1. molecular sieve working principle
1. Adsorption function: The adsorption of molecular sieve to substances comes from physical adsorption, and its crystal pores have strong polarity, and show strong adsorption ability to polar molecules (such as water) and unsaturated molecules.
2, screening function: the pore size distribution of molecular sieve is very uniform, only the molecular diameter is less than the hole diameter of the material, only have the opportunity to enter the molecular sieve crystal hole inside.
3, by the priority of adsorption, as well as the size of the size to distinguish between different substances of molecules, so the image is called "molecular sieve".
Molecular sieve it is a kind of aluminosilicate, mainly composed of silicon aluminum through the oxygen bridge, connected to form an open skeleton structure, in the structure there are many holes with uniform pore size and arranged neatly, large internal surface area of the hole. In addition, it also contains metal ions with lower electricity price and larger ionic radius and combined water. Because water molecules are continuously lost after heating, but the crystal skeleton structure is unchanged, many cavities with the same size are formed. The cavities are connected with many micropores with the same diameter. Material molecules with smaller diameter than the pore are adsorbed inside the cavity, while molecules larger than the pore are excluded, the molecules of different sizes and shapes are thus separated until the action of the sieving molecules is called a molecular sieve. Molecular sieve has high adsorption capacity, high selectivity and high temperature resistance. Because of its excellent performance, it is widely used in organic chemical industry and petrochemical industry, and it is also an excellent adsorbent for gas dehydration, and it is also increasingly favored in waste gas purification.
Types and Application of 2. Molecular Sieve
Molecular sieve type according to the use can be divided into: 3A molecular sieve, 4A molecular sieve, 5A molecular sieve, 13X molecular sieve series molecular sieve. The purpose of each molecular sieve is different. It is mainly used in pipeline in addition to water, air, natural gas, alkane, refrigerant and other gases and liquids. It has the characteristics of high adsorption and fast adsorption speed. It is mainly suitable for pressure swing adsorption. It can adapt to various sizes of oxygen, hydrogen, carbon dioxide and other gas pressure swing adsorption devices. It is widely used in micro-heat suction dryer, air separation equipment, pipeline water removal, oxygen and hydrogen production, steel plant, petrochemical oil refining.
1. 3A molecular sieve
Mainly used for petroleum cracking gas, olefins, oil refineries, oil field gas drying, chemicals, pharmaceuticals, industrial desiccant, such as insulating glass.
Chemical formula: ⅔ K2O × ¾ Na2O × Al2O3 × 2SiO2 × 4.5H2O
Main uses: drying ethanol and other liquids, hollow glass air drying, nitrogen-hydrogen mixed gas drying, refrigerant drying.
2. 4A molecular sieve
Mainly used for natural gas and various chemical gases and liquids, refrigerants, pharmaceuticals, electronic materials and volatile substances drying, argon purification, methane, ethane propane separation.
Chemical formula: Na2O × Al2O3 × 2SiO2 × 4.5H2O
Main uses: air, natural gas, hydrocarbon finish, deep dry gases and liquids, such as refrigerants; preparation and purification of argon; electrostatic drying of electronic components and moisture-sensitive substances; paint, polyester fiber, dye, dehydrating agent in paint.
3. 5A molecular sieve
Chemical formula: ¾ CaO × ¼ Na2O × Al2O3 × 2SiO2 × 4.5H2O
Main uses: natural gas drying, desulfurization, decarbonization; nitrogen and oxygen separation, nitrogen and hydrogen separation, oxygen preparation, nitrogen and hydrogen; petroleum dewaxing, separation of normal hydrocarbons and cyclic hydrocarbons from branched hydrocarbons. (Renewable)
4. 13X molecular sieve
It is mainly used for raw gas purification of large and medium-sized air separation units.
5, Special molecular sieve series for hollow glass
It can absorb the moisture and residual organic matter in the insulating glass at the same time, so that the insulating glass can remain smooth and transparent even at very low temperatures, and fully reduce the strong pressure difference between inside and outside. Insulating glass due to seasonal and day-night temperature differences. Thoroughly solve the problem of deformation and breakage caused by the expansion or contraction of ordinary insulating glass, and fully extend the service life of insulating glass.
6. Molecular sieve activated powder series
is a molecular sieve obtained by dehydrating the original portion of the molecular sieve. It has a certain degree of dispersion and rapid adsorption speed. Mainly used as additives for coatings, coatings, resins and related adhesives.