Other Technologies


The DTL™ process is a dry-gas-to-liquids technology that allows for flexible conversion of light olefins, present in FCC offgas, into either gasoline and distillate or concentrated aromatics, significantly increasing their value. The DTL™ process technology increases existing refinery naphtha or aromatics production through the conversion of dilute, light olefins, present in refinery FCC offgas. The DTL™ Process technology is focused on high conversion of ethylene and propylene, at low pressure conditions, without significant feed pre-treatment, to enable a cost-effective gas-to-liquids process solution for the refiner.

Using multifunctional polymerization, dehydrogenation, and aromatization catalysts, these hard-to-recover light olefins gases are converted into valuable C4+ polygas liquids.

Sweetened FCC dry-gas, comprising a mixture of hydrogen, methane, ethane and low concentration ethylene, propylene and butenes, is pre-treated, efficiently heated and reacted at high conversion, using proprietary multifunctional catalysts, to oligomerize and aromatize the contained mixed olefins. The product effluent is cooled to recover liquid polygas and a remaining fuel gas vapor. Natural gas or another supplemental fuel is used to replace the heating value of the olefins converted, if required. Polygas product is recovered and returned to the refinery. The recovery process will be customized for optimum integration with the refinery. Typical process scale and design allows for unit modularization to help reduce time of construction.


Key Features

The DTL™ process technology offers the following advantages:

  • High olefin conversion (>95%) and high C4+ liquid yield (~85%)
  • Standard refinery equipment (fixed bed reactor(s), fired heaters, absorption column, etc.), heat integration and a wide operating window
  • Compact footprint increases options for facilities siting and supports modular construction
  • Low CAPEX
  • Low operating pressures typically found downstream of the FCC wet gas compressor
  • Low utility requirements due to the exothermic reactions and energy integration
  • Customer-focused design to enable maximum octane-barrel production or maximum aromatics yield
  • Customer focused recovery design to enable optimum interface with the existing refinery
  • Robust catalyst solutions for handling a broad range of mixed olefin conversions and feed impurities
  • 13 commercial units in operation in China


INVISTA offers a comprehensive technology transfer package and proprietary catalyst for the DTL™ process technology. INVISTA is open to alternate project execution models that meet the needs of individual refineries.