6 replies to this topic

[lsoaresfernandes]

Hello all,

 

I have to figure out a control system to guarantee the discharge pressure of a pump to be 8 bar, no matter the flowrate. 

 

I was thinking about using a positive displacement pump with a recycle, but couldn´t understand how the control of the pressure would actually works. Can anyone help me?

[latexman]

It works like a self-contained backpressure regulator. It’s also called spill back control. If pump discharge pressure is below set pressure, the CV closes and less flow goes back to suction vessel. If pump discharge pressure is above set pressure, the CV opens and more flow goes back to suction vessel.

At each flow destination you will need one or more CV(s) and flow meter(s) or weigh system(s) for batching.

[Bobby Strain]

You didn't reveal much. So, now everyone is going to give you their guess. I'll wait until I see more information.

 

Bobby

[lsoaresfernandes]

Hi Bobby, sorry for that.

The situation is as follows: I have a process where liquid has to be pressurized before being heated, to enhance separation and avoid vaporization. A pump is then used to increase the pressure of the liquid from 2 to 10bar.

The pressurized liquid shall pass through 2 vessels and 1 heat exchanger, before being cooled down and stored. Usually I believe the vessels would have a pressure control system that would purge gas to keep the pressure inside it at a specific range, but since we dont have any gas, this cannot be done.

The solution I came up was to use a pressure valve at the end of the process, just before storing the liquid, but I wonder if there is any order way to control the discharge pressure of the pump. Maybe recycling it back?

[Nikolay_]

Hello,

 

To separate something you should have several phases (before cooling and storing). Is it possible to rise pressure with partial pressure of gases or vapor pressure?

[Bobby Strain]

You have the right solution. All the equipment downstream of the pump should be designed for the pump shutoff pressure.

 

Bobby

[lsoaresfernandes]

Nikolai,

It is oil/Water separation. Liquid/liquid.

Bob,

Thanks!