Experimental investigation on thermochemical heat storage using CaO/CaCO3 in a cyclone reactor

Abstract

In this study, a cyclone reactor with a secondary flow effect was applied to the CaCO3/CaO thermochemical energy storage system. An experimental platform for thermochemical energy storage with a cyclone reactor was built. A cold-state experiment was performed to study the feeding and conveying performance of CaCO3 and CaO particles. The experimental results reveal that the average feeding speeds of CaCO3 and CaO were 25.7–29.6 g/min and 3.5–11.0 g/min, respectively. The effects of different heating temperatures (750–950 °C) and inlet air velocities (4–14 m/s) on the reaction performance were studied. The results indicate that CaCO3 decomposes above 750 °C. The reaction degree increased with increased reaction temperature, and the peak value of the outlet CO2 concentration peaked (4.72 %) when the heating temperature was 950 °C, where the reaction degrees under different air velocities were similar. In addition, the inlet air velocity and the outlet relative humidity decreased owing to the formation of CO2 and CaO. In the energy release experiment, it was difficult to smoothly feed CaO into the cyclone reactor for synthesis owing to its characteristics, and no obvious change in the CO2 concentration was observed at the outlet. The energy storage reaction and flow characteristics were experimentally studied to provide a reference for the design of thermochemical energy storage reactors.