Molecular sieves | Detailed overview | Advantages And Disadvantages

 
There are various types of molecular sieves such as carbon molecular sieves (CMS), zeolites, limestone and silica gels, how do they work? In this blog we will discuss the purification technique molecular sieves. We discuss the following themes;

• What are molecular sieves?
• How does a molecular sieve work?
• What are the advantages of a molecular sieve?
• What are the disadvantages of molecular sieve?
• What can one actually remove with molecular sieves and from what?

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What is a molecular sieve?

A molecular sieve is a solid material with a pore distribution that is very uniform and is used for adsorption in both the liquid and the gas phase. There are various types of molecular sieves such as carbon molecular sieves (CMS), zeolites, limestone and silica gels. With molecular sieving there is made a distinction between the types based on the micro (smaller than 2 nanometers),meso (between 2 and 50 nanometers) and macro pores (larger than 50 nanometers)they have.

How does a molecular sieve work?

A molecular sieve works on the basis of adsorbing molecules that are small enough to enter the pore structure through diffusion. Molecules that are larger than the pores can not enter the molecular sieve. This mechanism of adsorption works both in the liquid phase as well as in the gas phase.

What are the advantages of a molecular sieve?

• Selective removal - the uniform pore size makes it possible to selectively remove molecules.
• High removal efficiency possible - the large amount of pores ensures high capacity.
• Reuse - Regeneration is common as a result of which the total operating costs can remain low

What are the disadvantages of a molecular sieve?

• Costs - molecular sieves are often more expensive than other techniques in the purchase price
• Fragile - molecular sieves can break which can result in particles that can get into a process
• Selective - not always applicable after removal of various molecules

What can be removed and from what with a molecular sieve?

Molecular sieves are used in both liquid and gas / air, see some examples below.

• Removal of water from LNG
• Removal of moisture from air
• Removing acid gases such asCO2 (carbon dioxide), H2S (hydrogen sulfide)for example from biogas
• Removal of mercaptans from gas or air
• Removal of hydrocarbons such as BTX (benzene, toluene and xylene)

in this blog we went into the basis of the purification technique molecular sieves. We did elaborate on the following themes what is a molecular sieve, how does a molecular sieve work, what are the advantages and disadvantages of molecular sieves and what can one actually remove with molecular sieves. Also read our other and future blogs about various purification techniques.