| 摘要 |
<p>A high purity nitrogen generator unit which has excellent energy efficiency and recovery of high purity nitrogen gas, is provided. In a rectification column 1, feed air is separated to oxygen-rich liquid air and nitrogen gas.The oxygen-rich liquid air in its bottom is reduced in pressure by a first expansion valve 21 and sent to a composition regulation column 3.The nitrogen gas in its top is condensed in a nitrogen condenser 2, the resulting liquid nitrogen is returned as a reflux liquid to the rectification column 1 and non-condensed gas is released.After oxygen-rich waste gas in the lower part of the composition regulation column 3 is reduced in pressure by an expansion turbine 6, it is released by way of a first heat exchanger 4. Mixed gas in the top of the composition regulation column 3 is introduced for recirculation into a first compressor 5. Another portion of the mixed gas is returned to the composition regulation column 3 by way of a second compressor 7, second heat exchanger 8 and second expansion valve 22.The second compressor 7 is driven by means of the expansion turbine 6.High purity liquid nitrogen taken out of the vicinity of the top of the rectification column 1 is evaporated for recovery in the second heat exchanger 8. <IMAGE></p> |
