Flammability Characteristics of Activated Cellulose Pulp

摘要

In 1999, the investigation of a cellulose pulp fire revealed that the flammability characteristics of cellulose wet with acid (i.e. "activated cellulose") are significantly different from the flammability characteristics of either the pure acid or the dry cellulose. The apparent flash point of the activated cellulose was observed to be less than 75℉, which is well below the flash point of the pure acid (F.P. = 126℉). Various observations and testing suggest that the reduction in the apparent flash point results from a "thin film" or "wicking" effect. This wick effect significantly improves the heat and mass transfer and thereby allows the acid vapor to mix readily with air at the surface of the pulp. Consequently, the vapors can be ignited and support combustion even though the temperature of the bulk mixture is lower than the measured flash point of the pure acid. The same effect is seen in oil lamps, whereby oil at the surface of the wick can be ignited and burn at temperatures well below the flash point of the oil. The same mechanism may allow a fire to propagate rapidly through the wetted pulp in a manner similar to a vapor flash fire.