Session: 17-05: Symposium Steinfeld - Concentrated solar power and thermal/thermochemical energy storage

Paper Number: 142156

142156 - Continuous Oxidation Reactor/heat Exchanger for High-Temperature Discharge (~1000 °C) of Thermochemical Energy From Metal Oxide Particles: Experimental Results 

Abstract: 

Thermochemical Energy Storage (TCES) with metal oxide particles is a promising technology for renewables dispatchability. TCES stores thermal energy chemically in metal oxide particles for short or long-term storage, releasing heat as needed. Some of the advantages of TCES include high energy densities and the ability to deliver high-temperature heat (~1000 °C). The charging/reduction step involves exposing the particles to high-temperature heat (~1500 °C), chemically reducing them, and releasing oxygen. Sustainable energy sources like Concentrated Solar (CSP) or excess renewable electricity are recommended for charging. The discharge/oxidation step requires precise reactor temperature and atmosphere control for efficient oxidation and heat transfer. Moreover, reactor scalability prerequisites include low-cost particle storage prior oxidation, sensible heat recuperation, and the use of  heat transfer fluid (HTF) different from the reactive gas. We proposed a continuous oxidation reactor for Mg-Mn-O particles. The oxidation of the particles occurs between 800 and 1000 °C under partial pressure of oxygen of 0.2 atm or higher, therefore, the use of atmospheric air is suitable for oxidation. The reactor design comprises a counter-flow narrow channel reactor/heat exchanger located between two moving beds. This design permits sensible heat transfer between gases and solids to allow particle and gas feeding/extraction at low temperatures, a key scalability enabler. The narrow channel reactor promotes the exothermic oxidation reaction and heat extraction. A reactor/heat exchanger of 1 kW of nominal heat duty was built using super alloy Hastelloy-X. The reactor geometry reduces the thermal resistance between particle bed and walls while maintaining adequate particle flowability. The heat exchanger comprises two finned narrow plates for enhanced heat transfer. Experimental runs using N₂ as heat HTF achieved sustained outlet temperatures of ~900 °C with particle flowrates of 2.2 g/s and a ~1000 °C reactor temperature. The measured oxidation conversions are higher than 65%. Additionally, the temperature profiles along the reactor walls confirmed the ability of exchanging sensible heat for effective particle and gas preheating/cooling. That feature eliminates the need of external particle or gas preheating and/or hot particle storage. It also permits the use of low-cost gaskets and seals. Current work focuses on maximizing thermal efficiency and oxidation conversion, while maintaining HTF outlet temperatures of approximately 900 °C or higher. This concept has the potential to scale up TCES technologies with metal oxide particles, offering decoupled charging and discharging steps, flexibility with HTFs, and ease of solids and gas handling. Further development could advance renewable energy storage and utilization.

Presenting Author: Juve Ortiz-Ulloa Oregon State University

Presenting Author Biography: Juve Ortiz-Ulloa is a Ph.D. candidate in Chemical Engineering at Oregon State University working under the advice of Dr. Nick AuYeung. He previously obtained a master’s degree in Energy Systems from the University of Melbourne. His work focuses on developing effective and scalable thermochemical energy storage materials and reactors for high temperature applications such as concentrated solar power and industrial heat.

Authors:

Juve Ortiz-Ulloa Oregon State University
Owen Ramsey Oregon State University
David Korba Mississippi State University
Michael Hayes Michigan State University
Philipp Schimmels Michigan State University
Kelvin Randhir Redoxblox
Nesrin Ozalp Illinois State University
Like Li University of Central Florida
Joerg Petrasch Redoxblox
James Klausner Redoxblox
Nicholas Auyeung Oregon State University