Novel energy-saving process for air separation liquefied compressed air

The invention relates to an energy-saving process for producing liquid oxygen by liquefying compressed air through an air separation system with a liquefying device. The air separation system mainly comprises a compressor, an air purification system, an expansion machine, a plate heat exchanger, a rectification system, a low-temperature valve, a low-temperature pipeline and the like. Compressed air after the air purification system enters the liquefying device to be liquefied into liquid air, the liquid air is converged with low-temperature liquid air before the air separation device enters the rectifying system, and the liquid air enters the rectifying system to produce liquid oxygen, so that the purposes of reducing the load of a main heat exchanger, reducing oxygen pipeline construction, reducing the operation risk of a traditional liquefying device and improving the air separation driving speed are achieved. Therefore, the purposes of energy conservation and efficiency improvement of the air separation de