Suchergebnisse

1 figura.-- Resumen de la comunicación oral presentada en la XV Reunión del Grupo Español del Carbón, 24-27 abril 2022, Granada (España).-- O69.-- D.L. GR 695-2022 ; Una de las opciones más relevantes para la reducción de emisiones de gases de efecto invernadero (GEI) en el sector del transporte es la producción de bio-combustibles sintéticos a partir de gas de síntesis. El proceso Biomass Chemical Looping Gasification (BCLG) es una prometedora opción para producir gas de síntesis de alta calidad mediante la gasificación de biomasa sin emisiones de CO2. En el proceso BCLG un transportador sólido de oxígeno (TO) circula entre dos reactores de lecho fluidizado interconectados, reactor de combustible (RC) y reactor de aire (RA), proporcionanado el oxígeno y el calor necesario para llevar a cabo la oxidación parcial de la biomasa obteniendo un gas de síntesis libre de nitrógeno bajo condiciones autotérmicas. En el RC se produce la gasificación de la biomasa y la combustión parcial de los gases producto con los sólidos, mientras que en el RA se regenera el TO en atmósfera de aire. El objetivo de este trabajo es investigar el efecto de las principales variables operacionales sobre el comportamiento y el rendimiento a gas de síntesis del proceso BCLG en una unidad en continuo de 50 kWt, utilizando ilmenita como TO. ; Este trabajo ha sido financiado por el Proyecto CLARA de Horizon 2020 European Union funding for Research & Invitation y por el AEI/FEDER, UE-ENE2017-89473R. ; Peer reviewed

12 figures.-- This article is part of the 2021 Pioneers in Energy Research: Javier Bilbao special issue. ; Biomass chemical looping gasification (BCLG) uses lattice oxygen from an oxygen carrier instead of gaseous oxygen for high-quality syngas production without CO2 emissions. In this work, the effect of the main operating variables, such as oxygen/biomass ratio (λ), gasification temperature, and steam/biomass ratio (S/B), was investigated using two low-cost materials: a Fe ore and a Mn ore. Oxygen fed to the air reactor for oxidation was used as an effective method for controlling the amount of lattice oxygen used for syngas production. The main variable that affected the process performance and the syngas quality was λ, while the fuel reactor temperature and the S/B ratio had a minor effect. Small performance differences found between the ores can be attributed to different degrees of CH4 and light hydrocarbons reforming in the process. The CO2 content in the syngas was high (40 −43%) under autothermal conditions because the gasification reactions required the heat to be generated by combustion. CH4 contents of around 10% were found in syngas, coming from the unburned or unreformed volatiles. Syngas yields around 0.60 Nm3/kg of dry biomass were found for both ores. Additionally, high biomass conversions (Xb > 94%) and carbon conversion efficiencies (ηcc > 95%) were obtained in all cases, showing the capability of the process of avoiding CO2 emissions to the atmosphere. No agglomeration was found in the bed during the BCLG process, although attrition rates were high, leading to lifetimes of 160 and 300 h for the manganese and iron ores, respectively. Migration of Fe or Mn to the external part of the particle, generating a metal concentrated shell, was observed. Its detachment was responsible for the decrease in the oxygen transport capacity (ROC) of the material with the operating time and the reduced lifetime. The results obtained here allowed the iron ore to be considered as an oxygen carrier suitable for the BCLG process. ; This work has been supported by the European Union's Horizon 2020 Research and Innovation Framework Programme under grant Agreement 817841 [Chemical Looping Gasification for Sustainable Production of Biofuels (CLARA)] and the AEI/FEDER, UE (ENE2017-89473R). ; Peer reviewed

12 figures, 3 tables. ; Biomass Chemical Looping Gasification (BCLG) is an autothermic gasification process that provides pure syngas for many applications, including liquid biofuels production. Finding low-cost materials that can be used in the process is a key issue, especially when they come from waste. In this sense, LD Slag is a by-product of the steel industry used as an oxygen carrier in Chemical Looping Combustion with good results. This work investigates the use of LD Slag as oxygen carrier in a continuous 1.5 kW BCLG unit. The effect of the main operational variables (temperature, oxygen-to-fuel and steam-to-biomass ratios) and the use of CO instead of steam as gasification agent were analysed. LD slag allowed the process with high biomass conversions, X > 90%, carbon conversion efficiencies, η > 90%, and syngas yields, Y ≈ 0.66 Nm/kg of dry biomass, at conditions corresponding to autothermal operation. A lifetime of 300 h under reducing conditions was inferred and agglomeration problems were never detected. LD slag can be considered a suitable material for BCLG since it is possible to obtain high-quality syngas at autothermal conditions from different types of biomass with low tar generation and CO emissions. ; This work has been supported by the European Union's Horizon 2020-Research and Innovation Framework Programme under grant agreement No 817841 (Chemical Looping gAsification foR sustainable production of biofuels - CLARA), and by the AEI/FEDER, UE - ENE2017-89473-R.