What are the applications of Molecular Sieve

Molecular sieve is a kind of silica-aluminate compound with cubic lattice, mainly composed of silica-aluminum connected by oxygen bridges to form an empty skeleton structure, and in the structure there are many pore channels with uniform pore size and neatly arranged cavities with large internal surface area. In addition, it also contains metal ions with lower electric valence and larger ionic radius and water in the chemically synthesized state. As the water molecules in the heating of continuous loss, but the structure of the crystal skeleton remains unchanged, the formation of a number of the same size of the cavity, the cavity and many of the same diameter connected to the microporous, these tiny holes of uniform diameter, than the diameter of the aperture of small molecules adsorbed to the inside of the pore to the aperture, and than the aperture than the large molecules excluded, and therefore can be shaped into a diameter of the size of the molecules, the polar degree of molecules, molecular boiling point, saturation of different molecules, the molecules, the molecules, the molecules. Boiling point of different molecules, different degree of saturation of molecules separated, that is, with "sieve" molecular role, it is called molecular sieve.

Commonly used molecular sieve models in the gas industry:

A type: potassium A (3A), sodium A (4A), calcium A (5A)

X type: calcium X (10X), sodium X (13X)

Y type: sodium Y, calcium Y

Molecular sieve has strong moisture absorption ability, used for gas purification treatment, should avoid direct exposure to the air when stored. The molecular sieve which has been stored for a long time and has absorbed moisture should be regenerated before use. The molecular sieve avoids oil and liquid water, and should avoid contacting with oil and liquid water as much as possible when it is used.

3A molecular sieve

3A molecular sieve refers to potassium A-type silica-aluminate, 3A molecular sieve can adsorb molecules whose critical diameter is not larger than 3A, which is commonly used in the industry for drying unsaturated hydrocarbon gases (e.g., ethylene, propylene, butadiene, etc.), drying polar liquids (e.g., ethanol, etc.), and it is the preferred desiccant required for the deep drying of the gas-liquid phase in the petroleum, chemical industry, and the refining and polymerization.

Application:

Refrigerant drying

Cracking gas drying

Natural gas drying

Dehydration of gas or air in insulating glass

Dehydration of methanol, ethanol and other polar compounds

Dehydration of unsaturated hydrocarbons (e.g. ethylene, propylene, butadiene).

4A molecular sieve

4A molecular sieve is sodium A-type silica-aluminate, 4A molecular sieve can adsorb molecules whose critical diameter is not larger than 4A, and it can adsorb water, methanol, hydrogen sulfide, carbon dioxide, sulfur dioxide, ethylene, propylene and so on, and any molecules that can be adsorbed on 3A-type molecular sieve can be adsorbed on 4A-type.

Applications:

Drying of refrigerant and drying of air in valve

Removal of carbon dioxide, ammonia, methanol from gas streams

Drying and purification of hydrocarbons such as natural gas, LPG, air, inert gases and atmospheres

Drying of electronic components, pharmaceuticals, foodstuffs, etc.

5A molecular sieve

5A molecular sieve refers to calcium A silica-aluminate. 5A molecular sieve can adsorb molecules with a critical diameter not larger than 5A, and any molecule that can be adsorbed on 3A and 4A molecular sieve can be adsorbed on 5A type. It can separate n-alkanes from branched chain hydrocarbons and cyclic hydrocarbons through selective adsorption process. It is currently used in industry for large-scale separation processes of n-isomeric alkanes.

Applications:

Separation of n-isomeric alkanes in the petrochemical industry

Variable pressure adsorption process for purification of hydrogen, oxygen

Drying and purification of oil, natural gas and other industrial gases, removal of impurities such as water, carbon dioxide and sulfur from gas streams.

13X molecular sieve

13X molecular sieve is an alkali metal silica-aluminum salt. The effective pore size of 13X molecular sieve in the form of sodium salt is 10 angstroms, adsorbing molecules not larger than 10 angstroms, which can be used as catalyst carrier, water and carbon dioxide co-adsorption, water and hydrogen sulfide gas co-adsorption, and it is mainly applied to drying of pharmaceuticals and air compression systems.

Applications:

Removal of hydrogen sulfide and mercaptans from hydrocarbons and natural gas;

Removal of carbon dioxide and water from air (air pre-purification) and other gases;

Separation of oxygen from air, protection of catalysts, removal of oxides from hydrocarbons.

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