Iran Occupational Health

  Background and aims: One of the most essential and important steps for improving safety level in existing or designing units is consequence evaluation of hazards such as fire, explosion and dispersion of hazardous chemical substances. Due to severe operational conditions, high explosive and flammable gases such as methane and hydrogen, hydrogen production process is causing major industrial accidents of the view life and financial losses. Therefore safety is main concern of hydrogen producers.

  Methods: First, all hazards and potential scenarios of hydrogen production were identified by applying HAZID Technique, and after collecting the required data, consequence modeling was done by means of professional software PHAST6.54. Death probability of people by means of valid equations of probit was calculated and ultimately, the severity of the consequences was estimated using conventional criteria .

  Results: The results revealed that, jet fire caused by a full bore rupture in Desulphurization reactor has the highest fatality (26person). The harm effect distance, maximum radiations of this incident were 250 m, 370 kW/m² respectively. A full bore rupture in Reformer can lead to the most dangerous flash fire. So that people at distance up 130 m from placing leakage and affected area 1505m² were exposed to concentration of 61120 ppm and all people would be killed. The most dangerous vapor cloud explosion caused by hydrogen purification absorbers, so that distances up to 60m from absorbers location all people would be killed and all process equipments and buildings will be completely destroyed. The safe distance of hydrogen production unit equals to 746 m from its boundary limit.

  Conclusion: Consequence evaluation is a quantitative and comprehensive method for estimation and evaluation of potential incidents severity of industrial hazardous units. The occurrence of incidents such as fires and explosions has the great life and financial losses in the hydrogen production process, Thus safety of industries nearby hydrogen production and consume must be specifically considered .