ABSTRACT
The contribution deals with the case study of the wastewater tank explosion in the coke production plant. Explosion occurred in the 250 m3 tank serving for storage of wastewaters from coke gas purification, namely ammonia containing waters and waters from separation of “benzol” composed from BTX (Benzene, Toluene, Xylene). The explosion occurred during maintenance of tank. None of these wastewaters entering the tank exhibited flash point in standard testing procedures, nevertheless the tank exploded due to the initiation of internal explosive atmosphere, initiated by sparking close to the ventilation tube on the top of the tank. The investigation of accident had shown that the explosive atmosphere was formed inside the tank by evaporation of BTX from wastewater, which is too slow to form flammable atmosphere during both open and close cup flash point tests, but which contains enough of flammable compounds to form explosive atmosphere by long time evaporation inside the tank.
