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

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 N-2 as carrier gas decreases because of the rapid expansion of particles. After 20 cycles with N-2 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 N-2 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. (C) 2021 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Automated summary

The study experimentally investigated the effects of key factors on the heat release performance of CaO in a fluidized bed reactor, indicating that CaO exhibits excellent cyclic stability in a fluidized state, the increase in cycle number leads to rapid particle expansion, and different carrier gas conditions influence the hydration conversion rate of CaO.