Method and device for reducing usage amount of liquid nitrogen during refining process of krypton and xenon

The invention relates to a method for reducing the usage amount of liquid nitrogen during the refining process of krypton and xenon. The cold source of a condensed evaporator in a fractionating toweris a low temperature gas formed through mixing liquid nitrogen and nitrogen; the operating temperature of each rectifying tower in the fractionating tower is different, and the low temperature nitrogen in the cold source of the condensed evaporator in each rectifying tower and normal-temperature nitrogen are mixed according to different proportions. The invention further relates to a device for reducing the usage amount of liquid nitrogen during the refining process of krypton and xenon. The device comprises the fractionating tower for refining krypton and xenon, a main heat exchanger and a circulating compressor, wherein the main heat exchanger is used for collecting nitrogen out of all condensed evaporators and reheating the nitrogen; and the circulating compressor is used for receivingthe reheated nitrogen and