Large-scale storage of renewable energy is necessary to increase reliability of this intermittently, but abundantly available resource. Of special concern is the storage of energy and its subsequent use in industrial processes requiring high temperature heat. A promising emerging technology is based on using redox reactions of metal oxides at high temperatures. The shelf-stable redox material MgMnO was identified as a potential candidate due to its high energy density, cyclic stability, high reaction temperature and good scalability. This work describes the conception, design, manufacturing, testing and improvement of a solid fuel reduction reactor used to charge the energy storage material MgMnO. The reactor enables continuous charging of the pelletized material via a packed bed moving through a 1500°C furnace. A counter-currently flowing sweep gas is used to separate the released oxygen from the charged material to prevent re-oxidation. It also acts as a heat recuperation carrier that cools charged particles and pre-heats particles before entering the reaction zone. This approach enables high thermal efficiency as the sensible heat is almost entirely recovered. A lab-scale reactor was built and tested successfully. Challenges such as particle flowability at high temperatures, fluidization of the bed, and low extent of reaction were encountered and solved by managing the counter-flowing gas and increasing the residence time of the particles in the reactor. The reactor output reached a maximum of 2500 W of charged chemical potential. Several models were developed and used to design experiments and validate the performance of the system. High energetic cost for separation of oxygen and sweep gas nitrogen was identified as a roadblock to improved efficiencies and potential scale-up of the system. This led to mathematical and experimental investigation of using water vapor as alternative sweep gas. Results show that water vapor is superior to nitrogen as a reducing agent and has a lower energetic cost of production. The proposed reactor can be scaled up and results of this study indicates that using the pelletized MgMnO pelletized material offers thermo-chemical energy storage at low-cost. The extraction of this energy at high temperature offers a path toward the decarbonization of a variety of industrial processes that are currently relying on the combustion of hydrocarbon fuels for high-grade heat.
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