Cause analysis of the fire and explosion during crude oil desulfurization in China

• Investigated inherent cause of fire and explosion accident that occurred on 16 July, 2010, during crude oil desulfurization.
• Assessed the thermal safety of the pure desulfurizing agent JH02, TS02, and crude oil–desulfurizing agent mixture.
• Explained why the direct cause was the thermal runaway initiated by the increasing instability of the mixture.
• Revealed that a more stable desulfurizing agent could not ensure the safety of the desulfurizing process.

A serious fire and explosion accident that resulted in massive crude oil leakage and severe environmental pollution occurred on 16 July, 2010, in Dalian Port, China. To investigate the root cause of accident and conduct a wide-range investigation, desulfurizing agent JH02, which has a similar ingredient to the desulfurizing agent HD used in Dalian Port, and TS02 were employed in this study to determine the role of desulfurizing agents in the accident. The thermal behavior of crude oil, desulfurizing agents, and their mixtures was measured by using a C80 calorimeter. By using the calorimetric data, the kinetic parameters of the chemical reaction, such as activation energy, pre-exponential factor, and self-accelerating decomposition temperature of crude oil, as well as JH02, TS02, and their mixtures, were calculated and compared. The results indicated that the direct cause of the accident was the thermal runaway initiated by the increasing instability of the crude oil–desulfurizing agent mixture. Excess pressure in the oil pipeline triggered the physical explosion, but it alone was not enough to cause a serious damage. Furthermore, a stable desulfurizing agent such as TS02 could not ensure a safe desulfurizing process. The results of this study would benefit the safety management of desulfurizing processes during production and storage.