| The study of performance of the organic compound tetrahydrofuran in the hydration process for the treatment of water and petroleum wastewater in the presence of salts |
| کد مقاله : 1180-ICOC |
| نویسندگان |
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مریم کرم الدین *1، خدیجه اسکندری سبزی2، فرشاد ورامینیان3 1کارشناس مسئول گروه طراحی فرایندهای نفت- کارشناس تحصیلات تکمیلی 2دانشجو 3هیات علمی- استاد |
| چکیده مقاله |
| Considering the importance of water resource management in the oil and gas industries and the necessity of treating produced wastewater prior to discharge into the environment, this study employed the hydrate formation method using the hydrate former tetrahydrofuran (THF) to desalinate and recover saline oily and non-oily water. Tetrahydrofuran is a stable, polar, cyclic organic compound (C₄H₈O) that acts as a hydrate former in the liquid phase. By decreasing the pressure and temperature required for hydrate formation, THF enables the production of hydrate crystals under milder operating conditions. The compound accelerates hydrate formation by occupying cage-like structures within water molecules, allowing salts and other impurities to remain in the brine. For this reason, THF is considered one of the most efficient promoters in hydrate-based desalination processes. Since many oil facilities are located in water-scarce regions, the ability to treat and reuse industrial saline water is increasingly important. The hydrate-based method, which relies on crystallization, separates relatively pure water as hydrate crystals while retaining impurities in the brine. The experimental tests were carried out in a 500-cc glass reactor under atmospheric pressure. The solution consisted of saline water and THF at a volumetric ratio of 1:17, along with three concentrations of n-heptane oil (5, 5.7, and 10 g/L). Sodium chloride concentration was adjusted within the range of 1–50 g/L. Based on the electrical conductivity measurements, a desalination efficiency of 62–93% was achieved, with the highest performance observed at a salt concentration of 10 g/L. Increasing salt concentration led to longer hydrate formation and growth times as well as lower final process temperatures, indicating the inhibitory effects of ions on hydrate structures. In contrast, variations in oil concentration exhibited no significant impact on desalination efficiency. In another set of experiments, THF hydrate formation was conducted in the aqueous phase with sodium chloride concentrations of 1, 1.5, 3, and 4.5 wt%. The removal efficiency of salts in this process ranged from 52 to 66%, which is lower than the salt removal observed in the corresponding oil-phase experiments. This indicates that water desalinating through THF hydrate formation is more suitable and effective for oily wastewater and petroleum brines compared to inorganic saline effluents. Additionally, in both organic and inorganic brines, lower salt concentrations resulted in higher removal efficiencies. Therefore, implementing a preliminary water treatment step prior to the hydrate process may be beneficial for improving the purity of the recovered freshwater. Based on the obtained results, the use of THF as an organic promoter under hydrate-forming conditions can be considered an effective method for treating and recovering saline water, particularly water contaminated with oilfield wastewater. Owing to its lower energy consumption compared to conventional thermal and membrane-based methods, this process holds significant potential for industrial applications, especially in refineries. |
| کلیدواژه ها |
| Petroleum Wastewater, Desalination, Tetrahydrofuran, n-Heptane oil |
| وضعیت: پذیرفته شده |