Effect of the Fe content on the behavior of synthetic oxygen carriers in a 1.5 kW biomass chemical looping gasification unit

• Published in: Fuel (Guildford) Vol. 309; p. 122193
• Main Authors: Samprón, Iván, de Diego, Luis F., García-Labiano, Francisco, Izquierdo, María T.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.02.2022; Elsevier BV
• Subjects: Aluminum oxide; Biofuels; Biomass; Chemical-looping gasification; Cold gas; Composition; Ferric oxide; Fuels; Gasification; Iron oxides; Nuclear fuels; Oxygen; Parameters; Syngas; Synthesis gas; Tar; Tars; Biomass; Tar; Biofuels; Chemical-looping gasification; Syngas
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2021.122193

•Effect of Fe content on the behavior of a synthetic oxygen carrier in BCLG.•Syngas composition, gasification parameters, and tars not affected by Fe content.•The higher the Fe content, the higher the Fe migration to the outer layer of particle.•Greater Fe migration, higher particle deterioration and shorter particles lifetime.•Fe10Al oxygen carrier maintained excellent structural properties during operation. Biomass Chemical Looping Gasification (BCLG) is a promising technology that enables the production of high-purity and N2-free renewable syngas under autothermal operating conditions. In this work, the effect of the Fe-content (10, 20, and 25 wt% as Fe2O3) of three synthetic oxygen carriers supported on alumina was studied in a 1.5 kWth BCLG continuous unit. Similar syngas compositions and gasification parameters, biomass conversion, syngas yield, cold gas efficiency, etc., were obtained for the three oxygen carriers when analyzing the effect of oxygen-to-fuel ratio (λ) and fuel reactor (FR) temperature. Tars were also unaffected by the Fe-content, the increase in the FR temperature being the only parameter that allowed their reduction. A deep characterization of the oxygen carriers showed that the increase of Fe-content in the oxygen carrier promoted the migration of iron to the outer layer of particles, being detached of them. Lifetimes of 900, 350 and 100 h (corresponding to approximately 4500, 1750 and 500 cycles) were found for the oxygen carriers with 10 wt%, 20 wt% and 25 wt% of iron oxide, respectively. Therefore, among the three oxygen carrier tested, the one composed by a 10% of Fe2O3 was shown to be the most suitable for BCLG, providing the longest lifetime whereas the same syngas composition and tar removal could be obtained regardless of the Fe-content.