Device for extracting pure nitrogen from polluted nitrogen high in extraction rate and low in energy consumption and extracting method thereof

Abstract

The invention discloses a method for extracting pure nitrogen from polluted nitrogen high in extraction rate and low in energy consumption. The method includes the following steps that polluted nitrogen enters a main tower and then conducts heat and mass transfer with top-to-bottom liquid on a tower plate or fillers in the main tower from bottom to top, part of pressure is pumped out at the tower top, and the polluted nitrogen serves as a product after being reheated through a main heat exchanger; after polluted liquid nitrogen discharged from the bottom of the main tower enters a subcooler to be cooled through the subcooler, polluted nitrogen evaporated from a main tower condenser is sent to a secondary tower, the polluted nitrogen conducts heat and mass transfer with top-to-bottom liquid on a tower plate or fillers in the secondary tower from bottom to top, the polluted nitrogen generated at the tower top is condensed through a secondary tower condenser, part of the condensed liquid returns to the secondary tower to serve as backflow liquid, and the other part of the liquid enters the main tower to serve as backflow liquid; the polluted nitrogen evaporated from the secondary tower condenser is reheated through the subcooler and the main heat exchanger, and then is sent to a polluted nitrogen compressor to be recycled and utilized. According to the method, the amount of the nitrogen extracted from the polluted nitrogen is higher than the amount of the nitrogen extracted from the air, and the nitrogen extraction rate reaches more than 90%.

Description

technical field [0001] The invention belongs to the field of industrial gas production, in particular to a device for purifying nitrogen from polluted nitrogen with high extraction rate and low energy consumption and an extraction method thereof. Background technique [0002] The user originally invested in an air separation unit, and its original air separation unit could not produce nitrogen or the original nitrogen output could not meet the production demand. If it invests in a nitrogen production unit separately, its investment cost and operating cost are high, so consider Invented a nitrogen making device for recovery and purification of polluted nitrogen waste gas. Contents of the invention [0003] In order to solve the defects and deficiencies in the above-mentioned prior art, the present invention provides a device and its extraction method for purifying nitrogen with advanced technology, low investment and operating costs, high extraction rate, energy saving and ...

AI Technical Summary

Problems solved by technology

[0002] The user originally invested in an air separation unit, and its original air separation unit could not produce nitrogen or the original nitrogen output could not meet the production demand. If it invests in a nitrogen production unit separately, its investment cost and operating cost are high, so consider Invented a nitrogen making device for the recovery and purification of polluted nitrogen waste gas

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