Study of Leakage and Explosion of Hydrogen and Blast Wall Failures in an Offshore Platform

Study of gaseous explosions and their effects on structures is helpful in designing offshore platforms. Specifically, reliable methods for the prediction of overpressures in offshore explosions are highly useful and are extensively researched. The selection and/or development of means of prevention, control and mitigation of explosions often depends on the comprehensive analysis of their probability of incidence and damage potential. This involves a number of factors, such as explosive gas leak size, location, composition, wind direction, and characteristics of probable ignition. This paper presents a 3D transient CFD based analysis tool for such purposes and the results of some simulations done using it. The first set of simulations is a validation exercise, which involves hydrogen leakage and explosion, and the computational results are compared with the experimental data. The second set of calculations involved simulation of a hydrogen gas leakage scenario on an offshore platform, followed by explosion studies for different scenarios to find the effect of various guidelines for the initial conditions in the reactive cloud. These results show that, the maximum explosion pressure occurs when stoichiometric initial mixture conditions are applied in the dispersed flammable region. The worst case explosion scenario thus observed has maximum over pressures and maximum blast wall displacement of about 18 to 20 times higher than the base case explosion.