Pump Horsepower Calculation

The power added to the fluid flow by the pump ( P o), is defined using SI units by:

where: PO = the output output power of the pump (W) = ρ g H Q

∆P

= the fluid density (kg/m3) = = the gravitational constant (9.81 m/s2) = = the energy Head added added to the flow (m) = 3 = the flow rate (m /s) =

=

99.99 bars =

Fluid Spec. Gravity =

Fluid Density =

48,902.3 1066 9.81 956.52 0

101.96 kg/cm2 =

1.13 @ 20/20 oC =

1,123.0 kg/m3 =

=

48.9 kW (Esta potencia no incluye in

956.52 meters

70.11 lb/ft3 =

9.37

eficiencia)

lb/gal

Art Montemayor

September 02, 2009 Rev: 0

Reciprocating Pump Performance

Reference Reference:: API Standar Standard d 674 Second Edition, June 1995 Positive Displacement Pumps - Reciprocating

The power required for driving a single-acting power pump shall be calculated as follows:

kW

 = ( Q ) ( ∆P ) + ( Q ) ( Pd   )  

1

   1 + P s  − 1     E ff   d  P

 

where, 6.5 m3/h = 101.01 BarA = 1.02 BarA = 0.95 99.99 Bar =

Q = Suction flow = Pd = Discharge pressure = Ps = Suction pressure = Eff = Overall Eff., fraction = P = (Pd - Ps) = kW =

28.6 gpm 1,465.08 psia 14.80 psia 1,450.28 psi

650.6 (No puede ser!)

Wrong answer; the equ

In U.S. Customary units, the above equation transforms to the following:

hp

=

( Q ) ( ∆P ) 1714

hp =

+

Q ( ) P( d   ) 1714

24.2

=

 1    1 + P s  −E ff 1  P        d   48.9 kW (Esto tiene sentido!)

Reasona

Note: The above API 674 equation for the kW requirement of a single-acting power pump is wrong The correct equation is said to be:

kW 

=

( Q ) ( ∆P )+ Q( P ) (   d  ) 

   1 + P s  − E  ff 1  P        d  

36

kW =

0.7

1

Still wrong answer; the equation is not c

Art Montemayor

Reciprocating Pump Performance

September 02, 2009 Rev: 0

Pump Horsepower Calculation GPSA Data Book Section 12

hp

=

Q h SpGr  3960

eff  

Gasoline Pump for SNG site hp h h spgr eff

= Unkn Unknow own n Hors Horsepo epowe wer  r  = 297 ft of head ∆P*2.31/spgr  = = 0.64 specific gravity = 70% pump % efficiency ∆P = 82 psi Q = 100 gpm = 3,429 B/Day Q = 36,000 B/Day = 1,050 gpm

hp =

7