Periodic Reporting for period 3 - MetalFuel (Towards a full multi-scale understanding of zero-carbon metal fuel combustion)
Berichtszeitraum: 2023-10-01 bis 2025-03-31
Energy-on-demand is a cornerstone of modern society. Currently, the primary source of energy is fossil fuel, but in view of undeniable climate warming, an alternative fuel is dearly wanted. Metal powders are a tantalizing, totally carbon-free and recyclable option for such a fuel. Its combustion products are solid metal-oxide particles, which, after capture, can be recycled to metal powders again using green electricity. The technology required to burn metal powder aerosols in a stable and reliable way is, however, still in its infancy. Rapid growth of the technology is unlikely, because fundamental understanding of combustion of dense metal aerosols is largely lacking. Herein lies a virgin field of fundamental research, with huge potential for practical application. Fundamental principles behind metal fuel flames are addressed in this proposal, in a step-wise, combined experimental & theoretical/numerical approach. On single-particle level, I will unravel the influence of mutual interactions. Their consecutive ignition will create combustion wave fronts traveling through metal aerosols. Such planar flame fronts will be created in the lab as well as studied numerically and subsequently used as building block for modeling 3D flames. Finally, Bunsen-type burners will be developed to characterize turbulent, 3D flames. Detailed experiments using microscopy for metal-(oxide) particle composition as well as new optical diagnostic techniques on dedicated, lab-scale metal aerosol burners will serve as benchmarks for validation of models. I have a 30 years track record in theoretical, numerical & experimental combustion research, focusing on fundamental aspects of combustion processes relevant to practical applications. In this project this experience will be the foundation from which to explore a new direction in fundamental combustion research. This METALFUEL project will boost to a new branch of combustion research, with the potential for disruptive applications.
WP1: Combustion of a Single Particle Surrounded by Similar Particles
The primary aim is to study individual metal particle combustion under different conditions. This involves employing various experimental techniques to monitor the burning particles in real-time. A newly designed single particle burner is used to ignite and observe particles via optical diagnostics. The focus is on understanding ignition temperatures, combustion time, and particle temperature history under varying air temperatures. Additionally, the study involves investigating the interaction between particles during combustion. This numerical part of this workpackage aims to construct detailed combustion models for single particles. The developed models involve a comprehensive description of the surrounding flow, temperature, and chemical composition. The development of these models is an iterative process, incorporating experimental data and molecular dynamics simulations to enhance accuracy. Future steps include investigating the chemical composition within the particles in more detail.
WP2: Planar (1D) Metal Fuel Flames
The experimental work in this workpackage involves exploring metal fuel flames using a V-shaped flame burner due to the identified limitations of the initial Heat Flux Burner (HFB). Preliminary results show good flame stabilization and burning velocity measurements. Ongoing development includes optical diagnostic systems to study parameters like flame structure and particle flow during combustion. The numerical efforts concentrate on developing and validating 1D flamelet models. These models help predict flame structures and assess the impact of different iron oxides on flame temperature and behavior.
WP3: Full 3D Metal Fuel Flames
A 3D iron particle jet flame in hot co-flow was designed for studying MILD metal dust flames. Methods for measuring particle temperature history were developed and verified. These achievements will be combined to measure the flame temperature field of a 3D iron flame. The numerical aspects involve developing and validating software to analyze iron aerosol combustors. The software has been applied to various burner simulations, aiming to address discrepancies between experimental and simulation results. This will improve the understanding of radiative heat transfer effects in burning iron aerosols, aiding in the development of more accurate models for large-scale simulations.
Overall, the project delves deeply into understanding metal particle combustion and metal fuel flames, combining experimental observations with sophisticated numerical models to gain comprehensive insights into the process.
The primary aim is to study individual metal particle combustion under different conditions. This involves employing various experimental techniques to monitor the burning particles in real-time. A newly designed single particle burner is used to ignite and observe particles via optical diagnostics. The focus is on understanding ignition temperatures, combustion time, and particle temperature history under varying air temperatures. Additionally, the study involves investigating the interaction between particles during combustion. This numerical part of this workpackage aims to construct detailed combustion models for single particles. The developed models involve a comprehensive description of the surrounding flow, temperature, and chemical composition. The development of these models is an iterative process, incorporating experimental data and molecular dynamics simulations to enhance accuracy. Future steps include investigating the chemical composition within the particles in more detail.
WP2: Planar (1D) Metal Fuel Flames
The experimental work in this workpackage involves exploring metal fuel flames using a V-shaped flame burner due to the identified limitations of the initial Heat Flux Burner (HFB). Preliminary results show good flame stabilization and burning velocity measurements. Ongoing development includes optical diagnostic systems to study parameters like flame structure and particle flow during combustion. The numerical efforts concentrate on developing and validating 1D flamelet models. These models help predict flame structures and assess the impact of different iron oxides on flame temperature and behavior.
WP3: Full 3D Metal Fuel Flames
A 3D iron particle jet flame in hot co-flow was designed for studying MILD metal dust flames. Methods for measuring particle temperature history were developed and verified. These achievements will be combined to measure the flame temperature field of a 3D iron flame. The numerical aspects involve developing and validating software to analyze iron aerosol combustors. The software has been applied to various burner simulations, aiming to address discrepancies between experimental and simulation results. This will improve the understanding of radiative heat transfer effects in burning iron aerosols, aiding in the development of more accurate models for large-scale simulations.
Overall, the project delves deeply into understanding metal particle combustion and metal fuel flames, combining experimental observations with sophisticated numerical models to gain comprehensive insights into the process.
The focus on not only combustion aspects but also on enhancing the overall efficiency of the oxidation-reduction cycle, coupled with advancements in hydrogen production and green steel production, shows a holistic approach to maturing the overall concept of metal energy carriers. These collective efforts represent a leap beyond the state of the art in the field, integrating cutting-edge methodologies, interdisciplinary collaborations, and robust technology transfer to pave the way for a transformative shift in the energy industry.
The introduction of the ICONIC concept within the MetalFuel program, leveraging the recirculation of hot flue gases, cooling, and re-mixing with fresh iron powder and air, represents a pioneering approach. Securing an ERC Proof of Concept to explore this concept further underlines the groundbreaking nature of this innovation. Besides that, the application of MD simulations to investigate the interactions between partly burnt iron particles and O2 molecules stands as a significant advancement. Collaborating with experts from Imperial College London in this field demonstrates a novel and successful step. This integration of MD simulations with a single iron particle combustion model has significantly improved agreement with experimental data, shedding light on the significance of internal iron particle structure during combustion and the previously underestimated impact of surface chemisorption on iron oxidation rates. Finally, I recognize the importance of material science and metallurgy in advancing the concept of metal energy carriers which signifies a progressive step. Collaborations with renowned institutions and the hiring of experts demonstrate a concerted effort to elevate the technology readiness level (TRL) of the MetalFuel program.
The introduction of the ICONIC concept within the MetalFuel program, leveraging the recirculation of hot flue gases, cooling, and re-mixing with fresh iron powder and air, represents a pioneering approach. Securing an ERC Proof of Concept to explore this concept further underlines the groundbreaking nature of this innovation. Besides that, the application of MD simulations to investigate the interactions between partly burnt iron particles and O2 molecules stands as a significant advancement. Collaborating with experts from Imperial College London in this field demonstrates a novel and successful step. This integration of MD simulations with a single iron particle combustion model has significantly improved agreement with experimental data, shedding light on the significance of internal iron particle structure during combustion and the previously underestimated impact of surface chemisorption on iron oxidation rates. Finally, I recognize the importance of material science and metallurgy in advancing the concept of metal energy carriers which signifies a progressive step. Collaborations with renowned institutions and the hiring of experts demonstrate a concerted effort to elevate the technology readiness level (TRL) of the MetalFuel program.