Abstract: Formation ofhydrate in wet-gas pipelines could bring potential safety hazard. Flow safety evaluation of wet-gas pipelines is of importance for guaranteeing production safety and minimizing losses. The first step of this evaluation is to calculate the probability of hydrate formation(HFP) in wet-gas pipeline. In this work, based on the reliability limit state method and the calculation of the hydraulics and thermodynamics for wet-gas pipeline, and using the water content in sour natural gas predicted by higher precision Har-PR and the conditions of hydrate formation estimated by Chen-Guo model, a probability limit state equation is established from the difference of temperature of hydrate formation and actual flow in the pipeline, and the probability of hydrate formation(FHP) in pipelines is calculated by combined probability method. The entrance data in the experimental hydrate flow loop is analyzed, and the results show that there is the Gaussian distribution for inlet pressure and temperature and the largest extreme value distribution for the inlet flow rate. A case calculation demonstrates that:(1)all mean values and standard deviations of random variables affect HFP in wet gas pipelines; (2)the sensibility of the HFP is different for different random process variables; (3)the probability of hydrate formation in entire pipeline is affected by both the sample numbers for single and combined random variables.

Key words: pipelines, wet gas, flow safety, two-phase flow, phase equilibria, hydrate, formation probability

摘要： 水合物的生成给湿气管道流动安全带来隐患，管道流动安全评价对于保障安全生产和减少损失具有重要意义。湿气管道内水合物形成概率的计算是湿气管线流动安全评价的基础。选择管道入口参数为随机因素，基于可靠性的极限状态法，选用较高精度的Har-PR预测酸性天然气含水量，在湿气管线水力和热力计算基础上，按Chen-Guo模型计算水合物形成条件，以实际流动温度和水合物形成温度之差建立概率极限状态方程，采用组合概率法计算管线的水合物形成概率。分析环道入口数据认为，入口压力、温度符合正态分布，流量符合最大极值分布。示例计算表明：随机变量的均值和标准差都影响着湿气管道的水合物形成概率；湿气管道的水合物形成概率对不同随机工艺参数的敏感性不同；单随机变量样本数和组合随机变量样本总数同时影响着全线的水合物形成概率。

关键词: 管道, 湿气, 流动安全, 两相流, 相平衡, 水合物, 形成概率