Device for co-producing liquid nitrogen and liquefied natural gas

The utility model discloses a device for co-producing liquid nitrogen and liquefied natural gas (LNG). A main heat exchanger is connected with a denitrifying tower; the liquid phase outlet of the denitrify tower, the main heat exchanger and an LNG flash tank are sequentially connected; the gas phase outlet of the denitrify tower is sequentially connected with the main heat exchanger and a nitrogen-methane fractionating tower; the liquid phase outlet of the nitrogen-methane fractionating tower is sequentially connected with the main heat exchanger and the LNG flash tank; the gas phase outlet of the nitrogen-methane fractionating tower is sequentially connected with the main heat exchanger, a nitrogen compressor, a nitrogen cooler, the main heat exchanger and a liquid nitrogen storage tank; the gas phase outlet of the liquid nitrogen storage tank is combined with the gas phase outlet of the nitrogen-methane fractionating tower while the liquid phase outlet of the liquid nitrogen storage tank is connected with a top inlet of the nitrogen-methane fractionating tower; and the main heat exchanger is connected with a compound refrigerator refrigerating system. The device has better environment-friendly benefit and economic benefit and high product yield.