Molecular sieve manufacturer: the role of molecular sieves in air purification systems

In the air separation plant, the molecular sieve purification system is installed after the air pre-cooling system. After the compressed air is cooled by the air pre-cooling system, the moisture, carbon dioxide, acetylene and other hydrocarbons in the air still exist. If the air is not purified, the frozen moisture and carbon dioxide will be deposited in the low-temperature heat exchanger, turboexpander or rectification tower. It will block channels, pipes and valves, and the accumulation of acetylene in liquid oxygen is more likely to explode. Therefore, the role of the molecular sieve purification system is to remove moisture, acetylene, carbon dioxide, propylene, butene and other impurities in the air, so as to ensure the air separation plant. Long-term safe and reliable operation.

At present, the air purifiers used in domestic air separation plants are divided into vertical and horizontal types according to the placement method. There are two types of single beds and bunk beds in terms of structure. The structure of the air purifier is relatively simple, but it occupies a large area and is limited in use. The adsorbent used in the single bed is molecular sieve, which is responsible for adsorbing harmful components such as moisture, carbon dioxide and hydrocarbons. Compared with the single-layer bed and the double-layer bed, the double bed has some advantages. Next, the molecular sieve manufacturer will explain its characteristics:

(1) Alumina can adsorb acidic components in the air (such as s02, no2, hcl, etc.), and these acidic components are harmful to the molecular sieve, because it will generate acid together with the water adsorbed by the molecular sieve and destroy the crystal lattice of the molecular sieve, That is, the molecular sieve is poisoned, thereby impairing the performance of the molecular sieve. After the double bed is used, alumina is used to absorb moisture in advance, which has a good protective effect on the molecular sieve and prolongs the service life of the molecular sieve.

(2) Molecular sieve has a stronger affinity for water than alumina, so more energy is consumed during desorption; the use of alumina to remove water can reduce energy consumption for regeneration.

(3) Replacing the molecular sieve required for adsorbing water with alumina can save costs, because the price of alumina is much cheaper than that of molecular sieve. In the air with a relative humidity of 100% (saturated), the hygroscopic performance of activated alumina is better than Molecular Sieve. After the lower layer of the adsorption bed absorbs the moisture in the saturated air with alumina, after the moisture concentration at the alumina is reduced, the upper molecular sieve is used for deep adsorption.