空分压缩余热自利用的理论增效极限研究  

Study on Theoretical Boundary of Efficiency Enhancement by Compression Waste Heat Self-utilization in Air Separation Units

作　　者：张涵玮 周霞 荣杨一鸣 王凯[1,2] 植晓琴 邱利民[1,2] ZHANG Hanwei;ZHOU Xia;RONG Yangyiming;WANG Kai;ZHI Xiaoqin;QIU Limin;无(Institute of Refrigeration and Cryogenics,Zhejiang University,Hangzhou 310027,China;Key Laboratory of Refrigeration and Cryogenic Technology of Zhejiang Province,Hangzhou 310027,China;POWERCHINA HUADONG Engineering Corporation Limited,Hangzhou 310014,China)

机构地区：[1]浙江大学制冷与低温研究所,杭州310027 [2]浙江省制冷与低温技术重点实验室,杭州310027 [3]中国电建集团华东勘测设计研究院有限公司,杭州310014

出　　处：《工程热物理学报》2023年第7期1762-1767,共6页Journal of Engineering Thermophysics

基　　金：国家自然科学基金青年项目(No.52106029)。

摘　　要：大规模空分系统中,利用各级空压机出口的低品位余热,经热驱动制冷循环转换后反馈用于冷却各级入口,可使实际过程进一步趋近于理想的等温压缩过程,实现压缩余热自利用和压缩过程自增效的目的。以10万规模空分中空压系统的余热回收为例,基于气体压缩和热功转换基础理论,构建理想情况下压缩余热反馈增效的热力学模型,分析该方法对压缩过程的理论增效极限。进一步,研究了压缩机级数、环境温度等关键因素对于压缩效率提升的影响规律。结果表明,在热机循环冷端温度和制冷循环热端温度为40℃的条件下,当环境温度为20℃时,四级自增效流程的理想节能率可达5.39%。此外,节能率与压缩机级数和环境温度分别呈负相关和正相关。整体而言,此方法理论上可达到的节能效果显著,具有较大的发展应用潜力。In a large-scale air separation system,low-grade waste heat at the outlet of air compressors at all stages could feed back to cool down inlet air after being converted by thermal-driven refrigeration cycle,which realizes the purpose of self-utilization of compression waste heat and selfenhancement of compression process by making the actual process further approach the ideal isothermal compression process.Taking the compression process in a 100000 m3/h scale air separation unit as an example,based on the basic theory of gas compression conversion of heat into power,a thermodynamic model of ideal efficiency enhancement by compression waste heat self-utilization was established.The theoretical boundary of this method to the improvement of compression process was analyzed.Furthermore,the infuence of key factors such as the number of compressor stages,the ambient temperature on compression eficiency was studied.The results show that when the heat sink temperature of the heat engine cycle and the heat source temperature of the refrigeration cycle are 40℃,and the ambient temperature is 20℃,the ideal energy saving ratio of the four-stage self-enhancing process can reach 5.39%.Furthermore,the energy saving ratio is negatively and positively correlated with the number of compressor stages and ambient temperature,respectively.On the whole,this method can achieve significant energy saving effect theoretically,and has a great potential for practical application.

关 键 词：空分 压缩热 制冷 卡诺循环 极限 

分 类 号：TK123[动力工程及工程热物理—工程热物理]