Temperature variation and smoke composition of flame-retardant conveyor belt in the early stage of friction accident

This study improves the roller friction experiment platform for monitoring the temperature of flame-retardant conveyor belt in order to realize the early warning of belt conveyor fire. Mass spectrometry is used to analyze the patterns of temperature rise and smoke composition of steel cord flame-retardant conveyor belt in the early stage of friction accident. Results show that as friction progresses, the flame-retardant conveyor belt exhibits symmetrical distribution of surface temperature, where the highest temperature gradually approaches to the center of the conveyor belt and the composition of smoke changes with temperature. The steel cord flame retardant conveyor belt warming process could be divided into three stages according to their warming rate and smoke composition output: stage of oxidation reaction (ambient temperature to 100 ℃), stage of substitution reaction (100~160.2 ℃), and pyrolysis reaction (after 160.2 ℃). The initial stage features low heat capacity of the conveyor belt with quickly-rising temperature, where the products are mostly alkyl and ester compounds. The second stage exhibits gradual increase of heat capacity, slowly-rising temperature, where the products are mostly nitro, ether, and carboxylic acid compounds. The last stage features stable heat capacity of the conveyor belt, the lowest heating rate, where the chlorine-containing compound is detected for the first time in the smoke composition.