4 replies to this topic

[J_Leo]

Hello,

I want to know how to control the interface level in a Waste Condensate Drum in order to have good oil skimming from water.  Process drains enter the drum intermittently. Please refer to the attached sketch I prepared for details. Is it possible to have good oil skimming without the interface level control valve on the Water Pump Discharge? The interlock can start the pump at high interface level and stop the pump at low level.

If interface level control valve is needed for better oil water separation, what kind of control valve should be used? Is simple on/off valve ok?

Where is a better location for the interface level transmitter at the water side?

Regards,

Leo

Attached Files

•  Waste Condensate Drum and Pump.pdf   425.41KB   19 downloads

[Bobby Strain]

It sounds like your challenge is to determine where the interface is. I presume you will send a variety of oils along with water. So, I presume you are using something like a conductance probe. You can use on-off control, but you need to be certain that you get separation at the lowest water level. If the drum is too small, then you need to look at some type of coalescer, or plate pack. And, you don't want to cycle the pump too frequently. Sounds like you are looking to change an existing operation. "Keep improving it until it no longer works", that's my motto.

 

Bobby

[J_Leo]

Bobby,

 

Thank you very much for your inputs. A little more explanation here,

 

This is a new design and it is not in operation yet. The waste condensate includes all the process drains from various sources such as Amine Drain Drum, Flare KO Drum, Fuel Gas KO Drum, etc.

The interface level control was originally designed W/O the level control valve. The interlock can start the pump at high interface level and stop the pump at low interface level. Later on, a comment was made to add the level control valve to maintain an oil interface level to efficiently skim the oil. I don't understand the purpose and unfortunately the person who made the comment is not available to talk any more.

 

I hope someone with operational or design experience can shed me some light.

 

Regards,

Leo

[Bobby Strain]

If it is a new design, look for the calculations that should have been done by the designer. No one can help you unless you go through the necessary calculations to check for separation adequacy. Otherwise we would be doing your job without compensation.

 

Bobby

[J_Leo]

Bobby,

 

There is no problem with the drum design. My only question is about the interface level control. Is it ok to run the system w/o the level control valve? If we have to use the level control, how should it work to maintain the interface level for efficient oil skim. The pump is in intermittent service. Is a single cap control valve ok?

 

This is just for my own learning purpose. The project was closed already.

 

Regards,

Leo