Catalytic gasification of municipal solid waste using eggshell-derived CaO catalyst: An investigation of optimum H2 production, production distribution, and tar compounds

This study reports the optimum hydrogen (H₂) production from municipal solid waste (MSW) via waste eggshell derived-CaO catalyst through gasification technology. The response surface model was applied to design the experiments and the data validation. Results showed that CaO catalyst had a better performance that enhanced 15 mol% more H₂ production than non-catalytic gasification by mainly involving reaction temperature and catalyst loading as the critical parameters. Tar content was efficiently declined from 11.34 wt. % to 4.7 , wt. %, which ultimately elevated the H₂ and syngas from 33.95 mol% to 51.27 mol% and 74.05 to 83.4674.05–83.46 wt. %, respectively. The model showed a strong interaction among the statistical parameters verified through the regression values; R² = 0.990, P-value = 0.000005, respectively. Scanning electron microscopy, X-ray diffraction, and Brunauer-Emmett-Teller techniques investigated the catalyst's structure hence; presented comparable results. From tar analysis, the aromatics were found as the dominant family followed by polycyclic aromatic, phenyls, aliphatic, aromatic heterocyclic, polycyclic, and aromatic ketones. Optimum H₂ production of 51.27 mol% (with H₂/CO ratio 2.82, LHV 9.47 MJ/Nm^3, and H₂ yield 22.74 mol kg-MSW⁻¹) was produced which can be a better alternative to depleting fossil fuels and utilized for liquid fuel manufacturing and power generation.