Quantitative risk assessment for ethylene oxide storage tank in Shree Vallabh Chemical in Ahmedabad
Keywords:
QRA , jet fire, AlOHA , thermal radiation , vapor cloud explosion , Hazard identification, Risk matrix.Abstract
Ethylene oxide (EO) is produced in large volumes and is mainly utilized as an intermediate raw material in the
manufacture Emulsifiers & De – Emulsifiers. EO is stored in horizontal storage tank in liquid state under pressure with
adequate cooling and only in well-ventilated area .Unfortunately, EO is highly flammable and in vapor form, is subject
to explosive decomposition, therefore it can pose risk s to personnel, equipment facilities and environment. With risks
becoming more complex and diverse, risk evaluation approaches are required to quickly identify hazards, effectively
assess safety performances. Risk Assessment is one of the majortechniques used byvarious industries throughout the
world. In this paper quantitative risk assessment of an ethylene oxide storage tank situated in Ahmedabad. The hazards
identification are carried out systematically,furthermore, identification of the worst possible accident scenarios which
arising from the tank due to the valve or pipe failure. The over pressure from Vapor Cloud Explosion and heat
radiation intensity from fire as considered as criteria for assessing the effects towards humans and structures. The
effect of thermal radiation on people is mainly a function of intensity of radiation and exposure time. The effect is
expressed in terms of the probability of death and different degrees of burn.For mentioned purpose, these scenarios are
further modeled in ALOHA software and the analyses are carried out primarily for weather classes such as 5 D, 1 F.
The prediction process show that , the most serious threat zone in case of stable weather will extend to a distance
greater than in neutral weather if the BLEVE or VCE takes place .On other hand , the red threat zone resulting from jet
fire will be less extended in stable weather as compared with neutral weather. Risk-Matrix has been established to
determine the risk rank of the EO storage tank.Based on the risk assessment study and the outputs from the model
, Set of measures and procedures which should be taken in order to reduce possibility and limit consequences of
accident.
