A type molecular sieve 4A | Обустройство дома

A type molecular sieve 4A | Обустройство дома

Type: spherical (particle size 1.8mm-2.5mm, 3.5mm-4.0mm)   Pore ​​size: 3A: 0.3 nm; 4A: 0.4 nm; 5A: 0.5 nm   Introduction to molecular sieves   A molecular sieve is an aluminosilicate compound having a cubic lattice. Molecular sieves have a uniform microporous structure with uniform pore diameters. These pores can adsorb molecules smaller than their diameter into the interior of the pores, and have preferential adsorption capacity for polar molecules and unsaturated molecules. The degree of saturation is different, the degree of saturation is different, molecules with different molecular sizes and different boiling points are separated, that is, they have the function of "sieving" molecules, so they are called molecular sieves. Because molecular sieves have the advantages of high adsorption capacity, strong thermal stability and other adsorbents, molecular sieves have been widely used.   performance   The molecular sieve is powdery crystal with metallic luster, hardness of 3 to 5, relative density of 2 to 2.8, natural zeolite has color, synthetic zeolite is white, insoluble in water, thermal stability and acid resistance with SiO2/Al2O3 composition ratio Increased by the increase. Molecular sieves have a large specific surface area of ​​300-1000 m2/g, and the inner crystal surface is highly polarized. It is a kind of high-efficiency adsorbent and a kind of solid acid. The surface has high acid concentration and acid strength, which can cause positive carbon. Ionic catalyzed reaction. When the metal ions in the composition exchange with other ions in the solution, the pore size can be adjusted, and the adsorption properties and catalytic properties can be changed, thereby preparing molecular sieve catalysts with different properties.   structure   The proteoglycan polymer thus constituted is zigzagly wound to form a microporous sieve-like structure called a molecular sieve. Molecular sieves only allow passage of substances smaller than their micropores, and have a barrier effect on macromolecular substances, bacteria and the like larger than their micropores. Make the matrix a defensive barrier that limits the spread of harmful substances such as bacteria. Hemolytic streptococci and cancer cells can produce hyaluronidase, decompose proteoglycans, destroy matrix structure, and spread. The proteoglycan polymer also binds a number of hydrophilic groups and can bind a large number of water molecules to form an extracellular "reservoir".   Characteristics   Molecular sieves are extremely hygroscopic (and therefore widely used as desiccants) for the purification of gases and should be protected from direct exposure to air. Molecular sieves that have been stored for a long period of time and have been hygroscopic should be regenerated before use. Molecular sieves avoid oil and liquid water. Avoid contact with oil and liquid water when using. The gas to be dried in industrial production is air, hydrogen, oxygen, nitrogen, argon, etc. Two adsorption dryers are connected in parallel, one is working, and the other can be regenerated. Work alternately and regenerate to ensure continuous operation of the equipment. The dryer is operated at 8-12 ° C and is regenerated by heating to 350 ° C. The molecular sieve regeneration temperatures of different specifications are slightly different. Molecular sieves have a good catalytic effect on certain organic gas phase reactions.   kind   Molecular sieves are available in both natural and synthetic zeolites. 1 Natural zeolite is mostly formed by the reaction of volcanic tuff and tuff sedimentary rocks in the marine or lacustrine environment. At present, more than 1000 kinds of zeolite minerals have been discovered, and 35 kinds are more important. Common examples include clinoptilolite, mordenite, erionite and chabazite. Mainly distributed in the United States, Japan, France and other countries, China has also found a large number of mordenite and clinoptilolite deposits, Japan is the country with the largest amount of natural zeolite extraction. 2 Since natural zeolites are resource-constrained, synthetic zeolites have been used in large quantities since the 1950s.   Commercial molecular sieves are commonly used to classify molecular sieves with different crystal structures, such as 3A, 4A, and 5A molecular sieves. Type 4A is the class A in the table, with a pore size of 4 Å; The Na-type molecular sieve containing Na+ is recorded as Na-A. If Na+ is replaced by K+, the pore size is about 3Å; that is, the molecular sieve of type 3A; for example, more than 1/3 of Na+ in Na-A is replaced by Ca2+, and the pore diameter is about 5Å; is the 5A molecular sieve.   model   Molecular sieve models commonly used in the gas industry;   Sodium type, such as type A: potassium A (3A), sodium A (4A), calcium A (5A);   Octagonal type, such as X type: calcium X (10X), sodium X (13X) and Y type: sodium Y, calcium Y;   Mercer type, (-M type): high silica type zeolite, such as ZSM-5.   Drying technology   Microwave drying technology solves the problems of slow drying speed, high energy loss and poor product quality in traditional dry molecular sieves.   1. The microwave drying molecular sieve is fast, and the microwave drying purpose can be achieved in a few minutes;   2. The microwave drying molecular sieve is uniform, achieving deep drying and good product quality;   3, static drying, no burning, less dust;   4, non-contact drying, to avoid contamination of molecular sieves;   5, microwave drying molecular sieve process safe, energy-saving, environmentally friendly use of electrical energy, internal and external drying at the same time, more than 50% energy saving than electric drying;   6. Shorten the production cycle and greatly reduce the occupation of working capital;   7. The microwave drying equipment cabinet temperature is below 40 °C to improve the working environment of workers;   8, the equipment is simple and convenient to operate