Storage Tank Overfill Vapor Cloud Explosions - Science, Causes, and Prevention

摘要

The 2009 Puerto Rico incident reminds us that few events are as devastating as a vapor cloud explosion initiated by a tank overfill. Any company that transfers a flammable liquid into a storage tank is vulnerable to the vapor cloud that is generated by a tank overfill. Because the liquid typically pours out from the top of the tank and falls into the secondary containment, the liquid may be contained but the vapor can easily traverse the secondary containment wall and find an ignition sources where either a vapor cloud explosion or a flash fire (deflagration) that may result. In either case, it is important to understand and prevent this type of incident. Although recent gasoline tank overfill vapor cloud explosions (VCEs) have made the news, much larger crude oil volumes are shipped throughout the world. Therefore, it seems reasonable to investigate how the VCA methodology can be applied to crude oil tank overfills. In this paper we build on the Vapor Cloud Analysis (VCA) proposed by the UK Health Safety Executive as documented in Research Report 908 and the FABIG Technical Note 12. We summarize the latest results but we extend the method so that it is applicable to crude oil tank overfills. In addition, we show how to positively eliminate the potential for these incidents without large investments or complex systems.