Technical article

The differences between molecular sieve 3A and molecular sieve 4A


Many people often have questions when purchasing molecular sieves. Which molecular sieve should I choose?
1. We often receive inquiries from customers about whether to use 3A molecular sieve or 4A molecular sieve? What's the difference between them?
In fact, when we purchase molecular sieves, we do not specify which molecular sieve is better, but only which molecular sieve is more suitable for our use. The main function of molecular sieve is to sieve a substance molecule through the pore size of its crystal internal structure. When we meet the process requirements of water removal, which is better, molecular sieve 3A or molecular sieve 4A?
First of all, this question should be specifically distinguished from the substances to be dehydrated. The molecular diameter of the substances to be dehydrated (dried) should be the size of the molecular diameter. If the dynamic molecular diameter of the substances to be dehydrated (dried) is more than 3nm and less than 4nm, we can only use molecular sieve 3A to remove water from such substances. Because if molecular sieve 4A is used, it will not only absorb the water in the material, but also absorb the materials that need dehydration, which is the first case.
Another situation is that if the kinetic diameter of the material to be dehydrated (dried) is greater than 4A, molecular sieve 4A is generally used, because molecular sieve 4A has a stronger ability to absorb water than molecular sieve 3A.

2. If both molecular sieve 3A and molecular sieve 4A can be used to remove water, which molecular sieve shall we use?
In this case, we can generally use molecular sieve 4A, because the water absorption capacity of molecular sieve 4A is more than 22%, while that of molecular sieve 3A is more than 21%. In general, the water absorption capacity of molecular sieve 4A is stronger than that of molecular sieve 3A; Moreover, the price of molecular sieve 4A is cheaper than that of molecular sieve 3A. Why is the price of molecular sieve 4A cheaper than that of molecular sieve 3A? Because molecular sieve 3A is an ion exchange based on molecular sieve 4A, which is equivalent to an additional process, the price of molecular sieve 4A is more expensive.
To sum up, we have a general understanding when using molecular sieve 3A and molecular sieve 4A.
3. In order to produce LNG, some of our customers also use molecular sieve 3A and molecular sieve 4A together. That is, dehumidification and carbon dioxide removal. Two types of molecular sieves act on the adsorption tower. Molecular sieve 3A is used for deep dehydration, while molecular sieve 4A is used for absorbing excess water and a little carbon dioxide. It depends on the design process of tower packing design company. Therefore, specific consultation is required for specific matters.

+86 799 6666455

+86 18179910932
Tracy Chen
WeChat and LinkedInClose
the qr code
the qr code