Technological Development And Engineering Design Of LNG Cold Energy For Air Separation System

Traditional air separation technology has high operating pressure, large powerconsumption, high energy consumption. Using LNG cold energy as a cold source of airseparation process has become an effective way to reduce energy consumption. However, theexisting LNG cold energy for air separation technology has shortcomings, such as: theresidual cool is not full used, large-scale production equipment, so that its application islimited, ant it needs to be re-sort, to expand its range of application.Based on the research of the existing LNG air separation systems, and the analysis of thekey technical parameters of the air pretreatment system, air distillation system and heattransfer system, a set of more optimized LNG cold energy of air separation process isproposed. According to the residual cool temperature characteristics of LNG air separationsystem, two sets of residual cool utilization joint processes: the residual cool of LNG airseparation system using for the cold storage-cold water air-conditioning system or the icemaking-cold water air-conditioning system are designed. Aspen-plus simulation software andthe exergy analysis method are using to research the two sets of system. The systematicexergy efficiency of the LNG air separation-cold storage-cold water air-conditioning systemis60.8%, which is higher than the LNG air separation-ice making-cold water air-conditioningsystem with54.7%. So the LNG air separation-cold storage-cold water air-conditioningsystem is chosen as the technology of engineering process.Based on the theoretical research above, this paper uses a certain LNG satellite station asthe research background, a combination of the cold LNG cold energy utilization technology, aLNG air separation-cold storage-cold water air-conditioning system which is suitable for thisLNG satellite station is determined. Through the technology of engineering process design,key equipment selection, technical and economic analysis and operational flexibility analysis:LNG flow of this program is6300Nm3/h, and the total investment is42.9million yuan, anaverage annual income12.09million yuan, project payback period is only3.55years. And thedevelopment potential analysis shows that with characteristics of miniature, skid-mounted andopen-stop feature, the process is suitable for the LNG satellite station which is located inremote and scattered areas, and its LNG cold energy is small and unstable. So the process isvery promising.