Cryogenic distillation system for nitrogen production based on Stirling cryocooler
A cryogenic distillation system for nitrogen production using Stirling cryocooler with large cooling capacity was proposed,aiming at the problem that the relevant technology of distributed liquid nitrogen supply system was not mature.According to different operating conditions of the system,three kinds of nitrogen production processes were set up based on Aspen HYSYS.The numerical simulation analysis of each process was carried out under the conditions of different air inlet temperatures,compressed air precooling temperatures and input cooling capacities of cryocooler.The liquefaction yield,nitrogen extraction rate and energy consumption were optimized.The results showed that using low pressure intake to compress air,using freeze-drying to purify raw gas,and then using atmospheric pressure rectification was the optimal process.Under the operating conditions of inlet temperature of 10 ℃,initial precooling temperature of 25 ℃ and input cooling capacity of 1 kW,the liquid nitrogen yield can reach 10.38 L/h,the nitrogen extraction rate was as high as 62.19％,and the specific power consumption was 1.105 kW·h/L.Compared with other small liquid nitrogen production systems,this system has the advantages of high yield,high nitrogen extraction rate and low specific power consumption.
Stirling cryocoolercryogenic distillationnitrogen production systemair purificationliquid nitrogen
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