LNG cold energy air separation device and method capable of improving liquid nitrogen capacity

Abstract

The invention provides an LNG cold energy air separation device and method capable of improving the liquid nitrogen capacity. Air is subjected to oxygen and nitrogen liquidation, separation and purification through the arrangement of an LNG cold box, a main heat exchanger cold box, a main tower cold box, a low-pressure nitrogen press and a circulating nitrogen press, low-pressure nitrogen can be supplemented into circulating nitrogen in the air separation process, thus, the extraction rate of oxygen and argon is guaranteed, the yield of liquid nitrogen is increased, meanwhile, the unit energyconsumption of air separation operation can be reduced, and the device and method are especially suitable for regions with small oxygen demanded quantities and large nitrogen demanded quantities; andin addition, by means of the LNG cold energy air separation device and method, the influences on upper tower liquid air and liquid nitrogen temperatures are lowered by independently arranging a liquidnitrogen product supercooler, then the influences on upper tower rectification are lowered, raw materials for producing the liquid nitrogen are increased by recycling the low-pressure nitrogen, and therefore the effects that in LNG cold energy air separation, the oxygen extraction rate is high, the nitrogen-oxygen yield ratio is large, products are flexibly adjusted, and the energy consumption islow are achieved.

Description

technical field [0001] The invention relates to the technical field of air separation technology, in particular to an LNG cold energy air separation device and method for increasing liquid nitrogen production capacity. Background technique [0002] At present, LNG cold energy air separation has been widely promoted and applied as a utilization method of LNG cold energy. Due to its characteristics of low energy consumption and high income, it has become the preferred cold energy utilization project of LNG receiving stations. With the increase in the number of LNG receiving stations and the demand for cold energy utilization projects, LNG cold energy air separation technology will be further promoted. [0003] The main products of LNG cold energy air separation include liquid oxygen, liquid nitrogen and liquid argon, and its production scale and product structure are affected by the surrounding liquid market. Generally speaking, heavy industrial areas have higher demand for l...

AI Technical Summary

Problems solved by technology

The current LNG cold energy air separation unit has a high extraction rate of oxygen and a low extraction rate of nitrogen, which can meet the needs of heavy industrial areas, but cannot meet the needs of light industrial areas

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