Abstract: The cold insulation effect of LNG pipeline will gradually become worse with the growth of time, so it is necessary to carry out on-line maintenance for the problem pipeline. However, in the process of on-line construction, there will be some problems, such as shrinkage deformation of pipe fittings, shrinkage displacement of cold insulation pipe shell, frost on the surface of pipeline and so on. Therefore, a new type of cold insulation structure was studied, which consist of elastic adjusting layer + foam glass + polyisocyanurate (PIR) + foam glass. The structure had been successfully applied to the high pressure pump in LNG station, and the cold insulation effect could meet the standard requirement of cooling loss no more than 25 W/m², and the external surface temperature of the structure was higher than the dew point temperature of 0.3 ℃. The new cold insulation structure can be used for reference for other LNG stations in China.

Key words: LNG pipeline, cold insulation structure, cooling loss, surface temperature, dew point temperature

摘要： LNG管道保冷效果随着时间的增加会逐渐变差,需要对问题管道进行在线维修。在线施工过程中遇到管件收缩变形、保冷管壳收缩位移、管道表面结霜等问题,为此,研究了一种新型保冷结构,其主要结构型式由弹性调整层+泡沫玻璃+聚异氰脲酸酯(PIR)+泡沫玻璃组成。该结构在LNG接收站高压泵管道上成功应用,经过检测,保冷效果能满足冷损失量不大于25 W/m²,保冷结构外表面温度高于露点温度0.3 ℃的标准要求。该新型保冷结构可以为国内其他LNG接收站提供借鉴与参考。

关键词: LNG管道, 保冷结构, 冷损失量, 外表温度, 露点温度