Explosibility of shredder dusts for electrical appliances

Abstract

Paying attention to a fact that a large number (about 19.5 million units which weigh about 720,000 tons) of major household electrical appliances (refrigerator, air conditioner, television set and washing machine) are discarded in Japan and that they are regulated to be recycled now, the authors investigated the explosibility of dusts produced in the recycling process (mainly polyuremane, metal and plastic dusts). Minimum explosive concentration, ignition temperature, ignition energy, influence of flammable gas on the dust explosion, K st value, etc. were investigated. The results of the investigation show that the shredder dusts are sensitive to explosion (minimum explosion concentration around 30-40 g/m 3 and ignition temperature about 500- 550 °C). The minimum ignition energy is about 40 inJ. The existence of flammable gas promotes the explosibility of dust cloud (explosibility increases to about two times). The K st value is about 70-75 bar-m/s. These indicate that the shredder dust can be easily ignited and lead to dust explosion.