Exergy-based methods for air separation.

Air separation by cryogenic distillation has been used for over 100 years as an industrial process for producing pure nitrogen, oxygen as well as argon, helium and other noble gases. Different configurations and sizes of air separation plants lead to different ranges of gaseous and liquid products and different purity, which depend on the potential consumer and the application. Air separation processes are energy and cost intensive.
In this paper, the exergetic, economic, and exergoeconomic analyses are discussed briefly, while attention is given to the LCA and the exergoenvironmental analysis as well as to exergy-risk-hazard analysis. The exergy-based methods are demonstrated using two configurations of an air separation plant. The results obtained from the exergetic analysis show that the overall exergetic efficiencies are approximately 35 % and 59 % for air separation plants with and without a nitrogen liquefaction block, respectively.

深冷精馏空分工艺作为生产纯氮、纯氧以及氩、氦等稀有气体的工业流程，已有百余年的应用历史。空分装置的不同配置与规模，会产出品类、量级各异的气态与液态产品，且产品纯度各不相同，这取决于目标用户与应用场景。空分过程属于高能耗、高成本的生产工艺。
本文简要阐述了㶲分析、经济分析与㶲经济分析，同时重点聚焦于生命周期评估（Life Cycle Assessment，LCA）、㶲环境分析以及风险-危害㶲分析。研究采用两套空分装置配置，对基于㶲的分析方法进行了实例演示。㶲分析结果表明，配备氮气液化单元与未配备该单元的空分装置，其整体㶲效率分别约为35%与59%。