Exploration of corn starch dust combustion and explosion mechanisms via thermal decomposition and functional group changes

In specific conditions, corn starch, due to its explosive characteristics as a fine powder, can act as a catalyst for a dust explosion. In this paper, test techniques were utilized to examine the thermal decomposition and ignition process of corn starch, as well as to probe into its fundamental combustion mechanism. Upon increasing the concentration of corn starch, there was an initial tendency for both the flame propagation velocity and length to rise, followed by a subsequent decrease. The results revealed that a large amount of volatile gases was precipitated from corn starch during pyrolysis, and these gases reacted with oxygen during combustion. The reaction rate was related to the concentration of corn starch, causing the flame propagation velocity and length to initially show an increasing trend and then decrease as the concentration of corn starch increased. Combined with the In-situ DRIFTS test, the study investigated the change process of surface functional groups during the combustion of corn starch. The combustion process of corn starch conforms to the mechanism of surface heterogeneous ignition. When combustion occurred rapidly, the temperature during volatile matter combustion reflectd that of corn starch particle combustion, making corn starch more prone to surface ignition.