Converting source-separated organics from municipal solid waste into high-quality bio-oil and hydrogen-rich syngas through a hybrid intermediate pyrolysis system

Abstract

The growing imperative for sustainable waste management and cleaner energy production has spurred global interest in advanced thermochemical processes for valorising municipal solid waste (MSW). This study investigates the thermo-catalytic reforming (TCR®) of pelletized source-separated organic (SSO) feedstock from landfill-diverted waste via a 2 kg h⁻¹ hybrid intermediate pyrolysis system to optimise yields of high-quality bio-oil and hydrogen-rich syngas. There is very limited research on thermo-catalytic reforming of SSO globally. As H₂, bio-oil, and biochar gain focus for climate mitigation, this TCR system offers balanced production of all three valuable by-products, leveraging the inherent catalytic activity of the biochar enriched with alkali and alkaline earth metals to enhance reforming reactions and H₂ yield. The research identifies optimal reactor/reformer temperatures for maximising bio-oil yield (6.20%), with the highest production observed at 500/500°C. At 500/650°C reactor/ reformer temperatures, syngas contained 36.36 vol% H₂ and 11.05 vol% CH₄, with a higher heating value (HHV) of 20.12 MJ kg⁻¹, suitable for use as feedstock in Fisher-Tropsch synthesis for chemicals or fuel production. The produced bio-oil has low viscosity (31.79 mPa s⁻¹), low aromatic hydrocarbon content, low total acid number (11.35 mg KOH g⁻¹), and reduced monocyclic and polycyclic aromatic hydrocarbons (6.02% and 15.92% at 400/650°C); biochar at optimal conditions displays low HHV and increasing inorganic content (from 6.02 to 8.89 wt%) with temperature, supporting potential soil remediation applications. These findings demonstrate that TCR® enables efficient waste-to-energy conversion and provides a scalable model for organics valorisation with potential to guide global strategies for MSW management.