molecular sieve drying is amorphous silicate or silicon aluminate, made of silicon oxygen tetrahedron or alumina tetrahedron by oxygen bridge is linked together to form a molecular size (usually from 0.3 to 0.3 nm) of concreted complete cavity system, which are characteristic of molecular sieve. However, with the deepening of the molecular sieve synthesis and application research, the researchers found that the phosphorus aluminate salts drying molecular sieve, molecular sieve and the skeleton of elements (silicon or aluminum or phosphorus) can also Be composed of B, Ga, Fe, Mn, Cr, Ge, Ti, V, Co, Cu and zinc, Be replaced, the concreted complete cavity also can achieve more than 2 nm, the size of the molecular sieve can Be divided by skeleton elements silicon aluminum type molecular sieve, phosphorus kind of molecular sieve and skeleton heteroatomic molecular sieve; According to the hole size, hole size less than 2 nm, 2 ~ 50 nm, and more than 50 nm molecular sieve respectively called microporous and mesoporous and macroporous molecular sieve. With large aperture, become a good carrier of larger molecular reaction, but for amorphous mesoporous materials of hole wall, causing its water thermal stability and thermal stability is not required for petrochemical industry application harsh conditions
Molecular sieve means having uniform pores, pore size and molecular size equivalent to a general class of substances. Application of molecular sieve is widely used, it can be used for efficient drying agent, selective adsorbents, catalysts
2015年8月31日星期一
2015年8月27日星期四
natural gas adsorbent,molecular sieve separation
natural gas adsorbent is a kind of crystal type of aluminum silicate, the crystal structure of neat and uniform pore size was in the order of molecular size, it only allows molecules into the smaller than the aperture diameter, so can according to the size of the molecules in the mixture screening. According to molecular sieve. As early as 200 years ago, b. g dragon, he named the first molecular sieve separation, the chemical composition in the general formula for molecular sieve zeolite molecular sieve type M and n are metal ions and the valence; X is the silica on the number of molecules; Y is the number of molecules of water; P is aluminum atomic number; Q is number of silicon atoms. Molecular sieves in chemical industry as a solid adsorbent, by adsorption material can desorption, molecular sieve can be recycled after use. Is also used in gas and liquid, dry, purification, separation and recycling. In the 1960 s, used as cracking catalysts in the petroleum refining industry, has now developed a variety of suitable for different molecular sieve catalysts for catalytic process.
2015年8月23日星期日
Summary of the dangers of molecular sieve xh-7
Health hazard: the goods for the central nervous system inhibitors. First cause excitement, then inhibition. Develops in oral acute poisoning: molecular sieve xh-7 acute poisoning. Generally can be divided into the excitement, four stage hypnosis, anesthesia, and suffocation. Into the third or fourth stage, patients with loss of consciousness, pupil dilation, irregular breathing, shock, heart failure and stop breathing cycles. Chronic effects: molecular sieve dryer high concentration of the goods in the production of medium and long-term contact can cause nose, eyes, mucous membrane irritation, and headache, dizziness, fatigue, easily excited, tremor, nausea, etc. Found for a long time can cause multiple neuropathy, chronic gastritis, fatty liver, liver cirrhosis, myocardial damage and organic psychosis and so on. Long-term exposure can cause dry skin, desquamation, cracked and dermatitis.
Combustion hazard: the goods flammable, stimulative.
2015年8月19日星期三
Preparation of molecular sieve xh-5
Until the 1930 s, fermentation is the only industrial molecular sieve xh-5 production methods. With the rapid development of petrochemical industry, synthesis of ethanol production is more and more big. But in the synthesis of ethanol mixed heterogeneous high carbon molecular sieve xh-9, to the person's senior neural paralysis, not suitable for used as a beverage, food, medicine, spices, and so on. Therefore, even in the petroleum chemical industry developed countries, fermentation of ethanol still occupies certain proportion.
2015年8月15日星期六
double glazing molecular sieve in physical applications
double glazing desiccant molecular sieve is an important organic solvent, which are widely used in medicine, paint, health supplies, cosmetics, grease, and other methods, accounting for about 50% of the total consumption of ethanol. double glazing molecular sieve is an important basic chemical raw materials, used in the manufacture of acetaldehyde and ethyl diene, ethylamine, ethyl acetate, acetic acid, ethyl chloride, etc., and derived the medicine, dye, coating, spices, synthetic rubber, detergent, pesticide and so on many of the intermediate products, the products up to more than 300, ethanol intermediate in chemical products use is decreasing gradually, many products such as acetaldehyde, acetic acid, ethyl alcohol is no longer using ethanol as raw materials and other raw materials instead. 75% ethanol aqueous solution has strong sterilization ability, is a common disinfectants. Can be used to make ethanol from specially prepared drinks. Similar to methanol, ethanol can be used for energy. Some countries have begun to separate using ethanol as fuel or mixed into gasoline (10%) used to save petrol.
2015年8月10日星期一
molecular sieve xh-11
molecular sieve xh-11 Also known as anhydrous alcohol, refers to the ethanol concentration is greater than 99% (mass). Mainly used as solvent for cosmetics, pharmaceutical and other industries. Supreme general of industrial ethanol concentration of 95%. To obtain anhydrous ethanol, may be further desiccant for insulated glass with the following three ways: (1) treated with lime industrial ethanol, make water into insoluble calcium hydroxide, ethanol, and then steamed out with sodium metal is dry, it is the old way. (2) the azeotropic distillation dehydration is a commonly used method in industry at present. Generally with benzene as azeotropic agent, steamed out of a boiling rectification tower over the course of the first, benzene, ethanol and water ternary azeotrope, again in the second azeotropic distillation steamed out binary azeotrope of benzene and ethanol, the steam out of the anhydrous ethanol in alcohol distillation. Because of the benzene in the product and about 0.5% (mass) of the residual, and benzene toxicity is bigger, has developed in recent years is pentane or hexane instead benzene as azeotropic agent. (3) with ion exchange agent or molecular sieve dehydration, then distillation.
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