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/Nm3, 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.