Numerical Study and Enhancement of Ca(OH)2/CaO Dehydration Process
A flow and heat transfer model in porous medium for the Ca(OH)2/CaO dehydration process is established.Three-dimensional numerical simulation is conducted to analyze the dy-namic changes of temperature and reactant concentration during the dehydration process of the Ca(OH)2/CaO thermochemical energy storage system.A series of measures are designed to enhance heat and mass transfer,such as adding various types of fins,porous channels and metal plates,changing the reactor height-to-diameter ratio and using a roundtable reactor.The temperature and pressure changes of the energy storage system under various operating conditions are analyzed.The results demonstrate that adding fins can enhance the heat transfer performance of the reactor and improve the dehydration rate.Adding porous channels not only can enhance heat transfer but also serve as a diffusion channel for water vapor,reducing the diffusion resistance of water vapor and enhancing mass transfer.Under the premise of constant porosity,increasing the height to diameter ratio of the reactor will enhance the heat transfer performance of the reactor,but it will increase the resistance of water vapor diffusion.When using a roundtable reactor,the speed of the dehydration reaction depends on the reaction rate at the maximum cross-section of the reactor.Heat transfer plays a major role in the dehydration process of the roundtable reactor compared to mass transfer.For reactors of research size,enhancing heat transfer has a greater effect on improving the perfor-mance of the reaction system than enhancing mass transfer.The result is helpful for the structural optimization and performance improvement of thermochemical energy storage reactors.
thermochemical energy storageCa(OH)2/CaOporous mediumfinporous channel
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