Rongjian manufactures zeolite molecular sieve in the four standard grades, 3A, 4A, 5A and 13X, in bead and pellet form. A molecular sieve is a crystalline aluminosilicate with a uniform pore size, so it adsorbs molecules small enough to enter the pores and passes the rest, which makes it the workhorse desiccant and adsorbent for deep gas and liquid drying.
The grade is chosen by pore size. 3A dries cracked gas, ethylene, propylene and ethanol without co-adsorbing them, 4A is the general-purpose drying sieve for air, refrigerants and solvents, 5A separates normal from iso-paraffins and runs oxygen and hydrogen PSA, and 13X has the widest pore for air-separation pre-purification and gas sweetening. We supply beads of 1.8 to 2.5 mm and pellets of 3.0 to 5.0 mm, in bulk.
Typical specifications for Rongjian molecular sieve, in bead (1.8–2.5 mm) and pellet (3.0–5.0 mm) form. Attrition is ≤0.1–0.2 wt% and packaged moisture ≤1.5%; full data per form is on each datasheet.
| GRADE | PORE SIZE | STATIC WATER ADS. (%) | KEY ADSORPTION CAPACITY | BULK DENSITY (G/ML) | CRUSH STRENGTH (N) | MAIN APPLICATIONS |
|---|---|---|---|---|---|---|
| 3A | 3Å (≈0.3 nm) | ≥21 | Ethylene ≤3 wt% (excluded) | ≥0.70 – 0.72 | ≥35 bead / ≥80 pellet | Drying of cracked gas, ethylene, propylene and ethanol |
| 4A | 4Å (≈0.4 nm) | ≥22 | Methanol ≥14 wt% | ≥0.70 – 0.72 | ≥35 bead / ≥80 pellet | General gas and solvent drying, refrigerant, water softening |
| 5A | 5Å (≈0.5 nm) | ≥22 | CO₂ ≥14.5 ml/g; n-hexane ≥12.5 wt% | ≥0.68 – 0.70 | ≥35 bead / ≥80 pellet | Oxygen and hydrogen PSA, natural gas desulfurization, n-paraffin separation |
| 13X | 10Å (≈1 nm) | ≥26.5 | CO₂ ≥17.5 wt% | ≥0.65 – 0.67 | ≥35 bead / ≥80 pellet | Air-separation pre-purification, gas sweetening, catalyst carrier |
Each grade is built for a different separation, set by its pore size. The four duties below cover most of where molecular sieve ships.
We have made molecular sieve since 2010, out of Jiangxi in China, and ship it by the tonne into oxygen plants, natural gas units, ethanol distilleries and petrochemical driers. Because we run the full grade range, the sieve is matched to the separation rather than forced to fit one stock product.
We hold 3A, 4A, 5A and 13X in bead and pellet form and adjust grade, size and packing to the order. Standard supply runs from small bags up to bulk bags and drums, with the test report shipped against every batch.
The sieve comes as round beads or extruded pellets, and the form is chosen for the bed. Beads flow and pack evenly, shed little dust and stand up to the pressure swings of a PSA unit, which is why oxygen and air plants favour them; pellets give a high adsorption capacity per litre and suit fixed drying beds. We make both, so the form follows the vessel and the cycle rather than whatever is in stock.
The same family of sieve covers deep drying, gas separation and gas treatment. It dries air, natural gas, refrigerants and solvents far below what silica gel or alumina reach; it runs the adsorbent bed in oxygen and hydrogen PSA; and it strips CO2 and sulphur compounds in natural-gas and air pre-purification. The grade and form are matched to which of these the plant is doing, since a PSA bed and a drying bed are not the same duty.
Outside the four standard grades, the sieve is made to the grade, the bead or pellet size and the packing a job needs, including special grades for a particular PSA cycle or an insulating-glass duty. Tell us the gas or liquid, the moisture or component to remove and the vessel, and the grade and size are set to the separation rather than taken off the shelf.
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Choose by pore size and the molecule you need to catch. 3A takes water while keeping reactive molecules like ethylene and ethanol out, 4A dries most gases and solvents, 5A separates straight-chain from branched hydrocarbons and runs oxygen PSA, and 13X handles larger molecules, carbon dioxide and air-separation clean-up.
Both are desiccants, but a molecular sieve has a precise pore size and a much stronger pull on water, so it dries a stream to a far lower dew point. Silica gel holds more water at high humidity and costs less, which suits general packaging, while molecular sieve is the choice for deep drying.
Yes. We supply beads for dense packing and low pressure drop in moving beds, and pellets for fixed beds and larger vessels. Both come in the standard grades, and we screen to a custom size on request.
Molecular sieve dries and purifies gases and liquids. It dehydrates natural gas, air, refrigerants and solvents, takes carbon dioxide and sulphur out of gas, concentrates oxygen in PSA units, and pushes ethanol past its water limit in distilleries.
Yes. A molecular sieve is regenerated by heating or by dropping the pressure, which drives off the adsorbed water or gas and restores the capacity. With proper cycles it runs for many regenerations before it needs replacing.
Yes. We ship by the tonne, factory-direct from Jiangxi, in bags, bulk bags and drums, with the quantity and packing set to your order and a test report against every batch.
A molecular sieve is a crystalline aluminosilicate, or zeolite, with pores of one exact size. It adsorbs molecules small enough to fit inside and passes everything larger, which is why it dries and separates with a precision that ordinary desiccants cannot match. The grade is chosen almost entirely by pore size.
3A has a 3-angstrom pore, set by potassium ions, which is large enough for water but too small for most other molecules. That makes it the safe choice for drying reactive or valuable streams such as cracked gas, ethylene, propylene and ethanol, where a wider pore would adsorb the product along with the water. It is the standard sieve for ethanol dehydration to fuel grade.
4A has a 4-angstrom sodium pore and is the most widely used grade. It adsorbs water, methanol, ethanol, carbon dioxide and hydrogen sulphide while excluding anything larger than about 4 angstroms. It dries air, refrigerants, solvents and natural gas, and also serves as a water softener and a static desiccant in sealed units.
5A opens the pore to 5 angstroms with calcium ions, so it admits straight-chain hydrocarbons but rejects branched ones, which lets it separate normal from iso-paraffins and run oxygen and hydrogen pressure-swing units. 13X has the widest pore, around 10 angstroms, and the highest water and carbon-dioxide capacity, so it pre-purifies air ahead of cryogenic separation, sweetens natural gas and acts as a catalyst carrier.
Beads of 1.8 to 2.5 mm pack densely with a low pressure drop and survive the movement of a switching bed, while pellets of 3.0 to 5.0 mm suit fixed beds and large vessels. Static water adsorption tells you how much the sieve holds, while crush strength and attrition tell you how long the bed lasts. A molecular sieve is regenerated by heat or by lowering pressure, so a single charge serves many cycles before replacement.
