Valorization of Municipal Solid Wastes and Paper Mill Sludge Through Their Steam Co-Gasification for the Production of Energy Carriers Rich in H<sub>2</sub> and Lean in Greenhouse Gas Emissions

This study aimed to explore the valorization of municipal solid wastes and paper mill sludge through their steam co-gasification, for the production of energy carriers rich in H2 and lean in CO2 greenhouse gas emissions. Waste concrete fines and paper sludge ash were investigated as CO2 sorbents and Na2CO3 as a catalyst. The experiments were carried out in a fixed bed reactor coupled with a thermal analysis-mass spectrometer unit. The analysis encompassed various aspects including the composition of the resulting gas and its heating value, H2 and syngas yield, fuel conversion and energy recovery, under different operating conditions. When quarry dust was used to capture CO2 at a calcium-to-carbon molar ratio of unity and 750 °C, H2 in the product gas was 75.7 mol%, molar ratio H2/CO was 7.19 and syngas yield was 0.65 m3/kg. When the Na2CO3 catalyst was added at a loading of 20%, H2 in the gas mixture was increased to 81%, the syngas yield to 2.82 m3/kg and conversion of fuel was complete. When paper sludge ash was used as CO2 sorbent a higher amount of CO2 was captured, however the selectivity towards H2 production was lower. The performance of Na2CO3 catalyst was better in the presence of quarry dust sorbent.