SCI和EI收录∣中国化工学会会刊

Chinese Journal of Chemical Engineering ›› 2022, Vol. 48 ›› Issue (8): 149-157.DOI: 10.1016/j.cjche.2021.08.018

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Co-adsorption behaviors of asphaltenes and different flow improvers and their impacts on the interfacial viscoelasticity

Hao Zhang1, Daiwei Liu1, Jiangbo Wen2, Guangyu Sun1,3, Chuanxian Li1,3, Xinya Chen1, Huihui Zhang1, Ze Duan1   

  1. 1. College of Pipeline and Civil Engineering, China University of Petroleum (East China), Qingdao 266580, China;
    2. School of Petroleum Engineering, Guangdong University of Petrochemical Technology, Maoming 525000, China;
    3. Shandong Key Laboratory of Oil & Gas Storage and Transportation Safety, Qingdao 266580, China
  • Received:2021-05-06 Revised:2021-08-24 Online:2022-09-30 Published:2022-08-28
  • Contact: Guangyu Sun,E-mail:sunguangyu@upc.edu.cn
  • Supported by:
    This work supported by the National Natural Science Foundation of China (51704315).

Co-adsorption behaviors of asphaltenes and different flow improvers and their impacts on the interfacial viscoelasticity

Hao Zhang1, Daiwei Liu1, Jiangbo Wen2, Guangyu Sun1,3, Chuanxian Li1,3, Xinya Chen1, Huihui Zhang1, Ze Duan1   

  1. 1. College of Pipeline and Civil Engineering, China University of Petroleum (East China), Qingdao 266580, China;
    2. School of Petroleum Engineering, Guangdong University of Petrochemical Technology, Maoming 525000, China;
    3. Shandong Key Laboratory of Oil & Gas Storage and Transportation Safety, Qingdao 266580, China
  • 通讯作者: Guangyu Sun,E-mail:sunguangyu@upc.edu.cn
  • 基金资助:
    This work supported by the National Natural Science Foundation of China (51704315).

Abstract: Commonly used flow improvers in oilfields, such as ethylene–vinyl acetate copolymer (EVA), poly(octadecyl acrylate) (POA), and polymethylsilsesquioxane (PMSQ) are proven to be effective to enhance the flowability of crude oil. However, the addition of these flow improvers may change the stability of the emulsion and make the crude oil treatment process challenging. In this research, the impacts of different flow improvers on the interfacial properties of the emulsions containing asphaltenes are systematically investigated. The co-adsorption behaviors of the flow improvers and asphaltenes are analyzed through dynamic interfacial tension (DIFT). The rheological properties of the interfacial layer after the adsorption are explored via dilational viscoelasticity. Significant difference is observed in the structural properties of the interface adsorbed by different flow improvers, which is attributed to different interactions between the flow improvers and asphaltenes. To investigate these interactions, conductivity, asphaltenes precipitation, dynamic light scattering (DLS), and contact angle experiments are conducted systematically. Results show that EVA and POA can alter the interfacial properties by changing the asphaltene dispersion state. The interaction between EVA and asphaltenes is stronger than that between POA and asphaltenes due to the difference in molecular structures. Unlike EVA and POA, the change of interfacial property with the addition of PMSQ is attributed to the partial adsorption of asphaltenes on PMSQ.

Key words: Asphaltene, Flow improver, Interfacial tension, Interfacial rheology, Emulsions, Adsorption

摘要: Commonly used flow improvers in oilfields, such as ethylene–vinyl acetate copolymer (EVA), poly(octadecyl acrylate) (POA), and polymethylsilsesquioxane (PMSQ) are proven to be effective to enhance the flowability of crude oil. However, the addition of these flow improvers may change the stability of the emulsion and make the crude oil treatment process challenging. In this research, the impacts of different flow improvers on the interfacial properties of the emulsions containing asphaltenes are systematically investigated. The co-adsorption behaviors of the flow improvers and asphaltenes are analyzed through dynamic interfacial tension (DIFT). The rheological properties of the interfacial layer after the adsorption are explored via dilational viscoelasticity. Significant difference is observed in the structural properties of the interface adsorbed by different flow improvers, which is attributed to different interactions between the flow improvers and asphaltenes. To investigate these interactions, conductivity, asphaltenes precipitation, dynamic light scattering (DLS), and contact angle experiments are conducted systematically. Results show that EVA and POA can alter the interfacial properties by changing the asphaltene dispersion state. The interaction between EVA and asphaltenes is stronger than that between POA and asphaltenes due to the difference in molecular structures. Unlike EVA and POA, the change of interfacial property with the addition of PMSQ is attributed to the partial adsorption of asphaltenes on PMSQ.

关键词: Asphaltene, Flow improver, Interfacial tension, Interfacial rheology, Emulsions, Adsorption