Aromatics Recovery – GT-BTX Select

GT-BTX Select® is GTC’s premier aromatics recovery technology. GT-BTX Select uses extractive distillation (ED) to purify benzene, toluene, and xylene (BTX) from refinery or petrochemical aromatics streams such as catalytic reformate or pyrolysis gasoline. The process is superior to conventional liquid-liquid extraction and other extraction processes in terms of lower capital and operating costs, simplicity of operation, range of feedstock, and solvent performance.  GT-BTX Select is the most reliable method for grassroots aromatics extraction units and has been applied in revamping all of the established LLE or ED technologies.  GT-BTX Select is unique in its ability to extract high purity aromatics with nearly complete recovery from 3-carbon  boiling range feedstock.  This technology is also the optimum choice to meet the gasoline specifications of reduced benzene.

Process Description

In our GT-BTX aromatics recovery technology, 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 non-aromatic 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 raffinate product and 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 form 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 ED systems
  • Energy integration reduces 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