Abstract
Hydrogen is an important carrier of clean energy, and its transport through existing natural gas pipeline networks has become an international consensus for large-scale delivery. The existing large-scale, long-distance transportation of natural gas relies on buried pipelines. However, there are significant differences in the physical and chemical properties of methane and hydrogen. Hydrogen mixed into the natural gas pipeline network for transportation may cause hydrogen embrittlement in the pipeline, which can lead to leakage and explosion accidents, causing serious injury to the surrounding personnel and property. In this study, numerical simulation was used to explore the leakage and diffusion laws of buried high-pressure hydrogen-blended natural gas (HBNG) pipelines as well as the initial explosion time (IET) and leakage of HBNG in forming the ground surface explosion zone under different hydrogen blending ratios (HBRs), soil properties, pipeline pressure, burial depth, soil temperature, leakage hole diameter, and other influencing factors. The results demonstrate that soil properties significantly influence the diffusion characteristics of gas leakage. The increases in leakage hole diameter, pipeline pressure, HBRs, and soil temperature all contribute to an earlier IET. The formation of IET is significantly delayed with increasing burial depth. The increase in HBR will lead to a decrease in gas leakage, and the two are negatively correlated. Multivariate function prediction models of IET and mass flow rate were established by coupling multiple influencing factors with average errors of 4.7 and 2.67%, respectively. This study provides a numerical reference for optimizing the maintenance and repair plans and emergency response plans after the HBNG pipeline leakage.