Molecular sieve adsorbent for separating oxygen from air by means of pressure swing adsorption and preparation method thereof

Abstract

The invention provides a molecular sieve adsorbent for separating oxygen from air by means of pressure swing adsorption and a preparation method thereof. The molecular sieve adsorbent comprises the following components based on parts by weight percent: 80-95% of CaLS molecular sieve with SiO2 / Al2O3=2.0, and 5-20% of binder. The preparation method comprises the steps of: preparing sodium potassium type low-silicon X type molecular sieve KNaLSX with SiO2 / Al2O3=2.0; exchanging 0.5-1.5ml of CaCl2 solution with the KNaLSX molecular sieve at 80-85 DEG C for 1-2h; washing and drying; mixing the molecular sieve with the binder; smashing; wetly stirring with auxiliary binder; drying to be shaped; and roasting at 450-550 DEG C for 1-5h. Compared with the prior art, the adsorbent has high Ca2+exchange degree, high molecular sieve crystallinity, large absorption quantity, fast absorption speed, low cost and good oxygen-nitrogen separation performance.

Description

technical field [0001] The invention relates to a molecular sieve adsorbent technology, in particular to a molecular sieve adsorbent for pressure swing adsorption air separation and oxygen production and a preparation method thereof. Background technique [0002] Low-silicon X-type molecular sieve, referred to as LSX, its SiO 2 / Al 2 o 3 It is 2.0-2.1, its cation position reaches the maximum and has the most adsorption centers, while the cation of the synthetic LSX molecular sieve is Na + and K + , directly used as pressure swing adsorption air separation oxygen generation adsorbent, its oxygen and nitrogen separation coefficient is not significantly higher than that of traditional air separation oxygen generation molecular sieve adsorbent 5A type molecular sieve and ordinary X type molecular sieve. Ordinary X-type molecular sieve, its SiO 2 / Al 2 o 3 2.35-2.50, the cation is Na + , also known as NaX. Therefore, Na must be + and K + Change to other metal cations, ...

AI Technical Summary

Problems solved by technology

[0003] U.S. Patent US4557736 reported X-zeolite exchanged by divalent cation calcium and strontium, claiming that it has higher nitrogen adsorption capacity and better nitrogen selectivity in air separation, but strontium resources are scarce and expensive

Chinese patent CN1034913 reported the use of divalent cation-exchanged lithium X zeolite adsorbent for oxygen and nitrogen separation, which improved the oxygen and nitrogen separation capacity, and the divalent cation was selected from Ba 2+ 、Co 2+ 、Cu 2+ 、Cr 2+ , Fe 2+ , Mg 2+ , Mn 2+ , Zn 2+ , but Li is still the main component, Li is expensive, and the preparation process is complicated, the utilization rate of Li is low, and the cost of the adsorbent is high.

However, it is difficult and expensive to prepare lithium-exchanged X-zeolite with high exchange degree, which makes the cost of adsorbent very high.