大型LNG储罐底部泡沫玻璃绝热层保冷性能

Cold performance of foam glass insulation in the large LNG tank bottom

通过理论分析和工程实例对比计算,得出泡沫玻璃绝热保冷层厚度与储罐底部冷损失、蒸发量、蒸发率关系式和关系曲线,证明在绝热层一定厚度范围内,冷损失、蒸发量、蒸发率均随绝热层厚度呈双曲线关系,降低较快,此后保冷性能趋于稳定。计算表明实际工程中所采用的绝热层普遍偏厚,如实例中绝热层厚度减少53.3%,冷损失仅为最大冷损失的7.58%,仅比实际值增加3.82%;日蒸发率为0.04%,仅比实际值增大0.02%,表明实际工程中大型LNG储罐底部绝热层厚度优化大有空间。

Relationship between the layer thickness of a foam glass cold insulation and cold loss,evaporation capacity,evaporation rate of the tank bottom were obtained by comparing the theoretical analysis and engineering examples calculation.The result shows that the cold insulation layer thickness exhibit hyperbolic function relationship with the cold loss,evaporation capacity and evaporation rate in a certain range.Cold performance of foam glass cold insulation decreases rapidly with the layer thickness at first but tends to be stable.Calculation result shows that the cold insulation thickness widely used in actual project is always too thicker.For an instance,if the cold insulation thickness is reduced by 53.3%,the cold loss reduces only 7.99% of the maximum design cold loss,which is only 3.82% larger than the actual value.Meanwhile,the daily evaporation rate is 0.05%,which is only 0.02% larger than the actual value.For the large LNG tank used in actual project,there is great space in optimizing the bottom insulation thickness.