inter pressure between Booster and PD pumps

[BRyad]

Hello,

I'm trying to size a positive displacement pumps wich delivers 1200 m3/d of oily water to be re-injected into a well at 150 (Wellhead pressure is 150 barg), the oily water is from a seperator at 12m from the grade with an operating pressure of 1.2 bara, the PD pump is 300m (include all the friction losses) from the seperator and the suction line is 6". My questions are:

1- When I propose only a PD pump, the NPSHA estimated (included acceleration head) is negative more than -100m is it clear that a booster pump is necessary or else... I ask this question because thera are some vendor's how propose a PD pump with NPSHRequired of 5.5m and the installation of dumpners reduce the pulsation and a solution for my very low NPSHA.

2- If a Booster pump is sued, How to determine the inter pressure between the booster an PD pump, knowing that the booster pump is at 200m (included all the friction losses) from the seperator.

3- In PD process data sheet, should I indicate the NPSHA with the estimated acceleration or without.


Regards

 

[BigInch]

You seem to be including head loss and distance in the same definition. Distance is one thing, head loss is another. Your pump must have enough head to compensate for lost head, not distance.

NPSHA should not include acceleration head; that would never be "available" as it is specifically a quantity of head that is NOT available, so it would be a negative number if you tried to include it in NPSHA.

Hard to say exactly, but it seems that your booster would need a head of at least 100 m. I might also imagine that your suction line diameter is far too small, except the velocity is very slow, so, given your apparent confussion with head loss and distance, I think you might have a number of mistakes in your calculations, or I don't understand anything about how your system fits together.

 

[micalbrch]

PLEASE, REFRAIN FROM DOUBLE POSTING !!! You make it difficult for others to help you. Here is my answer to your post in Chemical Plant Design & Operation:

1. I doubt that you have a NPSHA of more than -100 m. NPSHR of 5.5 m sounds reasonable for a PD pump.
2. To size the booster pump you need the flow and the head. If you have a triplex PD pump, the flow of the booster pump will have to min. 1.3 x flow of the PD pump. The head of the booster pump can be calculated as you have the flow and the pipe details.
3. One or the other. You must only mention "with acceleration head" or "without acceleration head".

 

[BRyad]

Sorry I'm new is a site, thanks for help