2024 New Design Molecular Sieve Dehydration For Natural Gas

Dehydration by Adsorption

Advantages of Zeolite 3A Unsaturated Hydrocarbons:

Very low dew point and water content can be obtained

Best suited for large volumes of gas under very high pressure

Dehydration of very small quantities of natural gas at low cost

Insensitive to moderate changes in gas temperature, flow rates, and pressure

They are relatively free from problems of corrossion, foaminig, ect

Some types can be used for simultaneous dehydration and sweetening

The 3A Molecular Sieve Methanoldehydration unit that can remove the water vapor from natural gas with about 30Nm3/h flow rate.

The amount of water vapor in the natural gas (feed gas) is about 110mg/Nm3. 

The amount of water vapor in the final gas should be <=0.1ppmv.

Some plants have used an adsorbent that contains Zeolite 3A within an activated alumina matrix. The idea being that when the high capacity molecular sieve adsorbent is dispersed within a lower capacity adsorbent that there would be over-all less ethylene adsorption resulting in less local heat rises. This lower capacity, lower heat generating, adsorbent still requires the preload step.

Regardless of which adsorbent is used, there have been problems. Solidified adsorbent masses have formed in the adsorbent bed ranging from size of basketballs to essentially all the bed having been solidified into a mass of polymer. The ceramic material used as support of the adsorbent bed has solidified into a pancake mass where only the area next to vessel wall is unaffected. There have been occurrences of serious heat formed inside the vessel as evidenced by the ceramic bed support particles being semi melted together, and being cracked and fused together with polymer. This heat is localized since no temperature increases are detected by any of the thermocouples in the adsorbent section. These solidification problems usually show up as high pressure drop across the adsorbent bed. Left uncorrected they will lead to loss of purification performance resulting in downstream reactor blockage and unscheduled plant shut-down.

If you have experienced some of these problems with your monomer purification, we can help. Successful operation can be obtained with your 3A or with a blended adsorbent.