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Producing benzene via extractive distillation

Distapex™ from Air Liquide Engineering & Construction is an extractive distillation process for recovering aromatic hydrocarbons (benzene) from a heart-cut feedstock. The technology has proven results in terms of reliability and availability, and ensures minimal impact on the environment thanks to its use of N-methylpyrrolidone (NMP) as a solvent. Customers also benefit from low operating costs.

Multiple advantages of NMP

In the Distapex™ process, a feedstock of pyrolysis gasoline is mixed with NMP solvent, causing aromatics in the feedstock to separate via extractive distillation. The raffinate, which contains the non-aromatics, exits via the top of the extractive distillation column, while the loaded solvent enters a stripper column. At the top of this column, the final aromatic product is recovered and routed to battery limit, while the lean solvent is recycled.

One major advantage of Distapex™ is its limited impact on the environment, thanks principally to the unique properties of NMP. The solvent has a low boiling point, meaning the process needs only medium-pressure steam to be effective. Furthermore, equipment requirements for Distapex™ are minimal and operating costs are low.


  • More than 99.5% of benzene recovered
  • Proven reliability and availability
  • NMP solvent has low environmental impact
  • Low operating costs
  • Minimal equipment requirements

Key figures

  • Capacity: up to 40 tons per hour
  • Utility costs: 8.8 US Dollars per ton
  • Steam consumption: 0.7 tons per ton benzene
  • Electricity consumption: 8 Kilowatts per ton benzene
  • Water consumption: 19 cubic meters  per ton benzene
  • Solvent loss: 0.01 kilograms per ton benzene