8 replies to this topic

[J_Leo]

Hello,

 

I used to see and design the mesh pad hanging inside the vapor liquid separator at the vapor outlet. Recently I saw one drum with mesh pad inside an enlarged nozzle with size much bigger than the required vapor outlet line. The vapor outlet line is flanged to the enlarged nozzle.

 

My understanding is this design can reduce the vapor space required in the drum and thus reduce the drum diameter. Since it is pretty rare to me I am not very confident to have a design like this.

 

Have anyone designed or seen this kind of arrangement before? What might be the disadvantages?

 

Thank you,

 

Leo

[Zauberberg]

Are you talking about a sleeve which is inside the vessel? Do you have a sketch of this design?

 

Demisters should be designed for much lower cross-sectional area than that of a vessel. Sometimes the mesh is fitted into a sleeve which is then welded to the vessel below the gas outlet flange.

[fallah]

J_Leo,

 

Lack of adequate info and a simple sketch...

 

It might by bigger mesh pad, the designer wanted using higher mesh size, say, to prevent mesh pad plugging...

 

Indeed, mesh pad locally extension toward the vessel inside can't so affect the required vapor space for efficient separation...

[Bobby Strain]

What you describe is probably a separator to handle lots of liquid and little gas.

 

Bobby

[J_Leo]

Thank you for all your inputs. I attached a simple sketch

 

I think Zauberberg and Bobby got the good points.

 

Fallah, I think the pad is moved outside of the drum just to save the space required between the pad and max liquid level. Usually it is 1 to 2 feet.

Attached Files

•  demister pad for horizontal drum.xlsx   10.85KB   63 downloads

Edited by J_Leo, 26 April 2015 - 01:59 PM.

[breizh]

J_leo ,

Take a look at the documents attached . This should support your work.

Hope this helps .

Breizh

Edited by breizh, 26 April 2015 - 08:41 PM.

[Sathya R]

Well it is feasible. It is innovative.

 

Discuss with the owner whether is acceptable, since it may deviate the company guidelines.

 

Ensure separation principles such as K Factor are followed in the design of the vertical leg (Gas Boot).

 

For systems with high liquid and less gas flows, this design will give smaller vessel size.  

[PingPong]

Horizontal separators with a vapor dome with demister are used already for decades.

 

I designed several myself. Nothing new. No risk.

 

A vapor dome with demister is also often used on kettle vaporizers that generate steam, or vaporize a feed to a process unit.

[J_Leo]

Dear Friends,

Thank you very much for your information. I have decided to go with the demister in the vertical leg/dome. We have chance to change the design during next design phase if the client doesn't like it.

Breizh, thank you for the attached material. I will read them.

Best regards,
Leo