Modeling the Leak of R290 Refrigerant to Determine the Evacuation Route and the Control Distance of the Ignition Source

Abstract

Modeling of R290 refrigerant leakage from an 8,949-liter storage tank, focusing on assessing the leakage distance that affects worker health and determining the safety distance for preventing sparks to prevent ignition and explosion. By using the ALOHA program and interpreting the results on Google Earth using 10 years of meteorological data (2015-2024), with the top 5 wind direction variables with the highest frequency from past statistics being south, southwest, east, northeast, and north, with wind direction ratios of 46.7, 23.8, 17.2, 9.8, and 1.6 percent, respectively, and simulating a situation with an average maximum wind speed of 31.7 knots, determining the leakage of R290 refrigerant from the pipeline flange under the R290 refrigerant storage tank with a leak size of 3 inches. The results of the modeling are divided into 5 toxic fog leak models according to the acute exposure guideline level (Acute Exposure Guideline Levels: AEGLs) at a concentration level of AEGL-1: 5,500 ppm., AEGL-2: 17,000 ppm. and AEGL-3: 33,000 ppm., found at distances of 205 meters, 98 meters and 62 meters, respectively. The leak was found to affect evacuation point No. 1, so the evacuation point must be designated as evacuation point No. 2 for safety in case of R290 refrigerant leak and 5 flammable gas cloud leak models based on gas concentrations at 2,100 ppm and 12,600 ppm (10 and 60 percent of the minimum flammable gas concentration) at distances of 390 meters and 119 meters, respectively, from the leak. These are used to define ignition control zones, prevent ignition and explosion at the leak point.