Enhanced multi-cycle CO2 capture and tar reforming via a hybrid CaO-based absorbent/catalyst: Effects of preparation, reaction conditions and application for hydrogen production

• Published in: International journal of hydrogen energy 2023-03, Vol.48 (27), p.9988-10001
• Main Authors: Rong, Nai, Han, Long, Ma, Kaili, Liu, Qi, Wu, Yuelun, Xin, Changjian, Zhao, Jianglin, Hu, Yanjun
• Format: Article
• Language: English
• Subjects: Biomass tar reforming; Ca2Fe2O5; Calcium looping; CO2 capture; Hydrogen production
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2022.08.022

A hybrid CaO-based absorbent/catalyst (Ca–Al–Fe) for calcium looping gasification (CLG) is prepared by a two-step sol-gel method. The effects of preparation and “carbonation-calcination” conditions on cyclic carbonation performance of Ca–Al–Fe are investigated. Calcination temperature of 900 °C and calcination time of 4 h are suitable parameters for absorbent preparation. The CaO conversion of Ca–Al–Fe increases with increasing carbonation temperature below 750 °C. Under severe calcination conditions such as high temperature, high CO2 concentration and long-term up to 40 cycles, Ca–Al–Fe still shows good cyclic CO2 capture reactivity. Moreover, the effect of Ca–Al–Fe on tar removal enhancement is investigated in comparison with three candidate absorbents (Ca、Ca–Fe and Ca–Al). During five toluene reforming cycles, Ca–Al–Fe presents the highest average H2 yield and the least deposited coke with an average hydrogen concentration of about 68.8%. The average toluene conversion with Ca–Al–Fe is about 26.41% higher than that using conventional CaO. •A hybrid CaO-based absorbent/catalyst performs well in cyclic carbonation, mechanical strength and tar reforming.•Effects of preparation and “carbonation-calcination” reaction conditions on cyclic CO2 capture performance are analyzed.•Multi-cycle toluene reforming are performed to verify effects on H2 yield via enhanced tar reforming and coke inhibition.