Session: 04-01: Energy Storage Systems and Applications

Paper Number: 156388

156388 - Numerical Modeling and Size Optimization of Thermal Energy Storage for Iron and Steel Production 

Abstract: 

The industrial sector is responsible for approximately 30% of the United States' greenhouse gas emissions, with industrial heat accounting for more than half of that. Within the industrial sector, iron and steel production are responsible for 90 million MtCO2 per year. Hydrogen direct reduction of iron (H2DRI) is a promising, more sustainable alternative pathway to commercially used processes, such as the blast furnaces or direct reduction of iron using natural gas. The H2DRI process requires hydrogen at high temperatures, up to 950°C, fed into a reduction reactor to produce reduced iron pellets that can be used in the downstream iron-making process. While combusting some of the hydrogen to preheat it is feasible, its economic viability is low due to the high price of green hydrogen. High-temperature electrically charged thermal energy storage (E-TES) systems can be charged using electricity and dispatch high-temperature heat, offering a more promising alternative. The use of E-TES can also help to buffer against variable electricity prices by charging during curtailment or when prices are low and running the system from storage when electricity prices are high. This shift in approach could provide more stable and cost-effective heat for industrial processes, especially in the context of H2DRI, thereby helping to decarbonize one of the most energy-intensive industrial sectors.

In this work, we have developed a heat transfer model for two different E-TES systems that can be used to heat up hydrogen for an H2DRI application: E-TES based on firebrick resistance-heated storage medium and E-TES that uses silica sand particles as the storage medium. These models are used to evaluate the performance of these E-TES systems under operational conditions relevant to H2DRI, assessing efficiency and losses during charging, storage, and discharge phases. Key factors such as thermal retention, material degradation, and heat delivery efficiency are considered to ensure reliable performance under varying industrial conditions. Following the thermal analysis, a comprehensive system model is developed to evaluate both the technical and economic performance of these E-TES options, focusing on their potential to provide high-temperature hydrogen for an H2DRI furnace.

The results of this analysis will provide insights into the feasibility and operational efficiency of integrating E-TES systems with H2DRI processes in the iron and steel industry. Additionally, a preliminary cost analysis highlights the economic considerations, offering a forecast of capital and operational expenditures. This economic assessment aims to understand the cost-effectiveness of E-TES in hydrogen heating applications for H2DRI, a critical step in advancing its commercial viability. The combined technical and economic insights from this study will guide further development and adoption of E-TES-based hydrogen heating solutions, supporting decarbonization efforts in heavy industry while addressing challenges related to energy cost volatility and green hydrogen expenses. Through this work, we aim to contribute to a more sustainable industrial pathway for iron and steel production.

Presenting Author: Prashant Saini NREL (National Renewable Energy Laboratory)

Presenting Author Biography: I am a Post-Doctoral Researcher at the National Renewable Energy Laboratory (NREL) in the United States, with a strong focus on solar thermal systems for industrial applications. I hold a Ph.D. in Mechanical Engineering from the Indian Institute of Technology Mandi, where my dissertation centered on designing and developing systems for the efficient utilization of solar heat in industrial settings. My research includes advancing Concentrated Solar Power (CSP) technologies, heat storage solutions, and system integration to reduce dependency on fossil fuels in industrial processes. Currently, I am engaged in projects that explore innovative ways to store and deliver solar heat for high-temperature applications, aiming to make renewable energy a practical choice for industries. Through my work, I seek to drive the adoption of solar-based energy systems that contribute to sustainable and low-carbon industrial operations.