Page 489 - Chemical process engineering design and economics

466 Chapter 8

Now, calculate the electric-motor horsepower. For an electric motor, the effi-
ciency is about 88%. Therefore, the motor horsepower is 8.002 hp (5.97 kW). The
next standard-size electric motor is 10 hp (7.46 kW), which results in a safety fac-
tor of 25.0%.

NOMENCLATURE

English

A area
discharge coefficient or drag coefficent
C D
C R rotameter coefficient
C v valve coefficient
D diameter
E friction loss
F friction factor

F force
G acceleration of gravity
gc conversion factor
h height
H head
K friction loss factor

L length
available net-positive-suction-head
required net-positive-suction-head
m mass flow rate
M molecular weight
p pressure
P power

Q volumetric flow rate

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