Pump Type Selection 1

[Sabergg1981]

Hi Everybody.
Let's start a discussion about pump type selection. It might be so easy for some of you but i want to consider all the corners and points for best selection.
We want to transfer 1.8 m3/hr hydrocarbon condensate via a 3" & 500 m pipe to a 8" & 110 bar transfer pipeline continuously. So we need a pump with Q=1.8 m3/hr and Delta P=90 Bar in continuous service.
Refer to pump selection chart as a approximation we fall in Reciprocating pump type. i think these types are not so suitable because of their packing type sealing.
Selecting a dosing pump for such a large capacity leads in selecting a special dosing pump with a continuous operation.
considering centrifugal leads in a multi stage one that are not so proper because of their price for such a small condition.
in the field of Non-Api pump , i m not so interested.
you should know if we consider the operation as intermittent, pump shall be pump Q=7 m3/hr & Delta P= 90 bar.

Let's share our knowledge and experinces.
tnx

 

[micalbrch]

How did you calculate the pressure of 90 bar? I do not understand that. For 500 m (horizontal?) through a 3" pipe, you'll never need 90 bar at this low flow. Or is this a resulting pressure which included the 8" transfer pipe friction losses, too? In any case it looks strange to me.

 

[LittleInch]

You need to decide if your process conditions are fixed enough that you can use a constant pressure pump (centrifugal) or you needed to pump a fixed amount or flow. Sounds to me like you needed some sort of pd pump, question is which one.

I don't really understand the comment about piston type and packing type sealing. Can you explain as it looks like the start choice to me.

Pump range is a bit Large for any one pump, I think tide need to look at two parallel as the friction loser are only a small part of your system curve.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[Sabergg1981]

@ micalbrch

Delta P of 90 Bar is none of our business. Of course process conditions dictate that. but for more clarifications, pressure of a 8" pipeline is a little more than 110 barg.
Yes. it's a strange case to decide.

 

[Sabergg1981]

@ Little Inch

I do apologize that i had forgotten mention our pump arrangement. we considered 1+1 configuration.
I didn't work with Piston type pumps but i know Piston type pumps have a packing type sealing and leakage of hydrocarbon may result in safety problems in site. so we are not interested in Piston type pumps.
Our process conditions are fixed but of course for 2 options of intermittent or continuous to decide better pump selection.

 

[rotw]

high delta P, very low flow - not good for a centrifugal multistage.
Look for Progressive cavity or helicoidal rotor pump for a fit for HP.

 

[Sabergg1981]

@ Rotaryworld

Can you please figure me the range of Progressive cavity pumps?

 

[rotw]

http://www.imo-pump.com/brochures/BR00PCGP.pdf

They say pumps available up to 150 bar on request. Although I am not sure about the delta it achieves.

 

[DubMac]

Maybe someone has already suggested this, but have you considered a diaphragm pump? Look at Lewa or Milton Roy. Few sealing issues there, but they are expensive.

 

[Pumpsonly]

PC pump is not for this application. Go for Lewa , Milton Roy or Bran & Luebe as DubMac suggested.
Not that costly for 1.8m3/hr. Select a multiplex pump to minimise pulsation or need to include a pulsation dampener.

 

[Sabergg1981]

@ Dubmac

i want to know that is dosing(Diaphragm pump) the best choice? or Can we change our mind to Non API pumps?

may be with some little works on Piston type pump's sealing we can do our best?

 

[DubMac]

Have you looked at an Axial Piston pump? Go look at Danfoss' website; they make one that could use a modified seal.

 

[Sabergg1981]

I was thinking may be it"s better to use a 2 centrifugal pumps in series to overcome a high head. Do you agree with me? Or economical problems confide us?

 

[LittleInch]

Saberg,

Looking back through these posts, you haven't really answered any questions which would enable anyone to give you clear guidance. We have a flow of either steady state at 1.8 or 7 in intermittent mode. Is the pressure difference fixed or variable?. Centrifugal pumps are great, but need to be controlled to work in their operating range, normally by control valves or very fixed inlet and outlet conditions.

A piston pump looks ideal, but even though you "haven't worked with piston pumps" you dismiss them as having a "packing type sealing" . Yes, some do, many don't, just specify what you need or look at the options from suppliers. Many centrifugal pumps have packing glands, many have mechanical seals or other types of seal. Are you going to dismiss them because some have packing glands??

First fully understand or explain your process requirements, then go looking at a range of pumps to meet it without dismissing any because of one type you might have come across some issue or heard about. No one makes a pump to leak so just buy a better seal and specify the conditions right and then decide.

You have all the information, we have about 10% of what we need to do the work or advise.


My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[rotw]

I agree with LittleInch.

Furthermore, Saberg, I dont see how you will manage to find a centrifugal pump developing such delta P (even if you reduce the head by using two pumps in serial) with a flow of Q=7 m3/hr.
Can you share any manufacturer brochure on this. It might be my knoweldge on pumps that is obsolete.

 

[mechanver]

hi all,
you can achieve your pumping condition using horizontal pumping system (HPS pump)
look at this catalog and tell me

 

[Sabergg1981]

@vLittleInch

About pump process conditions maybe your right and i didnt give you enough information. I siad before we can use these pumps in continuous service with Q=1.7 m3/hr or change the process condition to intermittent with Q=7 m3/hr. So we Face a two kind of problem and also economical matters lead us in true way.
About Delta P, we have a 90 bar of Delta P fixed without any change in suction or discharge for a period of 25 years.
About piston type pumps you're right. my approach to dismiss these type of pump is not true. but in this conversation no one gave us information about other sealing type of piston pumps. i want to ask you is there any method to reach a zero leakage in this type of pumps, something just like a inert gas in distance piece of piston compressor? i really have no enough information in this field.
if there are other process condition tell me.

@ Dear Rotary world
i was just a idea and i shall share it with our process departments to have a better approach.

thanks you all

 

[LittleInch]

Saberg,

At this flow rate and pressure delta you actually have so many options it is not really possible to narrow it down without getting data from vendors on price and delivery or whatever is really important to you.

Write up a data sheet and go out for quotes / start talking to vendors or agents local to you.

Very few seals work at zero leakage, condensate is not particularly volatile so don't ask for the impossible or it will eliminate too many choices and cost you a fortune for something you don't need.

Pulseless flow is better than vibrations from piston pumps, but this can be reduced and multi cylinder pumps are virtually pulse less.

You've been given a lot of options here, now you need to go and do some work to figure out what you need.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way