| abstract |
The invention relates to an air separation device for preparing full liquid in a nitrogen circulation process and a preparation method thereof, comprising an air filter, an air compressor, an air precooling unit, an air purification unit, a nitrogen booster, a nitrogen compressor, a high-low temperature booster turboexpander and a cryogenic separation cold box unit, wherein compressed air is subjected to heat exchange by a main heat exchanger and then enters a lower tower, part of circulating nitrogen is subjected to heat exchange by the nitrogen booster and then enters a high-temperature expander for expansion, and is reheated by the main heat exchanger and then enters the cryogenic separation cold box unit and enters a nitrogen booster inlet for completing circulation, the other part of circulating nitrogen is subjected to heat exchange by the high-temperature expander booster, the low-temperature expander booster and the main heat exchanger and is extracted from the bottom of the main heat exchanger, throttled by a throttle valve and then enters the top of the lower tower and is expanded by the low-temperature expander from the middle-lower part of the main heat exchanger, is separated in a gas-liquid separator and then is reheated by, the requirement of large cooling capacity is met, the energy consumption of the device is reduced, and the product extraction rate is improved. |