Long-term replenishment strategy of SiC-doped Mn-Fe particles for high-temperature thermochemical energy storage

Abstract

Thermal chemical energy storage (TCES) is a promising technology for large-scale energy storage, but long-term use of TCES materials can lead to attrition and reaction performance deterioration, compromising heat storage capacity and system continuity. To tackle this challenge, it is imperative to develop effective replenishment strategies and investigate the evolution of TCES materials. In this study, SiC-doped Mn-Fe particles exhibited superior performance, with only 1.87% mass loss ratio after 4.32×105 rotations attrition testing and a reaction conversion of 91.7% even after 800 reaction cycles. However, assessing material suitability for TCES systems necessitates analyzing both attrition resistance and reaction performance. A replenishment strategy was proposed, based on the attrition conversion factor and analysis of dissipated energy of particles in concentrated solar power (CSP) plants. Compared to undoped Mn-Fe particles, the annual replenishment ratio was reduced by one order of magnitude for SiC-doped particles, to only 1.26% (0.5 wt% SiC) and 0.994% (1 wt% SiC). The replenishment strategy and strengthened particles result in curtailed particle fines and particle flow interruption, and enhanced economics. Continuous replenishment strategy can undoubtedly cater to the requisite heat storage capacity demands for protracted system operation and extend system stability, promoting the advancement of TCES technology.