Method for improving nitrogen yield of air separation device

Abstract

The invention discloses a method for improving the nitrogen yield of an air separation device. The method includes the steps that according to required product nitrogen increasing amount, rectification packing or the plate number needed when a certain amount of waste nitrogen is rectified into pure nitrogen is calculated; the rectification packing or the plate number of an upper column on the air separation device is correspondingly increased according to a calculation result; by further rectifying and purifying the waste nitrogen of the upper column, the waste nitrogen is purified into pure nitrogen, and the product volume of the increased pure nitrogen is obtained. The method further includes the steps that mediums in a pure nitrogen channel and mediums in a waste nitrogen channel of the air separation device are exchanged, the lost cooling capacity, caused by reduction of the amount of the waste nitrogen, of a water cooling tower and a molecular sieve purifier is calculated, and cold loss is compensated for by additionally arranging a freezing machine and a liquid nitrogen evaporator. Besides, the yield of product nitrogen can change according to requirements in the range that the ratio of product oxygen to the nitrogen is 1:1 to 1:3. According to the method, the oxygen and nitrogen design proportion of an original air separation device is changed at low improvement cost, and the yield of pure nitrogen products is obtained to the largest extent.

Description

technical field [0001] The invention belongs to the field of low-temperature air separation oxygen production. Background technique [0002] The air separation device (referred to as air separation device or oxygen generator) used in modern low-temperature air separation and oxygen production technology (referred to as air separation technology or oxygen production technology), its conventional design separation product oxygen and product nitrogen output ratio is 1: 1~1:1.1, the remaining nitrogen components in the air are output in the form of dirty nitrogen, which is mainly used as molecular sieve regeneration gas in the air separation process and cooling gas for water cooling towers. According to the national standard nitrogen purity standard, it is divided into three grades of industrial nitrogen, pure nitrogen and high-purity nitrogen. Their purity is 99.5%, 99.99% and 99.999% respectively. The above-mentioned product nitrogen is usually referred to in this field. Nitr...

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Problems solved by technology

[0003] Currently, nitrogen, as a clean, dry, inert gas, is used more and more widely. Without adding a new air separation unit, the inherent design ratio of oxygen and nitrogen output in the existing air separation technology has been unable to meet the continuous growth. The demand for ground nitrogen, how to carry out technical adjustment and transformation of the existing air separation unit, and increase the output of product nitrogen to meet the demand within the allowable range of unit performance are existing technical problems

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