Feasibility of waste-to-hydrogen generation system based on gasification/pyrolysis: a comprehensive review of experimental studies

The reliance on fossil fuels has propelled technological growth but has led to pressing global challenges, including waste accumulation, resource depletion, and environmental degradation due to greenhouse gas emissions. With annual production of 464 million metric tons of biomass and 321.5 billion metric tons of plastic waste, innovative waste management strategies are essential. This study explores the co-pyrolysis of biomass and plastic waste as a promising approach to convert these materials into biofuels, particularly hydrogen. The paper emphasizes hydrogen's role as an energy carrier and feedstock, assessing eleven pathways for hydrogen generation while analyzing their environmental impacts, energy efficiency, and risks to ecological and human health. Although acid gas production ranks as the least impactful method, biomass gasification exhibits a larger ecological footprint. Additionally, the review highlights hydrogen generation via gasification and pyrolysis, emphasizing the importance of operational conditions, including temperature management and gas-cleaning systems. While gasification, operating at higher temperatures (800-1200 degrees C), produces more hydrogen, pyrolysis offers greater feedstock versatility and simpler residue management. The findings underscore the potential of waste-to-hydrogen technologies in advancing sustainability and reducing waste, advocating for effective hydrogen storage and transportation solutions.