氮含量对大型储罐BOG产生量的影响

The influence of nitrogen mole content on BOG generation of large storage tanks

为探究氮含量对大型LNG储罐内蒸发气体(BOG)产生量的影响,以某大型单容LNG储罐为例,建立BOG量计算模型,基于Aspen Plus软件,分析储罐内LNG饱和温度、密度、气化潜热随氮含量的变化规律,并与理论计算值进行对比,得出氮含量对蒸发率影响。结果表明:当压力为1.01325×10~5Pa时,随着LNG中氮含量的增加,饱和温度和汽化潜热减小,密度增大,且LNG汽化潜热和密度理论计算与软件模拟结果较为吻合,最大误差分别为7.24%和9.75%。LNG蒸发率随氮含量的增加而提高,氮含量在0~30%之间时,LNG蒸发率理论计算与软件模拟结果仅分别增加0.0018%/d、0.0003%/d。储罐BOG产生量随着氮含量的增加而增加,且理论计算与软件模拟结果较为吻合,误差不超过3.11%。

In order to study the effect of nitrogen content on the generation of boil - off gas （BOG） in large LNG storage tanks, a large single - capacity LNG storage tank was used as an example to establish the BOG calculation model. Based on Asp- en Pluse software, the variations of LNG saturation temperature, density, latent heat of gasification with nitrogen content in the tank were analyzed and compared with the theoretical calculation value. It was concluded that the influence of nitrogen content on evaporation rate was obtained. The following findings were obtained based on the above analysis. When the pressure is 1. 01325 × 10^5 Pa, the higher the nitrogen content of LNG, the smaller the saturation temperature and the latent heat of vaporization, the greater the density, and the theoretical calculation of latent heat of vaporization and density of LNG are in good agreement with the software simulation results and the maximum relative error is 7.24% and 9.75% respectively. The evaporation rate of LNG increases with the increase of nitrogen content. When the nitrogen content ranges from 0 to 30%, the differences between the theoretical calculation and the simulation results of LNG evaporation rate are only 0. 0018% /d and 0. 0003% /d respectively. The BOG in the storage tank increases with the increase of nitrogen content, the theoretical calculation is consistent with the software simulation results, and the relative error is not more than 3.11%.