Effect of eggshell- and homo-type Ni/Al2O3 catalysts on the pyrolysis of food waste under CO2 atmosphere

• Published in: Journal of environmental management Vol. 294; p. 112959
• Main Authors: Valizadeh, Soheil, Ko, Chang Hyun, Lee, Jechan, Lee, See Hoon, Yu, Yeon Jeong, Show, Pau Loke, Rhee, Gwang Hoon, Park, Young-Kwon
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.09.2021
• Subjects: CO2; Eggshell-type catalyst; Food waste; Nickel; Pyrolysis; Food waste; Eggshell-type catalyst; Pyrolysis; Nickel; CO2
• ISSN: 0301-4797; 1095-8630
• DOI: 10.1016/j.jenvman.2021.112959

This study highlights the potential of pyrolysis of food waste (FW) with Ni-based catalysts under CO2 atmosphere as an environmentally benign disposal technique. FW was pyrolyzed with homo-type Ni/Al2O3 (Ni–HO) or eggshell-type Ni/Al2O3 (Ni-EG) catalysts under flowing CO2 (50 mL/min) at temperatures from 500 to 700 °C for 1 h. A higher gas yield (42.05 wt%) and a lower condensable yield (36.28 wt%) were achieved for catalytic pyrolysis with Ni-EG than with Ni–HO (34.94 wt% and 40.06 wt%, respectively). In particular, the maximum volumetric content of H2 (21.48%) and CO (28.43%) and the lowest content of C2–C4 (19.22%) were obtained using the Ni-EG. The formation of cyclic species (e.g., benzene derivatives) in bio-oil was also effectively suppressed (24.87%) when the Ni-EG catalyst and CO2 medium were concurrently utilized for the FW pyrolysis. Accordingly, the simultaneous use of the Ni-EG catalyst and CO2 contributed to altering the carbon distribution of the pyrolytic products from condensable species to value-added gaseous products by facilitating ring-opening reactions and free radical mechanisms. This study should suggest that CO2-assisted catalytic pyrolysis over the Ni-EG catalyst would be an eco-friendly and sustainable strategy for disposal of FW which also provides a clean and high-quality source of energy. [Display omitted] •CO2 demonstrated a higher potential to produce gaseous products than N2.•Higher gas yield and lower bio-oil was obtained using Egg-shell than homo catalyst.•Eggshell catalyst exhibited higher stability compared to homo catalyst.•H2-rich gas was achieved by concurrent applying egg-shell catalyst and CO2.