Estimates of safety distances for hydrogen sulfide leak emission from gas refinery

Sa？etak Refinery processes need to organise and maintain work places safe for their workers, neighbours and the environment. Refineries are the source of many accidents and incidents due to the close proximity of dangerous substances, products and production processes. The aim of this study was to analyse the consequences of hydrogen sulphide leakage scenarios in gas refineries and determine the danger boundary and the risk limits of these scenarios. The study was descriptive-analytic cross-sectional and was carried out in gas refineries. To assess the gas dispersion modality and the effects of leakage scenarios the PHAST software (Process Hazard Analysis Software Tool) was used. Different leakage scenarios were considered and then various climatic conditions affecting these scenarios were identified. Ultimately, the consequences and the danger boundary and risk limits of these scenarios for the affected areas were determined with two-level criteria, LC (lethal concentration) and IDLH (immediately dangerous to life or health). The findings demonstrated that the hazard distance LC50 for hydrogen sulphide dispersion to restricted areas and the hazard distance of the IDLH for hydrogen sulphide toxic dispersion to impacted area were 224 meters and 386 m, respectively. Also, the results revealed that the ENI camp was situated in the dominant current direction, at a 200 m distance from gas refineries. In the event of a leakage accident, substantial loss of life and health damages can be expected. Consequently, it is mandatory that the location of the residents’ camp be changed and appropriate engineering control measures taken