Optimizing process parameters and materials for the conversion of plastic waste into hydrogen

This study has investigated hydrogen production from waste plastics using pyrolysis, steam methane reforming, and water-gas-shift reactions modelled via Aspen Plus. After evaluating multiple alternatives, polypropylene (PP) was selected as the feedstock. The research has been focused on how reformer temperature, steam-to-fuel ratio (S/F), reformer pressure, and pyrolysis temperature impact syngas composition, heating values, syngas (H2/CO) ratios, and yields of hydrogen (H2), methane (CH4), and carbon dioxide (CO2). Key findings have indicated that raising reformer temperatures to around 1000 degrees C maximizes hydrogen production in syngas, reaching peak levels of 2360 Nm3/Ton and 2525 Nm3/Ton for reformer temperature and steam-to-fuel ratio (S/F) ratios, respectively, via processes like steam methane reforming and the water-gas-shift reaction. Moreover, other parameters like steam-to-fuel (S/F) ratio and reformer pressure have produced the highest amount of hydrogen at 0.25 and 1 atm, respectively. Optimizing reformer temperature and steam-to-fuel ratio (S/F) have been selected as key in hydrogen production, with peak lower heating values (LHV) of 1.15 MJ/kg for temperature and 1.035 MJ/kg for S/F ratios, highlighting the importance of balancing these parameters for efficiency. Additionally, syngas' hydrogen (H2) composition increased with pyrolysis temperature, peaking at 8.5% at 700 degrees C. Finally, this research has provided valuable insights into optimizing process parameters for sustainable hydrogen production. Moreover, the simulation process has provided cost-effective adjustments and informed decision-making for sustainable and scalable technologies, benefiting researchers, investors, engineers, and policymakers involved in innovative hydrogen generation.