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  • Oil Refining
  • Petrochemicals
  • Gases
  • Alternative Fuels
  • Water


The SelectopolTM process is a variant of the Polynaphtha process aimed at producing an enriched N butene clean raffinate fraction for Petrochemical use. It utilizes the same catalyst as the Polynaphtha process but at lower severity in order to selectively convert the isobutene of an olefinic C4 fraction to high octane, low RVP gasoline blending stock that is easily separated from the C4 raffinate by fractionation.

Selectopol N butene raffinate is further processed into Metathesis or MEK processes and is eventually routed to the alkylation process where it improves the performance.

Axens Solutions’ Selectopol technology relies on the following main features:

  • Almost complete isobutene conversion while preserving N-butenes
  • Very High RON gasoline gasoline
  • Ideal C4 raffinate quality for Petrochemical use
  • Environmentally friendly catalyst
    • Fully regenerable catalyst
    • High mechanical strength allowing multiple regenerations
    • No pressure drop issue
    • Life time superior to 10 years has been industrially demonstrated
    • Easy catalyst loading and unloading without acidic waste
  • Mild operating conditions
  • Simple and low cost fixed beds process

The Selectopol process technology provides a low cost means of retrofitting existing MTBE units or debottlenecking existing alkylation units by converting almost all of the isobutene, without the need for additional isobutane.

Pretreatments are typically provided upstream of the Selectopol process (among them Axens Solutions Alkyfining process for dienes removal and molecular sieves ) to extend the oligomerization catalyst cycle.

When used in conjunction with the FlexEne concept, Selectopol can even bring a bonus by increasing Propylene and Distillate production through the recycling and further cracking of the oligomer product into the FCC riser.

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