3 replies to this topic

[asade abiodun]

Hi all,

Please i need information on the design criteria and sizing for sump pit.
The sump pit is to be designed for the collection of spillage of base oil during loading and offloading.

Base oil is viscous, but its flow through the channel to the sump pit is aid by water which could be available more during rainfall and washing around the area.

i need expertise in this area of design.

i appreciate your assistance


oochh... Merry Christmas and happy new year to you all

[djack77494]

asade,
The design of a sump pit is based more on somewhat arbitrary criteria rather than process requirements. Typically, you would want to fix a "working volume" or volume that is active between the high and low levels. You may have criteria that are based on a maximum size spill that is expected (plus maybe the quantity of wash water you think is needed to move the spilled fluid). Alternately, maximum rainfall may govern your design. Once you get past the volume needed, then you should consider what pumps you might want. For vertical pit pumps, the vendor will be able to provide you with his requirements for clearances between pumps, from the bottom of the sump, and from walls. When you combine all these requirements, you should be able to work out an acceptable design. Remember that there is not a single correct answer - you can vary the sump dimensions to meet other needs such as space availability.

[asade abiodun]

djack77494, thanks for your insight.

Is it possible to design the sump pit in such a way that wash water can be separated from the base oil and dispose effectively, while transferring the waste base oil for approval disposal.

I know that the separation can be aid by density, and principle of stokes law.

Please, i need insight to this concept of mine.

Appreciate any information.

Regards

[djack77494]

Is it possible to design the sump pit in such a way that wash water can be separated from the base oil and dispose effectively

Yes, this is of course possible. I note that you have now changed the topic from designing a sump based primarily on surge and physical requirements to one that is intended to be a two phase separator. As you suspected, you would apply Stoke's Law to determine your reuqirements. Allow an initial mixed area where the liquids enter the sump. You could (should) conservatively assume that the water and oil phases are completely mixed in this region. As you move along the main flow path of the separator sump, the phases will begin to separate in accordance with Stokes Law. Design enough of a path such that the fluids will completely separate into an oil rich and a water rich phase. Follow this with an area of the sump where the two phases are withdrawn (pumped out) in a way that respects the physical requirements.