Sviluppo di sistemi di produzione di idrogeno da scarti organici su taglie di 1-10 MW come scarti in ingresso

The sustained growth of global population, coupled with rising energy demand and escalating plastic and biogenic waste generation, places increasing pressure on global energy and environmental systems, underscoring the urgency of waste valorisation pathways and the transition toward more sustainable energy systems. In this context, gasification has emerged as a promising thermochemical pathway capable of converting heterogeneous solid waste streams into syngas, a versatile intermediate for energy and chemical production. This doctoral research systematically advanced the scientific understanding and technological development of gasification through a multi-scale and interdisciplinary approach, bridging feedstock characterization, experimental and modelling studies of the process, reactor design, and plant-level analysis. The study first investigated devolatilization, the initial stage of gasification, through combined experimental and modelling analyses of plastics and lignocellulosic biomass. These results elucidated the influence of feedstock properties, particle size, and pretreatment strategies on volatile release, tar distribution, and char formation, while providing kinetic formulations for integration into relevant scale simulations. Laboratory- and pilot-scale gasification experiments demonstrated the effectiveness of the process and highlighted the decisive role of catalytic reforming, hydrothermal carbonization, and sorption-enhanced approaches in improving syngas yield, hydrogen enrichment, and tar suppression. Complementary modelling efforts combined a kinetic-based Matlab framework with Computational Particle Fluid Dynamics (CPFD) simulations, enabling predictive analysis of multiphase flow and reaction kinetics under both atmospheric and pressurized conditions. To enhance industrial applicability and address plant-level requirements associated with process scale-up, throughput increase, and system integration, a pressurized internally circulating dual fluidized bed reactor concept was developed and validated through iterative design, sensitivity analysis, and systematic scale-up assessments. The resulting geometry ensured stable solids circulation, efficient heat transfer, and compact operation under elevated pressures. Finally, plant-scale simulations in Aspen Plus translated the outcomes into full process configurations for hydrogen, synthetic methane, and methanol production. Comparative assessments revealed trade-offs between efficiency, carbon utilization, and infrastructure compatibility, providing a structured basis for future techno-economic evaluation. Overall, this work consolidates gasification as a robust and scalable technology for the valorisation of plastic and biogenic waste, offering practical knowledge on devolatilization kinetics, gasification performances, syngas upgrading strategies, reactor fluid-dynamics, and process integration. The results contribute to advancing sustainable energy and chemical production pathways, supporting the transition toward circular economy systems and reduced reliance on fossil resources.