viscosity range for centrifugal pumps

[mirghaffari]

hi everybody,

in our crude oil project, i am face with a oil with high viscosity ( viscosity= 120 CP). our Preference is usage of centrifugal pumps. could you please help me that is possible or not? do yo have any experiance to pump this viscose liquid with centrifugal pump?

 

[1gibson]

That is not high viscosity, anyone at a tank farm or pipeline will have dealt with centrifugal pumps in this service. 600 cP or more, start to look at the numbers (correction factors for efficiency, head, flow) a little closer.

 

[BigInch]

Gibson is right. Hardly a correction is required at all until you get up to 500 cP or so.

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

 

[TD2K]

500 cP is higher than I'd expect before I would start looking at correction factors but you can definitely use a centrifugal in this viscosity range. The head is going to be lower than the pump curve will show for water and the Hp is going to be greater than you'd expect. The Hydraulic institute has the viscosity correction curves or you can also find them on the web

You'd have to google it, the URL I got about about 3 rows of characters

 

[Artisi]

Asking such a basic question would indicate it is unlikely you are in a position to correctly size any pumps. Pass it to someone with the necessary experience.

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.)

 

[25362]

http://www.engineersedge.com/pumps/viscous-liquid-pumps-review.htm

 

[1gibson]

You always need to look at correction factors, but over 500 or 600 cP you need to look at them "a little closer" and give them some consideration. If your efficiency correction approaches 50% with a centrifugal pump, there is probably a more economical way to move the fluid.

 

[mirghaffari]

thanks everybody

at this regard i found that i can select a centrifugal pumps for this viscousity with consideration of correction factor.

thanks again.

 

[25362]

Pay a visit to the following threads, they may interest you:


thread407-82566
thread407-85933
thread407-132336
thread407-159572
thread407-275718
thread407-282993
thread407-319538
thread378-184485
thread124-65964

 

[EnergyMix]

I think mirghaffari might now be confused. He stated in his original post that his viscosity was only 120 cp. All the talk of the 500 cp viscosities and need for correction factors may have him thinking he needs to apply those correction factors to his 120 cp viscosity pump.

 

[1gibson]

Not "those" correction factors, but he certainly needs to consider the appropriate correction factors for 120 cP. There will be head and flow corrections (about 3%) and efficiency correction will be much larger.

 

[25362]

120 cP could be, say, 150 cSt and probably above 650 SSU. To avoid higher viscosity levels due to cooling, it may be advisable to drain the pump when pumping is interrupted or when operating intermittently, and to keep the pump hot (at a proper temperature level) even when not working.

 

[ElSid1]

HEad will also be affected. Se calculation corrections for water vs. 30-50% glycol systems. If the manufacturer did not compensate on their curves, BHP and head will be affected. I have a powerpoint slides that show this. Doing a presentation on this very topic next week

 

[mirghaffari]

thanks a lot for your information.

but i have two mor question:

1- correction factor calculation is on me or on manufacture? i mean that when i mantioned the viscosity in data sheet, whome shall check the correction factor? i think the vendor will consider it in their performance curve. am i right?

2- i select the BB1 or BB3 pump for this application ( crude oil: Q= 1000 m3/hr, H=360 m and viscosity is 120cp) do you recoomend this type of pump?

 

[TD2K]

For higher viscosity applications I've typically seen the vendor handle the correction factors. They will supply the head/flow curve and BHp curve with water and then a 'corrected' curve to show the effect of the high viscosity on head, flow and power.

Can't help you on the pump question.

 

[25362]

FWIW, have seen claims that BB1 pumps can develop the needed differential pressure. For example:

http://www.dynapropumps.com/dvh_heavyduty.htm

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[mirghaffari]

thanks for your help. well noted

 

[ElSid1]

You need to let the manufacturer know what you are sending. If calculations are done correctly, You would have adjusted for viscosity and given the vendor head in WATER. You can then have then, as a double check, verify the selection at the viscocity you want. I use this method to verify my calculations and the checkers work. I was taught to always convert to FEET of WATER for everything. It avoids confussion down the line.

 

[ApplicationENG]

I would take a look at a BB2 if you done have a preference for a BB1.

Curves attached (on the second curve the correction factors are listed in the top right).

Again, contact an OEM - they will be glad to help.