5A Molecular Sieve specifications
| Property | Unit | Bead Ø1.6–2.5 mm | Bead Ø3.0–5.0 mm | Pellet 1/16" | Pellet 1/8" | Test condition |
|---|---|---|---|---|---|---|
| Static water adsorption | % wt | ≥ 22.0 | ≥ 22.0 | ≥ 21.0 | ≥ 21.0 | RH 50%, 25 °C |
| Bulk density | g/ml | ≥ 0.70 | ≥ 0.68 | ≥ 0.64 | ≥ 0.64 | Tapped |
| Crush strength | N | ≥ 30 | ≥ 80 | ≥ 30 | ≥ 80 | Avg. of 25 beads |
| Loss on attrition | % wt | ≤ 0.10 | ≤ 0.10 | ≤ 0.20 | ≤ 0.30 | — |
| Loss on ignition | % wt | ≤ 1.5 | ≤ 1.5 | ≤ 1.5 | ≤ 1.5 | 550 °C, 1 h |
| Particle size ratio | % | ≥ 98 | ≥ 98 | — | — | In stated size range |
Where is 5A Molecular Sieve used?
5A molecular sieve is used in PSA hydrogen units, n/iso-paraffin separation, small PSA oxygen units and the treatment of sour natural gas.
PSA hydrogen purification
Top layer that removes CO, N₂ and CH₄ from hydrogen.
n/iso-paraffin separation
Adsorbs linear paraffins and rejects branched isomers.
5A Molecular Sieve vs other adsorbents: which do you need?
Choose 5A when molecules up to 5 Å — n-paraffins, CO, CH₄ — must be adsorbed; use 4A for general drying and 13X for larger molecules or higher CO₂ capacity.
| Grade | Pore | Adsorbs | Typical use |
|---|---|---|---|
| 4A | 4 Å | H₂O, CO₂, H₂S | Natural gas, air, refrigerant drying |
| 5A (this product) | 5 Å | n-paraffins, CO, CO₂ | PSA hydrogen, paraffin separation |
| 13X | ≈ 10 Å | H₂O + CO₂ together, mercaptans | Gas sweetening, purification |
| Lithium LSX | X-type | N₂ (highest N₂/O₂ selectivity) | PSA / VPSA oxygen |
What is 5A Molecular Sieve?
5A molecular sieve is a calcium-exchanged A-type zeolite (CaA): replacing sodium with calcium widens the pore opening to about 5 Å.
Type
Calcium A-type zeolite
Adsorbs
n-paraffins, CO, CO₂, H₂S, H₂O
Excludes
iso-paraffins, aromatics, large molecules
How does 5A Molecular Sieve work?
5A separates by molecular size and polarity: straight-chain n-paraffins and small gases enter the 5 Å pores, while branched and cyclic molecules are excluded; in hydrogen PSA, CO, N₂ and CH₄ are held while H₂ passes.
- Feed enters under pressure — syngas, off-gas or a hydrocarbon stream.
- Target molecules are adsorbed — CO, N₂, CH₄ or n-paraffins stay in the pores.
- Product passes through — hydrogen or iso-paraffins leave the bed.
When should you use 5A Molecular Sieve?
Use 5A when you need to separate by molecular shape or remove CO, N₂ and CH₄ from hydrogen, rather than just dry a stream.
- Hydrogen purity target is 99.9% or higher.
- Linear and branched paraffins must be separated.
- Sour gas needs H₂S and CO₂ removal together with water.
How do you regenerate 5A Molecular Sieve?
In PSA units 5A is regenerated every cycle by pressure swing and purge; in thermal-swing service it is regenerated with hot, dry purge gas.
PSA
Pressure swing and purge
TSA temperature
250–300 °C
Bed life
8–10 years in PSA hydrogen
