Nitrogen production system for producing nitrogen having different purity and its nitrogen production method

摘要

PROBLEM TO BE SOLVED: To provide: a nitrogen production system that can produce high purity nitrogen containing a desired concentration of oxygen and ultrahigh purity nitrogen containing a desired concentration of argon in a single rectifying column while restraining an increase in electric power consumption; and a production process thereof.;SOLUTION: A nitrogen production system includes: a heat exchanger H, which cools material air; a nitrogen rectifying column including a rectifying unit C, into which the material air cooled by the heat exchanger H is introduced, and a condenser, which is located in a column top; a first introduction pipe, which introduces the material air from the heat exchanger H into a buffer unit located lower than a position of the rectifying unit C; a second introduction pipe for introducing oxygen-enriched liquefied gas into the condenser C from the buffer unit of the nitrogen rectifying column; a first derivation pipe for deriving ultra-high purity nitrogen from the rectifying unit C and recovering it; and a second derivation pipe for deriving high purity nitrogen from an intermediate stage of the rectifying unit C and recovering it.;SELECTED DRAWING: Figure 2;COPYRIGHT: (C)2019,JPO&INPIT