Research database

ReFuel - Strategies for the advanced hydrothermal liquefaction of recalcitrant bioresources to renewable fuel (ReFuel)

24 months (2023 - 2025)
Principal investigator(s):
Project type:
Nationally funded research - PRIN
Funding body:
Project identification number:
PoliTo role:


Europe must reach a 14% renewable share in transport fuels and a 27% penetration across energy sectors by 2030 (SET-Plan Declaration). Effective conversion of non-food/low ILUC biomass into advanced biofuels targets this result entailing lower use of fossil fuels. Hydro Thermal Liquefaction (HTL) is a promising thermochemical process effective in converting recalcitrant bioresources into a valuable “bio-crude” (BC). Despite HTL has been studied over decades, both at the fundamental and technological development levels, there are still poorly explored aspects to study. The only sustainable feedstock for industrial HTL are zero, or even negative cost residual and recalcitrant bioresources as sewage sludge (SS), food industry waste and the organic fraction of municipal solid waste (OFMSW). These are very complex matrixes made by inorganics, biogenic and not biogenic organics such as plastics. Moreover their random collective origin makes their composition highly different with time thus changing the performances of pilot HTL plants. Attempts have been made to overcome the hurdles of such variability also using pretreatment protocols. However, these approaches are empirically developed with an evident lack of knowledge on the mechanisms and the different reaction pathways activated in the process as well as on the mutual interactions between the different biomass constituents, especially for those of non-biogenic origin. Then the very effect of the different pretreatments proposed to dump seasonal variability of the biofeedstock are not yet sufficiently studied. The ReFuel project aims to get a deeper understanding of the effect of acid and alkaline pretreatments of OFMSW on their recalcitrance, mitigation of annual variability, improvement of yield and reduction of heteroatom content of achievable BC. This goal will be pursued by comparing the outcomes of pretreatment and HTL of a real feedstock, OFMSW obtained from Sicilian municipalities, and of selected model compounds representative of main OFMSW components (carbohydrates, lignin, protein, lipid, polyolefins) mixed to simulate real composition. HCOOH and KOH will be selected as pretreatment agents as they have improved yield and quality of BC from HTL of untreated SS (Prestigiacomo et al. 2021; Nazari et al. 2015). The real applicative interest of the project is demonstrated by the fact that at the Gela biorefinery is yet operative a continuous HTL pilot plant assigned to Eni Rewind that can that can produce about 100 kg of BC from HTL of OFMSW (WtF report). Refuel will enlarge the base of knowledge for an efficient exploitation of recalcitrant bioresources of interest for the production of Ministero dell'Università e della Ricerca MUR - BANDO 2022 renewable fuels in HTL and will be a sound basis for further researches in context more apt to collaboration with industry (Horizon Europe, PON).

People involved





ERC sectors

PE4_12 - Chemical reactions: mechanisms, dynamics, kinetics and catalytic reactions
PE4_18 - Environment chemistry
PE8_11 - Sustainable design (for recycling, for environment, eco-design)
PE8_2 - Chemical engineering, technical chemistry
PE8_6 - Energy processes engineering
PE8_9 - Production technology, process engineering

Sustainable Development Goals

Obiettivo 9. Costruire un'infrastruttura resiliente e promuovere l'innovazione ed una industrializzazione equa, responsabile e sostenibile|Obiettivo 15. Proteggere, ripristinare e favorire un uso sostenibile dell’ecosistema terrestre|Obiettivo 13. Promuovere azioni, a tutti i livelli, per combattere il cambiamento climatico*|Obiettivo 12. Garantire modelli sostenibili di produzione e di consumo|Obiettivo 11. Rendere le città e gli insediamenti umani inclusivi, sicuri, duraturi e sostenibili


Total cost: € 255,848.00
Total contribution: € 197,480.00
PoliTo total cost: € 127,718.00
PoliTo contribution: € 91,480.00