Waste to hydrogen: Steam gasification of municipal solid wastes with carbon capture for enhanced hydrogen production

Abstract

The research focuses on enhancing hydrogen production using a blend of municipal solid waste (MSW) with Biomass and mixed plastic waste (MPW) under the Bioenergy with Carbon Capture, Utilisation, and Storage (BECCUS) concept. The key challenges include optimising the feedstock blends and gasification process parameters to maximise hydrogen yield and carbon dioxide capture. This study introduces a novel approach that employs sorption-enhanced gasification and a high-temperature regenerator reactor. Using this method, syngas streams with high hydrogen contents of up to 93 mol% and 66 mol% were produced, respectively. Thermodynamic simulations with Aspen Plus® validated the integrated system for achieving high-purity hydrogen (99.99 mol%) and effective carbon dioxide isolation. The system produced 70.33 ${\text{mol}}_{H_2}/{\text{kg}}_{\text{feed}}$ when using steam as a gasifying agent while 37.95 ${\text{mol}}_{H_2}/{\text{kg}}_{\text{feed}}$ was produced under air gasification conditions. Case I employed a mixture of MSW and wood residue at a ratio of 1:1.25, with steam and calcium oxide added at 2:1 and 0.92:1, respectively, resulting in 68.80 ${\text{mol}}_{H_2}/{\text{kg}}_{\text{feed}}$ and a CO₂ capture efficiency of 92 %. Case II utilised MSW and MPW at a 1:1 ratio, with steam and calcium oxide at 2:1 and 0.4:1, respectively, producing 100.17 ${\text{mol}}_{H_2}/{\text{kg}}_{\text{feed}}$ and achieving a 90.09 % CO₂ capture efficiency. The optimised parameters significantly improve hydrogen yield and carbon capture, offering valuable insights for BECCUS applications.