Wind energy-driven medical waste treatment with polygeneration and carbon neutrality: Process design, advanced exergy analysis and process optimization

This study presents a novel and original rich-O₂ steam gasification-based process integrated with carbon capture, utilization, and storage (CCUS) for carbon-neutral valorization of medical waste (MW) in Hong Kong. The process employs a calcium loop to capture CO₂ from the gasifier-produced syngas, simultaneously facilitating H₂ production. The captured CO₂ is optionally utilized to generate high value-added products like ethylene, ethanol, and acetic acid through electroreduction. The process incorporates multiple steam Rankine cycles for converting waste heat to power, achieving a total energy efficiency of 71.38%. Advanced exergy analysis reveals over 70% endogenous exergy destruction in reactors and 79.05% avoidable exergy destruction in heat exchangers and condensers, which may be paid more attention. Driven by wind energy, the process has the potential to achieve zero CO₂ emission. Economic optimization demonstrates potential profits up to 10410 HK$/h with sufficient wind energy supply and 2548.2 HK$/h with limited supply. This study highlights the novelty of a carbon-neutral MW valorization approach, CCUS utilization, advanced exergy analysis, optimization and renewable wind energy for sustainability and economic viability.