(780e) Experimental Investigation of Carbon Dioxide Capture and High-Temperature Thermal Energy Storage Via Metal Oxide Chemical Looping in a Prototype Reactor for Solar Thermochemical Metal Oxide Looping

Two-step metal oxide carbonation–calcination chemical looping is a promising approach for solar-driven CO₂ capture from flue gases and as a high-temperature thermochemical energy storage system for solar-thermal power plants. The reversible two-step process involves the endothermic calcination of a metal carbonate (e.g. CaCO₃, SrCO₃) to the metal oxide driven by concentrated solar energy, followed by the exothermic carbonation of the metal oxide to capture CO₂ or provide a source of high-temperature heat.

A 1 kW solar-driven packed-bed reactor prototype has been designed and built to experimentally evaluate the process using CaCO3 as the sorbent. The packed bed of spherical sorbent particles is contained in an annular reaction zone surrounding a solar cavity and heated with concentrated solar radiation via the diathermal cavity wall. Gases are supplied to the reactor via inlet and outlet manifolds and distributed inside the reaction zone with gas distributors.

Reaction steps in experiments are conducted with alternating inert and CO₂ gas flows at varying flow rates and thermal radiation input from the ANU High flux solar simulator. Reaction rates and extents are determined by measuring the changes between inlet and outlet gas compositions under controlled operation. Sorbent particles are analysed before and after experiments for composition, structure, size, and morphology. The pressure drop across the particle bed and the temperature at selected points of the reaction bed, inlet gas temperature, and outlet gas temperature are measured and controlled.

We will present and discuss the reactor design, experimental set-up, and most recent experimental results obtained with the prototype reactor.