Pilot testing, validation and optimisation: The pre-processed waste will be tested at ETIA where a small-scale pyrolysis unit already located. In parallel to phase 1, Repsol will build a pilot plant (including the pyrolysis unit, condensation unit, gas purification system and liquid upgrading system) at its Tech Lab in Spain. The plant will serve as the basis for testing, validation and optimisation of the entire recycling process to be scaled up at the demonstration scale. The 10kg/hour of characterised plastic waste will be fed in this plant during trials. All the processes will be tested and validated at first in the pilot plant.
- The downstream process optimisation will be done to valorise the valuable and maximize the syngas produced from the pyrolysis unit. This will be done by designing and implementing a robust pyrolysis gas cooling-condensation system for gas separation and selective fractionation of liquids.
- The separated gas will then be purified to remove contaminants (sulphur, chlorine and other halides, and tar and heavy fractions) at ambient temperature and obtain specifications that allow integration downstream of the steam cracker furnaces.
- Pyrolysis oil will be separated in two fractions liquid and heavy to adjust quality requirement.
- Light pyrolysis oil will be upgraded in a process specially designed to remove pollutant remaining (chlorides, oxygen compounds, liquid olefins and di-olefins and other metal compounds). Upgraded light pyrolysis oil will have quality required for feeding conventional steam-cracker.
- The remaining heavy oil fraction from pyrolysis will be re-pyrolysed/thermally cracked under stronger conditions to yield additional valuable gas & char.
- Finally, char produced will be purified and valorised to be used by energy-intensive industries such as cement.
This entire process will be integrated into the pilot plant at Repsol.