A Breakage Model for Discrete Element Simulations Applied to Iron Ore Sinter

Michael Denzel

Research output: ThesisDoctoral Thesis

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Abstract

Due to mechanical stress during transport and storage, bulk material partly degrades and fines are produced. This can be problematic in various applications and is especially critical for blast furnace sinter. Fines have to be re-sintered and are responsible for additional high costs, energy demand and emissions. To analyze breakage behavior of blast furnace sinter a highly automated test rig for rapid single particle impact testing with integrated fragment analysis was developed. Fragment size distribution, fines production and breakage probability were investigated and clear trends were able to be determined. A general fines production curve was able to be calculated by introducing a size factor. A size-independent description with the tn-model was also performed. Neither a post-processing procedure nor bonded particle models were considered suitable to simulate the degradation of blast furnace sinter during transport and storage processes. A novel breakage model for the discrete element method using polyhedral particles is presented. The breakage model is based on a probabilistic particle replacement with Voronoi-tessellated fragments. In contrast to other particle replacement models with spheres, mass and volume remain constant. High mass flows and multiple breakage for processes with several damaging events, as found in industrial applications, can be simulated. The breakage model was verified and validated by a series of shatter tests and trials with two different transfer systems with different batches of sinter from two different manufacturers. Simulation and test results are consistent. Especially the fines are predicted with high accuracy. The breakage model was successfully applied to quantify particle breakage in a solid state material turbine used to reduce segregation effects during bunker filling.
Translated title of the contributionEin Bruchmodell für die Diskrete-Elemente-Methode angewandt an Hochofensinter
Original languageEnglish
QualificationDr.mont.
Awarding Institution
  • Montanuniversität
Supervisors/Advisors
  • Schenk, Johannes, Assessor A (internal)
  • Antretter, Thomas, Co-Supervisor (internal)
  • Kartnig, Georg, Assessor B (external), External person
  • Sifferlinger, Nikolaus August, Supervisor (internal)
DOIs
Publication statusPublished - 2023

Bibliographical note

no embargo

Keywords

  • particle breakage
  • discrete element method
  • blast furnace sinter
  • fines
  • polyhedral particles
  • voronoi tessellation
  • progeny distribution
  • comminution
  • single particle impact test

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