Leakage-Seepage-Diffusion Law And Potential Impact Area Of Buried Sour Natural Gas Pipelines

Once the buried sulfur-containing natural gas pipeline leaks will form a potential impact area for combustion,explosion and poisoning.In this case,the gas will burn or explode when it meets an open flame.Accidents caused by gas pipeline leakage often occur in China.It is a great threat to the lives of residents near the pipeline.At the same time,it causes huge economic loss,environmental pollution and bad social influence.Therefore,this paper will study the whole process of sulfur-containing natural gas seepage in soil and diffusion in the atmosphere and its concentration distribution pattern.The potential impact areas of sulfur-containing natural gas will be predicted based on the study patterns.The results will provide a reference basis for safety management,emergency response and risk assessment.The main contents of this paper are as follows:(1)In this paper,we will first analyze the properties of natural gas containing sulfur,introduce the basic control equations of gas flow and three pipeline leakage models.Apply theory to analyze the leakage of buried sour natural gas pipelines,simplify the physical model,and establish the soil seepage model and atmospheric diffusion model of sour natural gas.The feasibility of replacing soil with porous medium was analyzed by applying the theory of porous medium,and the viscous resistance coefficient and inertia resistance coefficient of soil under different porosity were calculated.(2)Through the simulation calculation of the soil seepage model of sulfur-containing natural gas,the law of gas seepage in the soil is analyzed.The results show that: the larger the soil porosity,the greater the pipeline pressure,the larger the leakage pore size,and the wider the seepage range in the soil.The larger the lateral seepage distance of the surface,the faster the gas seepage speed,the shorter the time to reach the soil surface,and the greater the leakage.The greater the buried depth of the pipeline,the wider the seepage range in the soil.The lateral seepage distance on the soil surface first decreases and then increases,and the seepage velocity first increases and then decreases.The longer it takes to reach the soil surface,the smaller the leakage.(3)Based on the gas soil seepage pattern,the atmospheric model gas inlet uses udf to control the size of the dynamic faceted area of the soil surface and the concentration of methane and hydrogen sulfide gases.Through simulation and analysis of the gas diffusion law in the atmosphere,it is found that: the gas diffusion speed in the atmosphere is much larger than the seepage speed in the soil.The greater the atmospheric wind speed,the closer the gas diffusion range to the ground,and the downwind diffusion distance first increases and then decreases.The higher the concentration of sulfur,the smaller the diffusion range of methane and the larger the diffusion range of hydrogen sulfide.(4)Based on the laws of seepage and atmospheric dispersion of natural gas containing sulfur in soil and related industry standards,the potential impact areas of methane and hydrogen sulfide components were delineated.The software for predicting the potential impact areas of buried pipeline leaks was programmed using VB language.