Study on the Toxic Range of Leakage and Diffusion in Buried High-Sulfur-Containing Natural Gas Pipelines

The presence of hydrogen sulfide in sulfur-containing natural gas makes the pipeline more likely to corrode and perforate during pipeline transportation, especially under the harsh and hidden environmental conditions of buried pipelines. This paper analyzes the distribution characteristics of the leakage diffusion flow field of sulfur-containing natural gas pipelines under different conditions by numerical simulation and establishes the prediction model of the diffusion toxicity range of sulfur-containing natural gas based on multiple regression theory. The results show that the pressure value and velocity value of the leaking gas in soil increase with the increase of the leakage time. The ground toxic range (GTR) is 0.688 m when the leakage occurs for 5 min and increases to 1.749 m when the leakage occurs for 30 min, indicating that the longer the leakage time, the greater the potential poisoning risk. The maximum error and average error of the prediction model are 9.203 and 2.932%, respectively, indicating the accuracy of the prediction results. This study provides data support for the GTR of buried sulfur-bearing natural gas pipelines after leakage, guidance for pipeline leakage monitoring, and a basis for the dangerous range of pipeline repair operations.