Safety distance analysis of dimethylether filling stations using a modified individual risk assessment method

The physical properties of dimethylether (DME) are similar to conventional fuels such as LPG and diesel, so DME has been recently considered one of the most promising candidates for a substitute for them. Equipment failures in gas stations lead to accidents that pose significant threats to people and property. Therefore, prior to commercialization, safety standards for DME need to be developed based on risk analysis. In this study, we focused on safety distance in DME filling stations. A hypothetical DME filling station was modeled based on a DME-LPG mixed filling station designed by KOGAS, and safety distances were suggested from a semi-quantitative risk estimation approach using individual risk calculations. Modified individual risk calculations were performed with consequence analysis and failure mode under varying accident scenarios. Compared with existing individual risk analysis, the modified-individual risk approach is supplemented with a weighting factor to graduate each accident scenario by historical analysis. Subsequently, the outcome shows the individual risk that suggests a safety distance. To compare with conventional fuel, we also performed a comparative study on the filling station fuels LPG and DME. According to the quantitative risk estimation results, we propose a separation distance based on accident scenarios for each facility. In conclusion, safe distances for DME facilities are lower than those that dispense LPG. Therefore, a DME filling unit can be placed at conventional gas stations without increasing the safety distance. The results will also be useful in determining the standard for safety management of renewable and sustainable energy.