Low-temperature rectification experiment system

The invention discloses a low-temperature rectification experiment system which comprises a main tower, a condenser, a reboiler and a pre-cooling tank, wherein vacuum cavities are formed in the outer parts of the main tower, the condenser, the reboiler and the pre-cooling tank; the main tower comprises a main tower filler section as well as a liquid distributor and a gas distributor which are arranged at the upper end and the lower end of the main tower filler section; the condenser is connected with the main tower through a main tower gas outlet pipeline and a main tower liquid inlet pipeline; the reboiler is connected with the main tower through a main tower gas inlet pipeline and a main tower liquid outlet pipeline; the precooling tank is selectively connected with the feeding hole of the reboiler or the middle part of the main tower through a pipeline according to different working conditions; a reboiler liquid extraction pipeline is arranged at the lower part of the reboiler; a condenser gas extraction p