GT-BTX is an aromatics recovery technology that uses extractive distillation (ED) to purify benzene, toluene and xylene (BTX) from refinery or petrochemical aromatic streams such as catalytic reformate, pyrolysis gasoline (Pygas) or coke oven light oil (COLO).
Hydrocarbon feed is preheated with hot circulating solvent and fed at a midpoint into the extractive distillation column (EDC). Lean solvent is fed at an upper point to selectively extract the aromatics into the column bottoms in a vapor/liquid distillation operation. The nonaromatic hydrocarbons exit the top of the column and pass through a condenser. A portion of the overhead stream is returned to the top of the column as reflux to wash out any entrained solvent. The balance of the overhead stream is the raffinate product, which does not require further treatment.
Rich solvent from the bottom of the EDC is routed to the solvent recovery column (SRC), where the aromatics are stripped overhead. Stripping steam from a closed-loop water circuit facilitates hydrocarbon stripping. The SRC is operated under a vacuum to reduce the boiling point at the base of the column.
Lean solvent from the bottom of the SRC is passed through heat exchange before returning to the EDC. A small portion of the lean circulating solvent is processed in a solvent regeneration step to remove heavy decomposition products.
The SRC overhead mixed aromatics product is routed to the purification section, where it is fractionated to produce chemical-grade benzene, toluene and xylenes.
Process advantages:
• Lower capital cost compared to conventional liquid-liquid extraction or other extractive distillation systems
• Energy integration options to further reduce operating costs
• Higher product purity and aromatic recovery
• Recovers aromatics from full-range BTX feedstock
• Distillation-based operation provides better control and simplified operation
• Proprietary formulation of commercially available solvent exhibits high selectivity and capacity
• Low solvent circulation rates
• Insignificant fouling due to elimination of liquid-liquid contactors
• Fewer hydrocarbon emission sources for environmental benefits
Licensor: GTC Technology
