After the argon fraction is extracted from the top Tower, it enters into the crude argon tower and conducts the separation of oxygen and argon by the rectification method. Generally, the components of crude argon from the top of the crude argon tower are: argon is more than 98%, nitrogen is less than 0.5%, and oxygen is less than 1.5%. Import Crude argon with purity over 98% into molecular sieve adsorber. There are two adsorbers in each group. One is equipped with 5A Molecular sieve to absorb nitrogen in crude argon; the other is equipped with 4A molecular sieve to absorb oxygen in crude argon. In order to release the adsorbents, two groups of adsorbents need to be set up to switch to use. The adsorber works at the temperature of 90 K. The crude argon enters into 5A Molecular sieve adsorber to remove nitrogen first, and then enters into 4A molecular sieve adsorber to remove oxygen. The process is shown in Figure 18. The gas from a group of molecular sieve adsorbers has a purity of 99.99% argon, which is pure argon.
The advantages of argon adsorption method lie in simple technological process, convenient operation and low cost. However, the purity of argon can only reach 99.99%. Due to the restriction of the selective adsorption capacity of the molecular sieve, the purity of 99.999% cannot be obtained. A high purity argon. Another disadvantage is that the working temperature of the adsorber is 90 K and the regeneration temperature is 423 K, which makes it difficult to design the adsorption structure. When the adsorber is working, the bed must be cooled down, which often needs to be cooled down by the jacket or through liquid oxygen in the pipe. If the uniform cooling temperature is to be reached, it will be very difficult for the adsorber with larger diameter required by large argon production equipment. Because of the two disadvantages above, the application of pure argon adsorption method is limited. At present, the capacity of domestic adsorption method argon is less than 10m3/h, only 150m3/hAir separation equipmentIt is adopted in the matching argon-making equipment, but has not been applied in the large argon-making equipment yet.
