The energy saving in liquid air separation plants improves the efficiency of the air compressor and consumes energy mainly in the air compressor and the circulating nitrogen press. In liquid air separation plants, the cold volume of liquid air separation plant is utilised in sections. The cold volume in the high temperature zone is pre-cooled by a glycol solution, and the compressed air of the air compressor allows the inlet temperature of each stage of the air compressor to be reduced from the conventional cooling to 31 to 278 K. This reduces energy consumption by around 13%. The low temperature zone cold is absorbed in the liquefier by the circulating nitrogen and then utilised. liquid air separation plant cold energy is utilised in the liquid air separation using a low temperature circulating nitrogen compressor with a low pressure nitrogen compressor discharge pressure of 9ba-13ba, which is actually equivalent to the first section of the circulating compressor, with the cooler being plate type. On the one hand, this solves the problem of low temperature cold source, on the other hand, the inlet temperature of the circulating compressor is low and the discharge temperature of the outlet is also low, the circulating nitrogen is first cooled in the liquefier to about 150 K before entering the nitrogen press, and the discharge pressure is chosen to be 30ba-45ba. 30ba of LNG pressure corresponds to a nitrogen liquefaction temperature of 123-126 K. 37ba or more, which is in a supercritical state, without a liquefaction section, and the nitrogen is liquefied directly. At the same time the circulator sets up a loop, while the pressure of LNG is at 0.2-03M, the vaporisation temperature is at 123K-126.8Mpa, the vaporisation temperature 190K is generally LG02-10M0 and the inlet temperature is at 122K-126K, and the inter-stage cooling of the nitrogen press is also carried out in the liquefier. Low-temperature nitrogen presses reduce energy consumption compared to room-temperature nitrogen presses, and the circulating gas volume is also small, and the whole energy consumption is also much lower, and this part of the liquefaction power consumption is 30% of conventional air separation equipment.
China's well-known enterprise, Kaifeng Dear Air Separation, has come out on top in the fierce international competition and undertaken the liquid air separation plant supporting project for the President's Dream Factory in the Philippines.
