3 replies to this topic

[chem101]

Hi:
Can someone please see the attached Glycol pump setup? Pump discharge line has PSV set at 1440 psig. The discharge of this PSV has check valve and line is connected to rich glycol line which has about 40-60 Psig Pressure. Should that be connected to the suction of the pump? Can we install a check valve on PSV discharge? What does API says about installing check valve?)
Please also see the recycle line on the pump.
On other have charcoal filter design pressure is 15 psig. (i don't agree with this design pressure. It should be at least 125 psig). The discharge of this PSV goes back to the same vessel. Can someone please verify this set up. I have talked to my department but no one agree with.

Attached Files

•  Glycol pump set up.pdf   47.53KB   67 downloads

[Art Montemayor]

Your flow sketch is drawn very poorly. You cross flow lines that are not connected. This is confusing.

Also, you fail to state that Rotor-Tech is an external gear pump type. I am very familiar with this pump and see no reason for a pump-around. You may have a special reason; I don’t know that. Why do you show what is a GEAR pump as a CENTRIFUGAL one? That is technically inaccurate and confusing.

My comments are limited because there is no detailed P&ID, scope of work, basis of design, process description, etc., etc. My comments to what you present are in bold RED, below.

Pump discharge line has PSV set at 1440 psig. The discharge of this PSV has check valve and line is connected to rich glycol line which has about 40-60 Psig Pressure. Should that be connected to the suction of the pump?
No. I always connect this PSV discharge directly back to the Lean TEG Surge Drum that feeds the TEG circulation pumps.

Can we install a check valve on PSV discharge?
You CAN install a check valve – but I would always refuse to accept this design. What is your reason or logic for this? I maintain that it is not necessary and serves no useful purpose. Plus, it is potentially hazardous.
What does API says about installing check valve?)
The API says nothing – but then, why should it? The Check valve is not required nor necessary.
Please also see the recycle line on the pump.
OK. But what is reason or logic for a recycle around a gear pump?
On other have charcoal filter design pressure is 15 psig. (I don't agree with this design pressure. It should be at least 125 psig). The discharge of this PSV goes back to the same vessel.
I always send the discharge of the carbon adsorbers and the sock filters to the closed drain system.
Can someone please verify this set up.
I have made my comments; I do not verify what you show as correct and safe. I do not agree with it.

[chem101]

Thank you Mr. Art for your comments.
I always enjoys and learn from your comments.

[chem101]

Hi Art:
you mention in the previous post that what is the logic behind re-cycle line on rotor tech pump.
The reason we are using is to send proper amount of Lean Glycol to the tower.

The dehydration System is designed for 8 GPM. The Rotor Tech pump maximum Capacity to pump glycol is 9.6GPM
The recycle line is there to recylce 1.6 gpm. In this way we can only use 8 GPM.

(Using 9.6 GPM Glycol will require Extra BTU)
I hope this help.
Thank you.

Edited by chem101, 12 April 2011 - 12:30 PM.