Quantitative risk analysis applied to refrigeration’s industry using computational modeling

Abstract

Ammonia has been used in refrigeration installations for years. It is a natural refrigerant and is replacing other synthetic fluids as it has zero ozone depletion potential and no global warming potential; however, an ammonia leak in a refrigeration plant can cause damage to the environment and human health as well. Here we evaluate the quantitative risk analysis of using ammonia in real industrial refrigeration in Rio de Janeiro. This work’s methodology used PHAST to achieve the assessment model of seven scenarios of ammonia leakage, which allowed the understanding of quantitative risk for ammonia leakage. For each scenario, three ammonia concentrations were simulated, and the gas dispersion distances and their zone of influence were analyzed. Results indicated the worst scenario reached 2677m and 665m and all accident scenarios showed that individual and societal risk were above the limit allowed by the Rio de Janeiro environmental agency. To reach the limits tolerable by the agency, two mitigation measures were proposed, guaranteeing a reduction in ammonia dispersion between 41 and 48% and 100% for each measure. Although the use of environmentally friendly refrigeration fluid is desired, the assessment needs to consider individual and societal risks to ensure that it will not affect the facility.

Keywords

• Quantitative risk analysis
• Environmental risk
• Individual risk
• Societal risk
• FN Curves
• PHAST