GE P&W GenGard Corrosion Treatment Programs User Manual

GenGard* Technology

For Open Recirculating Cooling Systems

• Maintains System Cleanliness

• Only Halogen Stable Technology in the World

• Uncompromised performance under stressed

conditions

Description and Use

GenGard* is the most advanced and effective water
treatment technology for open recirculating cooling
systems. GenGard treatment programs can be ap­plied across the entire pH spectrum from neutral to
alkaline and ensure uncompromising results even
under the most stressful conditions. The programs
incorporate the most advanced deposit and corro­sion additives available. The patented GenGard
technology includes a new Stress Tolerant Polymer
(STP), Alkaline Enhanced Chemistry (AEC) and halo­gen resistant azole (HRA) in combination with phos­phate-based steel corrosion inhibitors.

All GenGard treatment components are stable and
retain their effectiveness in the presence of chlorine
and other halogens. Halogen stability allows
Legionella compliance when chlorine or bromine
residuals are continuously applied at effective levels
(0.5-1.0 ppm free Cl
control and during periodic system disinfections
(> 5 ppm free Cl
GenGard provides the freedom to effectively re­spond to microbial upsets without a loss of deposi­tion or corrosion control.

The stress tolerant polymer (STP) is the culmination
of more than 30 years of polymer research at GE.

) for general microbiological

2

). Unlike conventional treatments,

2

Figure 1: Calcium phosphate inhibition at 400 ppm calcium
hardness, pH 8.2, 10 ppm PO

STP is designed to maintain phosphate-based and
zinc-based corrosion inhibitors soluble. (Figure 1)
The STP performance far exceeds that of conven­tional polymeric dispersants, providing exceptional
corrosion protection while preventing deposition
even in the most demanding applications. The STP
performance is not adversely affected by aluminum
carryover from influent clarifiers, high temperatures
encountered with low flow heat transfer equipment
or soluble iron generated from corrosion or entering
with the makeup water.

AEC is the only effective non-phosphorus calcium
carbonate scale inhibitor for open recirculating sys­tem operation above 2.5 LSI (Langelier Saturation
Index). Breaking the calcium carbonate supersatu­ration barrier of organic-phosphate scale inhibitors
(phosphonates), AEC provides excellent deposition
control under severe conditions where others fail.
AEC’s superior calcium tolerance and hydrolytic
stability permit high cycle operation even under the
most stressed conditions.

100

90

80
70
60
50
40
30

% PO4 Inhibition

20
10

0

Ter po ly mer C Ter po ly mer B Te rp ol yme r A AA/ AMPS SAA STP

5 ppm 10 ppm

Polymer Dosage (ppm)

, 160ºF (70ºC)

4

Fact Sheet

GenGard products include HRA, a modified azole
that provides unequaled copper alloy corrosion pro-

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FS1296EN.doc Jul-10

tection. HRA is halogen stable and capable of
maintaining effective corrosion inhibition even in
the presence of chlorine and bromine-based bio­cides. Conventional azole inhibitors, such as tolyl­triazole and benzotriazole, are readily halogenated
in the cooling water, preventing the establishment
and repair of a protective film on the metal surface.
HRA maintains its activity both in the water and on
the metal surface, ensuring continuous protection
for copper alloys. HRA also reduces copper levels in
the cooling water, minimizing copper discharge and
effectively controlling destructive galvanic pitting
on steel surfaces.

The GenGard GN8000 series of products are
designed for waters in the less corrosive alkaline
range above pH 7.8. GN8000 products utilize AEC as
the basic component to allow operation at highly
alkaline conditions without concern for scale forma­tion.

For More Information

For more information on the GenGard Technology,
please contact a GE account representative or visit
us on the web at www.ge.com/water.

Typical Applications

The GenGard GN7000 series of products are
designed for cooling systems operating in the near­neutral pH 6.8 - 7.8 range. They utilize high levels of
inorganic phosphate to promote the formation of a
thin, protective iron oxide film on steel surfaces.
This protective oxide film is extremely tenacious
and does not interfere with heat transfer. STP pro­vides the necessary calcium phosphate control to
maintain system cleanliness and uninterrupted op­eration. (See Figure 2.)

2 ppm STP/HRA

LCS <0.5 mpy
ADM <0.2 mpy

8 ppm AA/AMPS /BZT

LCS - 1.4 mpy
ADM - 0.6 mpy

Figure 2: Comparison of Halogen Stable vs. Conventional Treatment, neutral pH,
phosphate program, continuous chlorination (0.5 - 1.0 ppm free Cl2)

Page 2 Fact Sheet