Method and device for producing high-pressure nitrogen and low-pressure oxygen

Abstract

The invention relates to a method and device for producing high-pressure nitrogen and low-pressure oxygen. The high-pressure nitrogen and the low-pressure oxygen are simultaneously prepared by adopting three distillation towers comprising a high-pressure tower, a nitrogen tower and an oxygen tower. The high-pressure nitrogen is prepared in the nitrogen tower and the low-pressure oxygen is prepared in the oxygen tower. The method and device for producing the high-pressure nitrogen and the low-pressure oxygen can realize the simultaneous recycling of the pressure nitrogen and the pure oxygen, wherein the extraction rate of the pressure nitrogen ( wherein the oxygen content is less than 3ppm) reaches 75-80 percent, and the nitrogen pressure reaches 0.4-0.5MPa; the extraction rate of the pure oxygen (not less than 99.6 percent of O2) reaches 40-70 percent, the pressure reaches 0.02-0.05MPa; and the comprehensive electricity consumption of the oxygen and the nitrogen is only 0.18-0.2KWh / NM3(N2+O2), and the energy-saving effect is more remarkable.

Description

technical field [0001] The invention relates to a gas production process, in particular to a method and device for producing high-pressure nitrogen and low-pressure oxygen. Background technique [0002] With the rapid development of float glass, chemical and other industries, the demand for high-pressure nitrogen and low-pressure oxygen has increased sharply, and the high-purity nitrogen used in the float glass industry usually has higher requirements, and the general nitrogen pressure reaches 0.2-0.5 MPa, purity up to 99.999% (O 2 Concentration ≤ 3ppm). [0003] In the traditional air separation process, a separate preparation process for nitrogen and oxygen is used. The nitrogen preparation process includes: single tower positive flow nitrogen production process, the nitrogen pressure produced by it can reach 0.2-0.3MPa, and the nitrogen extraction rate is 55-65%; single tower reflux nitrogen production process, the nitrogen pressure produced by it can reach 0.4MPa ~1MP...

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Problems solved by technology

[0006] Patent US006079223A discloses a low-temperature air separation system, which separates air into nitrogen-rich vapor and oxygen-rich liquid, rectifies in a reflux condenser including a rectification section and a stripping section to obtain a medium-purity nitrogen product, and strips to obtain a medium-purity nitrogen product Oxygen products, nitrogen and oxygen products produced by this method have low purity

Patent US006230519B1 discloses a low-temperature air separation method for producing gaseous nitrogen and gaseous oxygen. The air is cryogenically rectified and separated into oxygen-rich fluid and secondary nitrogen fluid in the low-pressure tower, and then nitrogen and nitrogen are recovered from the upper and lower parts of the low-pressure tower according to the density. Oxygen, the refrigeration and cooling process of this method is complicated

Patent CN1038514A discloses an air separation process for producing high-pressure oxygen and high-pressure nitrogen. Air is compressed, adsorbed and impurity-removed, and then rectified through a two-stage rectification tower. Since both nitrogen and oxygen are rectified in the same tower, the production efficiency Low

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