PTQ Q3 2025 Issue

Non-aromatics (Ranate)

Vacuum

Aromatics (extract)

Vacuum

Aromatics (extract)

Extractive distillation column (EDC)

Solvent recovery column (SRC)

Extractive distillation column (EDC)

Solvent recovery column (SRC)

HC feed

Rich solvent

HC feed

SRC

Rich solvent

EDC

Regen. solvent + steam

SRC

EDC

Vacuum

178 C

Stripping steam

Solvent regenerator (SR)

2% lean solvent

Lean solvent

170 C

Lean solvent

Mag AFS

Stripping steam

Regenerated lean solvent

Slurry of solid Fe, Cl, other elements, Heavy HC (no solvent)

Slurry of solid Fe, other elements, Heavy HC & solvent

Figure 1 Simplified sulfolane solvent loop

Figure 2 MagAFS installed on solvent loop

that even the finest contaminants are eliminated, maintain - ing solvent purity.  Reduced regeneration frequency : By keeping solvent streams clean, the filter reduces the need for frequent regeneration cycles, thereby extending the lifespan of sol - vents and reducing downtime.  Cost savings : With fewer regeneration cycles and less need for fresh solvent make-up, operational costs are sig - nificantly lowered. Additionally, the reduced corrosivity of clean solvents minimises equipment maintenance and replacement costs.  Improved operational efficiency : Cleaner solvents lead to more efficient processes, as there is less risk of fouling and equipment damage. This results in smoother opera - tions and higher productivity. The MagAFS technology leverages a patented design and an external magnetic field to efficiently eliminate fer - romagnetic, paramagnetic, and diamagnetic solids and particles from both gas and liquid streams. This sophis - ticated filtration system is capable of removing ultrafine particles, including those smaller than 100 nm. Unlike traditional magnetic filtration systems that only target ferromagnetic materials, MagAFS can filter a diverse array of contaminants such as iron sulphides, coke fines, manganese, chromium, and silica. This extensive filtration capability ensures it effectively maintains solvent purity and prevents operational issues caused by particulate contaminants. By preserving full flow rate while filtering fines, MagAFS significantly enhances the operational lifespan of any downstream filtration systems, reducing the frequency of carbon and cartridge replacements, and minimises down - time, resulting in considerable cost savings. When the pro - cess stream enters the filter, it passes through a perforated metal cage and interacts with proprietary packing media under the influence of permanent magnetic bar assemblies. The magnetic field attracts the solids to the surfaces of the packing media, ensuring the filtered stream remains free from particulate contaminants. During the clean-up cycle, the filter cover plate is opened,

and the entire core assembly is removed from the filter housing. The magnetic bar assemblies are then extracted to release the collected solids, and the core assembly is washed with water or another suitable fluid before being reinserted. The cleaned core assembly is repositioned into the filter housing, and the top opening is sealed with a cover plate and gasket, ready for the next operational cycle. In some designs, the magnetic bar assemblies can be removed without the need to open the pressure boundary of the filter housing. This allows cleaning in place, resulting in the unit being safely flushed clean without the risks asso - ciated with intrusive dismantling. In this process application, sulfolane, a polar solvent, is used to selectively dissolve aromatic hydrocarbons from the hydrocarbon feed mixture within the distillation col - umn. The aromatic-rich liquid phase is then separated from the non-aromatic vapour phase. The aromatic-rich phase undergoes further processing in a solvent recovery unit to isolate the purified aromatics and regenerate the sulfolane for reuse. Case studies and results Extractive solvent system In the regeneration section, the use of MagAFS has shown remarkable results. The technology effectively replaced the existing cartridge filtration system and removed very high levels of solid contaminants, ensuring solvent purity and reducing the need for costly disposable filter cartridges. The filtration efficiency has become so effective that the solvent regenerating reboiler duty has decreased signifi - cantly and is not required to maintain continuous operation. This effectively reduces a significant high pressure steam load for the plant and, in turn, results in substantial energy savings. Figure 1 highlights a simplified process flow diagram of the process changes with the inclusion of the MagAFS filtration system. Figure 2 illustrates the designed flow scheme for the sulfolane solvent loop with simple circulation of solvent between the extractive distillation column and the sol - vent recovery column. On the solvent recovery column,

PTQ Q3 2025