lithium molecular sieve

Oxygen has a very wide range of uses in industry and daily life. Pressure swing adsorption air separation oxygen production is an emerging air separation oxygen production technology with high efficiency and low consumption. The core of the competition in this technical field is the lithium ion exchange low silicon to aluminum ratio X-type molecular sieve (LiLSX) high-efficiency adsorbent-lithium molecular sieve.



 Zeolite molecular sieve is a kind of aluminosilicate crystal, it will lose crystal water when heated to a certain extent, and form a large specific surface area. This adsorbent is composed of ion pores and a charged silicon-aluminum framework, so it has higher selectivity to polar molecules and unsaturated bond molecules. The principle of adsorption and separation of oxygen production is based on: non-polar O2 and N2 molecules are polarized to produce dipoles, while the induced dipoles of O2 and N2 molecules have an adsorption effect with the inherent dipoles of the adsorbent; under the same conditions, zeolite Molecular sieves have greater inducing force for N2 than O2, so the amount of N2 adsorbed is greater than the amount of O2.

 

 In the early days, the molecular sieves used in air separation oxygen production were mainly 5A and 13X molecular sieves, but their separation effect on N2 was not good, so there are many studies on the modification of zeolite molecular sieves, especially for NaX, CaA, LiX, AgX, LiAgX, etc. Various zeolite molecular sieves have been studied intensively. From the Monte Carol kinetic simulation results, it is inferred that the smaller the cation radius, the stronger the effect of N2, and the smallest atomic radius is Li+. Therefore, there have been more studies on lithium ion-modified zeolites in recent years. The adsorption capacity of nitrogen with LiX zeolite as adsorbent is 50% higher than that with NaX zeolite, which confirms the inference of Monte Carol simulation. There is a condition for the growth of the adsorption capacity of LiX zeolite, that is, the exchange degree of Li+ must be greater than 70%. At this time, the adsorption capacity of LiX zeolite will increase rapidly. The difficulty of exchanging cations with different properties on the molecular sieve is different, which is called the selection order of the molecular sieve. For example, the selection order of 13X molecular sieve is Ag+, Cu2+, Ba2+, Au3+, Th4+, Sr2+, Hg2+, Cd2+, The exchange of Zn2+, Ni2+, Ca2+, Co2+, K+, Au2+, Na+, Mg2+, Li+, Li+ ions on X-type zeolite is more difficult, and it is particularly difficult to achieve a high exchange degree, and Li+ ions themselves are relatively expensive ions. The degree of exchange also means an increase in costs.

 

 The "Henan Adsorption Molecular Sieve Engineering Technology Research Center" established by Luoyang Jianlong Micronano New Materials Co., Ltd. invented a new high-efficiency ion exchange process, which makes the exchange rate of the extremely difficult-to-exchange lithium ions on the LiLSX molecular sieve over 99% , And the utilization rate of expensive lithium is close to 100%; invented a roasting furnace with a special structure, which solves the problem that the structure of LiLSX molecular sieve is easily destroyed and easy to produce impurity crystals during roasting. The produced adsorbent not only maintains high nitrogen Adsorption performance, while having good mechanical strength and extremely low water content. The adsorbent has an oxygen-nitrogen separation ratio of more than 6.2 under normal pressure, and the power consumption of oxygen production is 0.32～0.35 (kwh/m³·O2).