Booster for Positive Displacement Pump?
Booster for Positive Displacement Pump?
(OP)
Gentlemen, first of all I would like to salute everybody and to express my appreciations regarding this Forum. I'm a poor beginner, so, please, be patient with me. Currently, I'm involved in a concept regarding the transfer of oil from a tank to a storage area far away from our tank. I suggested a twin screw pump (positive displacement) which can provide the required characteristics (68 m3 @ 100 bar), obviously, with a VSD. The process guys jumped on me, saying that booster pumps are a must in such applications. Is it correct? And if it is correct, what type of pump should I choose for booster, because I don't think a centrifugal one is recommended. And if it is recommended, what should be the characteristics for the booster pump(s)? The shaft power required by the twin screw pump is 400kW. Can anybody advise about the motor characteristics V / kW as the electrical guy is arguing with me.
Thank you very much in advance, and I hope to hear from you soon.
Eugen25
Thank you very much in advance, and I hope to hear from you soon.
Eugen25





RE: Booster for Positive Displacement Pump?
Johnny Pellin
RE: Booster for Positive Displacement Pump?
Thank you very much,
Eugen 25
RE: Booster for Positive Displacement Pump?
I am sorry that I keep asking you to restate the question. I was originally born in Arkansas, so English is not my native language.
Johnny Pellin
RE: Booster for Positive Displacement Pump?
**********************
"The problem isn't working out the equation,
its finding the answer to the real question." BigInch
http://virtualpipeline.spaces.live.com/
RE: Booster for Positive Displacement Pump?
RE: Booster for Positive Displacement Pump?
You have a NPSHA of more than 5'. Is there a positive static head on the suction side or does the PD pump have to lift a head? I'm not 100 % sure but I think twin screw pumps can lift a head.
Booster pumps are usually centrifugals. Their head should be 30-50 psig (but that is only a rough guideline!!!). Their flow must be minimum the flow of the PD pump. That must be checked too with the PD pump manufacturer. The necessary flow of a booster pump can be higher than the flow of the PD pump.
Power requirement seems pretty high if the flow is 68 m³/h. That is an efficiency of 47.2 % which is rather poor.
RE: Booster for Positive Displacement Pump?
If there is an occasional situation where your main pump can't keep up, a booster pump will kick in and take up the slack.
If your fluid is flowing over a long pipeline, then the pressure lost needs to be regained... with a booster pump down the line.
These people are probably experienced with long pipe lines, and they know that you need to return some pressure to the lines or the flow will stop.
Charlie
www.facsco.com
RE: Booster for Positive Displacement Pump?
"booster pumps""transfer pumps" to keep NPSH on the shipping pumps for some products, but when they are not shipping that product, they use the same transfer pumps to move that product from tank to tank. IMO, nobody seems to have made any sense of this system yet. So ... do you think we could just wait for the OP to answer the questions he's already got?**********************
"The problem isn't working out the equation,
its finding the answer to the real question." BigInch
http://virtualpipeline.spaces.live.com/
RE: Booster for Positive Displacement Pump?
Also, reading the characteristics of the twin srew pump, I understood that a booster pump should not be required unless there are some special requirements(and you cofirmed it). My concern is why the manufacturer stated that the max inlet pressure is 15bar as a booster pump should produce 2 - 3.5 bar on outlet (inlet for PD pump)? Micalbrch calculated a low efficiency. That is because I, deliberately, considered a low efficiency. Also, Micalbrch is stating that usually the booster pumps are centrifugal. Is our case "an usual one"? I'm asking this because the PD and the centrifugal are different types, different concepts... Can they work together? No conflicts?
JJ Pellin, the English language is not the native language for me. I'm from the Eastern Europe and the nearest English speaking country is about 2500km from my homecity...This is one more reason why I had to ask you for patience. Many thanks to everyone of you. Eugen25
RE: Booster for Positive Displacement Pump?
The twin screw manufacturer mentions someting about the max. inlet pressure, not something about the required inlet pressure. That is a big difference. And the limitation of 15 bar for the inlet pressure has technical (design) reasons. Such a high feed pressure occurs only under certain circumstances and with special fluids.
In general: A centrifugal pump as booster pump works fine with a PD pump if both are correctly sized.
Why did you calculate efficiency and motor power? Didn't you get the required motor power from the twin screw pump manufacturer?
RE: Booster for Positive Displacement Pump?
RE: Booster for Positive Displacement Pump?
RE: Booster for Positive Displacement Pump?
Second: I don't know why you think you need a booster to feed the PD. Will you be pumping hot gasoline with a very high vapor pressure or something? If not, one centrifugal-type should work.
You also won't be able to define a real pressure until you have some idea of the line profile, so I think you're running a little ahead of yourself right now. At least get an idea of the profile from Google Earth or something.
Don't worry about voltages yet. If you don't know the profile, you don't know the power or the pressure. Once you know that, then let the EE guys figure out what voltage you need to run a motor with the power requirements you have. If they can't get the voltage ... you can always go with either a diesel driver or install a generator. What other choice would you really have... not build the pipeline? Right now today you need the pipe diameter, pressure and power requirements. Focus on that.
**********************
"The problem isn't working out the equation,
its finding the answer to the real question." BigInch
http://virtualpipeline.spaces.live.com/
RE: Booster for Positive Displacement Pump?
If you want to pump rather clean oil (low or even no solids content), BigInch' recommendation to look for a centrifugal pump as an alternative will be a good advise. Although I have no clue how much a centrifugal is in comparison to a twin or triple screw pump. But that is something you can compare when you will have the proposals. Do not forget to compare the motor sizes too as energy costs should be considered.
Who calculated the pressure of approx. 90 bar?
RE: Booster for Positive Displacement Pump?
RE: Booster for Positive Displacement Pump?
TenPenny, thank you for the info. It helps a lot. Actually it confirms my supposition.
Gentlemen, thank you for lighting my way. It is a pleasure and a honor to have you close. All the best to all of you.
Eugen25
RE: Booster for Positive Displacement Pump?
OK somebody wants a booster. Why? Is it heavy heavy crude and the suction line loss is very high, or you have a something?
Mical,
Yes, it makes no sense. What I mean is that you have a maximum pipeline pressure and both types of pumps supposedly will reach that, but they CANNOT go over that. If the PD runs up the pressure to max the relief goes off, or it bends a rod. If the centrifugal runs up the pressure to max, the relief goes off, or it overheats. So you won't get any more pressure on the pipeline with one type of pump than you would get with the other type of pump. So, there is no reason to chose a PD over a centrifugal for preventing flow stoppage.
**********************
"The problem isn't working out the equation,
its finding the answer to the real question." BigInch
http://virtualpipeline.spaces.live.com/
RE: Booster for Positive Displacement Pump?
I think eugen25's preference for a PD pump was to have some kind of pressure margin in case the pressure is not 90 but 100 bar and he still needs the full flow. But let's leave it as it is. He is satisfied so far.
RE: Booster for Positive Displacement Pump?
It has also been my experience that many process guys don't understand the concept of the twin-screw beast. Many of these monsters require little to no NPSHa, and this point might not be getting through in his organization.
-Theron
RE: Booster for Positive Displacement Pump?
Mike Halloran
Pembroke Pines, FL, USA
RE: Booster for Positive Displacement Pump?
**********************
"The problem isn't working out the equation,
its finding the answer to the real question." BigInch
http://virtualpipeline.spaces.live.com/
RE: Booster for Positive Displacement Pump?
Thanks for the concern, but I'll address the OP in the way I see fit, and as I understand what he might want to know. If I offer him something that he finds valuable, that's for him to decide, not you.
Charlie
www.facsco.com
RE: Booster for Positive Displacement Pump?
Charlie, you're right. I didn't mean it in that context though. I was frustrated by the lack of progress in the question's definition at the time, and didn't follow your contribution much either. Looking back, I should have just asked you to explain what you meant. And even that, it looks like there's no need for now. Sorry.
**********************
"The problem isn't working out the equation,
its finding the answer to the real question." BigInch
http://virtualpipeline.spaces.live.com/
RE: Booster for Positive Displacement Pump?
Don't worry about it, and I probably should have put in an emoticon to show that I wasn't trying to be testy. You are probably the most respected (by me at least) pipe line guy here......with some valuable experience.
I actually saw the post as a guy not really understanding why people were telling him he needed a booster pump. I was hoping he could read a few things and have the penny drop. Sometimes all we need to do is blurt out what we know, and someone figures out what they want. The more we put out there, the more people learn.
Charlie
www.facsco.com
RE: Booster for Positive Displacement Pump?
Ya, I got caught up in a black hole while spiraling into that ∞ booster loop. There's really a lot of nonstandard terminology out there and I thought your booster function was starting to sound like a jockey pump.
We're OK here.
**********************
"The problem isn't working out the equation,
its finding the answer to the real question." BigInch
http://virtualpipeline.spaces.live.com/