Lignosulfonate-Based Ionic Liquids as Asphaltene Dispersants.

Area of Science:

• Petroleum Chemistry
• Materials Science
• Green Chemistry

Background:

• Asphaltenes in crude oil cause significant challenges in oil extraction and refining due to precipitation.
• Effective asphaltene dispersion is critical for cost-effective oil processing.
• Lignosulfonate (LS), a byproduct of papermaking, is an abundant and underutilized resource.

Purpose of the Study:

• To synthesize novel lignosulfonate-based ionic liquids (ILs) for asphaltene dispersion.
• To investigate the structural and thermal properties of the synthesized ILs.
• To evaluate the efficiency of these ILs in reducing asphaltene particle size and improving dispersion.

Main Methods:

• Synthesis of LS-based ILs by reacting sodium lignosulfonate with piperidinium chlorides of varying alkyl chain lengths.
• Characterization of ILs using FTIR-ATR and 1H NMR.
• Thermogravimetric analysis (TGA) for thermal stability assessment.
• Asphaltene dispersion index testing under varied conditions (time, temperature, concentration).
• Particle size analysis and kinetic modeling of the dispersion process.

Main Results:

• Four novel ILs ([C6C1Pip]2[LS], [C8C1Pip]2[LS], [C12C1Pip]2[LS], [C16C1Pip]2[LS]) were successfully synthesized and characterized.
• Synthesized ILs exhibited high thermal stability, attributed to long alkyl chains and piperidinium cations.
• All ILs showed high asphaltene dispersion indices, with [C16C1Pip]2[LS] achieving over 91.2% dispersion at 50,000 ppm.
• The ILs effectively reduced asphaltene particle size from 51 nm to 11 nm.
• Dispersion kinetics followed a pseudo-second-order model, consistent with molecular modeling.

Conclusions:

• Novel lignosulfonate-based ionic liquids are effective asphaltene dispersants.
• The long alkyl chain length on the piperidinium cation enhances dispersion performance.
• These ILs offer a sustainable and efficient solution for managing asphaltene-related challenges in the oil industry.