Molecular sieve is a synthetic bai du hydrated aluminosilicate (bubble zhi stone) or natural zeolite with the function of screening molecules. dao mainly functions in organic chemical and petrochemical industries, and is also an excellent adsorbent for gas dehydration, purifying pollutants in the air.
According to different pore sizes, molecular sieve models are: 3A (potassium A type), 4A (sodium A type), 5A (calcium A type), 10Z (calcium Z type), 13Z (sodium Z type), Y (sodium Y type), Sodium mordenite type, etc. The most basic structure of the molecular sieve framework is SiO4 and AlO4 tetrahedron, the crystal of the three-dimensional network structure is composed of ordinary oxygen atoms. This combination forms voids and channels with a molecular level and uniform pore size.
Molecular sieve has high adsorption capacity, strong selectivity and high temperature resistance. It is widely used in organic chemical industry and petrochemical industry, and is also an excellent adsorbent for gas dehydration. Increasing attention has also been paid to exhaust gas purification.
Principle of molecular sieve
Adsorption function bai: The molecular sieve’s adsorption of substances comes from du physical adsorption (Van der Waal zhi), which has a strong polarity and Coulomb field inside the crystal pores, dao shows a strong effect on polar molecules (such as water) and unsaturated molecules Adsorption capacity.
Sieving function: The pore size distribution of molecular sieve is very uniform, and only substances with a molecular diameter smaller than the pore diameter can enter the crystal cavity of the molecular sieve.
The use of molecular sieve
3A molecular sieve uses: drying of various liquids (such as ethanol); air drying; refrigerant drying; natural gas, methane gas drying; unsaturated hydrocarbons and cracking gas, ethylene, acetylene, propylene, butadiene drying.
4A molecular sieve uses: deep drying of gases and liquids such as air, natural gas, alkanes, and refrigerants; preparation and purification of argon; static drying of pharmaceutical packaging, electronic components, and perishable substances; as a dehydrating agent in paints, fuels, and coatings .
5A molecular sieve uses: pressure swing adsorption; air purification dehydration and carbon dioxide.
13X molecular sieve uses: gas purification in air separation devices to remove water and carbon dioxide; drying and desulfurization of natural gas, liquefied petroleum gas, liquid hydrocarbons; general gas deep drying.