Publications & Presentations

Publications

An experimental study on the ignition temperature of iron particles in an electrically-heated drop-tube furnace
D. Chang*, E. St. Germain*, R. M. Erb, X. Mi, J. M. Bergthorson, Y. A. Levendis
Fuel, 2026
*Co-first authors
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Thermoformable Boron Nitride Based All-Ceramics
J. E. Bice, E. St. Germain, S. J. Wohlever, G. Goddard, R. M. Erb
Advanced Materials, 2022
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Conference Presentations

Effects of Heating Rate and Oxide Layer Growth on the Ignition of Iron Powder
E. St. Germain, R. Erb, Y. Levendis
14th U.S. National Combustion Meeting, Eastern States Section of the Combustion Institute
March 2025
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Exploring the Practicality of Iron as a Sustainable Replacement to Coal
E. St. Germain, R. Erb, Y. Levendis
2024 MRS Fall Meeting & Exhibit, Materials Research Society
December 2024
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Generation of Iron Oxide Nanoparticles Through Iron Combustion
E. St. Germain, R. Erb, Y. Levendis
Mechanical and Industrial Engineering Graduate Research Expo, Northeastern University
October 2024
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Poster Presentations

Generation of Iron Oxide Nanoparticles Through Iron Combustion Best Poster Award
E. St. Germain, R. Erb, Y. Levendis
Mechanical and Industrial Engineering Graduate Research Expo, Northeastern University
October 2024

An Overview of the Iron Fuel Cycle
E. St. Germain, R. Erb, Y. Levendis
Radcliffe Science Symposium on Alternative Energy, Harvard University
September 2024

Understanding Rapid Iron Oxidation During Various Combustion Conditions for a Carbon-Free Energy Cycle
E. St. Germain, R. Erb, Y. Levendis
Princeton-Combustion Institute Summer School, Princeton University
June 2024

On the Performance of the Iron Fuel Cycle by Examining Combustion Products
E. St. Germain, J. Rossilli, R. Erb, Y. Levendis
RISE, Northeastern University
April 2024

Byproduct Generation in the Iron Fuel Cycle: Research and Outreach
E. St. Germain, D. Chang, R. Erb, Y. Levendis
ASEE Northeastern Section Conference, Fairfield University
April 2024

Understanding Rapid Iron Oxidation During Various Combustion Conditions for a Carbon-Free Energy Cycle
E. St. Germain, D. Chang, A. Panahi, R. Erb, Y. Levendis
Mechanical and Industrial Engineering Graduate Research Expo, Northeastern University
October 2023

Vibration-Assisted Tape Casting and Printing of Ceramics
C. Bucci, J. Ly, E. St. Germain, O. Woktunik, B. Zhang
Mechanical Engineering Capstone Day, Northeastern University
December 2022

Abstract

This manuscript reports on experimental research addressing the ignition temperature of iron particles in hot furnace gases and compares this experimental data to previous experiments and theoretical models. Iron particles of different sizes were injected into an electrically heated drop tube furnace in oxygen-containing gases with different mole fractions of nitrogen diluent (including air). Experiments were also conducted using other diluents (helium, argon and carbon dioxide) at a fixed mole fraction of oxygen. Though the ignition temperature of a combustible material is an extrinsic property influenced by structural and operating parameters, useful approximations can still be derived from experiments and theory. This investigation corroborated the onset and probability of ignition by three independent techniques: (a) visual observation of the luminosity of particles, (b) physical examination of the particle size and shape characteristics of the collected products of combustion and (c) assessment of the chemical composition of the collected particles. Results revealed that particle size, shape and particle concentration appeared to be influential, as 28–32 µm spherical particles started to ignite at temperatures above 1037 K, 45–53 µm spherical particles at temperatures above 1022 K, and irregular 49–62 µm particles at temperatures above 968 K. Ignition temperatures increased with decreasing particle concentrations. Tuning the oxygen mole fraction (in the range of 15–100 %) in nitrogen had no discernible effect on ignition temperature. Replacing nitrogen with helium increased the ignition temperature significantly. Replacing nitrogen with argon or carbon dioxide slightly influenced the ignition temperature.

Abstract

Thermoforming processing, traditionally reserved for thermoplastic polymers and sheet metals, is extended here to boron-based all-ceramics. Specifically, sintered boron nitride composite sheets manufactured via a combined vibration and tape-casting photopolymerization process exhibit a highly oriented microstructure that allows these preform sheets to flow as viscous Bingham pseudoplastics during compression molding. These sintered all-ceramic preforms are thermoformed into thin, complex parts with features down to 200 µm. Further, a new workflow is leveraged to generate bespoke all-ceramic heat spreaders that can be press-fit onto printed circuit boards and outperform metal heat sinks as a low-profile thermal management solution. This work offers a route for other all-ceramics that may be thermoformed through first fabricating pre-forms with highly-ordered anisotropic microstructures.

Abstract

While modern energy solutions such as solar and wind power are becoming increasingly economically feasible, infrastructure still needs to be built up before renewable energy is globally accessible. In the meantime, to cut back on the formation of greenhouse gases and pollutants, accessible alternatives to coal and oil need to be developed. One such alternative is iron, a solid fuel that can be easily transported and releases thermal energy through oxidation, a reaction which can be reversed through reduction. Through this process micrometric sized iron particles can be recycled using hydrogen and electricity from clean methods, easily stored or transported, and then ignited to release heat. The specifics of iron ignition depend on many variables, one of which is the thickness of an oxide layer. A thick oxide layer may delay ignition of particles while a fully pre-oxidized iron is unable to ignite and cannot be used as a fuel. Previous theoretical work done by XiaoCheng Mi examined how the ratio of a preexisting oxide layer affects the ignition temperature and time of iron particles through a series of simulators. These calculations assumed spherical iron particles which are exposed to a constant gas temperature. The work presented here aims to experimentally determine how the presence of an oxide layer affects the ignition temperature of both spherical and nonspherical iron particles and to compare these values to the currently published theories. This is examined by inserting particles of various peroxidation levels into a drop tube furnace at and above the predetermined ignition temperature of a similar particle with minimal peroxidation. Minimally oxidized particles will also be inserted into a tube furnace with various air flow rates, changing the rate at which the particles heat up and oxidize. So far, this pre-oxidation has been shown to increase the required ignition temperature of particles, since a significant oxide layer is formed around the falling particle before reaching the maximum furnace temperature. The results of these experiments will be used to determine ranges of ignition temperature based on the oxide thickness of particles with varying morphology, along with heating rates which oxidize particles without causing ignition with the aim to outline conditions which should be followed for iron fuel to be a viable alternative to carbon-based fuels. Additionally, by understanding the acceptable degree of pre-oxidation for set furnace conditions, requirements can be created on the humidity and temperature that iron particles can safely be stored.