Page 161 - Centrifugal Pumps Design and Application

10

Pipe line,
Pipeline
Waterflood,

and co2

Pumps

Pipeline Pumps

Unlike most other pump applications, pipelines constantly have
changes in throughput and product. This is particularly true in the trans-
portation of crude oil and hydrocarbons. This variation in liquid charac-
teristics, throughput, and pressure can result in a wide range of system
head curves, requiring extreme flexibility in pump operation. Selecting
pumps can be complicated, usually requiring multiple pumps installed in
series at each station. Selection may involve parallel operation, variable
speed, and/or modifications to meet future requirements.
As pumping requirements must match pipeline characteristics, the first
step in pump selection is analysis of the hydraulic gradient, and profile.
This defines the length and elevation change of the pipeline and is used to
establish pipeline pressure, pipeline horsepower, number of stations,
number of pumps, and appropriate mode of operation. Pipe size is deter-
mined from throughput requirements and optimum investment, plus op-
erating cost economics. Calculation of friction loss and static head estab-
lishes the pressure required to move throughput. With pipeline
throughput and pressure known, pump efficiency can be estimated and
pipeline horsepower calculated. The number of pumps required is then
estimated by selecting the preferred driver size. Number of stations is
estimated by the safe working pressure (S.W.P.) of the pipeline and the
pressure required to move throughput.