Eni SPA has initiated the environmental permitting process to convert subsidiary Versalis SPA’s conversion of the Priolo Gargallo steam-cracking plant in eastern Sicily by yearend 2028 into an integrated biorefining and chemical recycling hub, the company said on Oct. 9.
Eni confirmed the Italian Ministry of the Environment and Energy Security recently approved an application to begin the proposed project’s environmental impact assessment (EIA), marking the next phase in the operator’s transition of the Priolo site from conventional petrochemical production to renewable fuels and circular economy technologies.
The redevelopment plan will involve repurposing the area currently occupied by the Versalis-operated ethylene steam cracker, which will be gradually decommissioned, along with adjacent site service infrastructure. Upon completion, the project will include a new:
- 500,000-tonne/year (tpy) biorefinery.
- Biogenic feedstock pretreatment unit.
- Hydrogen production plant.
- 40,000-tpy chemical recycling plant for plastics.
First announced in 2024, the proposed plan to transform the Priolo site was formalized by an agreement with the Ministry of Enterprises and Made in Italy (MIMIT) in March 2025, the operator said.
Project details, technologies
The planned Priolo biorefinery—which will be Eni’s second in Sicily, following its conversion of the conventional 105,000-b/d Gela refinery into a biorefinery that began producing hydrotreated vegetable oil (HVO) in 2019—will process residues and waste of vegetable origin, animal fats, and vegetable oils to produce renewable HVO diesel, sustainable aviation fuel (SAF), and bio-naphtha.
As previously disclosed, the Priolo renewables refinery will be based on the Eni-Honeywell UOP LLC codeveloped proprietary Ecofining process technology to enable flexible conversion of various biogenic feedstocks into HVO and SAF, aligning with the European Union’s Renewable Energy Directive (RED II) and other emerging mandates for low-carbon aviation fuels.
Priolo’s planned chemical recycling plant will be based on Hoop chemical recycling technology developed by Versalis in partnership with Italian engineering firm S.R.S. (Servizi di Ricerche e Sviluppo).
Piloted in a demonstration Hoop unit at Versalis’ research site in Mantua, Italy, during June 2025, the technology uses high-performance pyrolysis integrated with artificial intelligence for process optimization and material recovery, as well as complements mechanical recycling by enabling recovery of plastic waste that is otherwise unsuitable for conventional reuse.
Once operable, the Priolo recycling plant will be able to process up to 40,000 tpy of mixed-plastic packaging waste to produce about 32,000 tpy of pyrolysis oil that can be used as feedstock to produce new plastic materials, including feedstock for food-grade and pharmaceutical packaging.
With the EIA now under way, Eni said it expects the conversion project—including the biorefinery and recycling plant—to be completed and commissioned by yearend 2028.
Advancing decarbonization
The Priolo project forms part of Eni’s broader decarbonization strategy, which targets over 5 million tpy of biorefining capacity by 2030.
Eni’s additional projects aimed at increasing renewable fuels production capacity include:
- The Sannazzaro de’ Burgondi refinery conversion (550,000 tpy capacity; startup in 2028).
- The Livorno refinery transformation (500,000 tpy; startup in 2026).
- International expansion through joint ventures in Malaysia and South Korea.
In September, Eni revealed the Sannazzaro project—led by subsidiary Enilive SPA—will involve repurposing the Sannazzaro refinery’s second hydrocracking unit (HDC2) for production of HVO and SAF based on Ecofining technology, as well as include installation of a pretreatment unit for biogenic waste feedstocks.
Eni—the first global operator to convert conventional refineries into biorefineries, starting with its Venice refinery in 2014—said the planned Priolo, Sannazzaro, and Livorno projects will position it to supply both domestic and international markets with low-carbon fuels across road, aviation, marine, and rail sectors.
