Used for absorb molecules with their critical diameters no more than 4A,have one of the largest use quantity for industrial.
Molecular Sieve 4a Detail:
Introduction
molecular sieve 4A is an alkali alumino silicate and able to absorb molecules with their critical diameters no more than 4A; it is the sodium forms of the Type a crystal structure. 4A molecular sieve has an effective pore opening of about 4 angstroms (0.4nm). 4A molecular sieve will adsorb most molecules with a kinetic diameter of less than 4 angstroms and exclude those larger. Such absorbable molecules include simple gas molecules such as oxygen, nitrogen, carbon dioxyde and straight chain hydrocarbons. Branched chain hydrocarbons and aromatics are excluded.
Typical Chemical Formula
Na2O. Al2O3. 2SiO2. 4.5 H2O
Si/Al ratio: SiO2/ Al2O3≈2
Pore diameter: About 4
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 | ≥0.66 | ≥0.66 | ≥0.66 | ≥0.66 |
Wear ratio | % | ≤0.20 | ≤0.40 | ≤0.20 | ≤0.20 |
Crushing strength | N | ≥30/cm | ≥45/cm | ≥30/piece | ≥70/piece |
Static water adsorption | % | ≥20.5 | ≥20.5 | ≥21 | ≥21 |
Static methanol adsorption | % | ≥15 | ≥15 | ≥15 | ≥15 |
Water content, as shipped | % | ≤1.5 | ≤1.5 | ≤1.5 | ≤1.5 |
Application
Drying and removing of CO2 from natural gas, LPG, air, inert and athmospheric gases, etc.
Removal of hydrocarbons, ammonia and methanol from gas streams
(ammonia syn gas treating)
Special types are used in the air break units of buses, trucks and locomotives.
Packed in small bags, it may be used simply as a packaging desiccant.
Regeneration
Naike molecular sieve Type 4A 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 4A molecular sieve, a temperature of 250-280°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.
Removal of water: Hot gas at 200-350°C and pressure 0.3-0.5Kg/cm2 flows through the molecular sieve bed for 3-4 h. lettemperature decreases down to 110-180°C, cooling.
Removal of organics: Regeneration is achieved by means of steam treatment to remove organics, and then remove water with method 1.
Conservation:
Room temperature, humidity <90%, non-expose to air; non-contactwithwater, acid and alkali...
Size
4A - 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”.
