Abstract
Chemical looping combustion combines combustion with inherent CO2 separation, offering a promising pathway for waste-to-energy with carbon capture. Yet its application to waste remains limited and knowledge transfer from other fuels is uncertain. This study analyzes 150 kWth pilot-scale tests using ilmenite as oxygen carrier firing waste-derived fuel and a reference biomass, aiming to establish a robust oxygen demand metric, and to identify dependencies between operating conditions and process performance metrics, oxygen demand and carbon capture efficiency. Omitting heavier hydrocarbons (C2–C8) from fuel reactor off-gas yielded inconsistent oxygen demand values with an underestimation of 30–60%. An alternative calculation method utilizing an oxygen balance enables process assessment with less comprehensive gas analytics. Here, the metrics align in magnitude but with systematic residual discrepancies. Fuel reactor temperature emerged as the most influential operating condition: higher temperatures consistently correlated with reduced oxygen demand (∼ 12–20 percentage points per 100 K, depending on whether C3–C8 hydrocarbons are included) and improved carbon capture (∼ 2 percentage points per 100 K). While primary combustibles (CO, H2, CH4) remained largely unaffected, heavier hydrocarbons (C2–C8) decreased nearly linearly with increasing temperatures. Other operating parameters showed only modest direct effects within the investigated operating window. Overall, the evaluation outlines high carbon capture efficiency, but also elevated oxygen demand. In the tested framework, performance is found primarily sensitive to temperature but additionally targeted strategies for enhanced hydrocarbon conversion through alternative oxygen carriers or process adaptations are further means for advancing chemical looping combustion with waste toward industrial application.