What are the specific steps for air separation using 13X molecular sieve?

1. Air Pretreatment

• Filtration: Filters are used to remove dust, impurities, and large – particle pollutants from the air, preventing these substances from entering the subsequent systems and affecting the separation effect or blocking the equipment.
• Compression: The air is compressed by an air compressor to increase its pressure, providing power for the subsequent separation operations. Meanwhile, the compression process also facilitates the subsequent cooling and drying treatments.
• Cooling and Drying: The compressed air has a relatively high temperature and contains a certain amount of water vapor. The air is cooled through a cooler, causing the water vapor to condense into liquid water. Then, the water is removed through a separator to avoid water freezing or affecting the performance of the molecular sieve during the subsequent separation process.

2. Adsorption Separation

• Loading of Molecular Sieve: The 13X molecular sieve is evenly loaded into the adsorption tower, ensuring that the loading amount and packing density of the molecular sieve meet the equipment requirements to guarantee a good adsorption effect.
• Introduction of Air: The pretreated air is introduced into the bottom of the adsorption tower. Under the action of pressure, the air passes upward through the molecular sieve bed layer evenly.
• Adsorption Process: The 13X molecular sieve has a uniform microporous structure and a large specific surface area, and it has a selective adsorption effect on different gas molecules. When the air passes through the molecular sieve bed layer, gas molecules with smaller diameters such as nitrogen, carbon dioxide, and water can enter the micropores of the molecular sieve and be adsorbed, while oxygen molecules, due to their relatively large diameters, cannot enter the micropores, thus achieving a preliminary separation of oxygen from other gases.

3. Desorption and Regeneration

• Pressure – reduction Desorption: When the molecular sieve in the adsorption tower is saturated with adsorption, the pressure of the adsorption tower is reduced, causing the adsorbed gas molecules to be released from the micropores of the molecular sieve. This process is called desorption. The pressure – reduction method can be achieved by slowly releasing pressure through a valve control or by using a vacuum pump to accelerate the desorption speed.
• Flushing and Regeneration: To improve the regeneration effect of the molecular sieve, usually, after pressure – reduction desorption, a small amount of dry gas (such as nitrogen) is introduced to flush the molecular sieve bed layer, further carrying out the desorbed gas out of the adsorption tower, and restoring the molecular sieve to its initial adsorption state.
• Switching Operation: Generally, an air separation device is equipped with multiple adsorption towers. When one adsorption tower is in the adsorption operation, other adsorption towers can be in operations such as desorption and regeneration. The alternate operation of each adsorption tower is realized by switching valves, ensuring the continuous progress of the air separation process.

4. Product Collection and Purification

• Oxygen Collection: After adsorption separation, the gas flowing out from the top of the adsorption tower is mainly oxygen, which is collected into the oxygen buffer tank for subsequent use or further treatment.
• Product Purification: The collected oxygen may still contain a small amount of impurity gases, such as argon. According to the requirements for oxygen purity, further purification methods such as cryogenic distillation and membrane separation can be adopted to improve the purity of oxygen to meet the usage requirements of different industrial fields.