Laboratory Investigation on the Spontaneous Combustion of a Lignocellulosic Biomass and Its Suppression by Chemical Inhibitors

摘要

To understand the risk factors of spontaneous combustion fire during the storage process of a biomass pile, the effects of various factors on its self-ignition process under adiabatic oxidation conditions were investigated. Thermogravimetry, differential scanning calorimetry, and Fourier transform infrared spectroscopy (FTIR) were used to analyze the behavior of a series of biomass samples before and after the inhibition. A total of 12 typical inorganic salts and antioxidants were used as chemical inhibitors for suppressing the spontaneous combustion of the lignocellulosic biomass. A steady increase in the heating rate of the compound can be observed with a decrease in the particle size from 4.00 to 0.18 mm. Samples with a moisture content of 1% are most susceptible to spontaneous combustion. Interestingly, the effect of the ventilation rate on the self-heating properties of the samples increases when the temperature is higher than 70 degrees C. In the 40-350 degrees C range, CaCl2, citric acid, MgCl2, and Na3PO4 reduce the heat release by 123.32-492.15 J/g. Among these compounds, CaCl2 exhibits the optimal inhibition effect. According to the FTIR results, the inhibitors mainly target the -OH, C-O, C-H, and C=O groups. Moreover, the weakening of these active sites by slowing their oxidation rate is the main responsible for retarding the spontaneous combustion of the biomass. This work contributes in the development of novel strategies to shed some light on the spontaneous combustion of biomasses.