[national porcelain selection] 3A, 4A, 5A, 13X molecular sieve difference

Release time:

2023-11-15

Website:https://zhuanlan.zhihu.com/p/364998425

Chemical formula of 1. 3A 4A 5A molecular sieve

3A molecular sieve chemical formula: 2/3K O₂ · Na₂ O · Al₂ O₂ · 2SiO₂.4.5H O₂

4A molecular sieve chemical formula: Na₂ O Al₂ O₂ 2SiO · 4.5H O2 O

5A molecular sieve chemical formula: 3/4CaO · 1/4Na · O · Al · O · 2SiO · 4.5H · O

Pore diameter of 2. 3A 4A 5A molecular sieve

The working principle of molecular sieve is mainly related to the pore size of molecular sieve, respectively.0.3nm/0.4nm/0.5nm, they can adsorb gas molecules whose molecular diameter is smaller than the pore size. The larger the pore size, the greater the adsorption capacity. The pore size is different, and the things that are filtered and separated are not the same. Simply speaking, 3a molecular sieve can only adsorb molecules below 0.3nm, 4a molecular sieve, the adsorbed molecules must also be less than 0.4nm, and 5a molecular sieve is the same. When used as a desiccant, a molecular sieve can adsorb up to 22% of its own weight in moisture.

3. 3A 4A 5A molecular sieve application industry

3A molecular sieve is mainly used for drying oil cracking gas, olefins, refinery gas and oil field gas, as well as chemical, pharmaceutical, insulating glass and other industries, such as liquid ethanol drying, hollow glass air drying, nitrogen and hydrogen mixed gas drying, refrigerant drying and so on.

4A molecular sieve is mainly used to dry natural gas and various chemical gases and liquids, refrigerants, drugs, electronic data and volatile substances, purify argon, separate methane, ethane and propane, such as air, natural gas, hydrocarbons, refrigerants Deep drying of other gases and liquids; preparation and purification of argon; static drying of electronic components and perishable materials; dehydrating agents in paints, polyesters, dyes and coatings.

5A molecular sieve is mainly used for natural gas drying, desulfurization and carbon dioxide removal; separation of nitrogen and oxygen, preparation of oxygen, nitrogen and hydrogen; petroleum dewaxing, separation of normal hydrocarbons from branched hydrocarbons and cyclic hydrocarbons.

However, renewableThe large specific surface area and polar adsorption of 5A molecular sieve can realize the deep adsorption of water and residual ammonia. The decomposed nitrogen-hydrogen mixture enters a dryer to remove residual moisture and other impurities. The purification device adopts double adsorption towers, one adsorbs dry ammonia decomposition gas and the other desorbs and heats (generally at 300-350℃) to achieve the purpose of regeneration.

13X molecular sieve, also known as sodium X molecular sieve, is an alkali metal aluminosilicate with certain alkalinity and belongs to a class of solid bases. Its chemical formula is Na2O · Al2O3 · 2.45 SiO2 · 6.0H2O, its pore diameter is 10A, and its adsorption is greater than 3.64A and less than 10A.

13X is mainly used in:

1) In the air separation unitgas purification, removal of water andCarbon Dioxide.

2) Natural gas,Liquefied petroleum gas, drying of liquid hydrocarbons andDesulfurization.

3) General gas depthDrying.