天然气掺氢在管道流动中的氢浓度分布

HYDROGEN CONCENTRATION DISTRIBUTION IN FLOW OF HYDROGEN BLENDED TO NATURAL GAS IN PIPELINE

  • 摘要: 天然气掺氢是解决氢气产地与使用地不匹配,进而实现氢气大规模、远距离输送的主要方法。由于氢气的存在会导致在役天然气管道出现氢脆引起安全事故。所以,研究天然气掺氢管路中氢气组分、速度、聚集的规律分析十分必要。本文选用天然气和氢气两种工质,构建T型掺混管路模型和变径管路模型;并基于Fluent软件对T型掺混管路和10种变径掺混管路进行数值模拟研究。结果表明,对于T型掺混管路,在管长是管径35倍处内依然有明显分层,宽度占据1/3管径。对于变径掺混管路,发现变径越靠近掺混中心、直径越窄、高度越低越容易发生氢气富集,氢气摩尔分数最高达到50%~60%,易引起管道的氢脆。研究结果可对天然气掺氢在管道中流动的氢浓度分布和管道变径选取提供参考。

     

    Abstract: Blending hydrogen into natural gas is the primary method to solve the mismatch between the origin and use of hydrogen and realize the large-scale and long-distance transportation for hydrogen. Hydrogen can lead to hydrogen embrittlement in natural gas pipelines and cause safety accidents. Therefore, it is necessary to investigate the regularity analysis of hydrogen composition, velocity, and accumulation in in-service natural gas pipelines. A T-type and a variable diameter type blending pipeline model have been constructed and researched for blending hydrogen in natural gas. The T-type results show that the pipe length of obvious layering and width are 35 times and 1/3 of pipe diameter, respectively. The results of variable diameter have been illustrated that the closer the blending center, the narrower of width and the lower of height with variable diameter can lead to hydrogen enrichment easily. Hydrogen embrittlement has been facile with a maximum hydrogen mole fraction of 50%~60% in blending nature gas pipelines. The results can provide a reference for the blending effect of natural gas with hydrogen and the selection of pipeline diameter.

     

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