求翻译：LNG储罐和大口径卸料管线的预冷是LNG储罐投产的主要环节，合理选择预冷介质，控制预冷过程的温降速率和压力是进行预冷作业的关键。是什么意思？

LNG storage tanks and large-diameter discharge line pre-cooling is a major part of the LNG storage tank production , the rational choice pre-cooling media , control the temperature drop rate and pressure pre-cooling process is critical to pre-cooling operation performed .

LNG tanks and large-caliber unloading lines the pre-cooling is LNG tank production at the main link, rational choice pre-cooling media to control the cold process of temperature drop rate and pressure is pre-cooled critical.

正在翻译，请等待...

LNG storage tanks and large diameter discharge pipe cooling is the major part of production of LNG storage tank, a reasonable selection of cooling medium, controlled cooling rate of temperature drop during pre-cold work and stress is key.

正在翻译，请等待...