Hydrogen production from municipal solid waste via chemical looping gasification using CuFe2O4 spinel as oxygen carrier: An Aspen Plus modeling

Abstract

Combined with carbon capture, chemical looping gasification (CLG) provides a clean and carbon-negative approach to converting municipal solid waste (MSW) into high-quality syngas without air separation units. An Aspen Plus simulation of the CLG process with continuous MSW feeding was constructed and investigated in this work. The CuFe2O4 spinel oxygen carrier (OC) was utilized to provide lattice oxygen. This model was validated using the experimental results from the literature to demonstrate its feasibility for CLG of MSW. The effects of gasification temperature, steam-to-municipal solid waste ratio (SMR) and OC mass flow (OCMF) on H2 selectivity were throughout investigated. Results demonstrated that at 750 °C, the H2 selectivity peaked at 51.44%. The H2 selectivity rose from 43.89% to 56.29% when SMR varied from 0.1 to 2.1. Lower OCMF availed H2 production. At 800 °C, SMR of 1.1 and OCMF of 100 kg h−1, 67.85% of the initially introduced H in the CLG process can be recovered as pure H2 by the end, resulting in an energy efficiency of 57.66% based on the low heat value (LHV) of MSW, the electricity consumption and H2. The process consumed 7.93 t/t H2 with a corresponding product cost of 2941.21 USD/t. Additionally, it contributes 66.90% and 66.73% to the overall global warming and acidification potentials of the entire process, respectively. The combined impact of temperature and SMR, while maintaining a constant OCMF, highlights that the temperature within the lower range primarily governs the H2 selectivity. Although both OC and steam can supply oxygen during CLG, their effects on gasification efficiency are diametrically opposed due to their varying oxidation capabilities. Notably, utilizing CuFe2O4 OC, the maximum H2 selectivity of 63.30% was achieved at 700 °C, SMR of 2.1 and OCMF of 100 kg h−1.