Untersuchung des Selbsterwärmungs- und Explosionsverhaltens von wasserstoff-direktreduziertem Eisen

Translated title of the contribution: Investigation of the self-heating and explosion behavior of hydrogen direct reduced iron

Michael Hohenberger

Research output: ThesisDoctoral Thesis


The iron and steel industry is striving to drastically reduce its carbon dioxid-emissions. The conventional blast furnace-converter route is intended to be replaced in the future by hydrogen-based direct reduction and electric steelmaking processes using green electricity. However, direct reduced iron (DRI) materials can have safety-related effects during transport and handling due to reoxidation, hydrogen formation, and dust explosion potential under certain conditions. The aim of this work is to investigate the influencing factors on the self-heating and explosion behavior of DRI materials. Material form (pellets, fines), temperature, and environmental influences (humidity, oxygen content, pre-oxidation) are considered. The experimental determination of oxidation kinetics was carried out by measuring oxygen uptake in a differential loop reactor under isothermal conditions (60, 110, and 160°C). The results indicate that electron and ion diffusion during oxide layer growth are rate-determining for mass transport. While temperature significantly affects the maximum oxygen uptake, other influencing factors can be categorized based on measured oxidation time. Compared to dry oxidation of pellets, fines and increased atmospheric humidity showed enhanced reactivity. As an example, the application of these results in a numerical model for calculating the self-heating propensity of a railway wagon is presented. Regarding explosion behavior, the impact of aging on DRI pellet abrasion and ground HBI (hot briquetted iron) dust was experimentally investigated. Realistic aging did not reduce dust explosion capability, and their attenuation performance can be described based on maximum explosion pressure. The presented research methods provide valuable insights into the safety aspects of DRI materials.The presented research methods provide the foundations for a comprehensive scientific description of the self-heating and explosion behavior of DRI materials, which can be used to create safety-related regulations.
Translated title of the contributionInvestigation of the self-heating and explosion behavior of hydrogen direct reduced iron
Original languageGerman
Awarding Institution
  • Montanuniversität
  • Raupenstrauch, Harald, Supervisor (internal)
  • Flachberger, Helmut, Assessor B (internal)
  • Lehner, Markus, Co-Supervisor (internal)
  • Siebenhofer, Matthäus, Assessor A (internal), External person
Publication statusPublished - 2024

Bibliographical note

embargoed until 28-05-2029


  • Direct reduced iron
  • DRI
  • HBI
  • Self-heating
  • Dust explosion
  • Oxidation kinetics
  • Aging

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