1.6-2.5mm 3-5mm 3A Zeolite Molecular Sieve Sphere/Pellet Adsorbent with High Separation Efficiency for Natural Gas Drying

3A molecular sieves are mostly used as catalysts and can also be applied in ethylene plant cracking gas dryers and air separation units. The particle size of 3A molecular sieves is generally expressed in "mesh", and they are commonly derived from their precursor, "zeolite".

When zeolite is processed into powder (known as zeolite powder), its properties need to be treated during the processing, such as treatment with strong acids. After high-temperature calcination to remove moisture, it gains water absorption capacity and can also adsorb other molecules.

Common molecular sieves can be classified into Type A, Type X, Type Y, etc. Among them, Type A can be further divided into 3A, 4A, and 5A; Type X can be divided into 10X and 13X; Type Y is mostly used as an additive for catalysts, mainly applied in petroleum cracking and to meet the subtle requirements of detailed project analysis.

The adsorption principle of molecular sieves is different from that of silica gel and anhydrous calcium chloride. The latter undergoes physical surface adsorption and simple chemical combination, while the former traps water through its own lattice structure. Generally speaking, after adsorption, molecular sieves will not release adsorbed moisture or other molecules at room temperature; the adsorbed moisture or other molecules can only be released when the temperature reaches about 650℃. It is worth noting that different types of molecular sieves will have different gas emissions at different temperatures, and this temperature is approximately 100℃.

Molecular sieves have a relatively fast adsorption rate. Generally, adsorption is completed after 5 hours of contact (which may vary depending on the contact area and contact rate).

Application Precautions and Examples of 3A Molecular Sieves

3A molecular sieves are mainly used for drying petroleum cracking gas, refinery gas, oilfield gas, olefins, etc. Specific applications include the drying of ethylene, acetylene, propylene, butadiene, as well as the dehydration of ethanol and various solvents. To prevent the adsorption of hydrocarbons above ethane, 3A molecular sieves are also used for dehydration of natural gas.

Its application examples are as follows:

1. Application of 3A Molecular Sieves in Isopropanol Dehydration

Isopropanol is an important chemical raw material and organic solvent, widely used in the chemical and pharmaceutical industries. A large amount of mixed waste liquid of isopropanol and water is generated during industrial production, so it is of great significance to achieve complete separation of isopropanol and water.

3A molecular sieves have a strong adsorption effect on moisture in isopropanol, with good regeneration effect, and can directly obtain high-concentration isopropanol. The adsorption and dehydration of isopropanol by 3A molecular sieves can directly yield high-concentration isopropanol, and the water absorption capacity of 3A molecular sieves has little relationship with the state of isopropanol (gaseous or liquid). However, the adsorption capacity of 3A molecular sieves for pure isopropanol is closely related to the adsorption state, which is smaller in gaseous adsorption.

Nearly a hundred experiments have confirmed that molecular sieves have good regeneration effect, long service life, and simple operation. Since 3A molecular sieves can realize the dehydration of isopropanol vapor, they can be operated in combination with ordinary distillation towers to achieve the purpose of energy saving.

2. Adsorption Effect of 3A Molecular Sieves on Trace Moisture in Ethyl Acetate Solution

Ethyl acetate often contains moisture, which forms an azeotrope with ethyl acetate. At atmospheric pressure, the azeotrope contains 8.5% water by mass. To obtain high-purity ethyl acetate, it is necessary to refine ethyl acetate. Common refining methods mainly include extraction refining process, azeotropic distillation with entrainer, and acetic acid extraction reactive distillation process, etc. The above refining processes have high energy consumption.

3A molecular sieves have a strong adsorption effect on moisture, with simple operation and easy regeneration. Using 3A molecular sieves to adsorb moisture in ethyl acetate solution can directly obtain high-purity ethyl acetate, with simple production process and low energy consumption.

The regeneration conditions during the cyclic adsorption process of 3A molecular sieves, the adsorption effect after regeneration, as well as the structural changes inside the molecular sieves after cyclic adsorption and their causes need further research, so as to reduce the deactivation rate of molecular sieves as much as possible while maintaining the adsorption effect.

Product Specifications