Semi Quantitative Risk Assessment of a Hydrogen

The safety of hydrogen generation facilities is the main concern in their process operation. This study was 12 conducted to identify the hazards and evaluate the risks of a hydrogen generation plant. For this purpose, 13 PrHA (Process Hazard Analysis) was applied for hazard identification while LOPA (Layer of Protection 14 Analysis) was used for risk assessment. The study was conducted in the hydrogen production unit 15 of Behshahr Industrial Complex, Iran in 2011 and 2012. In the process of risk assessment, the re16 cords of the accidents and plant flow diagrams were studied. Then, the knowledge of the experts and op17 erators were used through brainstorming prior to the application of LOPA technique. LOPA standard tem18 plate was applied using PHA-Pro6 software. The initiating events, consequences, independent protection 19 layers and probability of failure were determined for 16 scenarios in 7 nodes. The results showed that 20 without the application of IPLs, the risks of 2 scenarios needed immediate action, 9 scenarios required 21 action at next opportunity and 5 scenarios were operational. The application of IPLs would significantly 22 decrease the risks. The study concluded that LOPA has sufficient credibility for semi quantitative risk as23 sessment of high potentially hazardous plants. 24