高含硫天然气集输管道泄漏扩散数值模拟

Numerical simulation of leakage and dispersion of acid gas in gathering pipeline

利用CFD软件FLUENT对高含硫天然气集输管道破裂泄漏后的甲烷、硫化氢的扩散进行了数值模拟。结果表明,受重气扩散时沉积效应的影响,高含硫天然气泄漏扩散时近地面的横向污染范围比普通天然气更大,烟云高度明显降低。在自然风速影响下,随海拔高度的增加,危险气体向下风向偏移明显。压力为3.5MPa、含硫化氢5%的高压天然气管道断裂泄漏2min后,在环境风速影响下爆炸危险范围为下风向150～290m,中毒范围为下风向0～270m。山顶地形条件下的扩散规律与平地类似,山谷地形条件下硫化氢将发生沉积而不利于扩散。

The characteristics of the dispersion of H2 S and methane were firstly simulated by FLUENT software while the acid gas leaks from a gathering pipeline. It is found that the H2S pollution scope near the ground in horizontal is wide and the height of H2S cloud is low because of the influence of heavy gaseous-deposition. The excursion of H2S concentration increases in leeward direction with the elevation increasing because of the influence of natural wind. If the pipeline, for transportation of natural gas containing 5% H2S with pressure of 3.5. MPa, leaks for 2 minutes, the explosion range is from 150 to 290 m and poisonous range is from 0 to 270 m in leeward direction. The H2S diffusion characteristic is similar to that in plain area when a gathering pipeline breaks down at hilltop terrain.