01
Heavy residues
The asphalt produced from the heavy residues of refining is the IGCC feed: up to one million tonnes a year reach the gasifiers.
IGCC plant, integrated gasification combined cycle
A 532 MW power station inside the perimeter of the ISAB refinery in Sicily, fuelled by heavy refining residues.
Technology
A refinery and a power station in one process
An integrated gasification combined cycle plant (IGCC in the international acronym) is the technology with which the refinery closes its own energy cycle, turning the heaviest fraction of the barrel into electricity and hydrogen. Few exist in the world: an IGCC makes a refinery and a power station coexist within a single process configuration. The integration works both ways. The refinery supplies the feed, and the plant returns the hydrogen that strips sulphur from the fuels.
- 532 MW
- Installed electrical capacity
- Two parallel modules
- Syngas, natural gas or gas oil
- Since 2000
- Running at Priolo Gargallo
What happens inside
Asphalt or heavy refinery residue in. Electricity, hydrogen, sulphur and metals out.
02
Gasification
At high temperature and with a deficiency of oxygen, the asphalt turns to gas and becomes synthesis gas (syngas). Metal cake settles at the bottom of the gasifiers, a concentrate of metals sent for industrial recovery.
03
Clean-up
Leaving the gasifiers, the syngas still carries sulphur and impurities. Washing cleans it and recovers liquid sulphur, a raw material for the chemical industry. Once part of the hydrogen it carries has been recovered, the syngas goes to the gas turbines to generate electricity.
04
Combined cycle
The syngas feeds the two gas turbines; heat recovered from the exhaust raises steam, which drives two steam turbines for a further share of generation. Total installed capacity is 532 MW. Over the years the flexibility of the gas turbines has grown to the point of allowing them to run on natural gas or gas oil as well.
05
Separation unit
Up to 20,000 normal cubic metres an hour of high-purity hydrogen (99.9%) are recovered from the syngas and sent to the North and South Plants for the desulphurisation of gasoline and gas oils.
Residue as a system resource
Few technologies tie an industrial cycle so closely to a nation’s energy security.
01
Few in the world
Plants that integrate gasification with a combined cycle number a few dozen worldwide, and a handful in Europe. Refineries with electricity generation fed by their own production cycle are therefore rare.
02
Circular economy
Sulphur and metals return to industry as raw materials, hydrogen goes back to the refinery, and fresh water comes from desalinated seawater. Nothing leaves the cycle before it has given what it could.
03
A resource for the grid
Beyond generating electricity, the IGCC plant is qualified for the Dispatching Services Market and the Balancing Market: a flexible resource for Italy’s electricity system.
Milestones
From 2000 to today, in four dates
2000
The plant comes on stream and begins producing and selling electricity.
2014
On 1 July the IGCC business unit passes to ISAB.
2025
The conversion to natural gas opens access to the grid services markets.
2026
The plant enters the capacity market and obtains authorisation to run on gas oil.