6 replies to this topic

[bugti]

hi, we were having some flow issues through one of the Liquid feed driers of ISOMERIZATION Unit. when the drier vessel was opened we found out that the Mol sieve has changed its color from white to dark brown. My question is what might be the reason of this color change will it effect on the activity of the Mol Sieve.

[fallah]

bugti,

 

Has the vendor of the Mol Sieve been asked to explain about the reason of such color change...?

Edited by fallah, 20 July 2014 - 05:57 AM.

[PingPong]

Most likely cause is contaminants in the liquid feed to the driers accumulating on the molsieves..

 

If you kept some of the dark brown molsieves you could try to extract the dirt and analyse it to identify it.

If not you should have the liquid feed analysed thoroughly.

[Muhammad Waqas]

Are you using the Molecular Sieve after regeneration process ?

I think it should be used in as per regeneration cycle (8-hours heating up to 200F and then cooling, 8-hours usage).

[bugti]

We are receiving the feed from NHT and we have filters before the feed driers.
Yes waqas we are using the drier after regeneration.
Someone has told me that it might be due to the corrosion from NHT, we are sending sieve to the lab for testing for FeS in the mol sieves.

[Bobby Strain]

I'm reading a Stephen King book. You would think he knows the difference between drier and dryer. But he doesn't. Just like most chemical engineers.

 

Bobby

[Ali_gholamalian]

which MS changed? Hydrogen dryer or Hydrocarbon?

Each type of MS will change color under other impurities. Remember what you see in Dräger tubes, chemical reaction between specific component with molecular sieve inside the tube is the reason of color changing. also I never heard anything about corrosion under MS.