4 replies to this topic

[h.eghbali]

Hi everyone. I have a question.

In our fractionation plant, LPG stream is desulphrized in reactors and then headed to depropanizer and debutanizer towers where C3 and C4 will be recovered.

When we put fresh reactor in service, total Sulphur in C4 increase drastically while total Sulphur in C3 was remained constant!

IS there any explanation based on attached picture and the fact that in both C3 and C4 products, CH4S and C2H6S is present?

Thanks in advance.

P.S.: Unfortunately our lab department are not able to analyze each Sulphur components.

 

Attached Files

•  Untitled.png   21.69KB   1 downloads

[h.eghbali]

Not any answer?

[SilverShaded]

Both mercaptans boil higher than propane so not suprising quantitiy is increasing in C4.

 

Qustion is why with new catalyst your getting more mercaptans?  Whats the reactor supposed to be doing?  Are you sure the catalyst is active and placed in the reactor correctly?  Based on your drawing it looks like a simple guard bed?  Or is it supposed to be a merox unit?

[h.eghbali]

Both mercaptans boil higher than propane so not suprising quantitiy is increasing in C4.

 

Qustion is why with new catalyst your getting more mercaptans?  Whats the reactor supposed to be doing?  Are you sure the catalyst is active and placed in the reactor correctly?  Based on your drawing it looks like a simple guard bed?  Or is it supposed to be a merox unit?

 

Thanks. You got me wrong.

I mean mercaptans (CH4S and C2H6S) in C3 product is constant, while in C4 product increases. You are tight that boiling point of both mercaptans are higher than propane, but quantity of this two components in C3 and C4 product must increase simultaneously. 

Reactors are removing sulfur compounds.

[SilverShaded]

"but quantity of this two components in C3 and C4 product must increase simultaneously"

Not neccesarily.  C2H6S bils at 37C so why should any of it appear with the propane?  The answer is either because small amaount is absorbed by the propane (henrys constant?) or its physically entained with it.  No reason why it should go up in proportion as far as i can see.