THE EFFECT OF THE AQUEOUS PHASE pH AND SALINITY ON THE DEMULSIFICATION EFFICIENCY OF HEAVY OIL FROM UKRAINIAN DEPOSITS
DOI:
https://doi.org/10.18372/2310-5461.69.20955Keywords:
demulsifier composition, oil emulsion, hydrophilicity, lipophilicity, surfactant, dewatering degreeAbstract
The presence of water, mechanical impurities, and salts in oils, especially heavy oils, creates serious problems during oil transportation and processing at refineries. Such compounds contribute to the formation of stable oil emulsions, which requires the use of additional technologies for dehydration, desalination, and oil purification, increases operating costs, and leads to higher energy consumption.
Demulsification remains a key process for removing water and salts from crude oil. The effectiveness of demulsification depends on many factors, including the nature and properties of the oil and demulsifier, the concentration of the demulsifier, the type of emulsion formed, the temperature, pH, and the water and salt content in the oil. An analysis of publications and studies has shown that for heavy oils from Ukrainian fields, the influence of many of these factors has hardly been studied.
To solve this problem, the study investigated the demulsification process of heavy high-viscosity oil from the Bugruvativske field (Sumy region, Ukraine) using three compositions synthesized by the authors. The compositions are based on commercial demulsifiers of the Dissolvan brand (Clariant, Switzerland). The dependence of the effectiveness of these compositions on the NaCl concentration and pH was established. It was determined that the highest efficiency (93-95%) of the studied compositions, regardless of the type and ratio of components in them, is observed in a neutral environment (pH≈7). Increasing the pH to 10 or decreasing it to 2 significantly reduces the dewatering degree. It has been shown that despite a 1.1-1.3-fold decrease in the dewatering degree, when the salinity of the aqueous phase increases from 10,000 mg/L to 50,000 mg/L, the efficiency of demulsifiers remains at a fairly high level of 70-82%. Demulsifiers with a higher ethylene oxide content are more effective at lower salinity, while those with a higher propylene oxide content showed better results at high NaCl concentrations.
It was concluded that all synthesized compositions are effective in a neutral environment and high salinity of the aqueous phase. Different ratios of oxyethylated and oxypropylated components in the compositions and the use of different solvents affect their effectiveness.
To ensure the reliability and effectiveness of synthesized demulsifier compositions in industrial applications, future research should focus on understanding the optimization mechanism and more thoroughly investigating synergism in multicomponent systems.
References
Li, J., Xia, X., Gao, J., Chen, H., & Ma, J. (2025). Polyether demulsifier complexes for efficient demulsification of water-in-heavy oil emulsions. Molecules, 30(12), Article 2550. https://doi.org/10.3390/molecules30122550
Vasyliuk, L. M., & Vasyliuk, R. L. (2025). Optymizatsiia protsesiv promyslovoi pidhotovky nafty iz zastosuvanniam deemulhatoriv na rodovyshchakh Zakhidnoho naftopromyslovoho rehionu PAT «Ukrnafta». Naftohazova enerhetyka, 1(43), 50–61. https://doi.org/10.31471/1993-9868-2025-1(43)-50-61
Hadi, H. A., & Mohammed, T. J. (2020). Improvement in demulsification of Iraqi crude oil with water removal demulsifiers in oil fields. IOP Conference Series: Materials Science and Engineering, 737, Article 012194. https://doi.org/10.1088/1757-899X/737/1/012194
Raya, S. A., Mohd Saaid, I., Abbas Ahmed, A. & Abubakar Abukar, U. (2020). A critical review of development and demulsification mechanisms of crude oil emulsion in the petroleum industry. Journal of Petroleum Exploration and Production Technology, 10, 1711–1728. https://doi.org/10.1007/s13202-020-00830-7
Rajan, H., Yusuf, N. R., Mohsim, D. F., & Halim, N. H. B. (2023). Chemical demulsification of oil-in-water emulsion from gas condensate field. Substantia, 7(2), 7–19. https://doi.org/10.36253/Substantia-2035
Roshan, N., Ghader, S., & Rahimpour, M. R. (2018). Application of the response surface methodology for modeling demulsification of crude oilemulsion using a demulsifier. Journal of Dispersion Science and Technology, 39(5), 700–710. https://doi.org/10.1080/01932691.2017.1385480
Biniaz, P., Farsi, M., & Rahimpour M. R. (2016). Demulsification of water in oil emulsion using ionic liquids: Statistical modeling and optimization. Fuel, 184, 325–333. https://doi.org/10.1016/j.fuel.2016.06.093
Fortuny, M., Oliveira, C. B. Z., Melo, R. L. F. V., Nele, M., Coutinho, R. C. C., & Santos, A. F. (2007). Effect of salinity, temperature, water content, and pH on the microwave demulsification of crude oil emulsions. Energy Fuels, 21(3), 1358–1364. https://doi.org/10.1021/ef0603885
Dicharry, C., & Graciaa, A. (2007). Influence of pH and water content on the type and stability of acidic crude oil emulsions. Energy Fuels, 21(3), 1337–1342. https://doi.org/10.1021/ef060376j
Zaki, N. N., Abdel-Raouf, M. E., & Abdci-Azim A.-A. A. (1996). Propylene oxide-ethylene oxide blockcopolymers as demulsifiers for water-in-oil emulsions, II [1]. Effects of temperature, salinity, ph-value, and solvents on the demulsification efficiency. Monatshefte für Chemie, 127, 1239–1245. https://doi.org/10.1007/BF00807790
Hajivand, Р., & Vaziri A. (2015). Optimization of demulsifier formulation for separation of water from crude oil emulsions. Brazilian Journal of Chemical Engineering, 32(01), 107–118. https://doi.org/10.1590/0104-6632.20150321s00002755
Yazdanmehr, F. & Nistor, I. (2021). Demulsifier selection for water separation from heavy crude oil emulsions of Iranian oil field. Romanian Journal of Petroleum & Gas Technology, 2(73), 62–72. https://doi.org/10.51865/JPGT.2021.01.06
Pal, B., Kumar, R., & Naiya, T. K. (2021). Demulsification of crude oil-water emulsion using naturally formulated demulsifier. Petroleum Science and Technology, 39(21–22), 1027–1042. https://doi.org/10.1080/10916466.2021.1983599
Maddah, Z. H., & Naife, T. N. (2019). Demulsification of water in Iraqi crude oil emulsion. Journal of Engineering, 25(11), 37–46. https://doi.org/10.31026/j.eng.2019.11.03
Maaref, S., & Ayatollahi, S. (2017). The effect of brine salinity on water-in-oil emulsion stability through droplet size distribution analysis: A case study. Journal of Dispersion Science and Technology, 39, 721–733. https://doi.org/10.1080/01932691.2017.1386569
Sarmas-Farfan, J., Diaz-Barrios, A., Lehmann, T. E., & Alvarado, V. (2025). Demulsification kinetics of water-in-oil emulsions of Ecuadorian crude oil: Influence of temperature and salinity. Energies, 18(12), Article 3115. https://doi.org/10.3390/en18123115
Alves, D. R., Carneiro, J. S. A., Oliveira, I. F., Façanha, F., Santos, A. F., Dariva, C., Franceschi, E., & Fortuny, M. (2014). Influence of the salinity on the interfacial properties of a Brazilian crude oil–brine systems. Fuel, 118, 21–26. https://doi.org/10.1016/j.fuel.2013.10.05
Zhang, Y., Wang, F., & Li S. (2025). Comparison of phenolic antioxidants’ impact on thermal oxidation stability of pentaerythritol ester insulating oil. IEEE Transactions on Dielectrics and Electrical Insulation, 32(3), 1518–1527. https://doi.org/10.1109/TDEI.2024.3487148
Shyshchak, M., Topilnytskyy, P., Romanchuk, V., Yarmola, T., & Dudok, G. (2025). Development and research of demulsifier compositions for dewatering of heavy crude oils from Ukrainian fields. Chemistry & Chemical Technology, 19(2), 378–384. https://doi.org/10.23939/chcht19.02.378
Zhang, Y., Liu, H., & Xia, G. (2022). Synthesis and research of highly efficient polyether demulsifier. ChemistrySelect, 7(25), Article e202104573. https://doi.org/10.1002/slct.202104573
Gao, P., Xing, X.-C., Li, Y., Ngai, T., & Jin, F. (2014). Charging and discharging of single colloidal particles at oil/water interfaces. Scientific Reports, 4, Article 4778. https://doi.org/10.1038/srep04778
Zaman, H., Ali, N., Shah, A. H. A., Gao, X., Zhang, S., Hong, K., & Bilal, M. (2019). Effect of pH and salinity on stability and dynamic properties of magnetic composite amphiphilic demulsifier molecules at the oil-water interface. Journal of Molecular Liquids, 290, Article 111186. https://doi.org/10.1016/j.molliq.2019.111186
Abdel-Azim, A. A. A., Mekewi, M. A., & Gouda, S. R. (2002). Nonionic surfactants from poly(ethylene terephthalate) waste: II. Effect of temperature, salinity, pH-value, and solvents on the demulsification efficiency. International Journal of Polymeric Materials and Polymeric Biomaterials, 51(3), 265–274. https://doi.org/10.1080/00914030213037
Topilnytskyy, P., Yarmola, T., Romanchuk, V., & Kucińska-Lipka, J. (2021). Peculiarities of dewatering technology for heavy high-viscosity crude oils of Eastern region of Ukraine. Chemistry & Chemical Technology, 15(3), 423–431. https://doi.org/10.23939/chcht15.03.423.
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