Two-stage-tandem PSA (pressure swing adsorption) oxygen production system capable of increasing recovery rate of oxygen and operating method of two-stage PSA oxygen production system

Abstract

The invention belongs to the technical field of gas separation, and particularly discloses an equilibrium-adsorption-mechanism-based two-stage-tandem PSA (pressure swing adsorption) oxygen production system (namely oxygen, nitrogen and argon separation system) capable of increasing the recovery rate of oxygen and an operating method of the two-stage-tandem PSA oxygen production system. The first-stage PSA of the two-stage-tandem PSA oxygen production system refers to an equilibrium-adsorption-mechanism-based PSA oxygen and nitrogen separation system with a conventional nitrogen adsorbent such as zeolite, and the second-stage PSA of the two-stage-tandem PSA oxygen production system is an equilibrium-adsorption-mechanism-based PSA oxygen and argon separation system with an oxygen selective nitrogen adsorbent. According to the two-stage-tandem PSA oxygen production system and the operating method of the system, a conventional two-stage tandem PSA oxygen production system is improved, namely a set of mixed feeding loop is arranged in the second-stage PSA, and runs according to specified working steps, so that the recovery rate of oxygen is remarkably increased, and the overall oxygen recovery rate is also increased.

Description

technical field [0001] The invention belongs to the technical field of gas separation, and specifically relates to a "two-stage series pressure swing adsorption oxygen production system based on an equilibrium adsorption mechanism" (that is, an oxygen, nitrogen and argon separation system) that can improve the oxygen recovery rate and its operating method. Background technique [0002] Pressure swing adsorption (PSA) is an important and widely used gas separation method. The pressure swing adsorption oxygen production method is an important supplement to the cryogenic oxygen production process. The traditional PSA method for producing oxygen from air streams usually uses Nitrogen adsorbents such as CaA, CaX, NaX, and LiX are based on the equilibrium adsorption theory to produce oxygen. Because these adsorbents have a stronger adsorption capacity for nitrogen than oxygen, that is, selectivity, usually a selectivity of more than 3 can achieve a good energy efficiency ratio. Fo...

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Problems solved by technology

However, in the various methods adopted, that is, there are at least two different mass transfer zones in the two-stage or multi-stage PSA method, the more typical feature is that at least one of the mass transfer zones uses a carbon dioxide based on the principle of kinetic separation. Molecular sieves are used to separate oxygen and argon. The system cycle is complicated. A large number of buffer tanks and power equipment are used to perform necessary cleaning, replacement or displacement steps to obtain higher oxygen products. The energy consumption is huge and the cost is high.

[0005] Chinese patent CN201930684U discloses a non-cryogenic pressure swing adsorption separation device for oxygen-argon mixed gas. Two identical series adsorption systems based on the equilibrium adsorption mass transfer mechanism are used to construct a separation process, which realizes the separation of oxygen, nitrogen and argon. However, due to insufficient process construction, the oxygen recovery rate of the subsequent oxygen-argon separation system is still limited to less than 50%. 50%, the total oxygen recovery rate of the two-stage pressure swing adsorption system in series is limited to less than 25%, and the application is limited to a certain extent

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