Technical article

Molecular Sieve Desiccant


Q1: The difference between molecular sieve and desiccant?

1. The pore size of molecular sieve is controlled by the difference of processing technology, in addition to adsorbing water vapor, it will also adsorb individual gases.

2. When the temperature is below 230℃, it can still hold water molecules well.

3. A class of alumino silicate compounds with cubic lattice, mainly composed of silicon and aluminum connected by oxygen bridges to form an open skeleton structure, such as many channels with uniform pore size and orderly arrangement in the structure. A cavity with a large internal surface area.

4. In addition, it still contains metal ions with low electricity price but large ionic radius and combined water.

5. At present, the molecular sieve will be widely used in metallurgy, chemical industry, electronics, petrochemical industry, natural gas and industry.

6. Common molecular sieve models in the gas industry.

Q2: What is the principle of molecular sieve drying?

1. Potassium A (3A), Sodium A (4A), Calcium A (5A),.

2. Calcium X (10X), Sodium X (13X).

3. Molecular sieves have strong hygroscopic ability and are used for gas purification. Avoid direct exposure to the air during storage.

4. Molecular sieves that have no glands in storage time but have also absorbed moisture should be regenerated before use.

5. Minimize contact with non-oil and non-liquid water during use.

6. The gases used for drying in industrial production include air, hydrogen, oxygen, nitrogen, and argon. Robert uses five adsorption dryers in parallel, two of them work, and the second one can be regenerated.

7. Work and regenerate alternately with each other to ensure continuous operation of the equipment.

8. The dryer needs to work from below ℃, and needs to be regenerated from heating to about 350 ℃.

Q3: Is molecular sieve desiccant toxic?

1. When the above six kinds of humidity environment are full and water-absorbing molecular sieve samples are placed separately, especially in the desiccator indicator silica gel and molecular sieve, the six kinds of samples absorb moisture to some extent. Molecular sieve sample adsorption reached equilibrium in water release in my opinion, with an average moisture content of 16.3%.

2. Especially in the molecular sieve dryer, the average value of the adsorbed moisture content of the molecular sieve sample is 13.9%.

3. Especially in several humidity environments such as ambient temperature of 22.9% and 31.9%, especially when the temperature is not changed at all, there is a balance between the saturated water absorption rate of the molecular sieve and the environmental salinity.

4. If the humidity drops from 31.9% to 6.1%, that is, about 0.4% adsorption and no moisture release.

Q4: The preparation process of molecular sieve?

1. 25KG carton packaging, vacuum packaging in aluminum foil bag (for example) iron drum packaging precautions.

2. Molecular sieves should be prevented from adsorbing water and organic gases such as liquids before use. If they are used, they should be regenerated.

3. It is used for the dehydration of unsaturated hydrocarbon materials such as cracked gas, propylene, butadiene, and hexyne. It can indeed be used for drying of water, gas, polar liquid (such as ethanol) and natural gas.

4. The pore size of type 3A is slightly lower, which can be excluded in the process of water adsorption, and all individual molecules are expected to prevent the "co-adsorption" of hydrocarbons.

5. The 3A molecular sieve, 4A molecular sieve, 5A molecular sieve, and 13X molecular sieve produced by Jiangxi OIM can be regenerated but meet the requirements by heating and purging or evacuation at the same time.

Q5: What is the composition of the molecular sieve of the dryer?

1. It can be heated with dry gas such as nitrogen, air, hydrogen, saturated hydrocarbon, etc. until ℃ when the pressure of 0.5kg/m2 is passed into the molecular sieve bed for hours, and after a while, it is passed into the adsorber for drying or It is said that the cold gas is about an hour, and the isolated air is cooled to room temperature.

2. The available water vapor needs to first plan to replace the adsorbate from the molecular sieve, and then heat it up to (a new one). The regeneration can indeed be regenerated from superheated steam from ℃ to more inert gas. Adsorbate contact produces explosive mixtures (short gases).

3. The removal of gaseous substances can be done by vacuum removal and regeneration.

4. 4A molecular sieve and pore size as 4A, adsorb water, methanol, ethanol, hydrogen sulfide, sulfur dioxide, carbon dioxide, ethylene, propylene, will not adsorb certain molecules (including propane) with a diameter higher than 4A, in my opinion, for water The selective adsorption performance of most molecules is higher than anyone.

Q6: The difference between insulating glass desiccant and molecular sieve?

1. The pore volume distribution of various molecular sieves has a very high range.

2. If the molecular diameter is larger than the large pore diameter of the gel, it will all be excluded from the gel particles. This kind of situation is called total exclusion.

3. Even if the two kinds of all-exclusion molecules are different in thickness, they cannot have a separation effect.

4. Molecules with a diameter smaller than that of the gel pores can enter all the pores of the gel.

5. Even if all three molecules can even enter the pores of the gel, because the shape of the human brain is different, it will not have a good separation effect.

6. Strong molecular sieves have their range of use.

7. When a sample solution containing various types of molecules slowly flows through a gel chromatography column, each molecule performs four different movements on one side at the same time within the column.

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Tracy Chen
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