Molecular Sieve type 3A is an alkali metal alumino-silicate; it is the potassium form of the type A crystal structure. Type 3A has an effective pore opening of about 3 angstroms (0.3nm). This is large enough to allow in moisture, but excludes molecules such as unsaturated hydrocarbons which can potentially form polymers; and this maximises lifetime when dehydrating such molecules.
Typical Chemical Formula
0.45 K2O . 0.55 Na2O . Al2O3 . 2 SiO2 . 4.5H2O
SiO2 : Al2O3 ≈2
Technical Parameter
|
Item
|
Unit
|
Technical data
|
|
Shape
|
|
Pellet
|
Sphere
|
|
Diameter
|
mm
|
1.5-1.7
|
3.0-3.3
|
1.7-2.5
|
3.0-5.0
|
|
Size ratio up to grade
|
%
|
≥98
|
≥98
|
≥96
|
≥96
|
|
Bulk density
|
g/ml
|
≥0.64
|
≥0.64
|
≥0.68
|
≥0.68
|
|
Wear ratio
|
%
|
≤0.20
|
≤0.25
|
≤0.10
|
≤0.10
|
|
Crushing strength
|
N
|
≥45/cm
|
≥60/cm
|
≥30/piece
|
≥70/piece
|
|
Static water adsorption
|
%
|
≥20
|
≥20
|
≥20
|
≥20
|
|
Ethylene adsorption
|
%
|
≤3.0
|
≤3.0
|
≤3.0
|
≤3.0
|
|
Water content, as shipped
|
%
|
≤1.5
|
≤1.5
|
≤1.5
|
≤1.5
|
Typical Application
Drying of unsaturated hydrocarbons (e.g. ethylene, propylene, butadien)
Cracked Gas Drying
Drying of natural gas, if COS minimization is essential, or a minimum co-adsorption of hydrocarbons is required.
Drying of highly polar compounds, such as methanol and ethanol
Drying of liquid alcohol
Static, (non-regenerative) dehydration of insulating glass units, whether air filled or gas-filled.
Drying of refrigerants
Regeneration
Molecular sieve Type 3A can be regenerated by either heating in the case of thermal swing processes; or by lowering the pressure in the case of pressure swing processes.
To remove moisture from a 3A molecular sieve, a temperature of 200-230°C is required. A properly regenerated molecular sieve can give moisture dew points below -100°C.
The outlet concentrations on a pressure swing process will depend on the gas present, and on the conditions of the process.
Size
3A - Zeolites are available in beads of 1-2 mm, (10x18 mesh) 2-3 mm, (8x12 mesh) , 2.5-5 mm, (4x8 mesh) and as powder, and in pellet 1.6”, 3.2”.
Attention
To avoid damp and pre-adsorption of organic before running, or must to be reactivated.
