Heat release performance and evolution of CaO particles under fluidization for CaO/Ca(OH)2 thermochemical heat storage

• Published in: Process safety and environmental protection Vol. 155; pp. 166 - 176
• Main Authors: Bian, Zhiguo, Li, Yingjie, Zhang, Chunxiao, Zhao, Jianli, Wang, Tao, Lei, Wentao
• Format: Journal Article
• Language: English
• Published: Rugby Elsevier B.V 01.11.2021; Elsevier Science Ltd
• Subjects: Calcium hydroxide; Calcium oxide; CaO/Ca(OH)2 cycle; Carbon dioxide; Carrier gases; Conversion; Fluidization; Fluidized bed reactors; Fluidized beds; Heat; Heat release temperature; Heat storage; Heat transfer; Hydration; Particle size; Reactors; Slaked lime; Steam; Thermal cycling; Thermochemical heat storage; Heat release temperature; CaO/Ca(OH)2 cycle; Thermochemical heat storage; Fluidization
• ISSN: 0957-5820; 1744-3598
• DOI: 10.1016/j.psep.2021.09.019

The fluidized bed reactor has been recognized for large-scale CaO/Ca(OH)2 heat storage system. In this work, the effects of critical factors such as particle size, fluidization number, steam concentration in hydration, initial temperature, cycle number and type of carrier gas on heat release performance of CaO in the fluidized bed reactor were experimentally investigated. CaO under fluidization state exhibits excellent cyclic stability on the heat release performance. The decay in heat release temperature of CaO under fluidization state is less 10% of that under static state. With increasing the cycle number, the heat release temperature of CaO using N2 as carrier gas decreases because of the rapid expansion of particles. After 20 cycles with N2 as carrier gas, the average particle size of CaO increases by 46.2% and the hydration conversion of CaO reaches above 95%. The hydration conversion of CaO experienced 20 cycles using air as carrier gas is 20% lower than that using N2 as carrier gas due to the presence of CO2 in air. The experimental investigation of CaO/Ca(OH)2 heat storage provides an important reference for the development of CaO/Ca(OH)2 system using the fluidized bed reactor.