Molecular sieves are basically three dimensional aluminosilicate that contains cavities inside the crystal. Through various channels these cavities are interconnected with each other. These channels are called pores. All the pores have an exact diameter which is uniform. This diameter plays a very crucial role in the application of these zeolites. This means that the molecules which have a diameter smaller than the diameter of the pores will reach the cavities. This will obviously provide an accurate separation. Molecules which are absorbable will pass the pores and those which are not absorbable will not pass the pores.
What are the different types of molecule available? There are basically four types of molecular sieves available and those are defined by their pore grade. These grades are 3A, 4A, 5A and 13X. These are available in pellets and beads form. The key function of these molecular sieve is to remove water or moisture from various natural gases and liquids. There can’t be any comparison of molecular sieve when it comes to absorb the impurities. Molecular sieve is normally used for oxygen purification but molecular sieve can be used for oxygen generator as well.
13X molecular sieve is mainly used for this process. Oxygen generator is a machine that produces oxygen enriched gas from air by using the Pressure Swing Adsorption (PSA) method. This particular type of molecular sieve is very much effective for separating any sort of liquids whether it is nitrogen or anything from oxygen. Larger size molecules are absorbed by this process this is why it is the most reliable oxygen desiccant.
This molecular sieve is used for pure and fresh oxygen inhalation. The surrounding air is passed through the molecular sieve. And we already know that 13X molecular sieves have the ability to separate pure oxygen from nitrogen and other impurities due to its pore size about 10A0. The oxygen it produces is almost 94 to 95% pure. This process is very cost effecting compared to other type A molecular sieve purification process. Besides it doesn’t consume much of energy as well.
13X molecular sieve for oxygen generator is being used for highly pure oxygen production for the patients for the last several years. These molecules are also used for separating CO2 and LPG from enriched oxygen and for separating oxygenates from hydrocarbons. The dew point of the oxygen generated through this process is -50 to -750 C.
Can these molecular sieves be regenerated? Yes, these sieves can be regenerated. There are some specific methods for the same. Process like pressure change, heating, purging are mainly used with a carrier gas for the process. PSA process is also used for regeneration. The shelf life of the molecular sieves is 5 to 6 years. But special filters should be used to keep away the impurities.