摘要
对天然气扩散浓度进行研究,可以解决泄漏气体沿地面扩散所形成的危险区域预测问题,为管道运行和抢修提供安全保障,对于输气管线的风险后果定量分析具有重要的意义。为此,考虑到天然气泄漏扩散的特殊性,选取高斯模型作为扩散危害基本模型,给出了非正常泄漏状态下模型的修正函数。结合3种典型的泄漏扩散事故情景,模拟分析了天然气职业接触浓度限值和爆炸上、下限浓度所对应的扩散距离和危害区域面积;此外还对比分析了风速、泄漏孔径及泄漏时间等因素对扩散危害面积的影响。算例结果表明,管道发生连续泄漏时,危害区域的面积随风速的增大而减小,随泄漏孔径的增大而扩大。发生大规模瞬态泄漏时,在泄漏初期,人员产生不适症状的危害区域及爆炸危险区域都随时间的增加而逐渐扩大;随着时间的延长,泄漏气体不断被空气稀释而使得浓度降低,若时间足够长,危害区域将不再存在。
The leakage and diffusion of natural gas in pipeline may result in explosion and fire. Through analysis of the gas diffusion concentration, the hazardous areas can be predicted and safe guarantee for operating and repairing of pipeline can be achieved, which are of special interest for quantitative risk analysis. Considering the special nature of the leakage and diffusion of natural gas, the Gauss model is adopted as the basic diffusion model, and the model's correction function under the conditions of abnormal leakage is provided. With three typical diffusion scenarios as examples, the article analyzes the diffusion distances and hazardous areas according to OEL(occupational exposure limit), LEL( lower explosive limit )and UEL( upper explosive limit ) of nature-gas concentration. It is also analyzed the factors affecting the hazardous areas, such as wind speed, hole diameter of linepipe and release time of gas. The results show that when the pipeline's continuous release happens, the hazardous areas get smaller as wind speed becomes higher and the hole diameter becomes smaller. At the first-stage of large-scale instantaneous release, the hazardous areas get bigger as the time goes. If time is long enough, the hazardous areas will not exist as gas concentration is diluted by air.
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2006年第7期120-122,共3页
Natural Gas Industry
基金
国家自然科学基金项目(编号:50374056)资助。
关键词
天然气
输气管道
泄漏
扩散
模型
浓度
极限值
危害
面积
natural gas, pipeline, leakage, diffusion, model, concentration, limit, hazard, area
