Tetraethylammonium Acetate and Tetraethylammonium Bromide-Based Deep Eutectic Solvents as Thermodynamic CO2 Gas Hydrate Inhibitors

Abstract

The thermodynamic gas hydrate suppression behavior of four Deep Eutectic Solvents (DESs) was evaluated in this paper. The mixtures of Hydrogen Bond Acceptors (HBA), Tetraethylammonium Acetate (TEAAC), and Tetraethylammonium Bromide (TEAB) with Hydrogen Bond Donors (HBD), Mono-Ethylene Glycol (MEG), and Glycerol were used to make the DES. The DESs were made at a 1:7 molar ratio for the combinations of TEAAC:MEG, TEAAC:Glycerol, TEAB:MEG, and TEAB:Glycerol. The Hydrate Liquid-Vapor Equilibrium (HLVE) data for CO2 were evaluated through the T-cycle method at different temperature (273.15–283.15 K) and pressure (2–4 MPa) conditions in the presence and absence of 5 wt % aqueous DES solutions. The inhibition effects showed by the DESs, including average suppression temperature (ΔŦ) and gas hydrate dissociation enthalpies (ΔHdiss), were also calculated. The average suppression temperature values of the DESs ranged between 0.4 and 2.4, with the highest inhibition to lowest inhibition order being TEAB:Glycerol > TEAB:MEG > TEAAC:Glycerol > TEAAC:MEG. A comparison of the DES with conventional Thermodynamic Hydrate Inhibitors (THIs) showed that studied Deep Eutectic Solvents had better gas hydrate inhibition. The results proved that DES has the potential to be one of the promising alternatives in gas hydrate inhibition.

Prediction of Greenhouse Gases Solubility in Eutectic Solvents using COSMO-RS

“…Studies show that ESs might present environmental, economic, and technological advantages over traditional organic solvents [7] due to their low prices, low vapor pressure, non ammability, biocompatibility, biodegradability, and easy preparation processes [8][9][10][11]. Consequently, both DESs and ESs have received great attention in recent decades due to their potential to replace organic solvents in various applications, such as media for extracting and purifying biocompounds [12], hydrate inhibitors [13,14], metal processing and metal decomposition agents [15][16][17], two-phase aqueous system forming agents [18,19], and gas capture media [20][21][22].…”