pump selection for "oily" and "separated" water 1

[mirghaffari]

Dear colleagues,

i want to select the suitable pump for "oily water" and "separated water" application. i think the best selection is "progressive cavity pump". in similar project they use "VS4" type for this application! but my concern is the price of this type of pump.
coud you please advise me wich pump is more expencive? and whice one do you recommend?
1- gear pumps
2- vertical VS4 type pump
3- progressive cavity pump

thanks in advance.

 

[DubMac]

PC pump is a very good selection for oily water, especially if there are some abrasive solids (sand) included.

 

[bimr]

To select a pump, one needs a full understanding of the details of the application (which you have not provided).

However, a similar question was recently posted on this forum and may assist you.

http://www.eng-tips.com/viewthread.cfm?qid=333207

 

[bimr]

PC pumps will probably be the most expensive and may or may not be the optimum selection for the applications. The selection of a pump usually requires a full understanding of the application (which has not been provided).

A similar query was recently made for this type of application. Maybe it will answer your questions:

http://www.eng-tips.com/viewthread.cfm?qid=333207

 

[Artisi]

Might be an idea to do some research for yourself, Like phoning a few pump suppliers with your pump duties and then making some comparisons of the price, running costs etc.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[BigInch]

If price is your only criteria worth mentioning, then visit Sam's Discount House.

"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek

 

[Pumpsonly]

You need to clarify what is "separated water"
Is it water separated from the oily water which mean with very-very low oil content-- then centrifugal pump VS4 can be used and would be the most economical..

If you are pumping oily water to the "'separator" than PC pump will be the better choice for low shear making the separation of oil and water in the separator more effective.

 

[mirghaffari]

thanks for your reply.liqid type

to pumponly:
dear,we have a water separator sump that all washing liquid frome our equipment collect on it. this liquid may contain some small solids and swedge. then the oil of this liquid separate in one side of sump and remain water collect in other side. now we want to select the suitable pump for these two liquid type.
could you please help me to select the economical pump? VS4 or progressive cavity or other type?

 

[bimr]

If you want to install the pump directly inside of the sump, then you will limited to using the VSP pump. This option may work for pumping only the water, but will create an emuslsion problem when pumping oil and water. This option is not the best because your pump will have to be constructed of corrosion proof materials.

If you want to build a dry pit next to the sump, then your best option is a screw pump. The screw / centrifugal impeller pump with its open channel impeller design combines the gentle action of a screw pump and the high flow rates and cost efficiencies of a centrifugal pump. Most skimmers use screw pumps because the pumps will not form an emulsion, are tolerant of debris, do not require priming, and will handle viscous oil.

http://www.environmental-expert.com/products/trito...

http://www.hidrostal.co.uk/default.aspx?p=screwce

The PC pump will be more costly and will have higher maintenance costs with little or no benefit.

 

[ApplicationENG]

VS4 is the economical choice between a PC and centrifugal.

Also based on your last application descrition, it seems that this pump would only be handling runoff. Again. VS4 should be fine 99.9% of the time even with some solids.

If this is crude oil and not machine oil, id watch for H2S content as well.

 

[zdas04]

The "shear" comment above is key. For oil/water mixtures, any shear forces will increase the rate of emulsion formation and it can be difficult to break the emulsions. Progressing (not progressive) Cavity Pumps are very low shear and originally were used for pumping emulsions (not creating them). I use PCP for oily mixtures all the time. For water with incidental oil and solids, any pump will do and centrifugal pumps are the least expensive.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[mirghaffari]

well noted

thanks

 

[Pumpsonly]

Mirghaffari,
I will choose PC pump for the oil and VS4 for the water.
PC pumps are also available in vertical arrangement for installing in a sump.


ApplicationENG

VS4 is also a centrifugal pump.

 

[ApplicationENG]

haha. yes...yes they are. doing too many things at once.

 

[mirghaffari]

thanks pumponly,

in our same project, they select the pumps same as your idea. gear type for oil and vs4 for water. thanks for your help

 

[MortenA]

You should be avare that the various organic compounds mixed into the water may cause the polymer of the stator in a PC pump to swell. So be carefull when adressing this subject. The pump vendor will not always know.Best regards Morten

 

[mirghaffari]

what is your idea about submersible pumps? these type installed in bottom of tank and pump the liquid out.

 

[bimr]

Submersible pumps may sound simple and inexpensive. However, submersible pumps will be more expensive over the entire service life because submersible pumps have much higher maintenance costs.