| 摘要 |
PURPOSE: To improve a publicly known process for producing gaseous nitrogen with variable flow rate so as to eliminate a pump for making liquid nitrogen to flow. CONSTITUTION: In this process for the liquid nitrogen/rich liquid HPN swing type, the connection between the head of a fractionating column 4 and a liquid nitrogen holding tank 7 is effected, for the two flow directions of the liquid nitrogen, by a single conduit 12 equipped with a pressure-reducing device 13. The direction and the flow rate of the liquid nitrogen flow are controlled by the variations in the pressure of the column, and the holding tanks of liquid nitrogen and rich liquid are maintained at constant pressures.
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