The consequence distance of liquid ammonia release from a pipeline in complex terrain

Abstract

Ammonia is a high-efficiency and safe hydrogen storage medium. Pipeline transport offers significant economic benefits for long-distance ammonia transportation. However, due to ammonia's toxicity, accidental leaks during transportation can lead to catastrophic consequences. Therefore, a comprehensive understanding of the dispersion characteristics of liquid ammonia pipeline leaks is essential for safety measures. Prior studies focused on the ammonia dispersion over flat terrain, leaving a gap in understanding the impact of diverse terrains on dispersion dynamics. This study introduces a computational fluid dynamics model to simulate ammonia dispersion over complex terrain, quantifying the influence of topographical features on dispersion consequence distances. Firstly, validation of the numerical model is conducted using a custom-built open-circuit wind tunnel test platform. Secondly, the dispersion of ammonia is analyzed over six representative terrains, highlighting the influence of complex topographies on the consequence distances. Additionally, the effects of leakage flow rate, atmospheric stability, and leakage direction on dispersion over flat terrain are examined. Finally, a comprehensive assessment of potential risks associated with liquid ammonia pipeline leaks across various terrains is provided by the synthesis and analysis. The results indicate that flat terrain simulations cannot conservatively estimate consequence distances for most terrains. Therefore, incorporating local terrain data in dispersion simulations is recommended to determine the impact area accurately.