Effect of gas type and salinity on performance of produced water desalination using gas hydrates

Abstract

In recent years, formation of gas hydrate has been considered as a suitable method for brine water desalination. In this study, for saline produced water treatment, design of experiment with two factors, the type of gas and electrical conductivity of initial brine solution (EC0) as a measure of salinity, were applied and removal efficiencies were analyzed. For this purpose, two different hydrate formers, CO2 and natural gas (NG) were separately mixed with different produced water samples. The hydrate formation reactions were carried out at 274.2 K in 35 and 95 bar, respectively, and removal efficiencies of produced water samples were tested. It has been found that with a three-stage hydrate process, 86% of dissolved minerals can be removed by the desalination process using CO2 hydrate formation gas while this amount will be 82% when NG is applied as hydrate former. Analysis of experiments indicated that the desalting efficiency depends on the hydrate-forming gas (CO2 > NG) as well as the amount of EC0 (high EC0 > low EC0).

Investigation of the Effect of NaCl on the Kinetics of R410a Hydrate Formation in the Presence and Absence of Cyclopentane with Potential Application in Hydrate-Based Desalination

“…This is due to the fact that only molecules of water participate in hydrate structures and salts are not allowed to enter inside of hydrate structures . The main focus of researchers for the HBD process was designing a hydrate formation reactor to enhance the removal efficiency and selecting a suitable hydrate former to form hydrates at conditions close to the atmosphere. , To reduce the cost of the HBD process, it is crucial to utilize a hydrate former that can create hydrates at moderate pressures and temperatures . Therefore, formation of the intended hydrate former in the presence of seawater ions must be evaluated thermodynamically and kinetically.…”

Drivers, challenges, and emerging technologies for desalination of high-salinity brines: A critical review

“…Carbon dioxide, methane, propane, cycloalkanes, hydrofluorocarbons, and their mixtures have been studied for CHD [17,378,379]. Numerous experimental investigations on high-salinity desalination and hydrate formation in hypersaline conditions have been carried out in laboratories [381][382][383][384][385][386][387][388][389][390][391][392], but the technology has yet to be demonstrated, even at pilot-scale. Detailed reviews on CHD can be found in literature [17,378,379,393].…”

Gas Hydrate-Based Heavy Metal Ion Removal from Industrial Wastewater: A Review

“…Several studies have been performed in determining the phase equilibrium through a pilot scale set up [124][125][126][127][128][129] and the kinetics of hydrate formation have been boosted (by using secondary hydrate forming gases) [130][131][132][133]. Early commercialization of hydrate-based desalination was delayed based on the difficulty in separating the hydrate phase from the residual brine; however, the efficiency of salt exclusion has been examined, and ways to improve hydrate formation via subsequent treatment operations have been devised [133][134][135][136].…”