A MOLECULAR SIEVE IS A MATERIAL CONTAINING TINY PORES OF A PRECISE AND UNIFORM SIZE THAT IS USED AS AN ADSORBENT FOR GASES AND LIQUIDS. ZEOLITE MOLECULAR SIEVES POSSESS THE UNIQUE ABILITY TO SELECTIVELY ADSORB MOLECULES BY SIZE AND POLARITY SO THEY ARE VERY EFFICIENT AT DRYING AND PURIFYING LIQUIDS AND GASES, ESPECIALLY WATER (H2O).
Molecular Sieves
Description
A MOLECULAR SIEVE IS A MATERIAL CONTAINING TINY PORES OF A PRECISE AND UNIFORM SIZE THAT IS USED AS AN ADSORBENT FOR GASES AND LIQUIDS. ZEOLITE MOLECULAR SIEVES POSSESS THE UNIQUE ABILITY TO SELECTIVELY ADSORB MOLECULES BY SIZE AND POLARITY SO THEY ARE VERY EFFICIENT AT DRYING AND PURIFYING LIQUIDS AND GASES, ESPECIALLY WATER (H2O).
This also serves as the basis for separation, synthetic zeolites are available in a range of adsorption characteristics or selectivitys for commercial applications. Traditional molecular sieves work as desiccants, adsorbents, and ion exchangers. UOP also offers high-silica zeolites for non-traditional applications, including the removal of organic molecules that can cause odours or affect taste within food and beverage packaging.
ECP stock common grades and sizes of molecular sieve and can advise what type to use for your application. Molecular sieve is classified by its pore size in angstroms, the most common being 3A, 4A, 5A, and 10A, also known as 13X.
Typical Applications
Air Drying: Compressed air is dried for use with plastics processing, air brakes, sterile environments, sensitive instruments, packaging and other critical process operations. UOPs MOLSIV adsorbents play an essential role in these processes because of their high dew point depression and dynamic drying capacity. High strength and attrition resistant characteristics guarantee thousands of cycles under extreme conditions over a long lifetime.
Plastic Resin Drying: Molecular sieves are used in desiccant dryers to dry hygroscopic plastic resins for applications such as PET pre-form molding, highvolume extrusion of sheet and film, or large part injection molding. Because of their high affinity for moisture at very low dewpoints, molecular sieve desiccant dried air can produce dewpoints of -40°F and lower.
Instrument Air Drying: Molecular sieves are used in desiccant dryers to produce instrument grade air from compressor air.
Brake Air: Molecular sieves are used in heavy and medium-duty truck, bus, and train air brakes as self renewing dehydrators. Dehydrating the compressed air keeps the brake lines from freezing and corroding.
Specialty Air Applications: Molecular sieves are used to dry air for use in pharmaceutical, electronic and food packaging applications.
Industrial Gas Purification
High purity industrial gases such as O2, N2, H2 and CO are produced in a variety of ways. UOPs MOLSIV adsorbents play an essential role in these processes because of their high adsorption selectivity and capacity. In addition, UOPs aluminas are often used for dehydration applications.
H2& CO Production: Molecular sieves remove water and CO2 to prevent freezing in downstream cryogenic separation processes. O2& N2 Production: Molecular sieves remove water and CO2 from compressed air to prevent freezing in downstream cryogenic separation processes. H2 Production: Molecular sieves remove impurities such as hydrocarbons, CO and N2 from gas phase H2 production
3A Molecular Sieve
Pore size of 3Å. Adsorbs NH3 & H2O, good for drying polar liquids such as ethanol, air, refridgerant, natural gas, methane, cracked gas, ethylene, propylene or butadiene.
4A Molecular Sieve
Pore size of 4Å. It adsorbs H2O, CO2, SO2, H2S, C2H4, C2H6, C3H6 and ethanol. It is a general dryer of non-polar liquids and natural gases. It is an excellent absorber of carbon dioxide.
5A Molecular Sieve
Pore size of 5Å. Adsorbs normal (linear) hydrocarbons to n-C4H10, alcohols to C4H9OH, mercaptans to C4H9SH. Will not adsorb isocompounds or ring structures with more than four carbon atoms.
13X Molecular Sieve
Pore size of 10Å. Adsorbs di-n-butylamine and hexamethylphosphoramides better known as HMPA. It is used for water pre-purification due to its high affinity for water and carbon dioxide.
Speciality Molecular Sieves
Insulating Glass Desiccant/Molecular Sieve
You can avoid increased unit stresses and loss of insulating properties with UOPs molecular sieve adsorbents. Developed for residential and commercial sealed insulating glass, we have the most reliable, effective way to adsorb water and organic solvents within your dual pane windows. Using our adsorbents can keep your windows in the clear.
High capacity UOP MOLSIV adsorbents remove and trap water and solvents, maximizing the life of your units. We have a variety of products for different systems and needs:
Window systems with metal spacers
Units with a desiccant matrix or polymer spacer
Systems that require both water and organic vapor removal
Solvent-free systems
UOP 4A-DG
4A-DG adsorbent is a clay-bound, sodium form of the Type A molecular sieve. 4A-DG molecular sieve will adsorb molecules with critical diameters up to 4 angstroms. It adsorbs water, H2S, methanol, methyl mercaptan, and ethane, but not propane or larger hydrocarbons.
4A-DG adsorbent has been specially formulated for drying natural gas and natural gas liquids. It has demonstrated the ability to provide long service life and predictable, economical dehydration service. 4A-DG adsorbent can provide very low moisture levels required by cryogenic NGL recovery plants. It is also used for removing H2S and CO2 from natural gas.