Dysprosium Oxide-Supported CaO for Thermochemical Energy Storage

Abstract

A novel CaO-based material supported with Ca3Al2O6 and Dy2O3 was found to show excellent performance as a thermochemical energy storage material for use in solar thermal power plants. It retains a carbonation conversion capacity of 82.7% for a period of 40 cycles, as well as exothermic heats of reaction of 582.2 kJ kg−1, up to seven times greater than other materials found in the literature. The improved performance was attributed to the greater prevention of sintering and retention of high surface area by the addition of two inert supports: Ca3Al2O6 and Dy2O3. Long-term effectiveness of the novel material was also evaluated by using a sintering model. It retains an energy storage utilization of 6.2 kg kWh−1 after 30 years of cycling, while commercial limestone would require 81 tons kWh−1 equivalent. Limestone requires replacement every six thermal cycles, making it impractical for real thermochemical energy storage implementation. The extra cost associated with the addition of supports in this CaO-based material is justified by the long-term durability, which would imply a reduction in the overall capital and operational expenditure of the plant.

Thermodynamic and Structural Effects of Fe Doping in Magnesium Manganese Oxides for Thermochemical Energy Storage

“…A variety of TCES materials have been previously studied, including metallic hydrides, , hydroxides, carbonates, − and metal oxide materials. ,− The metal oxide materials are compatible with high-temperature power cycles and are operable in an open loop system, eliminating the reactant gas storage needed for the other systems . Mn 3 O 4 /Mn 2 O 3 was one of the earliest proposed metal oxide TCES systems because of its high reduction temperatures and its low cost and toxicity .…”