| 摘要 |
A relatively simple apparatus for producing nitrogen typically containing less than 10 vpm of nitrogen includes a unit 2 for producing nitrogen-enriched air by means other than fractional distillation and a rectification column 8, provided with a reboiler 10 and a condenser 12 for providing reflux, which is operated to produce a relatively pure nitrogen fraction at the top 16 of the column 8 and a less pure nitrogen fraction at the bottom 18 of the column 8. The unit 2 may be a plant for separating air by pressure swing adsorption. The nitrogen-enriched air that it produces is compressed in compressor 4 cooled by heat exchange in heat exchanger 6 and the reboiler 10 and is then expanded through expansion valve 14 into the column 6. <IMAGE> |
