Influence of the composition of solid biomass in the flammability and susceptibility to spontaneous combustion

Abstract

Biomasses are materials highly demanded nowadays for energy production. One of the main features of these materials is that they present a great variability in terms of chemical composition and physical behavior (O/C and H/C ratios, granulometric structure, ash content…). Nowadays, there is a lack of information concerning its characterization to determine its flammability and explosibility behavior. The objective of this study is to provide flammability and explosibility data as well as some parameters to assess the spontaneous combustion tendency of these products and to relate this thermal susceptibility with the composition. Initial results showed that risk assessments based on the activation energy were not effective for biomass as it is for coals, and that a greater tendency to self-ignition was observed in those biomasses having higher H/C ratios, on the contrary than in coals. This behavior can be explained because the most important stage for coals is the beginning of the self-heating reaction, which present a different resistance (activation energy) depending on its ranking, while biomasses present an initial stage easily achievable even at moderate temperatures, so the differentiation for biomasses should be found in the ability to spread this incipient reaction.