Molecular Sieve Zeolites
Adsorbent Purification and Separations
Molecular sieves are transition metal aluminosilicates with a uniform pore crystalline structure which operate on the size exclusion principle. Smaller molecules that fit into the pores are adsorbed while larger molecules pass through. These crystalline structures have pore openings of 3, 4, 5, or 10 Angstroms. Polarity of the molecules matter because the highly polarized molecules are adsorbed more readily into the pores than non-polar molecules. Molecules are selectively removed in this manner.
Molecular Sieves or Zeolites are used in the drying and purification of gases and liquids. They are effective at removing water from liquids and gases to extremely low levels. Molecular sieves are especially useful in cryogenic operations where liquefaction of gases is required and water must be eliminated to avoid freezing. These materials are used for purification of streams with in the petroleum industry; in the removal of sulfur species and oxygenates. 13X is used in air prepurification and 5A for the production of oxygen and hydrogen.
| Types
of Molecular Sieves |
|
| 3A Molecular Sieve | Used
in insulated glass to prevent fogging and deflection of dual pane
windows. Olefin drying and natural gas. Powders used in
formulations with polyurethanes and swiggle strips. |
| 4A
Molecular Sieve |
Dessicant
for drying of gases, air, natural gas and hydrocarbon liquids. 4A
will adsorb carbon dioxide. |
| 5A
Molecular Sieve |
Dehydration
and used for the removal of CO2, Water, and H2S from natural gas
units. Used in Isomerization units and Pressure Swing Adsorption
(PSA) for Hydrogen purification. Powders are used for
formulation. |
| 13X
Molecular Sieve |
Air
prepurification to remove water and CO2. 13X removes various
polar molecules from olefinic and light hydrocarbon streams.
Removes oxygenates from liquid hydrocarbon streams. Used in
Oxygen Removal Units (ORU) |