Before the fire, significant quantities of small pieces of titanium were observed on the liquid redistribution tray above the middle packing bed. Unit operations first became aware of the incident when a manway was moved and a flash fire occurred. This phase of the incident was over very quickly, however, several minutes later a bright spot of glowing metal appeared on the tower that rapidly grew in size and intensity. Shortly thereafter, a second glowing spot appeared on the tower about 10 feet above the first. The upper tower burn-through occurred in the area of the liquid redistribution tray above the middle packing bed.
Titanium is classified as a flammable metal.
Once small shavings are ignited, the fire is self-sustaining. Analytical results and consultation with titanium manufacturing experts confirmed a Class D metal fire involving titanium inside the tower. Conclusions A titanium fire caused the extensive damage to the tower. The presence of small particles of titanium in the middle packing bed significantly contributed to the ease of ignition of the titanium and accounted for the tower burn-through in these locations. The most likely mechanism for ignition is the presence of pyrophoric residue.