vacuum retorting of oil shale

例句：

1. 1. The process of vacuum retorting is essential for the extraction of oil from shale.
   真空炼油过程对于从页岩中提取油至关重要。
2. 2. Vacuum retorting technology has greatly improved the efficiency of oil shale processing.
   真空炼油技术大大提高了石油页岩加工的效率。
3. 3. The vacuum retorting process involves heating the shale at high temperatures and then extracting the oil through a vacuum system.
   真空炼油过程涉及在高温下加热页岩，并通过真空系统提取油。