Chemical looping steam reforming of ethanol without and with in-situ CO2 capture. (1st February 2022)

• Record Type: Journal Article
• Authors: Zeng, Pingchao; Dou, Binlin; Zhang, Hua; Wu, Kai; Zhao, Longfei; Luo, Chuanqi; Chen, Haisheng; Xu, Yujie
• Is Part Of: International journal of hydrogen energy. Volume 47:Number 10(2022)
• Page Start: 6552
• Page End: 6568
• Publication Date: 2022-02-01
• Subjects: Chemical looping steam reforming -- Sorption-enhanced chemical looping steam reforming (SE-CLSR) -- NiO/MgAl2O4 -- Hydrogen production; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2021.12.066
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Chemical looping steam reforming (CLSR) of ethanol using oxygen carriers (OCs) for hydrogen production has been considered a highly efficient technology. In this study, NiO/MgAl2 O4 oxygen carriers (OCs) were employed for hydrogen production via CLSR with and without CaO sorbent for in-situ CO2 removal (sorption enhanced chemical looping steam reforming, SE-CLSR). To find optimal reaction conditions of the CLSR process, including reforming temperatures, the catalyst mass, and the NiO loadings on hydrogen production performances were studied. The results reveal that the optimal temperature of OCs for hydrogen production is 650 °C. In addition, 96% hydrogen selectivity and a 'dead time' (the reduced time of OCs) less than 1 minute is obtained with the 1 g 20NiO/MgAl2 O4 catalysts. The superior catalytic activity of 20NiO/MgAl2 O4 is due to the maximal quantity of NiO loadings providing the most Ni active surface centers. High purity hydrogen is successfully produced via CLSR coupling with CaO sorbent in-situ CO2 removal (SE-CLSR), and the breakthrough time of CaO is about 20 minutes under the condition that space velocity was 1.908 h −1 . Stability CLSR experiments found that the hydrogen production and hydrogen selectivity decreased obviously from 207 mmol to 174 mmol and 95%–85% due to the inevitable OCs sintering and carbon deposition. Finally, stable hydrogen production with the purity of 89%∼87% and selectivity of 96%∼93% was obtained in the modified stability SE-CLSR experiments. Graphical abstract: Image 1 Highlights: High catalytic OCs were developed via the modified Pechi method. 20NiO/MgAl2 O4 attained 96% H2 selectivity and 1 minute 'dead time' in CLSR. The breakthrough time of CaO was 20 minutes in SE-CLSR. Stable H2 yield with high purity was obtained in the long-term modified SE–CLR.