Aerosol Combustion and Explosion Study
Abstract
The flammable and explosive hazards of aerosol, also referred as mist or spray, are usually ignored compared with the flammable and explosive hazards related to gas and dust. Numerous incidents in various industries have revealed the different behaviors between bulk liquid and aerosolized droplets. On January 31st, 1995, a series of fires and explosions destroyed Milliken & Co. carpet mill located in LaGrange, GA, USA. A rotating coupling failure caused the leak of heat transfer oil at high pressure and elevated temperature in the form of aerosol. The aerosol was ignited immediately, and the fire spread rapidly. The incident resulted in over $200 million loss. Heat transfer fluid with flash point above 200°C was believed that could not be ignited below the flash point. But the incident proved it is incorrect.
Flash point, the criterion for the flammability of liquid, becomes insignificant when the liquid is present in the form of aerosol. It is worth of a discussion on the criteria to assess aerosol flammable hazards. Unlike the standard measurements for gas and dust, aerosol flammability standard test methods, such as ASTM D3065-01, are not widely adopted owing to the lack of quantification. ASTM D3065-01 presents two standard test methods, the flame projection and closed drum tests, for the flammability of aerosol products. The flame projection method involves the spraying of aerosol directly into an open flame to measure whether the aerosol can be ignited. The closed drum test requires the spraying of aerosol directly into a closed drum containing an open flame. Those methods fail to build the relationship between the aerosol flammability and the aerosol property. Therefore, it is important to establish quantitative aerosol explosion testing procedures.
This work experimentally measures the maximum pressure (Pmax) and aerosol deflagration index (Ka) for n-octane and n-dodecane and compares the theoretical adiabatic pressure with the experimental results. Besides, two explosion models were used to simulate the pressure rise procedure. We also developed a liquid flammability rating system with the assistance of machine learning to quantify the flammable hazardousness of liquid. The future work mainly focuses on the design of the fan equipped aerosol explosion apparatus to well mix the aerosol. With the fan equipped vessel, we would like to propose a standard aerosol explosion testing procedure to ASTM.
Citation
Yuan, Shuai (2020). Aerosol Combustion and Explosion Study. Doctoral dissertation, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /200759.