Analysis of fire and explosion hazards and accident prevention for carbon black dust from pyrolysis of typical waste tires

Taking the waste tire pyrolysis process of a typical enterprise as a practical case, the fire and explosion characteristics of carbon black in both dust layer and dust cloud forms were analyzed. The results show that the minimum ignition temperature of the dust layer exceeds 400 ℃. If the dust layer comes into contact with a fire source under certain conditions, there is a potential fire risk. The minimum ignition temperature of the dust cloud is 620 ℃, and the particle size distribution is in the ultra-fine dust region. In the case of a carbon black dust cloud, the risk of fire and explosion is relatively high. Hazard and operability analysis (HAZOP) identified 12 risk scenarios in the carbon black post-treatment system (75% of which were level Ⅰ risks) and 8 potential leakage sources. Additionally, fire and explosion accident scenarios were constructed for carbon black dust leakage under various conditions. Based on the integrated safety management concept of “five flows–three transformations–three controls”, at the levels where “material flow” and “energy flow” are not out of control and “control flow” is error-free, several accident prevention and mitigation measures have been proposed. These include controlling the concentration of carbon black dust, enhancing the sealing performance of production equipment, formulating emergency plans for dust explosions, and installing real-time monitoring instruments for combustible dust. These results can provide a theoretical basis and feasible suggestions for the safety management of carbon black deep processing in waste tire pyrolysis.