A viable solution is the integration of molten as thermal energy storage (TES). In particular, molten salts mixtures offer the possibility to store energy in the form of heat relatively simply and at low cost to secure continuous heat supply in an energy system with high fluctuations of renewable energy sources5. For example, in concentrating solar power systems, molten salts mixtures are used as TES to enable continuous electricity generation. Based on this approach, solar thermochemical reactors have been implemented for several endothermic reactions5. This concept could be extended beyond solar power alone to utilize a diversified mix of renewable energy sources, further improving the reliability and efficiency of TES-based electrified reactors.
This study presents a case study of innovative electrified reactor configurations for steam methane reforming (SMR) process integrated with TES. In particular, mixtures of carbonate salts were examined as phase change materials (PCMs) for high-temperature applications (> 800 °C), which are typical operating conditions of many endothermic processes. The study investigates various aspects, including mixture stability, thermal properties, corrosion resistance of the most common reactor materials, and strategies to enhance the characteristics of PCMs to optimize performance under extreme operating conditions. The eSMR reactor had already been tested, modeled, optimized and sized for the reaction zone in previous studies. A configuration employing indirect resistive heating of the reactor tube was selected to ensure an intimate contact between the heat source and the catalytic zone. To enhance gas flow and heat transfer, a structured open-cell SiC foam catalyst was chosen, due to its high thermal conductivity and its improvement of gas flow dynamics. In this work, a CFD analysis was conducted to assess the feasibility and performance of integrating the selected TES into the reactor system, providing insights into heat transfer dynamics and system efficiency.
References:
(1) International Energy Agency. Net Zero by 2050 - A Roadmap for the Global Energy Sector; 2021. www.iea.org/t&c/.
(2) Soltani, R.; Rosen, M. A.; Dincer, I. Assessment of CO2 Capture Options from Various Points in Steam Methane Reforming for Hydrogen Production. Int J Hydrogen Energy 2014, 39 (35), 20266–20275. https://doi.org/10.1016/j.ijhydene.2014.09.161.
(3) Zheng, L.; Ambrosetti, M.; Tronconi, E. Joule-Heated Catalytic Reactors toward Decarbonization and Process Intensification: A Review. ACS Engineering Au 2023. https://doi.org/10.1021/acsengineeringau.3c00045.
(4) Hoang, A. T.; Pandey, A.; Martinez De Osés, F. J.; Chen, W.-H.; Said, Z.; Ng, K. H.; Ağbulut, Ü.; Tarełko, W.; Ölçer, A. I.; Nguyen, X. P. Technological Solutions for Boosting Hydrogen Role in Decarbonization Strategies and Net-Zero Goals of World Shipping: Challenges and Perspectives. Renewable and Sustainable Energy Reviews 2023, 188, 113790. https://doi.org/10.1016/j.rser.2023.113790.
(5) Giaconia, A.; Iaquaniello, G.; Caputo, G.; Morico, B.; Salladini, A.; Turchetti, L.; Monteleone, G.; Giannini, A.; Palo, E. Experimental Validation of a Pilot Membrane Reactor for Hydrogen Production by Solar Steam Reforming of Methane at Maximum 550 °C Using Molten Salts as Heat Transfer Fluid. Int J Hydrogen Energy 2020, 45 (58), 33088–33101. https://doi.org/10.1016/j.ijhydene.2020.09.070.