尹鹏博,王博,李臻超,等. 管道输送含杂质NH3的物性参数变化规律[J]. 油气储运,2025,x(x):1−11.
引用本文: 尹鹏博,王博,李臻超,等. 管道输送含杂质NH3的物性参数变化规律[J]. 油气储运,2025,x(x):1−11.
YIN Pengbo, WANG Bo, LI Zhenchao, et al. Variation patterns of physical property parameters for pipeline transportation of impurity-containing NH3[J]. Oil & Gas Storage and Transportation, 2025, x(x): 1−11.
Citation: YIN Pengbo, WANG Bo, LI Zhenchao, et al. Variation patterns of physical property parameters for pipeline transportation of impurity-containing NH3[J]. Oil & Gas Storage and Transportation, 2025, x(x): 1−11.

管道输送含杂质NH3的物性参数变化规律

Variation patterns of physical property parameters for pipeline transportation of impurity-containing NH3

  • 摘要:
    目的 管道输送是实现绿色氨能大规模运输最为经济且安全的方式之一,但管输NH3可能会因合成工艺与输送环境影响而混入杂质,造成NH3的相平衡特性及物性发生改变,进而影响管输效率,并给实际管输过程带来潜在安全隐患。
    方法 基于已有NH3物性实验数据,开展了常用气体状态方程(PR、SRK及BWRS)与Helmholtz自由能模型(THB)的对比分析,实现了含杂质NH3物性参数计算模型优选。同时,基于优选模型探究了NH3与不同含量H2、N2、O2及H2O杂质所组成二元混合物的相平衡特性与物性发展规律。
    结果 PR状态方程针对含杂质NH3混合体系的计算精度较高,以NH3+H2O混合物密度为例,采用PR状态方程得到的计算值与实验值的平均偏差为1.2%。非极性、极性杂质分别对NH3混合体系泡点线、露点线产生影响,造成气液两相区范围扩大,并使临界点位置发生偏移。非极性杂质(H2、N2、O2)造成相变点处NH3的密度与黏度突增现象消失且呈现显著下降趋势,使管输NH3发生相态转变时的流动更加平稳,杂质分子量越小、含量与温度越高,该影响效果越显著,但对气相状态下NH3的密度与黏度变化影响较小;非极性杂质还会导致相变点处NH3比热容减小并在更高压力位置发生突变,杂质分子量、含量及温度越高,该作用效果越明显。NH3密度、黏度及比热容的变化趋势受极性杂质H2O影响较小,其数值随H2O含量的增加而增加。
    结论 研究结果可用于指导杂质影响下的管输液氨相态控制,同时为含杂质液氨管道的输送特性预测、流动保障提供理论支持;建议结合未来液氨管道大规模建设运行后的实际杂质问题,后续开展更多杂质类型、不同含量情况下的氨基础热物性研究,以确保液氨管输过程的稳定性与安全性。

     

    Abstract:
    Objective Pipeline transportation is one of the most economical and safest methods for the large-scale transport of ammonia (NH3), which is recognized as a clean energy source. However, during this process, NH3 may become mixed with impurities due to the synthesis process and the transportation environment. These impurities can alter the phase equilibrium characteristics and physical properties of NH3, subsequently affecting transport efficiency and posing potential safety hazards to the pipeline transportation process.
    Methods Using existing experimental data on the physical properties of NH3, a comparative analysis was conducted among commonly used gas equations of states (PR, SRK, and BWRS) and the Helmholtz free energy model (THB). This analysis facilitated the selection of a suitable model for subsequent calculations of the physical properties of impurity-containing NH3. Based on the chosen model, the phase equilibrium characteristics and development patterns of physical properties were explored across binary mixtures of NH3 with varying concentrations of H2, N2, O2, and H2O.
    Results The calculation results indicated that the PR equation of state exhibited higher precision compared to the other options for the impurity-containing NH3 mixture systems. For example, when examining the density of the NH3+H2O mixture, the average deviation of the calculated values based on the PR equation of state from the experimental values was only 1.2%. Both non-polar and polar impurities were found to influence the bubble point and dew point lines of the NH3 mixture systems, resulting in an expanded gas-liquid two-phase region and a shift at the critical points. The non-polar impurities (H2, N2, and O2) transformed the abrupt increases in density and viscosity of NH3 at the phase transition points into significant declining trends. As a result, these impurities contribute to a more stable flow of pipeline-transported NH3 during phase transitions. This effect was particularly pronounced in systems containing these impurities with lower molecular weights, higher concentrations, and elevated temperatures. However, the effects on density and viscosity were less noticeable for NH3 remaining in the gaseous phase. The non-polar impurities also caused a decrease in the specific heat capacity of NH3 at the phase transition points, with a sudden change occurring at higher pressure levels. This effect became more evident with increasing molecular weights, concentrations, and temperatures of the impurities. The variation trends of NH3 regarding density, viscosity, and specific heat capacity were found to be less affected by the polar impurity of H2O, despite a corresponding increase in these values with rising H2O concentrations.
    Conclusion The research results provide guidance on the phase control of pipeline-transported liquid ammonia in the presence of impurities, offering theoretical support for predicting transport characteristics and maintaining a flowable state in pipelines carrying impurity-containing liquid ammonia. Future research is recommended to explore the fundamental thermophysical properties of ammonia, incorporating a wider range of impurities at varying concentrations, and addressing actual impurity-related issues that may arise from the large-scale construction and operation of liquid ammonia pipelines. This will help ensure the stability and safety of the liquid ammonia transportation process.

     

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