In air separation equipment, the role of molecular sieve is crucial, which mainly undertakes the core task of adsorption purification and gas pretreatment to ensure efficient separation of high purity oxygen, nitrogen and other products.
The moisture in the air may freeze and block the equipment at high temperature, or react with the gas in the subsequent process (such as nitrogen) to generate corrosive substances. Molecular sieve can selectively adsorb the moisture and reduce the dew point of air to below -60℃, avoiding the risk of icing at low temperature. In the pretreatment unit of the air separation equipment, the molecular sieve bed is a necessary link before the air enters the low temperature distillation column. Carbon dioxide reacts with oxygen to form solid dry ice, contaminating products and equipment. The molecular sieve removes CO₂ through physical adsorption and ensures that the impurity content of the air entering the distillation column is less than 1 ppm. the molecular sieve also adsorbs trace hydrocarbons (e.g., acetylene, hydrocarbons) in the air, preventing them from concentrating and exploding in the distillation column. Combined with activated carbon and other adsorbents, they form a multi-stage purification system to further enhance the separation efficiency. The molecular sieve can desorb impurities by heating (usually 200-300℃) and realize recycling. Its high temperature resistance (can withstand more than 400 ℃) is suitable for high temperature regeneration process of air separation equipment. High mechanical strength and wear resistance ensure the continuous and stable operation of the equipment. When the dried air enters the distillation tower, it can reduce the refrigeration energy consumption by about 15%-20%. Avoid the corrosion of moisture and impurities on the distillation tower plate and pipeline, and reduce the maintenance cost.
In air separation equipment, molecular sieve is the key material to guarantee gas purity, equipment safety and operation economy. Its role throughout the pretreatment, distillation and regeneration of the whole process, becoming an indispensable core component of modern air separation technology.
