Positive Displacement Pump Recomendations

[CRG]

Any thoughts regarding the best type of pump for: Crude oil with a few % solids. The majority of the solids are locked up in an emulsion (roughly 10 to 20%); however some of the large particles (300 microns) are oil wet outside of the emulsion. The majority of the solids are in the 1 to 10 micron size and are tightly locked up in the emulsion.

I need a reliable, low shear, positive displacement pump. Rate would be around 25 gpm at 200 psig.

Any suggestions or articles that would help me determine the best type of pump for this service would be appreciated.
My initial thought is to look into a progressive cavity pump.

 

[TenPenny]

You may want to look at a 2 screw or 3 screw style pump, such as from IMO or Warren.

These units are great for crude oil services, and in fact are used for things like Orimulsion, the bitumen emulsion fuel that was coming out of Venezuela.

In your application, you may want to run aroud 120 rpm, you're probably looking at 5-10 hp, so that's not too big.

 

[21121956]

Hello everybody:

CRG: take a look to this article, it can help you

http://www.vikingpump.com/documents/comparing_4_types_of_PD_Pumps.pdf

 

[TenPenny]

By the way, I dropped a 0, it was supposed to say 1200 rpm.

 

[zdas04]

I'm starting to see Progressing Cavity Pumps (PCP) mounted horizontally being used in similar applications. You have to be careful to specify elastomers that are compatible with your fluids, but if you can do that PCP's have a much lower fluid shear than any of the gear or reciprocating pumps which can be important in oil-field fluids.

David

David Simpson, PE
MuleShoe Engineering

http://www.muleshoe-eng.com

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

The harder I work, the luckier I seem

 

[dickon17]

25 gpm at 200 psi is difficult for a reliable pump on sandy crude oil. Continuous or intermittent duty? You might try a rubber lined gear pump like Bowie Pumps, but the 200 psi may be too high for them. Worth a phone call though.

 

[dickon17]

Try this company

http://www.kawa-pump.co.jp

They may have sales outside Japan.

 

[hydtools]

Look at a diaphragm pump.

Ted

 

[Artisi]

"dickon17 (Mechanical) 24 Nov 07 11:23
Try this company

http://www.kawa-pump.co.jp

They may have sales outside Japan."

These are commonly called hose-pumps and could prove ideal for your aplication and available from a number of manufacturers.

 

[bulkhandling]

Air diaphragm pump is a good choice if there is air source nearby. Be aware it generates pulsations.
Hose pump is the first one I thought, but you'll have to replace the hose a couple of times minumum in a year if the pump is continuous running.
Rotary lobe can also be used for slurry application. The bad point is, you may have to ask the vendor to visit your site if you got problem with the seals or other components. Some maintenance can only be done by the manufacturer.
Progressive cavity does have low shear as indicated by Zdas04. It generates continuous flow. Actually I do not get a reason why you should not use it except for its relatively high cost and large footprint.

 

[CRG]

Most diaphragm pumps have high NPSHR similar to reciprocals which rules out that option for my application. I will stick with my first consideration and use a low speed progressive cavity pump.

Thank you all for your advice.
CRG

 

[bosscat]

I have been working with the application of progressive cavity pumps for 10 years and would consider them the best choice for this application.

Low shear, low NPSHr, low pulsation, insensitive to viscosity, easily able to handle the flows/pressures discussed and reasonably tolerant of entrained solids/abrasives (we sometimes use them to pump things like dewatered sewage sludge and chicken carcasses!).

The main point to beware of, as already mentioned will be the selection of the correct elastomer for the stator, especially if the crude is warm or hot.

 

[KernOily]

Allow me to share some direct experience here... I suggest a reciprocating pump, e.g. Gaso, National Oilwell, Wheatley. They have been used in this exact service for over 80 years. Reliable as a rock, operator-friendly, somewhat tolerant of dry running, easy to service in the field, low vibration, low shear. My experience with this type of pump in this exact service is completely satisfactory.

A progressing cavity will work in this service but be prepared for maintenance hassles. They do not like to run dry, at all, and they do not like sand despite what anybody says. Even outfitted with special materials and special clearances, they will see high MTBF. Oil patch operators tend to have a tough time with these pumps. In my opinion and experience the PC pump is the 2nd choice behind the recip pump.

Same goes for gear pumps. The solids will eat them alive. I once retrofitted two Viking pumps with a singe duplex Gaso. The Vikings were failing about once every two weeks. The sand destroys the internal clearances.

Hope this helps!