采用斯特林制冷机的低温精馏制氮系统

Cryogenic distillation system for nitrogen production based on Stirling cryocooler

针对分布式液氮供应系统相关技术仍不成熟的问题,提出采用大冷量斯特林制冷机的低温精馏制氮系统.根据不同的系统运行条件,基于Aspen HYSYS搭建3种精馏制氮流程;对每个流程在不同的空气入口温度、压缩空气初步预冷温度、制冷机输入冷量条件下进行数值模拟分析.对液氮产率、氮提取率、单位产量能耗等进行优化计算,结果表明,采用低压进气,应用冷冻干燥法纯化原料气,之后进行常压精馏是最优流程;在入口温度为10℃,初步预冷温度为25℃,输入冷量为1 kW的运行工况下,系统液氮产率可达10.38 L/h,氮提取率高达62.19%,比功耗为1.105 kW·h/L.相对于其他小型液氮生产系统,新系统具有产率大、氮提取率高、比功耗低等显著优点.

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.