abstract
Concrete was evaluated as low-cost catalyst for in-situ application in an autothermal 80 kWth pilot-scale bubbling fluidized bed direct (air) biomass gasifier. To improve the understanding of the observed phenomena, the process was also evaluated in smaller-scale reactive system, namely an externally heated 3 kWth bench-scale bubbling fluidized bed. Concrete application showed promising results regarding the relative increase of H-2 concentration and H-2/CO molar ratio in the producer gas (up to 99.2 and 77.4%, respectively), indicating that this material can promote the water-gas shift reaction. However, this effect was dependent on the gas-solid contact time and catalyst temperature, being that it was only relevant when these parameters were at least 5.2 s and 746 degrees C, respectively. A maximum lower heating value of 7.5 MJ/Nm(3) of the producer gas was found with concrete application (23.8% relative increase), which is higher than commonly found in the liter-ature. Relative increases of up to 25.1, 55.3 and 47.0% for the specific dry gas production, cold gas effi-ciency and carbon conversion efficiency, respectively, were also found, consequently suggesting that, in addition to the promotion of the water-gas shift reaction, this material has potential to promote tar reforming/cracking and carbon gasification reactions. (C) 2021 Elsevier Ltd. All rights reserved.
keywords
STEAM GASIFICATION; TAR ELIMINATION; CARBON-DIOXIDE; TEMPERATURE; WASTE; DECOMPOSITION; POWDER; CAO; CO2
subject category
Thermodynamics; Energy & Fuels
authors
Pio, DT; Gomes, HGMF; Ruivo, LCM; Matos, MAA; Monteiro, JF; Frade, JR; Tarelho, LAC
our authors
Jorge Ribeiro Frade
Retired Professor
José Filipe Pinto Monteiro
PhD Student
Luís Carlos Marques Ruivo
PhD Studentacknowledgements
It is acknowledged the financial support from projects NOTA-RGAS (ref. POCI010145FEDER030661) , Inpactus-innovative products and technologies from eucalyptus, Project No 21874 funded by Portugal 2020 through European Regional Development Fund (ERDF) in the frame of COMPETE 2020 no 246/AXIS II/2017 and SusPhotoSolutionsSoluco~es Fotovoltaicas Sustent?aveis, PO Cen-tro 2020 (ref. CENTRO-01-0145-FEDER-0000 05) . Thanks are also due to the Portuguese Foundation for Science and Technology/Ministry of Science, Technology and Higher Education for the financial support to CESAM (UIDP/50017/2020thornUIDB/50017/2020) , CICECO (UIDB/50011/2020 & UIDP/50011/2020) , through national funds, and PhD grants (PhD grant ref. PD/BDE/128620/2017 (D.T. Pio) , PhD grant ref. BIM-INPACTUS/BR07/UA/07-01-2018 (H G M.F. Gomes) and PhD grant ref. SFRH/BD/129901/2017 (L C M. Ruivo) ) .