After four years of project development and execution, the new PolyFuel unit at Petrobrazi petroleum refinery in Romania has been started-up and is fully functional since April 2019. Based on the PolyFuel technology licensed by Axens (Rueil-Malmaison, France; www.axens.net), the OMV Petrom’s project at the Petrobrazi refinery enables operators to increase the fluid catalytic cracking (FCC) products value by upgrading liquefied petroleum gas (LPG) and light cracked naphtha into high-quality fuels. “The PolyFuel unit of Petrobrazi refinery is the first of its kind valorizing C4 and C5/C6 fractions into high-quality gasoline and middle distillates [diesel or Jet A1, or both], increasing the overall production of these products,” says Bruno Domergue, Axens Clean Fuels, Bio, Olefins and Gas business line director.
In the PolyFuel process (flowsheet), light olefins are oligomerized catalytically in fixed-bed reactors operating in series. Conversion and selectivity are controlled by reactor temperature adjustment, while the heat of reaction is simply removed by feed-effluent heat exchange. The reactor section effluent is fractionated to produce a gasoline fraction with low olefins content and a middle distillates fraction. A spare reactor is provided to ensure a continuous operation of the process, thus avoiding unwanted FCC shutdowns. The management of the reactors is optimized to maximize catalyst run-length.
The PolyFuel process uses the IP 811 catalyst that was first commercialized for Selectopol and Polynaphtha technologies. Thanks to its high activity and stability, IP 811 can be operated at high severity to maximize the middle distillates fraction without cracking. It is regenerable several times, allowing over 95% activity recovery, says Domergue.
Additionally, compared to alternative catalysts for this application, IP 811 has no pressure drop associated with it, and the cycle length is not limited by pressure-drop issues.