Techno-economic and environmental evaluation of hydrogen production from municipal solid waste via CaO-assisted gasification for biorefinery applications

Climate change and GHG emissions are driving the shift from fossil fuel refineries to biorefineries, with biomass and waste playing a key role in this transition. The objective of this study is to evaluate the use of organic waste sources, especially municipal solid waste (MSW), for H₂ production with economic potential. A process model in Aspen Plus v14® was used to study CaO-assisted gasification of five wastes (food, paper, textile, plastic, and MSW) under 650–900 °C and 500–2000 kg/h steam flow, with a fixed CaO-to-feed ratio of 1. Plastic waste demonstrated the highest hydrogen yield (up to 189.6 kg/h at 2000 kg/h steam), attributed to its higher hydrocarbon content and low oxygen ratio. The integration of CaO effectively captured over 50 % of the generated CO₂, significantly enhancing syngas purity and hydrogen production through equilibrium shifts, particularly via the water-gas shift reaction. From a techno-economic perspective, plastic waste presented the lowest syngas production cost ($236.86/tonne) and highest annual net profit ($3.20 million), considerably outperforming biomass-derived feedstocks. MSW also showed favorable economics, indicating its viability as a feedstock due to its mixed composition. Environmentally, biomass-based feedstocks (paper, food waste, textile) yielded lower CO₂ emissions (378.89–449.66 kg CO₂-e/hr), highlighting their biogenic carbon neutrality benefits. Conversely, plastic waste exhibited the highest CO₂ emissions (815.41 kg CO₂-e/hr), underscoring a trade-off between economic performance and environmental impact. This research shows a promising, sustainable waste-to-fuel solution supporting biorefineries and the circular economy.