近年来,随着碳捕集与封存的需求不断提高,CO2输送管道成为关键支撑,大规模发展趋势明显。相比气态输送,长距离CO2输送管道采用超临界输送模式经济性更好,但具有泄漏后压力台阶较高、管道止裂韧性要求较高、泄漏后果与油气介质不同等显著特点。尤其对于超临界CO2管道泄漏问题,受CO2密度大于空气、具有窒息性等特性影响,泄漏后果分析日益受到关注,值得深入研究。目前,国内外已经发布了相关CO2管道输送技术规范,但未见对泄漏后果定量分析方法与临界阙值指标的明确要求,对工程设计的详细指导尚显不足,且鲜有与实验测试结果分析比对的探讨。基于CO2相态特点,结合超临界CO2输送特点,探讨了超临界CO2泄漏后果的安全阙值选取问题,开展了国外超临界CO2管道破裂实验的深度调研,比对性地开展了超临界泄漏后果模拟分析。研究表明,推荐选择摩尔浓度4%作为CO2线路管道破裂影响范围评价浓度值;国外大规模CO2全尺寸破裂实验的泄漏影响范围大于同等规模天然气管道潜在影响半径;CO2管道破裂泄漏扩散范围受管道长度、管道外径影响较大,对管道压力影响敏感性较低。研究成果可为超临界CO2管道设计提供相关参考。

 In recent years, with the increasing demand for carbon capture and storage, CO2 transmission pipeline has become a key support and its large-scale development trend is obvious. Compared with gaseous transmission, long-distance CO2 transmission pipeline using supercritical transmission mode enjoys better economics, but there are significant characteristics such as higher pressure gradient after leakage, higher requirement of pipeline crack arrest toughness, and different consequences as compared to leakage from oil and gas process media. Especially for the supercritical CO2 pipeline leakage issue, due to its density being greater than air, asphyxiation and other characteristics, the analysis on its leakage consequences is increasingly gaining concern and worthy of an in-depth study. At present, relevant pipeline transmission specifications have been released at home and abroad, but there are no explicit requirements on quantitative risk analysis methods and critical threshold indicators for leakage consequences, which are still insufficient for reference in detailed engineering design. Furthermore, there are little discussions on analysis and comparison with experimental results. Based on the phase characteristics of CO2 and the characteristics of supercritical CO2 transmission, the issue of selecting the safety threshold for the consequences of supercritical CO2 leakage is discussed, and an in-depth study of overseas supercritical CO2 pipeline rupture experiments is conducted, and the simulation analysis of the consequences of supercritical leakage is carried out for comparison purposes. The study shows that the molar concentration 4% is recommended as the evaluation concentration value for the evaluation of impact range of CO2 pipeline rupture; the impact range of leakage in overseas large-scale CO2 full-size rupture experiments is larger than the potential impact radius of natural gas pipelines of the same scale; the dispersion range of CO2 pipeline rupture leakage is mainly influenced by the length and outer diameter of the pipeline, and the sensitivity to the impact of pipeline pressure is lower. The results can provide relevant references for supercritical CO2 pipeline engineering design.