Leonardo Colelli

An integrated process for the valorization of 1000 kg/h of heterogeneous plastic waste (Plasmix) into hydrogen, purified CO2, light and heavy liquid fuels, and electricity was developed and simulated using Aspen Plus. The process combines non-catalytic pyrolysis with sequential syngas upgrading, tar catalytic conversion, and extensive heat integration to maximize product recovery and economic performance. In the pyrolysis stage (600 °C, 12 bar), Plasmix is efficiently converted into gas, tar, char, and wastewater, with the gaseous fraction representing the largest product share (42.1%), followed by tar (23.0%), char (20.6%), and water (14.3%). The syngas stream is upgraded via reforming, water–gas shift, CO2 separation, and pressure swing adsorption to produce hydrogen (59 kg/h) and purified CO2 (533 kg/h), while the tar fraction is converted into liquid fuels, yielding 228 kg/h of light fuel and 23 kg/h of heavy fuel. Process integration enables substantial energy recovery, resulting in a net electricity export of approximately 18.2 MW. Economic evaluation shows a fixed capital investment of 12.21 M$, with annual revenues of 15.50 M$/year and operating expenditures of 5.33 M$/year, confirming strong baseline profitability. Sensitivity analysis identifies hydrogen and electricity selling prices as the dominant economic drivers, whereas the plastic waste fee provides a secondary contribution to profitability enhancement. Monte Carlo analysis further confirms robust financial performance under uncertainty, with predominantly positive net present values ranging from –33.6 to 129.9 M$, indicating limited downside risk and strong overall economic resilience. The internal rate of return varies between 0 and 52%, while discounted payback periods range from 0.7 to 10 years depending on market conditions. These results demonstrate that the proposed process achieves high mass valorization efficiency and economically resilient performance, providing a promising pathway for sustainable plastic waste-to-energy and waste-to-fuels integration within a circular carbon framework.

The European Union’s enhanced greenhouse gas (GHG) reduction targets for 2030 make the large-scale deployment of carbon capture and storage (CCS) technologies essential to achieve deep decarbonization goals. Within this context, this study aims to advance CCS research by developing and testing a pilot-scale system that integrates gasification for syngas and power production with CO₂ absorption and solvent regeneration. The work focuses on improving and validating the operability of a pilot plant section designed for CO₂ capture, capable of processing up to 40 kg CO₂ per day through a 6 m absorber and stripper column. Experimental campaigns were carried out using different amine-based absorbents under varied operating conditions and liquid-to-gas (L/G) ratios to evaluate capture efficiency, stability, and regeneration performance. The physical properties of regenerated and CO₂-saturated solvents (density, viscosity, pH, and CO₂ loading) were analyzed as potential indicators for monitoring solvent absorption capacity. In parallel, a process simulation and optimization study was developed in Aspen Plus, implementing a split-flow configuration to enhance energy efficiency. The combined experimental and modeling results provide insights into the optimization of solvent-based CO₂ capture processes at pilot scale, supporting the development of next-generation capture systems for low-carbon energy applications.

Chemical recycling of plastics holds great promise but remains constrained by sustainability issues, with polyethylene terephthalate (PET) epitomizing this challenge. Herein, we introduce a conceptually novel strategy that overcomes PET's intrinsic hydrophobicity by physically re‐engineering the polymer's microstructure to enable ultrafast alkaline hydrolysis under exceptionally mild conditions. We leverage the ability of propylene carbonate (PC)—an inexpensive, commercial, green solvent—to selectively dissolve PET, to thermally induce phase separation, and subsequently act as a carrier for water insertion between polymer chains. Upon complete PC replacement, the water uptake exceeds twice the polymer mass, preventing chain re‐compaction and establishing an interfacial environment that facilitates hydroxyl ion diffusion to ester bonds and depolymerization with minimal alkali consumption. As a result, water‐swollen PET fully depolymerizes (96% TPA yield) at atmospheric pressure within 5 min at 90 or under 2 h at room temperature, vastly outperforming conventional hydrolysis methods. The process achieves a 20‐fold reduction in energy footprint versus direct PET hydrolysis. It performs robustly on challenging, real‐world feedstocks—including textiles and mixed plastic waste—enabling selective depolymerization unaffected by PET crystallinity. A techno‐economic analysis (TEA) confirms energy efficiency and strong economic feasibility, demonstrating overall competitiveness with existing engineered technologies. Beyond PET, the physical mechanism underpinning the strategy offers a scalable and sustainable platform for recycling a wide range of condensation polymers.

Chemical recycling of plastics holds great promise but remains constrained by sustainability issues, with polyethylene terephthalate (PET) epitomizing this challenge. Herein, we introduce a conceptually novel strategy that overcomes PET's intrinsic hydrophobicity by physically re‐engineering the polymer's microstructure to enable ultrafast alkaline hydrolysis under exceptionally mild conditions. We leverage the ability of propylene carbonate (PC)—an inexpensive, commercial, green solvent—to selectively dissolve PET, to thermally induce phase separation, and subsequently act as a carrier for water insertion between polymer chains. Upon complete PC replacement, the water uptake exceeds twice the polymer mass, preventing chain re‐compaction and establishing an interfacial environment that facilitates hydroxyl ion diffusion to ester bonds and depolymerization with minimal alkali consumption. As a result, water‐swollen PET fully depolymerizes (96% TPA yield) at atmospheric pressure within 5 min at 90 or under 2 h at room temperature, vastly outperforming conventional hydrolysis methods. The process achieves a 20‐fold reduction in energy footprint versus direct PET hydrolysis. It performs robustly on challenging, real‐world feedstocks—including textiles and mixed plastic waste—enabling selective depolymerization unaffected by PET crystallinity. A techno‐economic analysis (TEA) confirms energy efficiency and strong economic feasibility, demonstrating overall competitiveness with existing engineered technologies. Beyond PET, the physical mechanism underpinning the strategy offers a scalable and sustainable platform for recycling a wide range of condensation polymers.

Heterogeneous catalysis plays a crucial role in various industrial processes, representing a key aspect also in the energy transition for the development of new technologies. Among them, Power to Gas (PtG), belonging to the e-fuels category, requires a deep study of catalysis to convert CO₂ and green hydrogen coming from the water electrolysis with renewable power into synthetic methane, contributing to carbon-neutral goals and net-zero emission targets. In this context, the preparation and characterization of Ru-based catalyst on alumina support are carried out through a patented experimental procedure to evaluate performance parameters for PtG applications. Two main preparations are performed to assess the differences of the final product, which is a 0.5 wt% Ru on 1/8” alumina sphere support in the dry form. In the first case, a laboratory-scale production is carried out to produce 300 g of catalyst (Batch 1), while in the second one, the preparation is brought to 3 kg of catalyst (Batch 2) by using a pilot plant. In both cases, wet impregnation technique is used to prepare the Ru-based catalyst. Beyond the production, analytical tests are performed to evaluate the main features of the product and ascertain the differences between the two productions.