Evaluation of Consequence Modeling of Fire and Explosion on Methane Storage Tanks in a CNG refueling Station

One of the most fuel materials that recently considered is compressed natural gas (CNG). Despite all the known benefits, storage, transportation and use of compressed natural gas as a fuel have risks such as explosions and fires. This study was aimed towards Consequence Modeling of Fire and Explosion on Methane Storage Tanks in a CNG refueling Station.

In this study, A CNG station was evaluated. Considering the results of the visit the CNG station, survey of the recent studies and events and review of experts' opinions, four scenarios of discharges, catastrophic rupture, jet fire and explosions in compressed natural gas storage tanks were evaluated. Then each of these scenarios by using the software is modeled and Possible Consequences of each scenario were evaluated. In order to Consequence Modeling and examine the outcome of Consequences in this study, the PHAST software version 6.7 was used.

In this study two jet fire and explosion scenarios of storage tanks were selected as the worst case scenarios. In jet fire scenario the maximum area affected by fire is 135/13 square meters in the leakage dimension of 150 millimeters. The results of CNG storages explosion modeling also showed that at a distance of 20 meters from storage tanks, the explosion pressure increase is 1 bar (The probability of death in this pressure is 100%) and gradually decrease by increase the distance from the storage tanks, as far as the distance of 400 meters, it reaches at 0.01 bar that is a safe area. It was also found, in the radius 52, 69 and 232 meters of the storage tanks there were 0.21, 0.14 and 0.02 bar increasing pressure, respectively.

The results of present study showed that leakage and damage of the storage tanks, can lead to deadly accidents, Particular in dual-purpose refueling stations (CNG and Gasoline). So according to the results of this study, increasing the number of this refueling stations in recent years, corrective actions in order to increasing the safety levels in methane gas storage tanks in CNG refueling Station is essential