Calcium looping heat storage performance and mechanical property of CaO-based pellets under fluidization

• Published in: Chinese journal of chemical engineering Vol. 36; no. 8; pp. 170 - 180
• Main Authors: Ma, Zhangke, Li, Yingjie, Li, Boyu, Wang, Zeyan, Wang, Tao, Lei, Wentao
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2021; School of Energy and Power Engineering,Shandong University,Jinan 250061,China%State Key Laboratory of Crystal Materials,Shandong University,Jinan 250100,China%Shandong Naxin Electric Power Technology Co.,Ltd.,Jinan 250101,China
• Subjects: Calcium looping heat storage; CaO-based pellets; Fluidization; Mechanical property; Calcium looping heat storage; Fluidization; CaO-based pellets; Mechanical property
• ISSN: 1004-9541; 2210-321X
• DOI: 10.1016/j.cjche.2020.10.002

In this work, the CaO-based pellets were fabricated using extrusion-spheronization method for calcium looping thermochemical heat storage under the fluidization. The CaO-based pellets doped with 10 wt% bagasse and 5wt% Al2O3 (denoted as Ca-P2-B10-Al5) possess the highest crushing strength of 4.21N and the highest heat storage density of 1621 kJ/kg after 30 cycles. [Display omitted] The CaO-based pellets were fabricated using extrusion-spheronization method for calcium looping thermochemical heat storage under the fluidization. The effects of adhesive, biomass-based pore-forming agent, binder and particle size on the heat storage performance and mechanical property of the CaO-based pellets were investigated in a bubbling fluidized bed reactor. The addition of 2% (mass) polyvinylpyrrolidone as an adhesive not only helps granulate, but also improves the heat storage capacity of the pellets. All biomass-templated CaO-based pellets display higher heat storage capacity than biomass-free pellets, indicating that the biomass-based pore-forming agent is beneficial for heat storage under the fluidization. Especially, bagasse-templated pellets show the highest heat storage conversion of 0.61 after 10 cycles. Moreover, Al2O3 as a binder for the pellets helps obtain high mechanical strength. The CaO-based pellets doped with 10% (mass) bagasse and 5% (mass) Al2O3 reach the highest heat storage density of 1621 kJ⋅kg−1 after 30 cycles and the highest crushing strength of 4.98 N. The microstructure of the bagasse-templated pellets appears more porous than that of biomass-free pellets. The bagasse-templated CaO-based pellets doped with Al2O3 seem promising for thermochemical heat storage under the fluidization, owing to the enhanced heat storage capacity, excellent mechanical strength, and simplicity of the synthesis procedure.