| 摘要 |
PROBLEM TO BE SOLVED: To provide an air separating method and an air separating device capable of eliminating energy loss at a high pressure duplex type rectification process.SOLUTION: A high-pressure duplex type rectification process of this invention comprises the steps of a low pressure raw material air generating step of cooling a part of purified high pressure raw material air to an intermediate temperature, thereafter applying adiabatic expansion to it to generate cold heated state and at the same time generating low pressure raw material air; a low-pressure distillation step for deep cold liquefaction separating between low pressure liquefaction nitrogen reducing pressure of high pressure liquefied nitrogen generated at an indirect heat exchanging step and low pressure raw material air to generate both low pressure nitrogen gas and low pressure oxygen enrichment liquefied air; the second intermediate pressure oxygen enrichment liquefied air feeding step for feeding the second intermediate pressure oxygen enrichment liquefied air with increased pressure of low pressure oxygen enrichment liquefied air during the intermediate pressure distillation step; and a purifying means regenerating step for feeding out low pressure nitrogen gas generated at the low pressure distillation step, heat recovering at a main heat exchanging step, and after this process, using it as regenerating gas for the purifying means. |
