage and safe transportation of natural gas in the form of hydrates is an ongoing endeavor. In this study, the kinetics of methane hydrate formation have been investigated in the presence of low-foaming, nonionic, 1-dodecyl-2-pyrrolidinone and tetrahydrofuran in aqueous solution in a stirred tank reactor. The first phase of experiments has been conducted at 5 MPa and 274.15 K with varying concentrations of 1-dodecyl-2-pyrrolidinone (0.1, 0.5, 1, and 2 wt %). Similarly, the second phase of experiments has been conducted with two different concentrations of THF (19.49 and 3.89 wt %) along with 0.5 and 2 wt % of 1-dodecyl-2-pyrrolidinone using methane gas as the hydrate former at 5 MPa and 282.55 K. The pressure and temperature conditions are chosen covering both sI and sII regions. Information on the number of moles of gas consumed during hydrate formation, induction time, water-to-hydrate/gas-to-hydrate conversion, and gas storage capacity are investigated. It is observed that 1-dodecyl-2-pyrrolidinone shows good hydrate promotion characteristics with pure water for all the selected concentrations, with 0.5 wt % being on the higher side. Also, it has been observed that 1-dodecyl-2-pyrrolidinone serves as an effective kinetic promoter for the mixed methane–tetrahydrofuran hydrate at a moderate pressure and temperature of 5 MPa and 282.55 K. This study will assist in storing multifold volumes of natural gas in compact hydrate crystals suitable for natural gas storage and transportation applications.

Effect of Methylamine, Amylamine, and Decylamine on the Formation and Dissociation Kinetics of CO2 Hydrate Relevant for Carbon Dioxide Sequestration

“…The outer core of the reactor is encased for water–glycol mixture recirculation to uphold the experimental temperature. The signals given out by the platinum resistance thermometer and the pressure transducer fastened to the reactor are inline to a data acquisition system and are logged every 5 s utilizing Delta DT series recorder program software …”

“…Schematic diagram of the experimental setup. Adapted with permission from Sahu et al Copyright (2021) American Chemical Society.…”

“…The gas intake at any point throughout the duration of hydrate formation was evaluated by the following expression: where (Δ n H ↓ ) t are the moles of CO 2 consumed at any time t ; V g is the volume of CO 2 gas in the reactor; P i is the initial pressure inside the reactor; Z i is the compressibility factor at the outset of hydrate formation; R is the molar gas constant; T is the mean temperature throughout the crystallization experiment; P t is the pressure inside the reactor at time t , and Z t is the compressibility factor of the gas inside the reactor at time t . , Z was calculated real time using Pitzer correlation . The moles of CO 2 consumed per mole of water were calculated as (Δ n H ↓ ) t /moles of water ( n water ) in our study.…”

Sulfonated Castor Oil as an Efficient Biosurfactant for Improving Methane Storage in Clathrate Hydrates

“…However, the slow kinetics of gas hydrate formation is one of the most serious obstacles to implementing this technology. − Therefore, the hydrate community has focused on using special additives, namely, gas hydrate promoters (GHPs), that can accelerate the hydrate formation. , GHPs are divided into thermodynamic and kinetic types . Thermodynamic GHPs such as tetrahydrofuran, tetra- n -alkyl ammonium halides, and cyclopentane alter the equilibrium conditions of gas hydrate formation toward higher temperatures and lower pressures. − This means that they provide milder conditions for the hydrate formation, but the gas capacity of the hydrate decreases . However, the rate of hydrate formation and the high degree of conversion of water to hydrate are critical technological parameters for hydrate-based technology .…”

Effect of Asphaltenes on the Kinetics of Methane Hydrate Formation and Dissociation in Oil-in-Water Dispersion Systems Containing Light Saturated and Aromatic Hydrocarbons

“…Under such conditions, a physicochemical process (rearrangement of molecules) ensues where gas (guest) molecules are trapped in the pentagonal or hexagonal cagelike structures formed by hydrogen-bonded water (host) molecules. Upon hydrate formation, the motion of the gas (guest) molecules is restricted, and the hydrate lattice is supported and stabilized by a van der Waals interaction between them and the cages. − Gas hydrates are nonstoichiometric compounds owing to the incomplete occupancy of all of the available sites (cages) by the gas molecule due to size restrictions …”