Flame characteristics of pulverized torrefied-biomass combusted with high-temperature air

Jun Li, Enrico Biagini, Weihong Yang, Leonardo Tognotti, Wlodzimierz Blasiak

Research output: Contribution to journalArticle

9 Citations (Scopus)
203 Downloads (Pure)

Abstract

In this work, the flame characteristics of torrefied biomass were studied numerically under high-temperature air conditions to further understand the combustion performances of biomass. Three torrefied biomasses were prepared with different torrefaction degrees after by releasing 10%, 20%, and 30% of volatile matter on a dry basis and characterized in laboratory with standard and high heating rate analyses. The effects of the torrefaction degree, oxygen concentration, transport air velocity, and particle size on the flame position, flame shape, and peak temperature are discussed based on both direct measurements in a laboratory-scale furnace and CFD simulations. The results primarily showed that the enhanced drag force on the biomass particles caused a late release of volatile matter and resulted in a delay in the ignition of the fuel-air mixture, and the maximum flame diameter was mainly affected by the volatile content of the biomass materials. Furthermore, oxidizers with lower oxygen concentrations always resulted in a larger flame volume, a lower peak flame temperature and a lower NO emission. Finally, a longer flame was found when the transport air velocity was lower, and the flame front gradually moved to the furnace exit as the particle size increased. The results could be used as references for designing a new biomass combustion chamber or switching an existing coal-fired boiler to the combustion of biomass.

Original languageEnglish
Pages (from-to)2585-2594
Number of pages10
JournalCombustion and Flame
Volume160
Issue number11
Early online date5 Jun 2013
DOIs
Publication statusPublished - Nov 2013

Keywords

  • CFD
  • flame
  • high temperature
  • pulverized solid biomass
  • torrefaction

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