Molecular Sieves

Molecular sieve (also called synthetic zeolite) is a kind of microporous aluminosilicate crystal. Its basic skeleton structure consists of silicon oxide, aluminum oxide tetrahedral. There are metal cation in its crystal lattice (such as Na +, K +, Ca2 +, Li +, etc.), these cation can balance the excess negative charge. According to their type of zeolite crystal structure is divided into A type, X type, Y type. According to molecular sieve aperture size, there are 3A, 4A, 5A, 10X, 13X. 4A molecular sieve is Na-A molecular sieve, aperture 0.4nm; if Na replaced by K, aperture 0.3nm, is 3A molecular sieve; if over 1/3 Na replaced by Ca2+, aperture 0.5nm, is 5A molecular sieve.

Molecular sieve adsorption capacity come from physical adsorption (Van der Waals forces), its cavities have a strong polarity and coulomb field which show a strong adsorption capacity to polar molecules (such as water) and unsaturated molecules. Molecular sieve has a uniform pore structure, which can separate different polarity, different saturation, different sizes and different boiling molecules. It has the effect of "sieving", so called molecular sieves.

Yuanying molecular sieve has quick adsorption speed, excellent adsorption performance, high crushing resistance, strong pollution resistance, large specific surface areas, big pore volume, more regenerative times, strong thermal stability, very long lifespan.

There are the following types of products: 3A molecular sieves, 4A molecular sieves, 5A molecular sieves, 13X molecular sieves, insulating glass molecular sieves, refrigerant molecular sieves, clay molecular sieves, carbon molecular sieves.

3A Molecular Sieves

Yuanying 3A molecular sieve has quick adsorption speed, high crushing resistance, strong pollution resistance, more regenerative times and long lifespan.

3A molecular sieve, also called Kalium A molecular sieve, is Kalium ion alkali metal alumino-silicate compound. Its effective pore diameter is 3A (0.3nm), it can selectively adsorb those molecules in fluid which dynamic diameter is less than 0.3nm (such as water molecules, ammonia molecules), lets molecule dynamic diameter more than 0.3nm go through molecular sieve layer bed, and then achieve the aim of fluid mixture. 3A molecular sieve has small aperture, while adsorbs water molecules it can reject all other molecules, thus effectively avoid “total adsorption” phenomena. 3A molecular sieve is a kind of excellent desiccant used for adsorbing water mainly.

Application: Drying and purification of oil cracking gas; C2 and C3 fraction drying; ethylene, propylene, butylene, butadiene, pentane drying and purification; dehydration and purification of raw material of methane, ethane and propane; purification of liquid carbon dioxide; dissolved acetylene drying; water, air, gases, polar liquids (such as methanol, ethanol) and natural gas drying and purification; refrigerator drying; catalyst support; etc. 3A molecular sieve are widely used in petroleum refining, petrochemical, chemical industry, metallurgy, electronics, defense, etc., while in pharmaceuticals, light industry, agriculture, environmental protection and many other aspects, has increasingly been applied.

4A Molecular Sieves

Yuanying 4A molecular sieve is nonpoisonous and tasteless, no irritations to eyes and skin, does not cause allergies. 4A molecular sieve deposition in the soil after washing will not cause pollution, furthermore can improve soil, so it is a natural and environment-friendly product.

4A Molecular Sieve is a kind of synthetic, with micropore cubic lattice of alkali metal aluminosilicate salt. It also called Sodium A molecular sieve, its structure is similar to NaCl. Due to its effective pore diameter is 0.4nm, so it is called 4A molecular sieve, its space network structure is staggered by silicon-oxygen tetrahedron (SiO4) and aluminium-oxygen tetrahedron (AlO4). 4A molecular sieve decides the adsorption order according to the polarity of different molecules, adsorbs only those with a molecular diameter of less than 4A. For small polar molecules and unsaturated molecules, the greater polarity, the higher degree of unsaturation, the stronger of selective absorption.

In the skeleton of 4A molecular sieve each oxygen atom is shared by two adjacent tetrahedrons, these structures formed a large crystal cave, positive ions and water molecules can be exchanged and reversible dehydration in the crystal cave. The ion-exchange of 4A molecular sieves is in crystals which have aluminium ions, each of aluminum ions with a negative charge, which can be combined with cations such as sodium, calcium and magnesium. Calcium ions and magnesium ions can replace sodium ions and enter crystal caves which were occupied by the sodium ions. It shows that sodium ions can be exchanged by Ca2+, Mg2+ ions in hard water, so 4A molecular sieve can soften water. 4A molecular sieve also can remove a small amount harmful heavy metal ions (such as Pb2+, Cd2+, Hg2+) in water, it is very important for purifying water.

4A molecular sieve adsorbs those substances which molecular diameter is less than 4A, such as water methanol, ethanol, hydrogen sulfide, sulfur dioxide, carbon dioxide, ethylene, ethane, propylene, ammonia, doesn’t adsorb molecules which diameter are greater than 4A (include propane), the selective adsorption performance to water than any other molecules.

4A molecular sieves application

(1) Argon gas making and purifying

(2) Detergent Builder: 4A molecular sieve as a detergent builder mainly used to exchange of calcium ions in water to soften water, remove dirt and prevent dirt deposition. 4A molecular sievesubstitute trisodium phosphate as detergent builder is a significant role on solving environmental pollution. 4A molecular sieve also is used for SOAP plasticizer, toothpaste abrasive, etc.

(3)Sewage Disposal: 4A molecular sieve as a softening agentinstead of domestic widespreadsulfonated coal, thereby reducing costs. In sewage 4A molecular sieves can remove ammonia nitrogen, Pb2+, Cu2+, Zn2+, Cd2+, etc. In addition to ensure water quality qualified, but also can recycle heavy metal.

(4) Metallurgical Industry separating agent:separation, extraction of potassium, rubidium and cesium in brine. In the industry it is used for collection, separation and extraction of metals and other processes.

(5) Petrochemical industry as catalyst, drying agent, adsorbent: depth drying gas and liquid such as air,  natural gas, LPG, inert gas, hydrocarbons, saturated hydrocarbons, refrigerant; dehydrating agent for paint, polyester, dyesand coatings.

(6) For agricultural soil conditioner.

(7) Medicine forsilver zeolite antibacterial agent

(8) Static desiccant for household refrigerating systems, pharmaceutical packaging, automotive air conditioning, electronic components, easy to wet and deteriorate material, perishable chemicals.

(9) Used in the R-12 and R-22 system, molecules adsorbed by 3A molecular sieve can all be adsorbed by 4A molecular sieve.

5A molecular sieves

5A molecular sieve, also called Calcium A molecular sieve, non-toxic, odorless, nonflammable, non-explosive, insoluble in water and organic solvents, but soluble in strong acid and strong base. Its pore diameter is 5×10-10m, can adsorb any molecules which pore diameter is smaller than 5×10-10m. In addition to the effect of 3A, 4A molecular sieves, it also can adsorb C3-C4 n-alkanes, ethylene chloride, bromoethane, butanol, etc. 5A molecular sieve can be applied to pressure swing adsorption separation, heterogeneous hydrocarbon separation and coadsorption of water and carbon dioxide. Yuanying 5A molecular sieve has ion exchange capacity and catalytic activity, also has a great affinity to water, under high temperature still has good adsorption ability, it has good catalysis to some organic gas phase reaction.

Let sodium aluminate, sodium silicate and sodium hydroxide hybrid reaction according to certain molar ratio (normally Al2O3:SiO2:Na2O:H2O=1:2:3:185), keeping temperature>40℃, with violent stirring, heating up reaction gel to102℃±2℃, remain this temperature till static crystallization, then filtration washing, adding calcium chloride for ion exchange (exchange 70%), then filtration washing, drying, adding adhesives kneading, molding, finally burning activating get 5A molecular sieve.

Application

1. The depth desiccation and purification of gases and liquids, purification of nitrogen, hydrogen, cleaning hydrogen sintering furnace

2. Through a selective adsorption process, isolated n-alkane frombranched-chain hydrocarbon and cyclic hydrocarbon, currently in industry used for large-scale pressure alkane separation process

3. Desiccation, desulfurization, removal of carbon dioxide for petroleum, petroleum gas and natural gas

4. Nitrogen oxygen separation, nitrogen hydrogen separation, making oxygen, nitrogen and hydrogen

5. Petroleum dewaxing, can be used as a adsorbent in dewaxing technology based on vapour as desorbent.

5A molecular sieve regeneration

1. Moisture removal: According to pressure, temperature and water of regenerate gas. Normally 200～350℃ dry gas under 0.3～0.5kg/cm through molecular sieve bed layer 3-4 hours, exit temperature 110～180℃, then cooling.

2. Removing organic matter: Used vapour instead of organic matter, then repeat step 1.

13X Molecular Sieves

13X molecular sieve, also called Natrium X molecular sieve, Zeolite 13X, is a kind of alkali metal silicon aluminate, its skeleton structure composed of silica and alumina tetrahedral FAU, main crystal holes are twelvering structures. To the X type molecular sieve,if silicon aluminum ratio is not the same, crystal structures are different. 13X molecular sieve silicon aluminum ratio≈2.6-3.0 (SiO2/Al2O3≈2.6-3.0), aperture 10A, it can adsorb any molecules which critical diameteris greater than 3.64A and less than 10A, as long as the molecules can be adsorbed by 3A, 4A, 5A type molecular sieve, they also can be adsorbed by 13X molecular sieve. Furthermore, 13X molecular sieve can adsorb bigger critical diameter molecules, such as aromatic hydrocarbons and branched chain hydrocarbons.

Application: Purifying the gas in the air separation device, removal of H2O, CO2 and hydrocarbons; natural gas, liquefied petroleum gas, liquid alkanes (propane, butane) dehydration and desulphurization (removal of H2S and thiol); general gas (such as compressed air, permanent gases) depth drying; ammonia synthesis gas drying and purifying; aerosol, propellant desulfurization and deodorization; pyrolysis gas removal of CO2; catalyst carrier; water and carbon dioxide coadsorption; water and hydrogen sulfide gas coadsorption etc.

Regeneration

3A, 4A, 5A, 10X, 13X molecular sieves can be regenerated by the method of heating with purging or evacuation.

1. Moisture removal: Normally 150～320℃ dry gas such as nitrogen, air, hydrogen, saturated hydrocarbon under 0.3～0.5kg/cm through molecular sieve bed layer 3-4 hours, then filled with cold dry gas to the adsorber about 2-3 hours, isolated from the air and cooling to room temperature;

2. Removing organic matter: Used vapour instead of organic matter, then repeat step 1. Also can be regenerated by 200-350℃ through hot vapour or inert gases;

3. Removal of gas substances: by the way of decompression.

Refrigerant Molecular Sieves

Refrigerant mainly consist of chloride and fluoride of containing hydrocarbons, refrigeration principle is that refrigerant quickly spread. In the process of refrigerant diffusion, some of water leakage and freeze in diffuser valve and block system, at the same time, the refrigerant hydrolysis to generate the corrosive gas such as hydrogen chloride and fluoride, the corrosive gas can cause refrigerant leakage, pipeline corrosion and shorten the service life of the refrigeration system. Refrigerant desiccant can adsorb water in refrigerant effectively, thus to avoid freezing, prevent freezing blocking system and corrosion.

Yuanying refrigerant desiccant does not affect the chemical stability of the refrigerant, and can adsorb organic acid and inorganic acid in refrigeration system. It has low dew point, high strength, low abrasion, strong water absorbing capacity, etc.

XH-5: for dehydration and drying of refrigerants R12, R22

XH-7: for dehydration and drying of new refrigerants R-134a in household and commercial refrigerators iceboxes and air conditioners

XH-9: for drying all kinds of refrigerants (except mixed refrigerant of containing difluoromethane), for example, refrigerants in refrigerators, freezers, air conditioners, and other refrigeration heat exchange device, is a kind of universal refrigerant desiccant;

XH-11: for dehydration and drying of refrigerants R404a, R404b, R407c, R410a, R507