天然气长输管道是复杂的系统工程,有必要针对各关键环节进行掺氢影响分析,以探究现有天然气长输管道掺氢运行的可行性。梳理了掺氢对现有管线钢的影响研究现状,分析了增压设备排压、排量变化,基于氢气理化特性,结合国内外现有天然气管道和输氢管道设计标准,对长输管道掺氢后管输流速、连接头密封性、调压计量设施等进行了研究。研究结果表明:氢会显著降低钢材力学性能,但还需开展针对性研究并建立相应标准体系;少量的一氧化碳可有效抑制管线钢氢脆,但国内标准没有最低含量要求,水露点、二氧化碳含量指标也低于国外掺氢管道标准;掺氢会降低离心式压缩机排压和排量;掺氢还会减小调压过程温降,导致声速变快,掺氢比接近10%时,现有超声波流量计、涡轮流量计计量精度不满足标准要求。结论认为,现有天然气管道掺氢运行需进一步建立相应评价模型和标准,并需对部分环节进行针对性调整和改进。

Long-distance natural gas pipelines are complex systems, and it is necessary to analyze the impacts of key aspects on hydrogen blending to explore the feasibility of hydrogen blending operation in existing natural gas long-distance pipelines. The current research status regarding the effects of hydrogen blending on existing pipeline steels is reviewed. Based on the physical and chemical properties of H2, combined with domestic and international design standards for natural gas and hydrogen transmission pipelines, the influences of compressor discharge pressure and displacement, gas velocity, joint sealing performance, pressure regulation, and metering facilities after hydrogen blending are analyzed. The research results indicate that hydrogen can significantly degrade the mechanical properties of steel, but targeted research and the establishment of corresponding standard systems are still needed. A small amount of carbon monoxide can effectively suppress the hydrogen embrittlement of pipeline steel, but there is no minimum content requirement in domestic standards, and the indicators for water dew point and carbon dioxide content are also lower than those in foreign standards for hydrogen-blended pipelines; hydrogen blending will reduce the discharge pressure and displacement of centrifugal compressors; it also decreases the temperature drop during the pressure regulation process, accelerates the speed of sound, and when the hydrogen blending ratio approaches 10%, the metering accuracy of existing ultrasonic and turbine flow meters fail to meet the standard requirements. It is concluded that, further studies are needed to establish appropriate evaluation models and standards for hydrogen blending in existing natural gas pipelines, accompanied by targeted adjustments and improvements in specific aspects.