含硫天然气管道潜在影响半径计算方法研究

发布时间：2018-02-24 04:29

本文关键词： 潜在影响半径含硫天然气管道硫化氢中毒喷射火计算模型　出处：《西南石油大学》2015年硕士论文　论文类型：学位论文

【摘要】：含硫天然气管道的潜在影响半径是指管道发生失效时,其周边公众安全和财产可能受到明显影响区域的半径。潜在影响半径的计算是管道高后果区识别的基础,是保证完整性管理有效实施的关键。我国在2005和2006年依照基本国情颁布了输气管道完整性管理标准,标准中天然气管道的潜在影响半径根据ASMEB31.8S中推荐的模型确定。该模型在喷射火热辐射单点源模型的基础上提出,由于不考虑泄漏气体引发的中毒后果,ASME B31.8S明确指出不适用于含硫天然气管道。多年来,国内外学者对硫化氢中毒潜在影响半径计算模型的研究相对较少,有关含硫天然气泄漏扩散计算的现存文献大多没有充分考虑其独有特点,考虑因素少,这导致计算结果的不可靠,难以在工程实际中运用。因此,针对含硫天然气管道失效的特点提出含硫天然气管道潜在影响半径的计算模型是当今急待解决的难题。故本文开展了以下几个方面的研究： (1)通过对含硫天然气管道的失效诱因、电化学腐蚀机理、开裂机理的研究,将含硫天然气管道的主要失效模式确定为氢致开裂、氢鼓泡、应力定向氢致开裂和硫化物应力开裂导致的全管径断裂。通过对含硫天然气管道失效泄漏事件树的分析,讨论喷射火、闪火、爆炸、硫化氢中毒等多种失效后果的发生概率,将含硫天然气管道的典型失效后果确定为喷射火和硫化氢中毒两类。基于以上研究,根据文献资料确立了含硫天然气管道潜在影响半径计算的基本方法和步骤； (2)根据已确定的主要失效模式,针对含硫天然气管道的泄漏速率随时间不断变化的特点,基于流体力学基本方程所推导出的天然气管道的泄漏速率一般计算模型建立起全管径断裂条件下天然气管道的泄漏速率计算模型。运用PHAST软件对模型中关键参数泄漏速率衰减因子λ展开计算,并通过对λ变化曲线的拟合得到所对应的计算式； (3)通过对不同喷射火热辐射计算模型优缺点的比较,确定选择固体火焰模型中的Chamberlain模型作为基础模型。基于Chamberlain模型建立含硫天然气管道火灾潜在影响半径计算模型,并合理确定火焰表面积、视觉因子、气体泄漏速率、热辐射通量阈值等各模型参数的取值方法； (4)通过分析确定含硫天然气管道泄漏扩散的三大特点：失效模式以全管径断裂为主、泄漏速率随时间不断变化、扩散过程由喷射阶段和被动扩散阶段两部分组成。基于以上分析,从现存气体扩散模型中选择高斯模型作为基础模型,建立了硫化氢中毒潜在影响半径的多气团叠加计算模型。根据相关文献资料,分别对气团质量、扩散参数、泄漏气团高度、硫化氢中毒阈值等模型参数的计算方法进行研究,通过代入相应参数,并对模型进行简化,得到多气团叠加计算模型的最终表达式； (5)针对计算模型相对复杂的问题,运用VB语言编制了硫化氢中毒潜在影响半径计算软件HSCC,并对其计算可靠性进行分析。选定7条实例管道,确定计算风速,运用所建立的火灾潜在影响半径计算模型对各管道分别计算,并将计算结果与基于点源模型的计算结果进行对比。运用HSCC对各条管道的硫化氢中毒潜在影响半径进行计算,并根据计算结果对管道失效后,地面硫化氢浓度的变化规律展开研究。通过火灾潜在影响半径和硫化氢中毒潜在影响半径计算结果的对比,得出含硫天然气管道潜在影响半径应根据硫化氢中毒潜在影响半径确定的结论。
[Abstract]:The potential influence radius of sulfur - containing natural gas pipeline is the radius of pipeline ' s failure . The calculation of potential influence radius is the key to ensure the effective implementation of integrity management . ( 1 ) The main failure mode of sulfur - containing natural gas pipeline is determined to be hydrogen - induced cracking , hydrogen bubbling , stress - oriented hydrogen - induced cracking and sulfide stress cracking by studying the failure - inducing factors , electrochemical corrosion mechanism and cracking mechanism of sulfur - containing natural gas pipeline . The failure leakage event tree of sulfur - containing natural gas pipeline is analyzed , and the typical failure consequences of sulfur - containing natural gas pipeline are determined as two types of injection fire and hydrogen sulfide poisoning . Based on the above research , the basic methods and steps for calculating the potential influence radius of sulfur - containing natural gas pipeline are established . ( 2 ) according to the established main failure mode , the leakage rate calculation model of the natural gas pipeline is established based on the characteristic that the leakage rate of the sulfur - containing natural gas pipeline changes with time , the leakage rate of the natural gas pipeline is calculated based on the basic equation of the fluid mechanics , and the leakage rate calculation model of the natural gas pipeline under the condition of full pipe diameter fracture is established by using the PHAST software , and the corresponding calculation formula is obtained by fitting the fitting of the 位 variation curve ; ( 3 ) Based on the comparison of the advantages and disadvantages of different injection thermal radiation calculation models , it is determined that the model of fire potential influence radius of sulfur - containing natural gas pipeline is established on the basis of lain lain model , and the value methods of parameters such as flame surface area , visual factor , gas leakage rate and heat radiation flux threshold are reasonably determined . ( 4 ) By analyzing the three characteristics of determining the leakage and diffusion of sulfur - containing natural gas pipeline , the failure mode is dominated by the whole pipe diameter fracture , the leakage rate is changed with time , the diffusion process is composed of two parts of the injection stage and the passive diffusion stage . Based on the above analysis , a multi - gas mass superposition calculation model with the potential influence radius of hydrogen sulfide poisoning is established from the existing gas diffusion model . According to the relevant literatures , The calculation method of model parameters such as mass , diffusion parameter , leakage gas mass height and hydrogen sulfide poisoning threshold is studied , and the final expression of multi - gas mass superposition calculation model is obtained by substituting corresponding parameters and simplifying the model . ( 5 ) The calculation software HSCC for the potential influence radius of hydrogen sulfide poisoning is compiled with VB language , and the calculation reliability is analyzed by using the VB language . The calculation results are compared with the calculation results based on the point source model . The potential influence radius of the sulfur - containing natural gas pipeline is calculated according to the results of the potential influence radius of the fire and the potential influence radius of hydrogen sulfide poisoning .

【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE832

【参考文献】