Desulfurization of Diesel Using Ionic Liquids: Process Design and Optimization Using COSMO-Based Models and Aspen...

Area of Science:

• Chemical Engineering
• Environmental Science
• Materials Science

Background:

• Sulfur dioxide emissions from fossil fuels cause significant health and environmental issues.
• Conventional hydrodesulfurization (HDS) is energy-intensive and struggles with complex organosulfur compounds, hindering ultralow sulfur diesel (ULSD) production.
• Ionic liquids (ILs) show potential for diesel desulfurization, but industrial-scale feasibility and process integration remain underexplored.

Purpose of the Study:

• To screen commercially available ionic liquids for efficient diesel desulfurization.
• To evaluate process configurations and ionic liquid regeneration methods for industrial application.
• To develop an optimized process for producing ULSD using Aspen Plus simulations.

Main Methods:

• Screening of 26 ionic liquids using COSMO-based models and Aspen Plus simulations.
• Evaluation of extractive regeneration (E-RE) and stripping regeneration (S-RE) methods.
• Process simulation for ULSD production with complete IL recycling.

Main Results:

• 1-butyl-3-methylimidazolium thiocyanate demonstrated superior performance for extractive desulfurization (EDS) and regeneration.
• E-RE effectively removed dibenzothiophene (DBT), while S-RE was more suitable for thiophene and benzothiophene (BT) removal.
• An optimized process achieved <10 ppm total sulfur, meeting ULSD standards with efficient IL recycling.

Conclusions:

• Ionic liquids, particularly 1-butyl-3-methylimidazolium thiocyanate, present a viable alternative to HDS for ULSD production.
• Integrated EDS and regeneration processes are crucial for economic feasibility and environmental compliance.
• Process simulation using Aspen Plus validates the potential for industrial-scale implementation.