Citation

Fu S, Chen H, Watt SD, Sidhu HS, Luangwilai T, Shu Y. Fire Technol. 2021; 57(4): 1803-1825.

Copyright

(Copyright © 2021, Holtzbrinck Springer Nature Publishing Group)

DOI

10.1007/s10694-021-01091-4

PMID

unavailable

Abstract

The self-heating and spontaneous ignition process pose a fire risk for industrial biomass piles during storage. Most studies, from theoretical to numerical, pay more attention on the effect of pile size on self-heating and self-ignition, which in essence is due to chemical reactions. However, the effect of ambient humidity on the self-heating and spontaneous ignition process, which is due to physical process of water evaporation and vapor condensation, is not well understood. In fact, fire accidents and the related experimental studies have shown that the sudden increase of ambient humidity would cause the rapid increase of biomass pile temperature, leading to spontaneous ignition. In order to fill this knowledge gap, this work proposed a computational self-heating model, coupling heat and mass transfer process and both the microbial and chemical reactions. The processes of moisture evaporation, transportation and convective exchange of vapor were considered in this model to study the effect of humidity on self-heating process. The model was validated against the full-scale experiments of Zhanjiang Biomass Power Plant firstly. The numerical results show that the sudden increase of ambient humidity can lead to a quick increase of pile temperature due to the condensation process. Spontaneous ignition is highly dependent upon the heat generation evolution of the chemical reaction within the pile. The sudden increase of humidity could speed up the chemical reaction process, leading to a fire. This study helps understand the role of humidity on self-heating process during biomass storage.

Language: en

Keywords

Ambient humidity variation; Eucalyptus bark; Moisture; Numerical model; Self-heating; Spontaneous ignition