Gasification of spent pot-lining from the aluminum industry

Abstract: Aluminum production generates enormous spent pot lining (SPL) waste of around one million tons yearly, and these wastes are usually disposed in landfills. Hence, the technical feasibility of SPL gasification using both equilibrium and reactive high-fidelity modeling was evaluated in this study. Three SPL with different washing treatment, i.e., water (WWSPL), acid treated (ATSPL), and full treated (FTSPL, a combination of both water and acid washing) were used for the modeling. The equilibrium model considered twelve species, while the high-fidelity simulation was modeled with multiple species. Moreover, the high fidelity model is governed by the steady non-isothermal Navier–Stokes equation coupled with the discrete phase in Eulerian–Lagrangian scheme. The process metrics were assessed via the produced syngas fraction (CO/H₂) and gasification efficiency (GE). The equilibrium analysis of WWSPL, ATSPL, FTSPL, respectively, resulted in GE of 40, 65, and 75%. The corresponding syngas molar fractions for CO and H₂ were 0.804 and 0.178 at 1450 °C; 0.769 and 0.159 at 1100 °C; and 0.730 and 0.218 at 1150 °C. These results suggest the potentiality and feasibility of gasifying the treated SPL, which was considered in the high-fidelity. Although the results show different trend from equilibrium for the FTSPL gasification (i.e., small molar fraction of CO₂ and H₂O and high syngas fraction dominated by CO at 0.75 and 0.1 H₂ at best GE of 70%), it re-emphasizes the potential of the gasification of FTSPL as recyclable/renewable energy source. Graphical abstract: [Figure not available: see fulltext.].