Page 51 - Handbook of Materials Failure Analysis

44 CHAPTER 2 Failure analysis in chemical industries

1.00E+00
8.00E-01
6.00E-01
Potential versus Eoc (V) 2.00E-01
4.00E-01

0.00E+00
-2.00E-01
-4.00E-01
CT Bleed water
-6.00E-01
CT Feed water
-8.00E-0
1.00E-09 1.00E-08 1.00E-07 1.00E-06 1.00E-05 1.00E-04 1.00E-03
(a) Current density (A/cm )
2

1.00E+00
8.00E-01
Potential versus Eoc (V) 4.00E-01
6.00E-01

2.00E-01
0.00E+00
-2.00E-01
-4.00E-01
Engine auxiliary water
-6.00E-01
Engine jacket water
-8.00E-01
1.00E-09 1.00E-08 1.00E-07 1.00E-06 1.00E-05 1.00E-04
(b) Current density (A/cm )
2
FIGURE 2.10
Potentiodynamic cyclic polarization of heat-exchanger plates. (a) CT feed water and
(b) CT bleed water.

and bleed water was confirmed by cyclic polarization. The unability of plate samples
to passivate in CT bleed water also validated the aggressiveness of environment and
hence could be a cause of pitting and perforation of plates.

3.2.7 Recommendations
Keeping in view the process design requirements, visual observations, and electro-
chemical testing under simulated conditions in laboratory, the following recommen-
dations were advised:

1. The feed water in the CT should be of R/O quality.