Analysis of CO2 reaction of thermochemical energy storage system at high temperature by superimposed micro-scale thermal imaging method (Conference Presentation)

Abstract

Thermochemical energy storage (TcES) is one of the solutions that use reversible endothermic and exothermic chemical reactions for heat storage and output, respectively. It has several advantages such as a high thermal storage density, and a constant temperature output owing to chemical equilibrium, etc. Recently, carbonation and decarobonation reaction process in Li metal oxide is proposed for use in thermochemical energy storage (TcES) and chemical heat pump (CHP) systems at around 700 °C with the cyclic reaction durability. This system is unique because there is no reported material that can be used for TcES at around 700 °C, even though this is becoming a very important temperature range for heat utilization in solar thermal power plants, high-temperature gas-cooled reactors, and for hydrogen production by fuel reforming. In this study, the method signal imposing visualized a lithium orthosilicate/carbon dioxide (Li4SiO4/CO2) reaction by absolute temperature image transformed from the decoded imposed analog temperature data. The exothermic carbonation, the endothermic solid-liquid phase change, and the endothermic decarbonation are thermally visualized above 700 °C. The analysis of the reaction surface of the carbonateoxide external shell is to be utilized to quantify the lithium diffusion to further form carbonate.