3A, 4A and 5A zeolite molecular sieves for drying and gas separation
We are a European B2B supplier of 3A, 4A and 5A zeolite molecular sieves for industrial dryers, adsorbers and PSA units. We supply them as loose beads: 3A and 4A remove water from gases and liquids, and binderless 5A is used for gas separation.
Available as original Grace SYLOBEAD 3A and 4A, Honeywell UOP MOLSIV 4A and Jalon 4A grades, and as equivalents of these and of BASF and Arkema Siliporite grades. Most orders are dispatched within 2-5 working days.
Molecular sieves 3A, 4A and 5A are synthetic type A zeolites with nominal pore openings of about 3, 4 and 5 Å. Pore size helps determine which molecules can enter the crystals, but it is not an absolute cut-off. Adsorption also depends on polarity, stream composition and operating conditions. Choose the type according to what must be removed and what must remain in the stream.
3A molecular sieve
Zeolite 3A is the potassium form of type A. It adsorbs water while excluding most larger molecules from its pores, which limits co-adsorption of the product being dried. It is used to dry ethanol, methanol and other polar liquids, cracked gas and olefins such as ethylene, propylene and butadiene, and natural gas containing H₂S and CO₂ where COS formation must be minimised.
4A molecular sieve
Zeolite 4A is the sodium form of type A and the general-purpose drying grade: air, natural gas, LPG, inert gases, solvents, liquid hydrocarbons and refrigerants. It is used in plastic granulate dryers and PSA air dryers. Besides water, 4A also adsorbs CO₂, methanol, ammonia and other small molecules, so check the full composition of your stream before you choose it.
5A molecular sieve
Zeolite 5A is the calcium form of type A. Our 5A is binderless, with beads consisting almost entirely of active zeolite and an open transport pore system that supports fast mass transfer. It is used mainly for gas separation in pressure swing (PSA) and vacuum swing (VSA) adsorption units. In hydrogen PSA units, 5A is often combined with 13X: 5A takes up nitrogen and carbon monoxide, and 13X removes CO₂.
The first table compares 3A, 4A and 5A: their zeolite form, pore opening, bead sizes and main use. The second table lists each grade with its data from the technical data sheet: bead size, bulk density, crush strength and water adsorption. “min.” is a specification minimum; “typical” is a typical value, not a specification. Confirm the specification of the supplied grade before ordering.
Parameter
3A
4A
5A
Zeolite type
Type A, potassium form
Type A, sodium form
Type A, calcium form, binderless
Nominal pore opening
3 Å
4 Å
5 Å
Bead sizes
1.6-2.5 mm; 2.5-5 mm; 0.5-0.9 mm and 1.0-1.5 mm for insulating glass
Drying of ethanol, methanol, cracked gas and olefins; insulating glass units
General drying of gases and liquids
Gas separation in PSA and VSA units
Data by grade
Grade
Bead size
Bulk density [kg/m³]
Crush strength [N]
Water adsorption [% w/w]
Molecular sieve 3A
1.6-2.5 mm
725-795
min. 25
min. 21.0 (20 °C, 55% RH)
Molecular sieve 3A
2.5-5 mm
725-795
min. 50
min. 21.0 (20 °C, 55% RH)
Molecular sieve 3A for insulating glass
0.5-0.9 mm; 1.0-1.5 mm
720-850, typical
not stated
20 (25 °C, 75% RH), typical
SYLOBEAD 3A MS-564C
1.6-2.5 mm
730, typical
30, typical
17.5 (25 °C, 10% RH) and 21.5 (25 °C, 80% RH), typical
Molecular sieve 4A
1.6-2.5 mm
725-795
min. 25
min. 21.5 (20 °C, 55% RH)
Molecular sieve 4A
2.5-5 mm
725-795
min. 50
min. 21.5 (20 °C, 55% RH)
Molecular sieve 4A
3-5 mm
min. 720
min. 80 (average of 25 beads)
min. 22.5 (25 °C, 75% RH)
SYLOBEAD 4A MS-514
1.6-2.5 mm
750, typical
30, typical
18.5 (25 °C, 10% RH) and 22.5 (25 °C, 80% RH), typical
SYLOBEAD 4A MS-512
2.5-5 mm
730, typical
60, typical
18.5 (25 °C, 10% RH) and 22.5 (25 °C, 80% RH), typical
UOP MOLSIV 4A
8×12 mesh (1.41-2.38 mm)
689, typical
31, typical
22 (25 °C, water vapour pressure 2.33 kPa), typical
Binderless molecular sieve 5A*
1.6-2.5 mm
620-700
min. 25
min. 23.5 (20 °C, 55% RH)
Additional information: the data sheets measure bulk density in different ways (after compaction, after tapping, without compaction or by sock loading), so compare density and water adsorption values together with their test conditions.
* Binderless 5A is used for gas separation, so its data sheet also gives its nitrogen capacity: min. 9.5 cm³(STP)/g, measured on an activated sample at 30 °C and 900 mbar.
Applications
Applications of 3A, 4A and 5A molecular sieves
Natural gas and LPG drying
3A dries natural gas that contains H₂S and CO₂ where COS formation must be minimised. 4A dries natural gas and LPG and also removes CO₂ from them.
Cracked gas and olefins
3A dries cracked gas and easily polymerising unsaturated hydrocarbons such as ethylene, propylene, acetylene and butadiene, because these molecules are excluded from its pores.
Alcohols, solvents and other liquids
3A dries ethanol, methanol and other polar liquids. 4A dries solvents, oils, liquid hydrocarbons and refrigerants.
Air, inert and technical gases
4A dries air and gases such as nitrogen, hydrogen, helium and argon. 4A and 3A are used in plastic granulate dryers, and 4A in PSA air dryers.
Ammonia synthesis gas
4A removes ammonia and methanol from gas streams in ammonia synthesis gas treatment.
PSA and VSA gas separation
Binderless 5A is used in pressure swing and vacuum swing adsorption units. In hydrogen PSA units, 5A is often combined with 13X: 5A takes up nitrogen and carbon monoxide, and 13X removes CO₂.
3A molecular sieve for insulating glass units
For insulating glass production, we supply 3A molecular sieve in fine beads of 0.5-0.9 mm and 1.0-1.5 mm for filling spacer bars, manually or on automatic lines. Its 3 Å pores take up water but not nitrogen or oxygen, so the unit keeps a low dew point and avoids pressure changes in the cavity that can deflect the panes. The grade is designed for use with solvent-free sealants, and its data sheet states compliance with EN 1279. It is an equivalent of 3A grades for insulating glass such as Arkema Siliporite NK 30, and it is supplied in 25 kg boxes and 150 kg drums.
How pore size influences the application
Ethanol and 4A: ethanol (4.53 Å) is larger than the nominal 4A opening, yet it is partly co-adsorbed on 4A and 5A. The sodium ions that sit in the 4A pore windows can move aside for polar molecules such as ethanol, and thermal vibration makes the effective opening larger than the nominal one. This is why 3A is used to dry ethanol. A molecule can enter the pores when it is smaller than the pore opening; near the opening the limit is not sharp. Isobutane (5.28 Å) is larger than the nominal 5A opening. Larger molecules, such as xylenes, enter 13X molecular sieve. Sources: kinetic diameters from Pérez-Botella E., Valencia S. and Rey F., Chemical Reviews 2022, 122, 17647, Table 2; H₂S from Pérez-Pellitero J. and Pirngruber G. D., Structure and Bonding 2020, Fig. 2; ethanol on LTA zeolites from Chaibi A., Boucheffa Y. and Bendjaballah-Lalaoui N., Microporous and Mesoporous Materials 2021, 324, 111285; ion gating and thermal vibration from Chen K. et al., Chemical Society Reviews 2022, 51, 1139; 3A for ethanol drying from Kupiec K. et al., Adsorption Science & Technology 2008, 26, 209. Nominal pore openings from manufacturers’ datasheets.
Pore opening and co-adsorption
Water enters all three types. 3A excludes ethanol, methanol and most hydrocarbons from its pores, making it suitable for selective drying. 4A can also adsorb CO₂, ammonia, methanol and ethanol, while 5A admits larger molecules and is used for gas separation. Check possible co-adsorption against the full stream composition and operating conditions.
Regeneration
Molecular sieves are regenerated by raising the temperature (TSA), by reducing the pressure (PSA, VSA) or by purging with a dry gas. Temperature, flow and duration depend on the application and are usually part of the process design. They must take into account the limited resistance of the sieve to thermal and hydrothermal stress.
Before filling the adsorber
Contact with humid air reduces the capacity of the sieve before it is even in the adsorber. Keep the beads in their sealed packaging until filling, and fill the vessel in a dry place. Check that the bead size and crush strength suit the bed design, flow and pressure drop.
Molecular sieve 3A, spherical, 1.6-2.5 mm and 2.5-5 mm. CAS 1318-02-1.
Molecular sieve 4A, spherical, 1.6-2.5 mm, 2.5-5 mm and 3-5 mm. CAS 1318-02-1.
Molecular sieve 3A for insulating glass, spherical, 0.5-0.9 mm and 1.0-1.5 mm.
Binderless molecular sieve 5A, spherical, 1.6-2.5 mm.
Original products: SYLOBEAD 3A MS-564C and SYLOBEAD 4A MS-514 and MS-512 from Grace, and UOP MOLSIV 4A in 8×12 mesh from Honeywell UOP, and Jalon 4A.
Equivalents:
3A: an equivalent of 3A grades such as BASF Molecular Sieve 3A and Grace SYLOBEAD MS-562C;
3A for insulating glass: an equivalent of Arkema Siliporite NK 30;
4A: an equivalent of 4A grades such as BASF Molecular Sieve 4A, Arkema Siliporite NK10 R and Honeywell UOP MOLSIV 4A;
5A: an equivalent of binderless 5A grades such as BASF 5ABF.
We can also compare grades supplied in other forms, such as Honeywell UOP MOLSIV 3A-EPG pellets. Send the brand and exact grade you use now so that we can compare the data sheets, particle sizes and process requirements. An equivalent is not a guarantee of identical performance. TDS and SDS are available on request.
Product names such as SYLOBEAD, MOLSIV and Siliporite belong to their respective owners and are used for reference only.
Depending on the grade, 3A, 4A and 5A molecular sieves are packed in sealed 5-litre plastic canisters, 25 kg net plastic drums or cardboard boxes, airtight steel drums of 130-150 kg net and big bags of 450-800 kg. Other packaging is available on request.
Most orders are dispatched within 2-5 working days. The price depends on the grade, quantity and packaging and is given in the quotation.
Replacing the bed in a dryer or adsorber?
For a quotation and the technical data sheet, please send us:
the medium and the component to remove;
the type and bead size used now, or its datasheet;
the fill mass or vessel volume and the quantity you need.
Frequently asked questions about 3A, 4A and 5A molecular sieves
3A has a pore opening of about 3 Å and adsorbs water while excluding most larger molecules, such as ethanol and unsaturated hydrocarbons. 4A has a pore opening of about 4 Å and also adsorbs CO₂, methanol, ammonia and other small molecules. Choose 3A for selective drying where co-adsorption of larger product molecules must be limited, and consider 4A for general drying after checking the full stream composition.
3A is the usual choice for drying ethanol and methanol, because these molecules do not enter its pores. For other solvents, such as acetone, send the solvent composition, its water content and the target water content, so that we can compare the suitable types.
Molecular sieves are delivered with a low moisture content in sealed packaging. For process applications, our 3A data sheet recommends starting the first cycle by regenerating the bed with dry process gas. For other grades, follow the equipment instructions and the product documentation.
By raising the temperature, by reducing the pressure or by purging with a dry gas. The conditions depend on the process and are usually set in the equipment design. Send your current regeneration method and conditions with your enquiry, and we will check them against the data sheet of the grade.
Check the bead size against your adsorber specification. For comparable grades under the same operating conditions, smaller beads generally offer faster mass transfer but a higher pressure drop. Check crush strength in the data sheet for the selected grade and bead size. Available sizes: 3A in 1.6-2.5 and 2.5-5 mm; 4A in 1.6-2.5, 2.5-5 and 3-5 mm and 8×12 mesh (1.41-2.38 mm); 5A in 1.6-2.5 mm; 3A for insulating glass in 0.5-0.9 and 1.0-1.5 mm. For a recommendation, send the vessel dimensions, flow rate, allowed pressure drop and the bead size you use now.
Store molecular sieves in airtight packaging in a dry room until use, so that they do not adsorb moisture from the surroundings. Close opened packaging carefully to protect the beads against water, other vapours and contamination. Handle the beads in a way that avoids dust.
Request a quote for 3A, 4A and 5A molecular sieves
Send the medium, the component to remove, the type and bead size used now and the quantity you need. We will reply with a quotation and the technical data sheet.
