Design and performance verification of a fast-reaction thermogravimetric analyzer

Abstract

Ca(OH)2/CaO fluidized thermochemical heat storage can provide considerable heat storage power, and is a promising large-scale energy storage technology. Owing to the limitations of existing gas–solid reaction kinetics research equipment, there is a lack of Ca(OH)2/CaO reaction kinetics research under fluidization conditions, with a lack of reliable reference data for the design and operation of fluidized bed reactors. In response to the above-mentioned problem, and through our research, we developed a fast-reaction thermogravimetric analyzer to provide samples with excellent heat and mass transfer conditions close to fluidization. The fast-reaction thermogravimetric analyzer enables the reaction of Ca(OH)2 to mainly take place under isothermal conditions by rapidly moving the high-temperature reactor, as well as inputting purge gas at a high flow rate to provide excellent mass transfer conditions for the sample, while obtaining real-time and reliable mass data for thermal analysis kinetics studies. Through an in-depth performance verification, the apparent activation energy of char combustion in a TGA (144.82 kJ/mol), fast-reaction thermogravimetric analyzer (88.32 kJ/mol), and fluidized bed reactor (47.23 kJ/mol) were obtained by the model-free method (iso-conversional). The comparison of data proved that the fast-reaction thermogravimetric analyzer could obtain kinetic parameters similar to a fluidized bed reactor, which was also verified using other materials. Therefore, the fast-reaction thermogravimetric analyzer developed in this study can provide a new solution for studying the reaction kinetics of fluidized thermochemical heat storage for Ca(OH)2/CaO, in addition to acting as a reliable reference for the design and operation of fluidized bed reactors.