Page 187 - Centrifugal Pumps 2E

166 Centrifugal Pumps: Design and Application

pump conditions range in capacity up to 5,000 GPM and heads up to
11,000 feet (Figure 10-33). Pumps are normally multi-stage with hori-
zontal-split or double-case construction. As many applications use corro-
sive formation water as the pump fluid, special precautions must be taken
in material selection. Among the major factors that must be considered in
liquid analysis are:

• Salinity.
» Aeration.
» Particulate matter.
» Hydrogen sulfide (sour gas) content.
»Inhibiting additives.
« pH.
• Continuous or intermittent service.
• Composition of attached piping.

Some materials used successfully in waterflood applications are shown
in Table 10-1. The groupings are listed in order of increasing corrosion
resistance,

CO 2 Pumps

When waterflood production is no longer effective, injection of CO 2
and other gases (enhanced recovery) can recover up to 70% of the re-
maining oil. CO 2 can be transported as a gas, using compressors or as a
liquid using centrifugal pumps.
Due to the questionable lubricating properties of liquid CO 2, special
precautions must be taken where the possibility of internal metal-to-

Table 10-1
Materials for Waterflood Service
Pressure Wear
Group Casing Impeller Shaft Parts
1 Steel CA-6NM* 410 SS* 410 hardened
2 CA-6NM* CA-6NM* 410 SS* 410 hardened
3 316SS 316SS Monel 316LWith
or K-500 stellite
17-4 PH or overlay
17-4PH
4 Duplex Duplex Monel Duplex alloy
SS SS K-500 with stellite
overlay
• When # ZS & present or suspected, hardness shall not exceed R<22 (240HB),