Zeolitic Molecular Sieve

Applications of it

Uses of it

To trace the origin, naturally occurring Zeolites are crystalline hydrated aluminosilicates of the alkalis and alkaline earths that are generally found in volcanic sediments. Zeolites derive its usefulness because of their chemical composition and physical form. Zeolites have a framework structure that surrounds interconnected cavities which is filled by relatively large cations and water molecules. The cations contain primarily sodium, potassium, and calcium, as well as some water. These particles enjoy considerable freedom of movement within the structure. These give the zeolites their cation exchange and reversible dehydration properties.

Did You Know? Zeolite is a Greek Word meaning "Stone that boils. " Originally The term was coined in the Eighteenth century byd Axel Fredrik Cronstedt a Swedish mineralogist. He observed, that upon rapidly heating a natural mineral, now what we call Zeolite the stones began to dance as the water started evaporating.

Zeolite has several unique features that has enabled the successful synthesis of its several varieties. Over the years it has found a number of applications in industries that include the use of synthetic zeolites as ion exchange agents, desiccants, catalylists in petroleum refining, adsorbents for gas separations, and carriers in detergents. In the separation of mixtures, Zeolites because of the porous frameworkcan act as molecular sieves to separate molecular compounds in the mixture, based on their shape and size. Zeolites have the enormous potential of providing accurate and specific separation of gases. These includes among others the removal of Carbon dioxide and Sulphur dioxide from low-grade streams of natural gas Cation-containing zeolites are popularly used in gas separation. Especially when the molecules are seggrgated on the basis of their electrostatic interactions with metal ions.

Both natural and synthetic zeolites or Zeolitic Molecular Sieves are used in the PSA separation process. Unlike natural, synthetic zeolites are produced in energy-intensive chemical processes. They are significantly more costly than natural zeolite. Let us see how Zeolitic Molecular Sieves are used in the PSA separation process.

Click Here for properties of different Zeolite adsorbents

Application of Zeolitic Molecular Sieve for Oxygen Production:
As we all know Pressure swing adsorption depends on air being filtered through adsorbents A zeolte that is very succesfully used has the chemical composition of Na12[(AlO2)12((SiO2)12].27H2O. This Zeolite, used for PSA oxygen has been innovatively designed so that nitrogen gas is adsorbed onto its bed while oxygen (and argon) passes through. The zeolite gets quickly saturated with nitrogen, so two zeolite beds can be used jointly, one filters air while the other regenerates.

The shape of the zeolite used for oxygen production is like a die. A sort of internal cage is formed with holes drilled on each face. The corners of the die that (provides the framework) are Slicon Dioxide and AlO2 units.

Illustration showing use of Zeolitic Molecular Sieve in PSA production process.



Using Natural Zeolites for upgrading of natural gas and methane:
Pressure swing adsorption plants (PSA) also utilize natural zeolites. In this case as depicted in the diagram Zeolitic Molecular Sieves are used to remove water, carbon dioxide and sulphur dioxide thereby producing a pipe-line quality natural gas which might otherwise had proved to be useless as it contained a high concentrations of impurities.