Abstract:

Massive release of sour gas and dispersion of fatal hydrogen sulfide brought about by gas sweetening unit leakage are a major threat to the safety of sour gas processing plant.By analyzing the leakage and atmospheric conditions, the scene of accident, caused by the leakiness of gas sweetening unit, were determined.Based on large eddy simulation of turbulent flows, H₂S dispersion in complex terrain was simulated.The peak time for accident was estimated, hazard regions were ranked and the influences of terrain on dispersion could be summarized as spatial obstacle, channeling and aggregation.Dose-response relationship for acute H₂S poisoning was used to assess the cumulative effects of H₂S on the public and calculate the lethal percentages.The maximum distances, downwind deflection angles, maximum widths and areas of the lethal regions were obtained.The application in one sour gas processing plant in mountainous area shows that the accident will cause high death risk around the plant and adjacent road, and not lead to mortality in the nearby residential area and planned highway.Based on the features of the accident, recommendations to establishing emergency planning zone, taking immediate shelter and implementing priority relief are suggested for emergency response.

Key words:

含硫天然气, 脱硫装置, 泄漏, 扩散, 数值模拟

摘要：

脱硫装置泄漏导致的含硫天然气大量释放和致命H₂S扩散，是天然气净化厂安全生产的严重威胁。通过分析含硫天然气泄漏和大气扩散条件，确定导致重大人员死亡后果的脱硫装置泄漏事故场景。基于湍流大涡模拟理论，对复杂地形H₂S扩散进行数值模拟，确定峰值影响时间、危害区域分布及地形影响作用。采用急性中毒剂量-反应模型分析H₂S累积毒害和死亡百分比，确定致死区域的最大距离、下风向偏转方向、最大宽度和区域面积。以某山区天然气净化厂为例进行评价，分析表明厂区整体和临近道路区域内死亡风险很高，但事故不会导致周边居民区和高速公路人员的重大死亡。根据事故特点，推荐制定应急计划区域、采取就地庇护和实施优先救助的应急救援策略。

关键词:

含硫天然气, 脱硫装置, 泄漏, 扩散, 数值模拟