Effect of gasification reactions on biomass char conversion under pulverized fuel combustion conditions

Hao Luo, Zhimin Lu*, Peter Arendt Jensen, Peter Glarborg, Weigang Lin, Kim Dam-Johansen, Hao Wu*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

The effect of gasification reactions on biomass char conversion under pulverized fuel combustion conditions was studied by single particle experiments and modelling. Experiments of pine and beech wood char conversion were carried out in a single particle combustor under conditions of 1473-1723 K, 0.0-10.5% O2, and 25-42% H 2 O. A comprehensive progressive char conversion model, including heterogeneous reactions (char oxidation and char gasification with CO2 and H2O), homogeneous reactions (CO oxidation, water-gas shift reaction, and H 2 oxidation) in the particle boundary layer, particle shrinkage, and external and internal heat and mass transfer, was developed. The modelling results are in good agreement with both experimental char conversion time and particle size evolution in the presence of oxygen, while larger deviations are found for the gasification experiments. The modelling results show that the char oxidation is limited by mass transfer, while the char gasification is controlled by both mass transfer and gasification kinetics at the investigated conditions. A sensitivity analysis shows that the CO oxidation in the boundary layer and the gasification kinetics influence significantly the char conversion time, while the water-gas shift reaction and H2 oxidation have only a small effect. Analysis of the sensitive parameters on the char conversion process under a typical pulverized biomass combustion condition (4% O2 , 13% CO2 , 13% H2 O), shows that the char gasification reactions contribute significantly to char conversion, especially for millimeter-sized biomass char particles at high temperatures.

Original languageEnglish
JournalProceedings of the Combustion Institute
ISSN1540-7489
DOIs
Publication statusAccepted/In press - 2020

Keywords

  • Char conversion
  • Gasification
  • Particle modelling
  • Pulverized fuel combustion

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