Comparison of the thermal decomposition behaviors of fine sodium bicarbonate under different pressures

Fine sodium bicarbonate, as a powder suppressant, is typically used for fire/explosion inhibition. This work aims to explore the changes in thermal decomposition kinetics of fine sodium bicarbonate (D₉₀ =1 μm) under different pressures to determine the precise kinetic parameters for explosion inhibition. As the pressure increases, the onset decomposition temperature increases, and the maximum mass loss rate decreases when the nonisothermal method is used. Through the isothermal method, we find that the curves decrease linearly with each constant-temperature platform, allowing us to calculate the decomposition rates and kinetic parameters by the Arrhenius equation. Notably, increasing pressure affects the thermal decomposition of fine sodium bicarbonate by decreasing the prefactor A , with little influence on the activation energy Ea . All the thermal decomposition models under different pressures follow the chemical reaction mechanism function F1 ( f(a)=1-a ). This paper provides a clearer understanding of the sodium bicarbonate decomposition path in high-pressure scenarios, and the obtained kinetic parameters can be directly used as input parameters for numerical simulation, such as explosion inhibition.