Synthesis, characterization and performance of lignin carboxyl betaine zwitterionic surfactants for application in enhanced oil recovery

The objective of this study was to synthesize lignin carboxyl betaine zwitterionic surfactants (LCBS) from alkali lignin through a three-step reaction involving epoxidation, amination, and quaternization. The synthesized LCBS were characterized using infrared spectroscopy (IR) and thermogravimetric (TG) analysis. To assess their potential for enhanced oil recovery (EOR), the physicochemical properties of the LCBS surfactants, such as surface tension, emulsification, temperature resistance, salt resistance, and interfacial properties, were evaluated using standard experimental methods for surfactants applied in oil displacement. The LCBS surfactants exhibited higher surface activity, with low surface tension values ranging from 29.65 mN m(-1) to 31.85 mN m(-1) at the corresponding critical micelle concentration (cmc), also the significant emulsifying performance of LCBS surfactants was proved in the emulsifying experiments. Moreover, the synthesized LCBS surfactants were found to be suitable for use in harsh reservoirs of high-salinity and high-temperature, as confirmed by the temperature and salt resistance measurements. The interfacial tension (IFT) tests between Huabei crude oil and LCBS surfactants suggested that these surfactants could effectively extract the crude oil containing heavy components such as colloid and asphaltene, and ultra-low IFT values could be achieved with the addition of weak alkali.

Automated summary

The study focused on synthesizing lignin carboxyl betaine zwitterionic surfactants (LCBS) from alkali lignin through a three-step reaction. The synthesized LCBS were characterized and their physicochemical properties were evaluated for enhanced oil recovery (EOR). Results showed that the LCBS surfactants exhibited high surface activity, emulsifying performance, temperature resistance, and salt resistance. Low interfacial tension (IFT) values were achieved with the addition of weak alkali, suggesting the effectiveness of LCBS surfactants in extracting crude oil containing heavy components.