Influence of Long-Term CaO Storage Conditions on the Calcium Looping Thermochemical Reactivity

Area of Science:

• Chemical Engineering
• Energy Storage
• Materials Science

Background:

• Calcium looping is a promising thermochemical energy storage system for solar power plants.
• Long-term storage capability is a key advantage, but storage conditions' impact on performance is understudied.

Purpose of the Study:

• To experimentally evaluate the influence of storage conditions on calcium looping performance.
• To assess the effects of low-temperature (50-200 °C in CO2) and high-temperature (800 °C in N2) solid storage.

Main Methods:

• Lab-scale experiments simulating different solid storage conditions.
• Analysis of carbonation extent and multicycle performance after storage.
• Conceptual process engineering evaluation of storage scenarios.

Main Results:

• Carbonation is limited below 200 °C, allowing extended storage even in CO2.
• Multicycle performance is largely unaffected by low-temperature (CO2) or high-temperature (N2) storage.
• High-temperature storage enhances energy density (+40-62%) and plant efficiency (+2-4%) due to easier heat integration.

Conclusions:

• Calcium looping demonstrates viable long-term energy storage for solar applications.
• High-temperature storage offers significant advantages in energy density and overall plant efficiency.
• Adequate energy integration is crucial for realizing efficient long-term energy storage performance.